為使本領域技術人員可瞭解本發明的特點及效果，以下謹就說明書及權利要求書中提及的術語及用語進行一般性的說明及定義。除非另有指明，否則文中使用的所有技術及科學上的字詞，均為本領域技術人員對於本發明所瞭解的通常意義，當有衝突情形時，應以本說明書的定義為准。
本文描述和公開的理論或機制，無論是對或錯，均不應以任何方式限制本發明的範圍，即本發明內容可以在不為任何特定的理論或機制所限制的情況下實施。
本文中，若無特別說明，“包含”、“包括”、“含有”及類似用語涵蓋了“基本上由……組成”和“由……組成”的意思，即“A包含a”涵蓋了“A包含a和其他”、“A基本上由a組成”和“A由a組成”的意思。本文中，若無特別說明，“基本上由……組成”可以理解為“80%以上、優選90%以上、更優選95%以上由……組成”。
本文中，為使描述簡潔，未對各個實施方案或實施例中的各個技術特徵的所有可能的組合都進行描述。因此，只要這些技術特徵的組合不存在矛盾，各個實施方案或實施例中的各個技術特徵可以進行任意的組合，所有可能的組合都應當認為是本說明書記載的範圍。
本發明提供了將一種或多種正極材料的原料或半成品加工成電池正極材料的工藝方法、裝置及系統，實現了熱空氣/氧氣與物料高效逆流接觸獲得最大傳熱/傳質推動力。本發明包括但不限於製備鎳鈷錳三元正極材料、鎳鈷鋁三元正極材料、磷酸鐵鋰、磷酸錳鐵鋰、磷酸鈷鋰、磷酸錳鋰、錳酸鋰、鈦酸鋰、NCMA(鎳鈷錳鋁四元正極材料)、NC(鎳鈷酸鋰)、NM(鎳錳酸鋰)等。
本發明的正極材料製備方法包括以下步驟：(1)預處理，(2)流化床燒結，和任選的(3)後處理。
預處理
本發明中，預處理用於將正極材料的原料或半成品處理成適於進入流化床進行燒結的形態。例如，預處理可以包括：混合不同種類的正極材料的原料或半成品，對正極材料的原料或半成品的顆粒大小進行篩選，將正極材料的原料或半成品配製成漿料，和/或對漿料進行乾燥或預熱。
本發明中，正極材料的原料或半成品包括但不限於：氧化鋰、氫氧化鋰、鋰鹽(如碳酸鋰)、過渡金屬氫氧化物、過渡金屬氧化物、過渡金屬鹽、氧化鋁、氫氧化鋁、鋁鹽，氧化鋰、過渡金屬氧化物和氧化鋁中的兩種或兩種以上的複合氧化物，氫氧化鋰、過渡金屬氫氧化物和氫氧化鋁中的兩種或兩種以上的複合氫氧化物，鋰鹽、過渡金屬鹽和鋁鹽中的兩種或兩種以上的複鹽，前述物質的水合物，前述物質的複合物等。過渡金屬包括但不限於鎳、錳、鈷、鉻、鐵、鈦等。可以理解的是，正極材料的原料或半成品所含的金屬元素通常包括鋰和一種或多種過渡金屬，任選地還可包括鋁。
在一些實施方案中，正極材料的原料或半成品可以包括以下成分的混合物或複合物：(a)鋰鹽，和(b)選自過渡金屬氫氧化物和過渡金屬碳酸鹽中的一種或多種。例如，正極材料的原料或半成品可以包括鎳、鈷、錳的複合氫氧化物(在本領域中也可稱為前驅體)和鋰鹽(如選自氫氧化鋰、碳酸鋰、氧化鋰中的一種或多種)，鎳、鈷、錳的複合氫氧化物的化學式可以為Ni
xCo
yMn
z(OH)
2，其中x、y、z各自大於0且＜1，且x+y+z=1。也可以使用其他正極材料(鎳鈷鋁三元正極材料、磷酸鐵鋰、磷酸錳鐵鋰、磷酸鈷鋰、磷酸錳鋰、錳酸鋰、鈦酸鋰、NCMA(鎳鈷錳鋁四元正極材料)、NC(鎳鈷酸鋰)、NM(鎳錳酸鋰))的前驅體和鋰鹽的組合作為正極材料的原料或半成品，以獲得對應的正極材料。
本發明中，鋰鹽可以為選自氫氧化鋰、碳酸鋰、碳酸氫鋰、氧化鋰、硫酸鋰、硫酸氫鋰、氟化鋰、氯化鋰、溴化鋰、硝酸鋰、醋酸鋰、過氧化鋰、草酸鋰、磷酸鋰和磷酸氫鋰中的一種或多種，例如選自氫氧化鋰、碳酸鋰、碳酸氫鋰、氧化鋰、硫酸鋰、硫酸氫鋰、氟化鋰、氯化鋰、溴化鋰、硝酸鋰、醋酸鋰和過氧化鋰中的一種或多種，優選選自氫氧化鋰、碳酸鋰、碳酸氫鋰和氧化鋰中的一種或多種，更優選選自氫氧化鋰和碳酸鋰中的一種或兩種。鋰鹽原料可以是水合鋰鹽，例如氫氧化鋰可以是單水氫氧化鋰。鋰鹽與鋰源具有相同的含義。在一些實施方案中，正極材料的原料或半成品含有基本上一種鋰鹽，所述“基本上一種鋰鹽”是指僅一種鋰鹽，或者兩種或更多種鋰鹽的混合物，其中一種鋰鹽占總鋰鹽的至少90wt%以上。
過渡金屬氫氧化物的實例包括M(OH)
2+n，其中M為選自鎳、鈷、錳、鋁、鐵和鈦中的一種或多種，n為0-2、例如0.1、0.2、0.5、1。例如，過渡金屬氫氧化物可以為M(OH)
2+n，其中M為Ni
xCo
yMn
z或Ni
xCo
yAl
z，x+y+z=1，x為0.3-0.9、例如0.4、0.5、0.6、0.7、0.8，y為0.01-0.4、例如0.02、0.05、0.1、0.2、0.3，z為0.01-0.4、例如0.02、0.05、0.1、0.2、0.3，n為0-0.2、例如0、0.01、0.02、0.05、0.1。過渡金屬氫氧化物也可以為M(OH)
2+n，其中M為Ni
aCo
b或Ni
aMn
b，a+b=1，a和b各自獨立為0.1-0.9、例如0.2、0.3、0.4、0.5、0.6、0.7、0.8，n為0-0.2、例如0、0.01、0.02、0.05、0.1。在一些實施方案中，過渡金屬氫氧化物還可以為摻雜和/或包覆的M(OH)
2+n，摻雜和/或包覆元素包括但不限於Al、Zr、Sr、Mg、Ti、B、鑭系、鹵素、Mo、Cu、V、Ca、Ru、W、Os、Fe、Ga、In、P、Cr、Ce、Nb、Y、Sn、Ta、Ni、Co、Mn、Si、Ba等中的一種或多種。
過渡金屬碳酸鹽的實例包括M(CO
3)
1+m，其中M為選自鎳、鈷、錳、鋁、鐵和鈦中的一種或多種，m為0-1、例如0.05、0.1、0.25、0.5。例如，過渡金屬碳酸鹽可以為M(CO
3)
1+m，其中M為Ni
xCo
yMn
z或Ni
xCo
yAl
z，x+y+z=1，x為0.3-0.9、例如0.4、0.5、0.6、0.7、0.8，y為0.01-0.4、例如0.02、0.05、0.1、0.2、0.3，z為0.01-0.4、例如0.02、0.05、0.1、0.2、0.3，m為0-0.1、例如0、0.005、0.01、0.025、0.05。過渡金屬碳酸鹽也可以為M(CO
3)
1+m，其中M為Ni
aCo
b或Ni
aMn
b，a+b=1，a和b各自獨立為0.1-0.9、例如0.2、0.3、0.4、0.5、0.6、0.7、0.8，m為0-0.1、例如0、0.005、0.01、0.025、0.05。在一些實施方案中，過渡金屬碳酸鹽還可以為摻雜和/或包覆的M(CO
3)
1+m，摻雜和/或包覆元素包括但不限於Al、Zr、Sr、Mg、Ti、B、鑭系、鹵素、Mo、Cu、V、Ca、Ru、W、Os、Fe、Ga、In、P、Cr、Ce、Nb、Y、Sn、Ta、Ni、Co、Mn、Si、Ba等中的一種或多種。
在一些情況下，例如對正極材料進行摻雜和/或包覆改性時，正極材料本身也可以作為正極材料的原料或半成品。
在一些實施方案中，本發明所使用的正極材料的原料或半成品包含正極材料前驅體和鋰鹽。
適用於本發明的正極材料前驅體的類型不受特別限制，包括但不限於錳酸鋰正極材料前驅體、鈷酸鋰正極材料前驅體、鎳酸鋰正極材料前驅體、二元正極材料前驅體(例如鎳錳酸鋰正極材料前驅體、鎳鈷酸鋰正極材料前驅體等)、三元正極材料前驅體(例如鎳鈷錳酸鋰正極材料前驅體、鎳鈷鋁酸鋰正極材料前驅體等)、四元正極材料前驅體(例如鎳鈷錳鋁酸鋰正極材料前驅體等)、磷酸鐵鋰正極材料前驅體等。在一些實施方案中，前驅體為鎳鈷錳酸鋰正極材料前驅體，例如523鎳鈷錳的氫氧化物前驅體(Ni
0.5Co
0.2Mn
0.3(OH)
2)、811鎳鈷錳的氫氧化物前驅體(Ni
0.8Co
0.1Mn
0.1(OH)
2)。“523”、“811”是指鎳、鈷、錳的莫耳比為5:2:3或8:1:1。
適用於本發明的正極材料前驅體(本文簡稱為前驅體)可以是採用本領域已知方法製備的正極材料前驅體，也可以是採用本發明中公開的方法製備的正極材料前驅體。正極材料前驅體可以由金屬鹽溶液、沉澱劑和絡合劑，或由二價鐵鹽溶液、磷酸鹽溶液、pH調節劑和氧化劑反應而成。例如，錳酸鋰正極材料前驅體、鈷酸鋰正極材料前驅體、鎳酸鋰正極材料前驅體、二元正極材料前驅體、三元正極材料前驅體和四元正極材料前驅體可以由金屬鹽溶液、沉澱劑和絡合劑進行共沉澱反應而得到的氫氧化物和/或碳酸鹽。本文中，金屬鹽溶液所含的金屬元素及其配比通常與所製備的正極材料前驅體中的金屬元素及其配比相一致。金屬鹽溶液可以是一種金屬鹽的溶液，也可以是多種金屬鹽的混合溶液，例如用於製備鎳鈷錳正極材料前驅體的金屬鹽溶液可以是鎳鹽、鈷鹽、錳鹽的混合溶液。金屬鹽溶液的溶劑通常為水。金屬鹽溶液所含的金屬鹽可以是已知可用於製備相應的正極材料前驅體的金屬的鹽，通常為水溶性鹽，例如硫酸鹽、鹽酸鹽等。製備氫氧化物前驅體的沉澱劑可以是氫氧化鈉溶液(即液堿)、氫氧化鉀溶液等。製備碳酸鹽前驅體的沉澱劑可以是碳酸鈉、碳酸鉀等。絡合劑可以是氨水等。共沉澱反應後進行適當的陳化，以使正極材料前驅體轉化完全。在一些實施方案中，本發明使用採用如下方法製備的正極材料前驅體：使金屬鹽溶液(例如鎳鹽、鈷鹽、錳鹽的混合溶液)、液堿和氨水進行共沉澱反應，產物經過陳化，得到正極材料的氫氧化物前驅體。共沉澱反應條件可以是常規的。金屬鹽溶液(例如鎳鹽、鈷鹽、錳鹽的混合溶液)的濃度可以為1-5mol/L，例如2mol/L、3mol/L、4mol/L。對於含多種金屬鹽的溶液，金屬鹽溶液的濃度是指溶液中金屬元素的總莫耳濃度。沉澱劑(例如液堿)的濃度可以為2-10mol/L，例如3mol/L、5mol/L、8mol/L。絡合劑(例如氨水)濃度可以為1-10mol/L，例如2mol/L、5mol/L、8mol/L。反應體系pH可以為9-12，例如10、11。反應溫度可以為40-70℃，例如50℃、55℃、60℃。陳化時間可以為2-10h，例如4h、5h、6h、8h。
磷酸鐵鋰正極材料前驅體可以由二價鐵鹽溶液、氧化劑和磷酸鹽溶液反應而成，反應後可以進行適當的陳化和清洗。可以先使用氧化劑將二價鐵鹽氧化為三價鐵鹽，再加入磷酸二氫銨，之後任選或優選地可加入分散劑。二價鐵鹽可以是硫酸亞鐵等。氧化劑可以是雙氧水。磷酸鹽可以是磷酸二氫銨等。反應體系中，鐵與磷的莫耳比可以為1:(1-1.2)，例如1:1.05、1:1.1、1:1.15。分散劑可以是聚乙烯醇分散劑。分散劑的用量可以為反應體系總品質的0.1-2%，例如0.2%、0.5%、1%。二價鐵鹽溶液、氧化劑和磷酸鹽溶液的濃度各自可以為0.5-5mol/L，例如1mol/L、2mol/L、3mol/L、4mol/L。反應溫度可以是30-100℃，例如40℃、50℃、60℃、70℃、80℃、90℃。陳化時間可以為2-10h，例如4h、5h、6h、8h。磷酸鐵鋰正極材料前驅體的主要成分是磷酸鐵，任選或優選地還可以含有碳源，例如葡萄糖、蔗糖等。碳源的含量可以是磷酸鐵品質的1%-10%，例如2%、4%、5%、6%、8%。
正極材料前驅體通常呈顆粒狀。前驅體的D50粒徑優選在1-20μm之間，更優選在2-15μm之間，例如3μm、4μm、5μm、7μm、9μm、10μm、11μm、12μm、13μm、14μm。前驅體顆粒的形狀可以是球形、長條形、不規則形狀等。在一些實施方案中，前驅體顆粒呈球形。在一些實施方案中，前驅體顆粒為由奈米粒子團聚成的二次球狀粉體；優選地，奈米粒子的片徑在100-300nm之間，例如150nm、200nm、250nm。組成前驅體顆粒的奈米粒子的形狀可以是片狀、球形、長條形、不規則形狀等。在優選的實施方案中，組成前驅體顆粒的奈米粒子呈片狀，這有利於提供鋰離子進出正極材料的通道，提升鋰離子電池的性能。在前驅體為磷酸鐵鋰正極材料前驅體的實施方案中，優選將前驅體研磨至50-200nm，例如100nm、150nm，這有利於改善磷酸鐵鋰正極材料的性能。
正極材料前驅體顆粒可以是不含水的乾燥顆粒，也可以是保留一定水分的含水顆粒。在一些實施方案中，本發明使用含水的正極材料前驅體顆粒，例如使用從製備正極材料前驅體的反應體系中分離出的前驅體(未乾燥，保留一定的水分)，這樣無須乾燥後再加水配成漿料。使用含水的正極材料前驅體顆粒時，正極材料前驅體顆粒的含水量可以為5-20wt%，例如10wt%、15wt%。可以理解的是，在計算前驅體混鋰漿料中的正極材料前驅體含量時，正極材料前驅體質量不包括含水前驅體顆粒中水的品質。
適用於本發明所使用的正極材料的原料或半成品的鋰鹽包括但不限於氫氧化鋰、碳酸鋰、硝酸鋰、醋酸鋰、硫酸鋰、氯化鋰、氟化鋰、草酸鋰、磷酸鋰、磷酸氫鋰等。在一些實施方案中，鋰鹽為氫氧化鋰，例如單水氫氧化鋰。可以理解的是，在計算前驅體混鋰漿料中的鋰鹽含量時，鋰鹽的品質不包括水合鋰鹽中水的品質。
鋰鹽原料通常呈粉體狀。鋰鹽原料的D50粒徑可以在5-15μm之間，例如6μm、7μm、8μm、9μm、10μm、11μm、12μm、13μm、14μm。鋰鹽原料的形狀可以是圓形、長條形、不規則形狀等。在一些實施方案中，鋰鹽原料是不規則形狀的粉體。
本發明中，第一漿料是指包含正極材料的原料或半成品和分散劑(包括但不限於水)的分散體系。本文所述的第一漿料包括未完全乾燥的正極材料的原料或半成品。在一個具體的實施方案中，第一漿料包括鋰鹽和未乾燥或未完全乾燥的前驅體。
在一些實施方案中，本發明使用的第一漿料為正極材料前驅體混鋰漿料(本文簡稱為前驅體混鋰漿料)。本發明的正極材料前驅體混鋰漿料含有正極材料前驅體顆粒、鋰鹽和水。
在一些實施方案中，本發明的前驅體混鋰漿料中，正極材料前驅體顆粒表面包覆有鋰鹽。在一些實施方案中，本發明的前驅體混鋰漿料中的正極材料前驅體顆粒中滲透有鋰鹽。包覆和滲透的鋰鹽以奈米粒子形式存在。相對於固相干法方式混合前驅體和鋰鹽，本發明的前驅體混鋰漿料中，鋰鹽以顆粒更小的方式與前驅體均勻混合，更利於反應。
本發明的正極材料前驅體混鋰漿料任選或優選地還含有無機奈米粒子。無機奈米粒子其所含的元素要求有利於或者不影響產品的性能。添加無機奈米粒子的作用是使前驅體混鋰漿料發生凝膠化。本發明通過向前驅體混鋰漿料中引入具有凝膠特性的摻雜元素，提高造粒後的顆粒強度。因此，在前驅體混鋰漿料含有無機奈米粒子的實施方案中，前驅體混鋰漿料呈凝膠態。本發明中，無機奈米粒子不包括奈米粒子形式的鋰鹽。
適用於本發明的無機奈米粒子可以是氧化物奈米粒子，包括但不限於奈米氧化矽、奈米氧化鋁、奈米氧化鋯等。在優選的實施方案中，採用向前驅體混鋰漿料中添加無機溶膠(例如矽溶膠、鋁溶膠、鋯溶膠等)的方式引入無機奈米粒子。本文中，無機溶膠是指無機奈米粒子分散在溶劑(通常為水)中形成的穩定的或亞穩態的分散體系。本文中，矽溶膠、鋁溶膠和鋯溶膠分別是指奈米氧化矽、奈米氧化鋁和奈米氧化鋯在水中的分散液。
本發明將不含無機奈米粒子的前驅體混鋰漿料稱為第一正極材料前驅體混鋰漿料(簡稱第一前驅體混鋰漿料)，將含有無機奈米粒子的凝膠化的前驅體混鋰漿料稱為第二正極材料前驅體混鋰漿料(簡稱第二前驅體混鋰漿料)。
本發明中，第一和第二正極材料前驅體混鋰漿料的含水量優選為20-40wt%，例如23wt%、25wt%、27wt%、30wt%、33wt%、35wt%、38wt%。將含水量控制在前述範圍內有利於造粒。
本發明中，第一正極材料前驅體混鋰漿料室溫下表觀黏度優選為1000-5000cps，例如2000cps、3000cps、3500cps、4000cps。這有利於後續凝膠化和造粒。
本發明中，第二正極材料前驅體混鋰漿料中，所述無機奈米粒子的含量優選為所述正極材料前驅體質量的0.1%-1%，例如0.2%、0.3%、0.4%、0.5%、0.6%、0.7%、0.8%、0.9%。這有利於使前驅體漿料發生凝膠化。
本發明中，第一和第二正極材料前驅體混鋰漿料中，正極材料前驅體(即正極材料前驅體中的金屬原子總和)和鋰的莫耳比可以為1:(1.01-1.05)，例如1:1.02、1:1.03、1:1.04。第二正極材料前驅體混鋰漿料中，正極材料前驅體和無機奈米粒子中的除氧以外的原子的莫耳比可以1:(0.0005-0.005)，例如1:0.001、1:0.002、1:0.003、1:0.004。
在正極材料前驅體為磷酸鐵鋰正極材料前驅體的一些實施方案中，正極材料前驅體混鋰漿料包含磷酸鐵、鋰鹽和水。磷酸鐵優選為奈米磷酸鐵，優選粒徑為50-200nm，例如100nm、150nm。鋰鹽可以選自氫氧化鋰、碳酸鋰、硝酸鋰、醋酸鋰、硫酸鋰、氯化鋰、氟化鋰、草酸鋰、磷酸鋰和磷酸氫鋰中的一種或多種，優選為碳酸鋰。正極材料前驅體混鋰漿料中，鐵和鋰的莫耳比可以為1:(1-1.05)，例如1:1.01、1:1.02、1:1.03、1:1.04。正極材料前驅體混鋰漿料任選或優選地還包含碳源，碳源的含量可以為磷酸鐵品質的1-10%，例如2%、4%、5%、6%、8%。正極材料前驅體混鋰漿料的含水量可以為20-90wt%，例如30wt%、50wt%、70wt%、80wt%。在進行造粒前，可以對正極材料前驅體混鋰漿料進行適當的乾燥以降低含水量，例如可以將含水量降低至20-40wt%，例如25wt%、30wt%、35wt%。
本發明中，正極材料前驅體混鋰漿料可採用濕法工藝制得，例如通過混合正極材料前驅體、鋰鹽和水制得，其中正極材料前驅體可以是本文任一實施方案所述的正極材料前驅體顆粒。
在一些實施方案中，先將鋰鹽和水混合成鋰鹽漿料，再對鋰鹽漿料和正極材料前驅體進行混合，這有利於混合均勻。優選地，使用捏合機將鋰鹽漿料和正極材料前驅體混合均勻。捏合機攪拌轉速優選為50-200rpm，攪拌時間優選為10-30分鐘。
本發明的製備正極材料前驅體混鋰漿料的方法進一步地還可以包括：向第一正極材料前驅體混鋰漿料中添加無機溶膠，混合均勻，使混合物凝膠化，得到第二正極材料前驅體混鋰漿料。
本發明中，無機溶膠的濃度優選為5-25wt%，例如10wt%、20wt%。無機溶膠的用量優選為無機溶膠的用量為所述正極材料前驅體質量的0.5%-10%，例如1%、2%、3%、4%、5%、6%、7%、8%、9%。這有利於混合物的凝膠化。
在優選的實施方案中，使用捏合機捏合第一正極材料前驅體混鋰漿料和無機溶膠。捏合第一正極材料前驅體混鋰漿料和鋁溶膠的時間優選為10-30分鐘，例如15分鐘、20分鐘，這有利於漿料的凝膠化。
在製備磷酸鐵鋰正極材料前驅體混鋰漿料的一些實施方案中，將磷酸鐵、水、鋰鹽和任選的碳源混合均勻，即可得到磷酸鐵鋰正極材料前驅體混鋰漿料。例如，可以先將磷酸鐵與水或碳源的水溶液混合均勻，任選地進行研磨，然後再加入鋰鹽分散均勻。任選或優選地可以對磷酸鐵鋰正極材料前驅體混鋰漿料進行適當的烘乾以降低含水量，以利於造粒。
本發明包括採用本發明的製備正極材料前驅體混鋰漿料的方法製備得到的正極材料前驅體混鋰漿料。採用本發明的製備正極材料前驅體混鋰漿料的方法製備得到的正極材料前驅體混鋰漿料可具有前文所述的正極材料前驅體混鋰漿料的各項特徵。
微球成型
本發明的正極材料製備方法的預處理步驟可以包括微球成型。
本發明中，微球成型是將第一漿料製備成微球，為後續工段提供具有優異氣固流動效果的前驅體顆粒微球。本發明中，微球是指粒徑≥20μm的顆粒。在一些優選的實施方案中，微球的粒徑為20~300μm，例如50μm、80μm、100μm、125μm、150μm、180μm、200μm、220μm、250μm、270μm。將微球成型獲得的顆粒的粒徑控制在該範圍內，有利於顆粒的流化。如果粒徑過小，則顆粒無法有效流化；如果粒徑過大，則顆粒只能局部噴動而其他部分處於非流化狀態。在本發明優選的粒徑範圍內，顆粒能夠呈現合理的流化曲線。微球可以含有一定量的液體成分。可以採用噴霧的方式進行微球成型。在這些實施方案中，微球成型通過讓霧化的漿料與高溫氣體接觸，使漿料在乾燥的過程中成型為微球。用於微球成型的第一漿料的pH優選為4~12，例如5、6、7、8、9、10、11，這有利於保證正極材料穩定存在的氛圍。第一漿料的固含率優選為5~75wt%，例如10wt%、15wt%、20wt%、25wt%、30wt%、35wt%、40wt%、45wt%、50wt%、55wt%、60wt%、65wt%、70wt%，這有利於微球噴霧成型。在本發明優選的第一漿料的pH、固含率範圍內，漿料適合於進行本發明的微球形成。第一漿料的pH、固含率過高或過低，則漿料無法有效噴出或是無法成型。
如圖1所示，微球成型之前可對第一漿料進行粗砂磨。粗砂磨是為了破碎後續工段(例如微球成型後的篩分、燒結後的篩分)返回的大顆粒，並混合破碎大顆粒所得的粉體和第一漿料。可以使用砂磨機進行粗砂磨。
微球成型之後可對顆粒進行篩分，獲得滿足一定的粒徑範圍要求的顆粒。篩分所剩的不滿足要求的顆粒(例如大顆粒)可以返回粗砂磨工段。例如，在一些實施方案中，微球成型後進行篩分，篩選粒徑在20~300μm的顆粒進入後續工序(例如多級逆流旋流預熱工段)，其他不符合該粒徑範圍的顆粒回到粗砂磨工段，與第一漿料再進行混合。可以使用篩分機進行篩分，也可以通過多級逆流旋流預熱的方式進行篩分。
可以使用本發明的微球成型裝置進行微球成型。本發明的微球成型裝置為特殊設計的氣固接觸設備。可以將後續工序(例如多級逆流旋流預熱工段)中的氣體(例如熱空氣、熱氧氣)通入微球成型裝置中，實現能量的多重利用。特殊設計的對稱環-核氣體分佈裝置能夠實現氣體的均勻分佈，進而實現窄顆粒粒徑分佈。可以使用經過特殊設計的反拉瓦爾噴管將第一漿料分散到均布的氣體(例如熱空氣、熱氧氣)中。
如圖2所示，在一些實施方案中，本發明的微球成型裝置包括：微球成型塔筒體26、對稱環-核氣體分佈裝置20、至少一個漿料輸入機構25、微球成型塔底錐29、氣體匯出機構27和固體顆粒出口28。其中，所述微球成型塔筒體26呈圓筒形，為第一漿料與氣體接觸的場所。所述對稱環-核氣體分佈裝置20位於所述微球成型塔筒體26上方，用於向微球成型塔筒體26提供均勻分佈的氣體。所述對稱環-核氣體分佈裝置20包括至少兩個進氣管道21。所述至少兩個進氣管道21優選對稱切向排布於對稱環-核氣體分佈裝置20的側壁。對稱環-核氣體分佈裝置20的下部設置有預分布器24，用於分佈進入微球成型塔筒體26的氣體。對稱環-核氣體分佈裝置20的底部具有與微球成型塔筒體26的頂部連通的開口。所述漿料輸入機構25包括伸入微球成型塔筒體26內部的帶噴嘴的噴管，用於向微球成型塔筒體26提供第一漿料。當漿料輸入機構25的數量大於一個時，各漿料輸入機構25優選對稱分佈於微球成型塔筒體26。漿料輸入機構25的噴嘴距離對稱環-核氣體分佈裝置20的高度(d1)優選為微球成型塔筒體26直徑(d2)的1/50~1/25，例如1/45、1/40、1/35、1/30。這能夠防止漿料受氣流擾動後黏黏到對稱環-核氣體分佈裝置20底部。所述微球成型塔底錐29呈倒錐形。所述微球成型塔底錐29的頂部與微球成型塔筒體26的底部連通。微球成型塔底錐29的錐角優選為15度~50度，例如20度、25度、30度、35度、40度、45度。這有利於噴霧所得微球顆粒滑落收集。可以根據微球顆粒摩擦角實驗結果得到的顆粒堆積角設計微球成型塔底錐29的錐角。所述固體顆粒出口28位於微球成型塔底錐29的底部，可以為圓形管或矩形管，用於將微球排出微球成型裝置。所述氣體匯出機構27包括設置在微球成型塔底錐29側面的氣體出口，用於將氣體排出微球成型裝置。所述氣體出口可以是管道。
在一些實施方案中，氣體匯出機構包括經由微球成型塔底錐的側面伸入微球成型塔的氣體匯出管。氣體匯出管可以為圓形管或矩形管。在一些實施方案中，氣體匯出管在微球成型塔底錐內的開口向上，且氣體匯出機構還包括設置在氣體匯出管在微球成型塔底錐內的開口周圍的微球阻擋結構，以防止微球進入氣體匯出管。微球阻擋結構可以包括設置在氣體匯出管在微球成型塔底錐內的開口的上方的微球阻擋結構錐體，微球阻擋結構錐體的頂點朝上，微球阻擋結構錐體的底部與微球成型塔底錐連通，使得氣體能夠進入氣體匯出管但微球不會落入氣體匯出管。微球阻擋結構還可以包括設置在氣體匯出管在微球成型塔底錐內的開口的四周的微球阻擋結構柱體，所述微球阻擋結構柱體的頂部與微球阻擋結構錐體相連，所述微球阻擋結構柱體的底部與微球成型塔底錐連通，以更好地保證微球不會落入氣體匯出管。可以根據微球顆粒摩擦角實驗結果得到的顆粒堆積角設計微球阻擋結構錐體的錐角。
如圖3所示，本發明的微球成型裝置中的對稱環-核氣體分佈裝置經過特殊設計，包括至少兩個進氣管道31、環形氣體預分布室32、匯出管33和至少一個預分布器34。其中，所述環形氣體預分布室32呈圓臺狀。所述預分布器34位於所述對稱環-核氣體分佈裝置的下方。所述預分布器34與所述環形氣體預分布室32通過設置在所述環形氣體預分布室32內的匯出管33連通。所述至少兩個進氣管道31對稱切向分佈於環形氣體預分布室32的側壁。所述匯出管33為至少一個豎直管道，位於環形氣體預分布室32中心，使得環形氣體預分布室32和預分布器34連通。進氣管道31、環形氣體預分布室32和匯出管33形成氣體折返結構，使得氣體在環形氣體預分布室32內發生折返。在一些實施方案中，匯出管33的數量為一個。在一些實施方案中，匯出管33的上端開口與環形氣體預分布室32頂部之間的距離(d3)小於進氣管道31的上沿與環形氣體預分布室32頂部之間的距離(d4)，以利於氣體折返後再通過匯出管33離開環形氣體預分布室32。多個預分布器34可以串聯連接。預分布器34可以是已知的適用於氣-固流化床的氣體分佈器。對稱環-核氣體分佈裝置的上述設計有利於氣體(例如熱空氣、熱氧氣)在塔內均勻分佈，從而有利於實現顆粒的窄粒徑分佈。
在一些實施方案中，如圖4所示，微球成型裝置的漿料輸入機構的噴管基於反拉瓦爾噴管和旋轉射流進行設計。噴管包括噴嘴41和噴管管道42。噴管管道42的直徑(d5)與噴嘴41的直徑(d6)的比例優選為1:1~1:4。優選地，噴嘴41的張角(∠α)為15°~60°，以有效霧化分散漿料。噴嘴41可採用中心熱氣體噴射環隙旋轉漿料射流組合或中心漿料射流環隙熱氣體旋流噴射保護組合。通過調節輸入機構線速和底端與頂端壓降(過噴管前後壓降)，以保證顆粒不被磨損和噴物料的均勻。
使用本發明的微球成型裝置進行微球成型時，高溫氣體通過切向的進氣管道31對稱進入對稱環-核氣體分佈裝置，旋流自下而上折返後自匯出管33沿軸向離開環形氣體預分布室32，經過預分布器34後與來自漿料輸入機構的漿料接觸；在微球成型塔筒體內完成微球成型過程；氣體和前驅體成型顆粒分別從微球成型塔底錐的氣體匯出機構和固體顆粒出口排出。微球成型的操作條件可以為：操作溫度50~500℃、優選為75~300℃，例如100℃、150℃、200℃、250℃、275℃；操作壓力0.5~5bar，例如1bar、2bar、3bar、4bar、4.5bar；操作固氣比為0.001~10kg/kg，例如0.01kg/kg、0.05kg/kg、0.1kg/kg、0.5kg/kg、1kg/kg、2kg/kg、3kg/kg、4kg/kg、5kg/kg、6kg/kg、7kg/kg、8kg/kg、9kg/kg。
在一些實施方案中，微球成型所使用的第一漿料為本發明所述的正極材料前驅體混鋰漿料，所得到的第一漿料顆粒為正極材料前驅體混鋰顆粒。優選地，用作第一漿料的正極材料前驅體混鋰漿料為本文任一實施方案所述的第二正極材料前驅體混鋰漿料。本發明包括採用本發明所述的微球成型工藝對本發明所述的正極材料前驅體混鋰漿料進行微球成型(即造粒)，以及由此得到的正極材料前驅體混鋰顆粒。
在微球成型前任選地可以對正極材料前驅體混鋰漿料進行預處理，例如將本發明的正極材料前驅體混鋰漿料與其他正極材料的原料或半成品混合，對漿料進行過篩、粗砂磨、乾燥、預熱等。
本發明的正極材料前驅體混鋰顆粒(簡稱前驅體混鋰顆粒)包含正極材料前驅體顆粒、鋰鹽、水和無機奈米粒子，所述正極材料前驅體顆粒表面包覆有鋰鹽。在一些實施方案中，前驅體混鋰顆粒中，正極材料前驅體顆粒中滲透有鋰鹽。滲透或者包覆的鋰鹽呈奈米粒子形態。本發明的正極材料前驅體混鋰顆粒中，前驅體和鋰鹽以緻密方式結合，從而提高鋰鹽在前驅體內傳質反應，降低孔隙率，提高熱傳導效率。
本發明的正極材料前驅體中，以下特徵可以如前述的本發明的正極材料前驅體混鋰漿料的任一實施方案所述：正極材料前驅體的種類、粒徑、形狀、結構，鋰鹽的種類、粒徑、形狀，正極材料前驅體和鋰的配比，正極材料前驅體和無機奈米粒子的配比。
本發明的正極材料前驅體混鋰顆粒可以含有少量水，含水量優選不超過10wt%，例如0.5wt%、1wt%、2wt%、3wt%、4wt%、5wt%。正極材料前驅體混鋰顆粒的D50粒徑優選為100-500μm，例如200μm、210μm、230μm、240μm、250μm、300μm、350μm、400μm，休止角優選為30-60°，例如35°、38°、40°、45°、50°、55°。這有利於後續燒結。
多級逆流旋流預熱
本發明的正極材料製備方法的預處理步驟可以包括多級逆流旋流預熱。
本發明中，多級逆流旋流預熱是對正極材料原料顆粒、正極材料半成品顆粒或第一漿料顆粒進行加熱(可視為流化床燒結和/或包覆前的預熱)，同時對顆粒大小進行篩選。多級逆流旋流預熱實現了稀相氣固多級逆流旋流接觸並實現固體顆粒的篩分。如圖1所示，在一些實施方案中，本發明對經過微球成型而得到的顆粒直接進行多級逆流旋流預熱。也可對經過微球成型而得到的顆粒先進行篩分、再進行多級逆流旋流預熱。多級逆流旋流預熱中加熱的熱量來源可以是後續工序(例如流化床燒結和/或包覆)中的高溫氣體(例如熱空氣、熱氧氣)，從而更好地實現預熱。經多級逆流旋流預熱篩選所剩的不滿足要求的顆粒(例如小顆粒)可以輸送回在前工序(例如粗砂磨)。
可以使用本發明的多級逆流旋流預熱裝置進行多級逆流旋流預熱。如圖5所示，本發明的多級逆流旋流預熱裝置包括至少兩級旋流器和連接所述旋流器的管道。其中，所述至少兩級旋流器(例如兩級、三級、四級、五級、六級、七級、八級、九級、十級或十級以上旋流器)相互上下串聯，優選以梯形連接的形式上下串聯。所述至少兩級旋流器中的第一級旋流器(即位於多級逆流旋流預熱裝置底部的旋流器)用於接收高溫氣體，例如來自於流化床燒結和/或包覆工段的熱空氣、熱氧氣，並將部分高溫氣體輸送給上一級旋流器(第二級旋流器)。所述至少兩級旋流器中的最高級旋流器(即位於多級逆流旋流預熱裝置頂部的旋流器)，用於接收顆粒，例如微球成型工段輸送來的顆粒，並將部分顆粒輸送給下一級旋流器。第一級旋流器和最高級旋流器之間的每一級旋流器用於接收上一級旋流器輸送的顆粒以及下一級旋流器輸送的氣體，並將部分氣體輸送給上一級旋流器，將部分顆粒輸送給下一級旋流器。旋流器調控氣體反應物攜帶自身內部存在的固體顆粒產生渦流，基於氣體與固體顆粒的離心力不同實現氣固換熱後的分離並同時實現對固體顆粒粒徑分佈的篩選。本發明的多級逆流旋流預熱裝置還可包括篩檢程式。篩檢程式可以與最高級旋流器連接，用於過濾由最高級旋流器排出的氣體。
如圖6所示，在一些實施方案中，旋流器為經過特殊設計的離心式氣固分離裝置，包括：旋流器入口61、主體筒體62、氣體出口63、旋流葉片64和顆粒出口65。所述旋流器入口61設置在主體筒體62的頂部，供氣體和顆粒進入旋流器。所述氣體出口63設置在主體筒體62的側壁，供氣體離開旋流器。氣體出口63可以呈管狀。氣體出口63的數量可以是兩個或兩個以上，優選對稱切向分佈於主體筒體62的側壁。所述旋流葉片64設置於主體筒體62內部，用於產生旋流。所述顆粒出口65設置於主體筒體62底部，供顆粒離開旋流器。所述旋流器利用產生的離心力將內部存在的吸附劑甩至所述主體筒體62的邊壁，以使內部存在的顆粒在重力的作用下，通過底端顆粒出口65及連接管路進入下一級旋流器；換熱後的氣體通過氣體出口63進入到對應的上一級旋流器。
多級旋流器以梯形連接的形式上下串聯時，各級旋流器的旋流器入口與下一級旋流器的氣體出口通過管道相連，各級旋流器的顆粒出口與下一級旋流器的旋流器入口通過管道相連。。例如，如圖5所示，當三級旋流器以梯形連接的形式上下串聯時，第三級旋流器的旋流器入口與第二級旋流器的氣體出口通過管道相連，第三級旋流器的顆粒出口與第二級旋流器的旋流器入口通過管道相連，第二級旋流器的旋流器入口與第一級旋流器的氣體出口通過管道相連，第二級旋流器的顆粒出口與第一級旋流器的旋流器入口通過管道相連。
可通過氣體出口直徑(d7)與旋流器主體筒體直徑(d8)的比值的調變實現固體顆粒的粒徑調控。本發明中，氣體出口直徑與旋流器主體筒體直徑的比值優選為0.25~0.75，例如0.3、0.4、0.5、0.6、0.7，採用該比值範圍可以將收集到的固體顆粒的粒徑的控制在25~350μm範圍內，該粒徑範圍內顆粒流化品質最佳。在一個實施方案中，收集到的固體顆粒的粒徑為50μm、75μm、100μm、125μm、150μm、175μm、200μm、225μm、250μm、275μm、300μm、325μm。本文中，如無特別說明，粒徑為中值粒徑。可以採用顯微鏡法確定顆粒的中值粒徑。
多級逆流旋流預熱的操作溫度可以為500-1200℃，例如600℃、700℃、800℃、850℃、900℃、950℃、1000℃、1100℃。
流化床燒結和任選的進一步包覆
流化床燒結和任選的進一步包覆是將預處理後的顆粒進入流化床反應器進行燒結和任選的進一步包覆。如圖1所示，在一些實施方案中，本發明將多級逆流旋流預熱得到的顆粒提供給流化床反應器進行燒結和任選的進一步包覆。在另一些實施方案中，本發明將微球成型得到的正極材料前驅體混鋰顆粒直接提供給流化床反應器進行燒結和任選的進一步包覆，或者將微球成型得到的正極材料前驅體混鋰顆粒經過多級逆流旋流預熱後再提供給流化床反應器進行燒結和任選的進一步包覆。
流化床燒結和/或包覆優選為多段流化床燒結和任選的進一步包覆。可以使用本發明的流化床反應器進行多段流化床燒結和任選的進一步包覆。本發明的流化床反應器是一種多段密相氣固接觸裝置，能夠在單裝置內實現多反應條件控制以完成燒結和包覆等多種功能。
如圖7所示，本發明的流化床反應器包括流化床反應器本體101、至少一個多孔板或傘型擋板102、溢流管103、顆粒輸入機構104、流體入口106、可選的流體分佈器105和可選的包覆物料輸入機構(圖7未示出)。其中，多孔板或傘型擋板102設置在流化床反應器本體101內的床層高度上，每一個多孔板或傘型擋板102將流化床反應器本體101內部切分成上下相鄰的兩段床層。至少兩根溢流高度不同的溢流管103分設在每相鄰兩段床層之間，用於將相鄰兩段床層的上段床層內顆粒傳輸到相鄰兩段床層的下段床層，避免因為氣量大而導致顆粒無法進入下段床層。顆粒輸入機構104設置於最上段床層對應的流化床反應器本體101側壁，用於向流化床反應器輸入顆粒物料。流體入口106設置於流化床反應器本體101的底部，供氣體進入流化床反應器。在各段床層內可實現不同溫度的控制進而分別實現燒結和/或包覆。各段床層內的停留時間可通過操作條件與多孔板或傘型擋板的結構參數進行調節。任選地或優選地，流體分佈器105設置於所述流化床反應器本體的底部，用於分佈通過所述流體入口106進入流化床反應器本體101的氣體。流體分佈器可以是已知的適用於氣-固流化床的氣體分佈器。本發明通過上述優化的流化床反應器的部件連接關係以及進一步優選採用流體分佈器提高包覆均勻性。
在一些實施方案中，顆粒輸入機構104包括鬆動開口的顆粒輸送管道以及側開縫的顆粒分佈筒，從而避免顆粒在顆粒輸入機構中發生堵塞。
在一些實施方案中，包覆物料輸入機構包括噴管，噴管優選基於反拉瓦爾噴管和旋轉射流進行設計。噴管包括噴嘴和噴管管道。噴管管道與噴嘴的直徑比例優選為1:1~1:4。優選地，噴嘴的張角為15°~60°，以有效霧化分散漿料。噴嘴可採用中心熱氣體噴射環隙旋轉漿料射流組合或中心漿料射流環隙熱氣體旋流噴射保護組合。通過調節輸入機構線速和底端與頂端壓降，以保證顆粒不被磨損和噴物料的均勻。本發明通過該優化的包覆物料輸入機構的結構設計提高包覆均勻性。
後處理
本發明中，後處理是任選執行的。後處理主要是將經流化床燒結和/或包覆得到的材料(例如微球型正極材料)的細微性分佈控制在要求範圍內。對經流化床燒結和/或包覆得到的材料可以進行選自以下一項或多項的後處理：細砂磨、篩分與包裝。
採用本發明的方法能夠製備得到晶粒粒徑範圍在1000~5000nm之間的正極材料。正極材料的晶粒粒徑範圍可以控制在例如1500~5000nm之間、1000~2500nm之間、1300~2300nm之間、1500~2500nm之間、1500~2000nm之間的較窄區間內，粒徑一致性好，不存在或基本不存在粒徑小於100nm的晶粒。在一些實施方案中，正極材料不存在或基本不存在粒徑小於500nm的晶粒。本文中，當正極材料顆粒是由一次顆粒組成的二次顆粒時，晶粒粒徑是指組成二次顆粒的一次顆粒粒徑。同時正極材料具有很好的化學成分、振實密度、比表面積等品質的一致性，且具有改善的初始放電容量和首次庫倫效率。
現有動態燒結過程中，難以保證正極粉體材料的充分流動，易發生局部甚至全域的黏接失流。為獲得優異且穩定的流動與混合作用，本發明經過大量實驗，獲得粒徑與密度範圍，提出了包含以下一項或多項設計的新型正極材料製備方法、裝置和系統：
在預處理中，可對第一漿料進行微球成型，獲得粒徑較大的具有較好流動性的顆粒，減少了額外的製備前驅體顆粒的步驟，且可無需使用黏合劑來精確控制粉體粒徑；使用本發明的微球成型裝置能夠提高受熱均勻性，實現顆粒的窄粒徑分佈，同時利用熱氣體與冷粉體的逆流換熱，增加了能量利用率，降低了成本；進一步使用基於反拉瓦爾噴管和旋轉射流設計的漿料輸入機構能夠保證顆粒不被磨損和噴物料的均勻；
在預處理中，可對正極材料原料顆粒、正極材料半成品顆粒或第一漿料顆粒(例如經微球成型得到的顆粒)進行多級逆流旋流預熱，使得顆粒的大小適合流化床燒結，同時實現顆粒的預熱，利用熱氣體與冷粉體的多級逆流旋流換熱，增加了能量利用率，降低了成本；
在流化床燒結和/或包覆中，使用本發明的流化床反應器能夠實現穩定且優異的流動與混合，縮短燒結耗時，提高受熱均勻性，在燒結部分在流化床內部可以引入包覆，進一步使用基於反拉瓦爾噴管和旋轉射流設計的包覆物料輸入機構能夠保證顆粒不被磨損和噴物料的均勻，提高包覆均勻性。
本發明能夠取得以下有益技術效果：本發明提供了製備正極材料的低碳工藝技術，實現了熱能的綜合利用，例如在微球成型工藝和多級逆流旋流預熱工藝中均可使用來自在後工序的熱空氣/氧氣，實現了氧氣/空氣的迴圈利用；本發明提供的流化床反應器實現了正極材料的動態均勻燒結和快速燒結；本發明提供了高效的正極材料製備方法，耗時短，可有效降低雜質污染的概率，工藝集成度高，能量和物料可得到有效的回收利用，傳質/傳熱一致性高，使得產品具有出色的一致性和包覆的均勻性；本發明可以使用未乾燥或減少乾燥的正極材料前驅體進行預處理和後續燒結，減少了正極材料前驅體的乾燥工序，節約了成本；本發明易於工程放大。
下文將以具體實施例的方式描述本發明。應理解，這些實施例僅僅是闡述性的，而非限制本發明的範圍。對於本文以及實施例中所用的試劑、方法、條件等，除非另有說明，否則均為常規的試劑、方法和條件。下列實施例中未注明具體條件的實驗方法，通常按照常規條件，或按照製造廠商所建議的條件。
設備例1：微球成型裝置
如圖2所示，本設備例的微球成型裝置包括：微球成型塔筒體26、對稱環-核氣體分佈裝置20、漿料輸入機構25、微球成型塔底錐29、氣體匯出機構27和固體顆粒出口28。微球成型塔筒體26呈圓筒形，為第一漿料與氣體接觸的場所。對稱環-核氣體分佈裝置20位於微球成型塔筒體26上方，用於向微球成型塔筒體26提供均勻分佈的氣體。對稱環-核氣體分佈裝置20的側壁上對稱切向排布兩個進氣管道21。對稱環-核氣體分佈裝置20的下部設置有預分布器24。對稱環-核氣體分佈裝置20的底部具有與微球成型塔筒體26的頂部連通的開口。漿料輸入機構25包括伸入微球成型塔筒體26內部的帶噴嘴的噴管，用於向微球成型塔筒體26提供第一漿料。漿料輸入機構25的數量為一個。漿料輸入機構25的噴嘴距離對稱環-核氣體分佈裝置20的高度(d1)為微球成型塔筒體26直徑(d2)的1/30。微球成型塔底錐29呈倒錐形。微球成型塔底錐29的頂部與微球成型塔筒體26的底部連通。微球成型塔底錐29的錐角為30度。固體顆粒出口28位於微球成型塔底錐29的底部，為圓形管，用於將微球排出微球成型裝置。氣體匯出機構27包括經由微球成型塔底錐的側面伸入微球成型塔的氣體匯出管。氣體匯出管為圓形管。氣體匯出管在微球成型塔底錐內的開口向上，且氣體匯出機構還包括設置在氣體匯出管在微球成型塔底錐內的開口周圍的微球阻擋結構。微球阻擋結構包括設置在氣體匯出管在微球成型塔底錐內的開口的上方的微球阻擋結構錐體，微球阻擋結構錐體的頂點朝上，微球阻擋結構錐體的底部與微球成型塔底錐連通，使得氣體能夠進入氣體匯出管但微球不會落入氣體匯出管。微球阻擋結構還包括設置在氣體匯出管在微球成型塔底錐內的開口的四周的微球阻擋結構柱體，微球阻擋結構柱體的頂部與微球阻擋結構錐體連通，微球阻擋結構柱體的底部與微球成型塔底錐連通。
如圖3所示，本設備例的微球成型裝置中的對稱環-核氣體分佈裝置包括兩個進氣管道31、環形氣體預分布室32、匯出管33和一個預分布器34。環形氣體預分布室32呈圓臺狀。預分布器34位於環形氣體預分布室32的下方。預分布器34與環形氣體預分布室32通過設置在環形氣體預分布室32內的匯出管33連通。兩個進氣管道31對稱切向分佈於環形氣體預分布室32的側壁。匯出管33為一個豎直管道，位於環形氣體預分布室32中心，使得環形氣體預分布室32和預分布器34連通。匯出管33的上端開口與環形氣體預分布室32頂部之間的距離(d3)小於進氣管道31的上沿與環形氣體預分布室32頂部之間的距離(d4)。
本設備例的微球成型裝置中的漿料輸入機構的噴管基於反拉瓦爾噴管和旋轉射流進行設計。噴管管道的直徑(d5)與噴嘴的直徑(d6)比例為1:2，噴嘴的張角為25°，噴嘴採用中心熱氣體噴射環隙旋轉漿料射流組合。
設備例2：多級逆流旋流預熱裝置
如圖5所示，本設備例的多級逆流旋流預熱裝置包括三級旋流器、連接各旋流器的管道、篩檢程式、以及連接第三級旋流器和篩檢程式的管道。三級旋流器以梯形連接的形式上下串聯。第一級旋流器(即位於多級逆流旋流預熱裝置底部的旋流器)用於接收高溫氣體，並將部分高溫氣體輸送給上一級旋流器(第二級旋流器)。第三級旋流器(即位於多級逆流旋流預熱裝置頂部的旋流器)，用於接收正極材料原料顆粒、正極材料半成品顆粒或第一漿料顆粒，並將部分顆粒輸送給下一級旋流器(第二級旋流器)。第二級旋流器用於接收上一級旋流器(第三級旋流器)輸送的顆粒以及下一級旋流器(第二級旋流器)輸送的氣體，並將部分氣體輸送給上一級旋流器，將部分顆粒輸送給下一級旋流器。第三級旋流器的旋流器入口與第二級旋流器的氣體出口通過管道相連，第三級旋流器的顆粒出口與第二級旋流器的旋流器入口通過管道相連，第二級旋流器的旋流器入口與第一級旋流器的氣體出口通過管道相連，第二級旋流器的顆粒出口與第一級旋流器的旋流器入口通過管道相連。第三級旋流器的氣體出口通過管道與篩檢程式相連。
如圖6所示，本設備例的多級逆流旋流預熱裝置中的旋流器為離心式氣固分離裝置，包括：旋流器入口61、主體筒體62、氣體出口63、旋流葉片64和顆粒出口65。旋流器入口61設置在主體筒體62的頂部，供氣體和顆粒進入旋流器。氣體出口63設置在主體筒體62的側壁，供氣體離開旋流器。旋流葉片64設置在所述主體筒體62內部，用於產生旋流。顆粒出口65位於主體筒體62底部，供顆粒離開旋流器。氣體出口63直徑(d7)與主體筒體62直徑(d8)的比值為0.5。
設備例3：流化床反應器
如圖7所示，本設備例的流化床反應器包括流化床反應器本體101、兩個多孔板102、溢流管103、顆粒輸入機構104、流體入口106和流體分佈器105。多孔板102設置在流化床反應器本體101內的床層高度上，兩個多孔板102將流化床反應器本體101內部切分成上下相鄰的三段床層。四根溢流高度不同的溢流管103分設在最上層床層和中間層床層之間。三根溢流高度不同的溢流管103分設在中間層床層和最下層床層之間。顆粒輸入機構104設置於最上段床層對應的流化床反應器本體101側壁。流體入口106設置於流化床反應器本體101的底部，供氣體進入流化床反應器。在各段床層內可實現不同溫度的控制進而分別實現燒結和/或包覆。流體分佈器105設置於流化床反應器本體101的底部，用於分佈通過所述流體入口106進入流化床反應器本體101的氣體。顆粒輸入機構104包括鬆動開口的顆粒輸送管道以及側開縫的顆粒分佈筒，從而避免顆粒在顆粒輸入機構中發生堵塞。
本設備例的流化床反應器中的包覆物料輸入機構的噴管基於反拉瓦爾噴管和旋轉射流進行設計，噴管管道與噴嘴的直徑比例為1:2，噴嘴採用中心熱氣體噴射環隙旋轉漿料射流組合。
實施例1
按照圖1所示的工藝，使用Ni
0.8Co
0.1Mn
0.1(OH)
2漿料與粉碎後的LiOH混合形成第一漿料，第一漿料的固含率控制為45wt%，pH控制為8.5，該漿料的外觀如圖8(左圖)所示。第一漿料與後續多級逆流旋流預熱裝置篩分的不合格小顆粒混合經過粗磨砂後，進入設備例1的微球成型裝置，操作溫度為250℃，操作壓力為1bar，固氣比為5kg/kg，形成中位粒徑為100μm的顆粒，該顆粒流動性好(接觸角為約40
o)，其流化曲線如圖9所示，可以看到其中氣速從小到大和氣速從大到小的兩條曲線之間存在鼓包，表明顆粒能夠有效流化；使該顆粒進入設備例2的多級逆流旋流預熱裝置預熱至900℃，篩選後的顆粒中位粒徑為125μm；然後進入設備例3的流化床反應器進行燒結，流化床內流化狀態好，氣固接觸均勻；經後處理工段得到最終產品，進行以下測試，結果如下：
(1)產品組成一致性：採用電感耦合等離子光譜儀(ICP)測量，選取5個不同區域進行測量，Ni品質分數方差為1.0%，Co品質分數方差為2.5%，Mn品質分數方差為2%，Li品質分數方差為1.5%；
(2)產品粒徑一致性：採用掃描電子顯微鏡(SEM)測量，選取10個不同區域進行測量，組成二次顆粒的一次顆粒晶粒呈1500~5000nm的較窄區域分佈，其中一個區域的SEM照片如圖10所示；
(3)振實密度：選取5個不同區域進行測量，方差為13%；
(4)比表面積：使用物理吸附儀測量，選取5個不同區域進行測量，方差為1.8%；
(5)扣電(4.3V/0.1C)：將燒結得到的正極材料、導電劑SP和黏結劑PVDF以95:2.5:2.5的品質比均勻混合後，加入NMP中，製備得到正極漿料，將正極漿料塗覆於鋁箔上，烘乾，輥壓得到正極極片，載量為12mg/cm
2，使用珠海賽維SWSD006電解液、科晶16μm隔膜，組裝成紐扣電池，在25℃環境0.1C充放電測試初始放電容量和首次庫倫效率，結果顯示初始放電容量為210mAh/g，首次庫倫效率為89%。
實施例2
按照圖1所示的工藝，使用Ni
0.8Co
0.1Mn
0.1(OH)
2漿料與粉碎後的LiOH混合形成第一漿料，第一漿料的固含率控制為45wt%，pH控制為8.5。第一漿料與後續多級逆流旋流預熱裝置篩分的不合格顆粒混合經過粗磨砂後，進入設備例1的微球成型裝置，操作溫度為250℃，操作壓力為1bar，固氣比為5kg/kg，形成中位粒徑為100μm的顆粒，該顆粒流動性好(接觸角為約40
o)；使該顆粒進入設備例2的多級逆流旋流預熱裝置預熱至900℃，篩選後的顆粒中位粒徑為125μm；然後進入加裝包覆物料輸入機構的設備例3的流化床反應器進行燒結和包覆，包覆物料為鋁溶膠，包覆物料經預熱至150℃後通過包覆物料輸入機構噴射至流化床內；流化床內流化狀態好，氣固接觸均勻；經後處理工段得到經包覆改性的正極材料，進行以下測試，結果如下：
(1)產品組成一致性：採用電感耦合等離子光譜儀(ICP)測量，選取5個不同區域進行測量，Ni品質分數方差為1.0%，Co品質分數方差為2.5%，Mn品質分數方差為2%，Li品質分數方差為1.5%，Al品質分數方差為1.25%；
(2)產品粒徑一致性：採用掃描電子顯微鏡(SEM)測量，選取10個不同區域進行測量，組成二次顆粒的一次顆粒晶粒呈1500~5000nm的較窄區域分佈；
(3)振實密度：選取5個不同區域進行測量，方差為13%；
(4)比表面積：使用物理吸附儀測量，選取5個不同區域進行測量，方差為1.8%；
(5)扣電(4.3V/0.1C)：測試方法同實施例1，初始放電容量為210mAh/g，首次庫倫效率為89%。
實施例3
將2mol/L的金屬鹽溶液(莫耳比Ni:Co:Mn=5:2:3)、5mol/L的液堿和5mol/L的氨水通過3根進料管分別泵入反應釜中進行生產；控制反應釜pH為11，反應溫度為55℃，所得前驅體溢流至陳化槽，陳化時間為4h，然後離心，得到523鎳鈷錳的氫氧化物前驅體，該前驅體為由150nm-200nm片狀奈米粒子團聚成的D50在10-11μm之間的二次球狀粉體。按照鋰原子與(Ni+Co+Mn)原子之和的莫耳比為1.03∶1.00的比例配比配料。稱取4.3kg單水氫氧化鋰(D50在7μm左右不規則粉體)和2.5kg去離子水，高速分散配置成氫氧化鋰漿料；將10.1kg 523鎳鈷錳的氫氧化物前驅體(其中幹物質品質分數為90%)投入捏合機內，開啟攪拌，將氫氧化鋰漿料加入捏合機內，攪拌均勻得到第一前驅體混鋰漿料，室溫下用黏度計(4號轉子)測得表觀黏度約為3000cps，電鏡下觀察，鋰鹽顆粒在前驅體表面均勻包覆。
按照圖1所示的工藝，使用第一前驅體混鋰漿料作為第一漿料，第一漿料與後續多級逆流旋流預熱裝置篩分的不合格小顆粒混合經過粗磨砂後，進入設備例1的微球成型裝置，操作溫度為250℃，操作壓力為1bar，固氣比為5kg/kg，形成顆粒，該顆粒流動性好；使該顆粒進入設備例2的多級逆流旋流預熱裝置預熱至900℃，篩選後的顆粒中位粒徑約為125μm；然後進入設備例3的流化床反應器進行燒結，流化床內流化狀態好，氣固接觸均勻；經後處理工段得到最終產品，進行以下測試，結果如下：
(1)產品組成一致性：採用電感耦合等離子光譜儀(ICP)測量，選取5個不同區域進行測量，Ni品質分數方差為1.0%，Co品質分數方差為2.5%，Mn品質分數方差為2%，Li品質分數方差為1.5%；
(2)產品粒徑一致性：採用掃描電子顯微鏡(SEM)測量，選取10個不同區域進行測量，組成二次顆粒的一次顆粒晶粒呈1500~5000nm的較窄區域分佈；
(3)振實密度：選取5個不同區域進行測量，方差為13%；
(4)比表面積：使用物理吸附儀測量，選取5個不同區域進行測量，方差為1.8%；
(5)扣電(4.3V/0.1C)：測試方法同實施例1，初始放電容量為172Ah/g，首次庫倫效率為89%。
實施例4
將2mol/L的金屬鹽溶液(莫耳比Ni:Co:Mn=8:1:1)、5mol/L的液堿和5mol/L的氨水通過3根進料管分別泵入反應釜中進行生產；控制反應釜pH為11，反應溫度為55℃，所得前驅體溢流至陳化槽，陳化時間為5h，然後離心，得到811鎳鈷錳的氫氧化物前驅體，該前驅體為由150nm-200nm片狀奈米粒子團聚成的D50在3-4μm之間的二次球狀粉體。按照鋰原子、(Ni+Co+Mn)原子之和、鋁原子莫耳比為1.03∶1.00∶0.001的比例配比配料。稱取4.3kg單水氫氧化鋰(D50在7μm左右不規則粉體)和3.0kg去離子水，高速分散配置成氫氧化鋰漿料；將10.4kg步驟(1)得到的前驅體濾餅(其中幹物質品質分數為89%)投入捏合機內，開啟攪拌，將氫氧化鋰漿料加入捏合機內，攪拌均勻得到第一前驅體混鋰漿料，室溫下用黏度計(4號轉子)測得表觀黏度約為3500cps，電鏡下觀察，鋰鹽顆粒在前驅體表面均勻包覆。將第一前驅體混鋰漿料和260g鋁溶膠(其中Al
2O
3品質濃度為20%)投入到捏合機內，開啟攪拌15分鐘後，使混合物坯體凝膠化，15分鐘後關閉攪拌，所得凝膠化的混合物即為第二前驅體混鋰漿料。
按照圖1所示的工藝，使用第二前驅體混鋰漿料作為第一漿料，第一漿料與後續多級逆流旋流預熱裝置篩分的不合格小顆粒混合經過粗磨砂後，進入設備例1的微球成型裝置，操作溫度為250℃，操作壓力為1bar，固氣比為5kg/kg，形成顆粒，該顆粒流動性好；使該顆粒進入設備例2的多級逆流旋流預熱裝置預熱至900℃，篩選後的顆粒中位粒徑約為125μm；然後進入設備例3的流化床反應器進行燒結，流化床內流化狀態好，氣固接觸均勻；經後處理工段得到最終產品，進行以下測試，結果如下：
(1)產品組成一致性：採用電感耦合等離子光譜儀(ICP)測量，選取5個不同區域進行測量，Ni品質分數方差為1.0%，Co品質分數方差為2.5%，Mn品質分數方差為2%，Li品質分數方差為1.5%，Al品質分數方差為1.25%；
(2)產品粒徑一致性：採用掃描電子顯微鏡(SEM)測量，選取10個不同區域進行測量，組成二次顆粒的一次顆粒晶粒呈1500~5000nm的較窄區域分佈；
(3)振實密度：選取5個不同區域進行測量，方差為13%；
(4)比表面積：使用物理吸附儀測量，選取5個不同區域進行測量，方差為1.8%；
(5)扣電(4.3V/0.1C)：測試方法同實施例1，初始放電容量為210Ah/g，首次庫倫效率為89%。
對比例1
按照圖1所示的工藝，與實施例1的區別在於不進行微球成型，即使用Ni
0.8Co
0.1Mn
0.1(OH)
2漿料與粉碎後的LiOH混合形成第一漿料(固含率為45wt%，pH值為8.5)並直接進入設備例2的多級逆流旋流預熱裝置，此時前驅體顆粒的粒徑僅3~10μm，流動性差(接觸角為約60°)，易在多級逆流旋流預熱裝置的旋流器的料腿發生堵塞；顆粒通過多級逆流旋流預熱裝置預熱至900℃，進入設備例3的流化床反應器進行燒結，此時由於顆粒迎風面積過小且顆粒間范德華力過大，造成底部流化氣體無法有效將顆粒有效托起，氣固接觸效率低，且由於氣固接觸不均勻會使得局部結塊進而失流；經後處理工段得到最終產品，進行以下測試，結果如下：
(1)產品組成一致性：採用ICP測量，選取5個不同區域進行測量，Ni品質分數方差為5%，Co品質分數方差為10%，Mn品質分數方差為12%，Li品質分數方差為10%；
(2)產品粒徑一致性：採用SEM測量，選取10個不同區域進行測量，組成二次顆粒的一次顆粒晶粒呈50nm~ 2000nm很寬的區域分佈；
(3)振實密度：選取5個不同區域進行測量，方差為15%；
(4)比表面積：使用物理吸附儀測量，選取5個不同區域進行測量，方差為7%；
(5)扣電(4.3V/0.1C)：測試方法同實施例1，初始放電容量為197 mAh/g，首次庫倫效率為78%。
對比例2
按照圖1所示的工藝，與實施例1的區別在於不進行多級逆流旋流預熱，即使用Ni
0.8Co
0.1Mn
0.1(OH)
2漿料與粉碎後的LiOH混合形成第一漿料(固含率為45wt%，pH值為8.5)，進入設備例1的微球成型裝置，操作溫度為250℃，操作壓力為1bar，固氣比為5kg/kg，形成中位粒徑為100μm的顆粒，該顆粒流動性好(接觸角為約40°)；使微球成型得到的顆粒直接進入設備例3的流化床反應器進行燒結，由於不經過多級逆流旋流預熱裝置，無法進行有效的細微性篩分，顆粒分佈較寬，且顆粒處於150℃的低溫狀態，進入流化床後，冷顆粒與高溫氧氣氛圍接觸以及不同粒徑顆粒燒結速率不同，導致了正極材料均一性變差；經後處理工段得到最終產品，進行以下測試，結果如下：
(1)產品組成一致性：採用ICP測量，選取5個不同區域進行測量，Ni品質分數方差為5%，Co品質分數方差為10%，Mn品質分數方差為12%，Li品質分數方差為10%；
(2)產品粒徑一致性：採用SEM測量，選取10個不同區域進行測量，組成二次顆粒的一次顆粒晶粒呈50nm~ 2000nm很寬的區域分佈；
(3)振實密度：選取5個不同區域進行測量，方差為15%；
(4)比表面積：使用物理吸附儀測量，選取5個不同區域進行測量，方差為7%；
(5)扣電(4.3V/0.1C)：測試方法同實施例1，初始放電容量為187 mAh/g，首次庫倫效率為75%。
由實施例1和對比例1-2的實驗結果可以看出，相比不進行微球成型或多級逆流旋流預熱，採用本發明的製備方法製備得到的正極材料具有更高的化學成分、振實密度、比表面積等品質的一致性，晶粒粒徑分佈在1500~5000nm的較窄區域，沒有粒徑特別小的晶粒，且具有更佳的初始放電容量和首次庫倫效率。
對比例3
使用Ni
0.8Co
0.1Mn
0.1(OH)
2漿料與粉碎後的LiOH混合形成第一漿料，將固含率控制為80%，pH控制為3，該漿料的外觀如圖8(右圖)所示。該漿料無法通過漿料輸入機構25噴入設備例1的微球成型裝置。
In order to enable those skilled in the art to understand the features and effects of the present invention, the terms and terms mentioned in the specification and claims are generally described and defined below. Unless otherwise specified, all technical and scientific terms used herein have the usual meanings understood by those skilled in the art for the present invention. In case of conflict, the definitions in this specification shall prevail. The theories or mechanisms described and disclosed herein, whether true or false, should not limit the scope of the present invention in any way, ie, the present invention can be practiced without being limited by any particular theory or mechanism. In this article, unless otherwise stated, "comprising", "comprising", "comprising" and similar expressions cover the meanings of "consisting essentially of" and "consisting of", that is, "A includes a" covers "A contains a and others", "A consists essentially of a" and "A consists of a". Herein, unless otherwise specified, “consisting essentially of” can be understood as “more than 80%, preferably more than 90%, more preferably more than 95% of”. Herein, for the sake of concise description, all possible combinations of the technical features in each embodiment or embodiment are not described. Therefore, as long as there is no contradiction in the combination of these technical features, each technical feature in each embodiment or example can be combined arbitrarily, and all possible combinations should be regarded as within the scope of this specification. The invention provides a process method, device and system for processing one or more raw materials or semi-finished products of positive electrode materials into battery positive electrode materials, which realizes efficient countercurrent contact between hot air/oxygen and materials to obtain maximum heat transfer/mass transfer driving force. The present invention includes but is not limited to the preparation of nickel-cobalt-manganese ternary positive electrode materials, nickel-cobalt-aluminum ternary positive electrode materials, lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium manganate, lithium titanate, NCMA ( Nickel cobalt manganese aluminum quaternary positive electrode material), NC (lithium nickel cobalt oxide), NM (lithium nickel manganese oxide), etc. The preparation method of the cathode material of the present invention comprises the following steps: (1) pretreatment, (2) fluidized bed sintering, and optional (3) posttreatment. Pretreatment In the present invention, pretreatment is used to process the raw material or semi-finished product of the positive electrode material into a form suitable for entering into a fluidized bed for sintering. For example, pretreatment may include: mixing raw materials or semi-finished products of positive electrode materials of different types, screening the raw materials or semi-finished products of positive electrode materials for particle size, preparing raw materials or semi-finished products of positive electrode materials into slurry, and/or treating slurry Dry or preheat. In the present invention, the raw materials or semi-finished products of positive electrode materials include but are not limited to: lithium oxide, lithium hydroxide, lithium salt (such as lithium carbonate), transition metal hydroxide, transition metal oxide, transition metal salt, aluminum oxide, hydroxide Aluminum, aluminum salts, composite oxides of two or more of lithium oxide, transition metal oxides, and aluminum oxide, lithium hydroxide, transition metal hydroxides, and aluminum hydroxide of two or more Compound hydroxides, double salts of two or more of lithium salts, transition metal salts and aluminum salts, hydrates of the aforementioned substances, complexes of the aforementioned substances, etc. Transition metals include, but are not limited to, nickel, manganese, cobalt, chromium, iron, titanium, and the like. It can be understood that the metal elements contained in the raw material or semi-finished product of the positive electrode material generally include lithium and one or more transition metals, and optionally may include aluminum. In some embodiments, the raw material or semi-finished product of the positive electrode material may include a mixture or composite of (a) lithium salt, and (b) one or more selected from transition metal hydroxides and transition metal carbonates. For example, the raw materials or semi-finished products of positive electrode materials can include composite hydroxides of nickel, cobalt, and manganese (also referred to as precursors in the art) and lithium salts (such as those selected from lithium hydroxide, lithium carbonate, and lithium oxide). One or more), the chemical formula of the composite hydroxide of nickel, cobalt, manganese can be Ni x Co y Mn z (OH) 2 , wherein x, y, z are each greater than 0 and <1, and x+y+z= 1. Other cathode materials (nickel-cobalt-aluminum ternary cathode material, lithium iron phosphate, lithium manganese iron phosphate, lithium cobalt phosphate, lithium manganese phosphate, lithium manganate, lithium titanate, NCMA (nickel-cobalt-manganese-aluminum quaternary cathode material) can also be used ), NC (lithium nickel cobalt oxide), NM (lithium nickel manganese oxide)) precursors and lithium salts are used as raw materials or semi-finished products of positive electrode materials to obtain corresponding positive electrode materials. In the present invention, the lithium salt can be selected from lithium hydroxide, lithium carbonate, lithium bicarbonate, lithium oxide, lithium sulfate, lithium hydrogensulfate, lithium fluoride, lithium chloride, lithium bromide, lithium nitrate, lithium acetate, lithium peroxide , one or more of lithium oxalate, lithium phosphate and lithium hydrogen phosphate, for example selected from lithium hydroxide, lithium carbonate, lithium bicarbonate, lithium oxide, lithium sulfate, lithium hydrogensulfate, lithium fluoride, lithium chloride, lithium bromide, One or more of lithium nitrate, lithium acetate and lithium peroxide, preferably one or more selected from lithium hydroxide, lithium carbonate, lithium bicarbonate and lithium oxide, more preferably one or more selected from lithium hydroxide and lithium carbonate or two. The lithium salt raw material can be a hydrated lithium salt, for example, lithium hydroxide can be lithium hydroxide monohydrate. Lithium salt has the same meaning as lithium source. In some embodiments, the raw material or semi-finished product of the positive electrode material contains essentially one lithium salt, and the "essentially one lithium salt" refers to only one lithium salt, or a mixture of two or more lithium salts, wherein one lithium salt The salt accounts for at least 90wt% or more of the total lithium salt. Examples of transition metal hydroxides include M(OH) 2+n , wherein M is one or more selected from nickel, cobalt, manganese, aluminum, iron and titanium, and n is 0-2, such as 0.1, 0.2, 0.5 ,1. For example, the transition metal hydroxide can be M(OH) 2+n , where M is Ni x Co y Mn z or Ni x Co y Al z , x+y+z=1, and x is 0.3-0.9, such as 0.4 , 0.5, 0.6, 0.7, 0.8, y is 0.01-0.4, such as 0.02, 0.05, 0.1, 0.2, 0.3, z is 0.01-0.4, such as 0.02, 0.05, 0.1, 0.2, 0.3, n is 0-0.2, such as 0, 0.01, 0.02, 0.05, 0.1. The transition metal hydroxide can also be M(OH) 2+n , wherein M is Ni a Co b or Ni a Mn b , a+b=1, a and b are each independently 0.1-0.9, such as 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, n is 0-0.2, such as 0, 0.01, 0.02, 0.05, 0.1. In some embodiments, the transition metal hydroxide can also be doped and/or coated M(OH) 2+n , the doped and/or coated elements include but not limited to Al, Zr, Sr, Mg, Ti, B, Lanthanides, Halogen, Mo, Cu, V, Ca, Ru, W, Os, Fe, Ga, In, P, Cr, Ce, Nb, Y, Sn, Ta, Ni, Co, Mn, Si One or more of , Ba, etc. Examples of transition metal carbonates include M(CO 3 ) 1+m , wherein M is one or more selected from nickel, cobalt, manganese, aluminum, iron and titanium, and m is 0-1, such as 0.05, 0.1, 0.25 , 0.5. For example, the transition metal carbonate can be M(CO 3 ) 1+m , where M is Ni x Co y Mn z or Ni x Co y Al z , x+y+z=1, and x is 0.3-0.9, for example 0.4 , 0.5, 0.6, 0.7, 0.8, y is 0.01-0.4, such as 0.02, 0.05, 0.1, 0.2, 0.3, z is 0.01-0.4, such as 0.02, 0.05, 0.1, 0.2, 0.3, m is 0-0.1, such as 0, 0.005, 0.01, 0.025, 0.05. The transition metal carbonate can also be M(CO 3 ) 1+m , wherein M is Ni a Co b or Ni a Mn b , a+b=1, and a and b are each independently 0.1-0.9, such as 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, m is 0-0.1, such as 0, 0.005, 0.01, 0.025, 0.05. In some embodiments, the transition metal carbonate can also be doped and/or coated M(CO 3 ) 1+m , the doped and/or coated elements include but not limited to Al, Zr, Sr, Mg, Ti, B, Lanthanides, Halogen, Mo, Cu, V, Ca, Ru, W, Os, Fe, Ga, In, P, Cr, Ce, Nb, Y, Sn, Ta, Ni, Co, Mn, Si One or more of , Ba, etc. In some cases, such as doping and/or coating modification of the positive electrode material, the positive electrode material itself can also be used as a raw material or a semi-finished product of the positive electrode material. In some embodiments, the raw material or semi-finished product of the positive electrode material used in the present invention comprises a precursor of the positive electrode material and a lithium salt. The type of positive electrode material precursors suitable for the present invention is not particularly limited, including but not limited to lithium manganate positive electrode material precursors, lithium cobaltate positive electrode material precursors, lithium nickelate positive electrode material precursors, binary positive electrode material precursors (such as lithium nickel manganese oxide cathode material precursor, lithium nickel cobalt oxide cathode material precursor, etc.), ternary cathode material precursor (such as nickel cobalt lithium manganese oxide cathode material precursor, nickel cobalt lithium aluminate cathode material precursor, etc. ), quaternary positive electrode material precursors (such as nickel cobalt lithium manganese aluminate positive electrode material precursors, etc.), lithium iron phosphate positive electrode material precursors, etc. In some embodiments, the precursor is a nickel-cobalt-manganese lithium cathode material precursor, such as the hydroxide precursor of 523 nickel-cobalt-manganese (Ni 0.5 Co 0.2 Mn 0.3 (OH) 2 ), the hydroxide of 811 nickel-cobalt-manganese precursor (Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 ). "523" and "811" mean that the molar ratio of nickel, cobalt and manganese is 5:2:3 or 8:1:1. The cathode material precursor suitable for the present invention (herein referred to as the precursor for short) can be a cathode material precursor prepared by a method known in the art, or a cathode material precursor prepared by a method disclosed in the present invention. The precursor of the positive electrode material can be formed by reacting a metal salt solution, a precipitating agent and a complexing agent, or by reacting a ferrous iron salt solution, a phosphate solution, a pH regulator and an oxidizing agent. For example, lithium manganate positive electrode material precursor, lithium cobaltate positive electrode material precursor, lithium nickelate positive electrode material precursor, binary positive electrode material precursor, ternary positive electrode material precursor and quaternary positive electrode material precursor can be made of metal salt Hydroxide and/or carbonate obtained by co-precipitation reaction of solution, precipitating agent and complexing agent. Herein, the metal elements and their proportions contained in the metal salt solution are generally consistent with the metal elements and their proportions in the prepared cathode material precursor. The metal salt solution can be a solution of a metal salt, or a mixed solution of multiple metal salts. For example, the metal salt solution used to prepare the precursor of the nickel-cobalt-manganese positive electrode material can be a mixed solution of nickel salt, cobalt salt, and manganese salt. The solvent of the metal salt solution is usually water. The metal salt contained in the metal salt solution may be known metal salts that can be used to prepare the corresponding cathode material precursors, usually water-soluble salts, such as sulfates, hydrochlorides and the like. The precipitating agent for preparing the hydroxide precursor may be sodium hydroxide solution (ie liquid alkali), potassium hydroxide solution, and the like. The precipitating agent for preparing the carbonate precursor can be sodium carbonate, potassium carbonate and the like. Complexing agent can be ammonia water etc. Appropriate aging is carried out after the co-precipitation reaction, so that the precursor of the positive electrode material can be completely converted. In some embodiments, the present invention uses the cathode material precursor prepared by the following method: metal salt solution (such as a mixed solution of nickel salt, cobalt salt, manganese salt), liquid alkali and ammonia are carried out coprecipitation reaction, and the product is aged to obtain the hydroxide precursor of the positive electrode material. Co-precipitation reaction conditions can be conventional. The concentration of the metal salt solution (such as a mixed solution of nickel salt, cobalt salt, and manganese salt) can be 1-5 mol/L, such as 2 mol/L, 3 mol/L, 4 mol/L. For a solution containing multiple metal salts, the concentration of the metal salt solution refers to the total molar concentration of the metal elements in the solution. The concentration of the precipitating agent (such as liquid alkali) can be 2-10 mol/L, such as 3 mol/L, 5 mol/L, 8 mol/L. The concentration of complexing agent (such as ammonia water) can be 1-10 mol/L, such as 2 mol/L, 5 mol/L, 8 mol/L. The pH of the reaction system can be 9-12, such as 10,11. The reaction temperature may be 40-70°C, such as 50°C, 55°C, 60°C. The aging time can be 2-10h, such as 4h, 5h, 6h, 8h. The lithium iron phosphate cathode material precursor can be formed by reacting a ferrous iron salt solution, an oxidizing agent and a phosphate solution, and can be properly aged and cleaned after the reaction. An oxidizing agent can be used to oxidize the ferrous salt to ferric salt, then ammonium dihydrogen phosphate is added, and then a dispersant is optionally or preferably added. The divalent iron salt may be ferrous sulfate or the like. The oxidizing agent can be hydrogen peroxide. The phosphate may be ammonium dihydrogen phosphate or the like. In the reaction system, the molar ratio of iron to phosphorus can be 1:(1-1.2), such as 1:1.05, 1:1.1, 1:1.15. The dispersant may be a polyvinyl alcohol dispersant. The amount of dispersant can be 0.1-2% of the total mass of the reaction system, such as 0.2%, 0.5%, 1%. The concentrations of the ferrous salt solution, the oxidizing agent and the phosphate solution may each be 0.5-5 mol/L, such as 1 mol/L, 2 mol/L, 3 mol/L, 4 mol/L. The reaction temperature may be 30-100°C, such as 40°C, 50°C, 60°C, 70°C, 80°C, 90°C. The aging time can be 2-10h, such as 4h, 5h, 6h, 8h. The main component of the lithium iron phosphate cathode material precursor is iron phosphate, and optionally or preferably may also contain carbon sources, such as glucose, sucrose, and the like. The content of carbon source can be 1%-10% of the quality of iron phosphate, such as 2%, 4%, 5%, 6%, 8%. Cathode material precursors are usually in granular form. The D50 particle size of the precursor is preferably between 1-20 μm, more preferably between 2-15 μm, such as 3 μm, 4 μm, 5 μm, 7 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm. The shape of the precursor particles can be spherical, elongated, irregular, etc. In some embodiments, the precursor particles are spherical. In some embodiments, the precursor particles are secondary spherical powders agglomerated by nanoparticles; preferably, the diameter of the nanoparticles is between 100-300nm, such as 150nm, 200nm, 250nm. The shape of the nanoparticles constituting the precursor particles can be flake, spherical, long strip, irregular shape, etc. In a preferred embodiment, the nanoparticles that make up the precursor particles are in the form of flakes, which is beneficial to provide passages for lithium ions to enter and exit the positive electrode material, and improve the performance of lithium-ion batteries. In the embodiment where the precursor is the lithium iron phosphate positive electrode material precursor, it is preferable to grind the precursor to 50-200 nm, such as 100 nm, 150 nm, which is beneficial to improve the performance of the lithium iron phosphate positive electrode material. The positive electrode material precursor particles can be dry particles without water, or water-containing particles retaining a certain amount of water. In some embodiments, the present invention uses water-containing positive electrode material precursor particles, for example, uses a precursor (not dried, retaining a certain amount of moisture) separated from the reaction system for preparing the positive electrode material precursor, so that water does not need to be added after drying Dubbed slurry. When using water-containing positive electrode material precursor particles, the water content of the positive electrode material precursor particles may be 5-20wt%, such as 10wt%, 15wt%. It can be understood that when calculating the content of the positive electrode material precursor in the precursor-mixed lithium slurry, the quality of the positive electrode material precursor does not include the quality of water in the aqueous precursor particles. Lithium salts suitable for raw materials or semi-finished products of positive electrode materials used in the present invention include but are not limited to lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate, lithium sulfate, lithium chloride, lithium fluoride, lithium oxalate, lithium phosphate, Lithium hydrogen phosphate, etc. In some embodiments, the lithium salt is lithium hydroxide, such as lithium hydroxide monohydrate. It can be understood that when calculating the lithium salt content in the precursor mixed lithium slurry, the quality of the lithium salt does not include the quality of the water in the hydrated lithium salt. Lithium salt raw materials are usually in the form of powder. The D50 particle size of the lithium salt raw material can be between 5-15 μm, such as 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm. The shape of the lithium salt raw material can be round, long, irregular, etc. In some embodiments, the lithium salt raw material is an irregularly shaped powder. In the present invention, the first slurry refers to a dispersion system comprising a raw material or a semi-finished product of the positive electrode material and a dispersant (including but not limited to water). The first slurry described herein includes raw materials or semi-finished products of positive electrode materials that are not completely dried. In a specific embodiment, the first slurry includes a lithium salt and an undried or incompletely dried precursor. In some embodiments, the first slurry used in the present invention is a positive electrode material precursor mixed lithium slurry (herein referred to as precursor mixed lithium slurry). The cathode material precursor mixed lithium slurry of the present invention contains cathode material precursor particles, lithium salt and water. In some embodiments, in the precursor mixed lithium slurry of the present invention, the surface of the positive electrode material precursor particle is coated with lithium salt. In some embodiments, the cathode material precursor particles in the precursor mixed lithium slurry of the present invention are permeated with lithium salts. The coated and infiltrated lithium salts exist in the form of nanoparticles. Compared with mixing the precursor and lithium salt by the solid-phase dry method, in the precursor mixed lithium slurry of the present invention, the lithium salt is uniformly mixed with the precursor in a smaller particle size, which is more conducive to the reaction. Optionally or preferably, the cathode material precursor mixed lithium slurry of the present invention also contains inorganic nanoparticles. The elements contained in inorganic nanoparticles are required to be beneficial or not affect the performance of the product. The effect of adding inorganic nanoparticles is to make the precursor mixed lithium slurry gel. In the present invention, the strength of granulated particles is improved by introducing doping elements with gel properties into the lithium-mixed precursor slurry. Therefore, in the embodiment where the precursor mixed lithium slurry contains inorganic nanoparticles, the precursor mixed lithium slurry is in a gel state. In the present invention, inorganic nanoparticles do not include lithium salts in the form of nanoparticles. Inorganic nanoparticles suitable for the present invention may be oxide nanoparticles, including but not limited to nano-silicon oxide, nano-alumina, nano-zirconia, and the like. In a preferred embodiment, the inorganic nanoparticles are introduced by adding an inorganic sol (such as silica sol, aluminum sol, zirconium sol, etc.) to the lithium-precursor slurry. Herein, the inorganic sol refers to a stable or metastable dispersion system formed by dispersing inorganic nanoparticles in a solvent (usually water). Herein, silica sol, aluminum sol and zirconium sol refer to the dispersion liquid of nano silicon oxide, nano aluminum oxide and nano zirconium oxide in water respectively. In the present invention, the precursor mixed lithium slurry not containing inorganic nanoparticles is called the first positive electrode material precursor mixed lithium slurry (abbreviated as the first precursor mixed lithium slurry), and the gelatinized slurry containing inorganic nanoparticles The precursor mixed lithium slurry is called the second positive electrode material precursor mixed lithium slurry (abbreviated as the second precursor mixed lithium slurry). In the present invention, the water content of the lithium-mixed slurry of the first and second cathode material precursors is preferably 20-40wt%, such as 23wt%, 25wt%, 27wt%, 30wt%, 33wt%, 35wt%, 38wt%. Controlling the water content within the aforementioned range is beneficial to granulation. In the present invention, the apparent viscosity of the first cathode material precursor mixed lithium slurry at room temperature is preferably 1000-5000cps, such as 2000cps, 3000cps, 3500cps, 4000cps. This facilitates subsequent gelation and granulation. In the present invention, in the second cathode material precursor mixed lithium slurry, the content of the inorganic nanoparticles is preferably 0.1%-1% of the mass of the cathode material precursor, such as 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. This facilitates gelation of the precursor slurry. In the present invention, in the first and second cathode material precursors mixed with lithium slurry, the molar ratio of the cathode material precursor (that is, the sum of the metal atoms in the cathode material precursor) to lithium can be 1:(1.01-1.05) , such as 1:1.02, 1:1.03, 1:1.04. In the second cathode material precursor mixed with lithium slurry, the molar ratio of atoms other than oxygen in the cathode material precursor and the inorganic nanoparticles can be 1:(0.0005-0.005), for example 1:0.001, 1:0.002, 1:0.003, 1:0.004. In some embodiments where the positive electrode material precursor is a lithium iron phosphate positive electrode material precursor, the positive electrode material precursor mixed lithium slurry includes iron phosphate, lithium salt and water. The iron phosphate is preferably nanometer iron phosphate, preferably with a particle size of 50-200nm, such as 100nm, 150nm. The lithium salt can be selected from one or more of lithium hydroxide, lithium carbonate, lithium nitrate, lithium acetate, lithium sulfate, lithium chloride, lithium fluoride, lithium oxalate, lithium phosphate and lithium hydrogen phosphate, preferably lithium carbonate. In the cathode material precursor mixed lithium slurry, the molar ratio of iron and lithium may be 1:(1-1.05), for example 1:1.01, 1:1.02, 1:1.03, 1:1.04. Optionally or preferably, the cathode material precursor mixed lithium slurry also contains a carbon source, and the content of the carbon source can be 1-10% of the iron phosphate quality, such as 2%, 4%, 5%, 6%, 8%. The water content of the positive electrode material precursor mixed with lithium slurry can be 20-90wt%, such as 30wt%, 50wt%, 70wt%, 80wt%. Before granulation, the cathode material precursor mixed lithium slurry can be properly dried to reduce the water content, for example, the water content can be reduced to 20-40wt%, such as 25wt%, 30wt%, 35wt%. In the present invention, the positive electrode material precursor mixed with lithium slurry can be prepared by wet process, for example, by mixing the positive electrode material precursor, lithium salt and water, wherein the positive electrode material precursor can be as described in any embodiment herein Cathode material precursor particles. In some embodiments, the lithium salt and water are first mixed to form a lithium salt slurry, and then the lithium salt slurry and the positive electrode material precursor are mixed, which is conducive to uniform mixing. Preferably, a kneader is used to uniformly mix the lithium salt slurry and the positive electrode material precursor. The stirring speed of the kneader is preferably 50-200 rpm, and the stirring time is preferably 10-30 minutes. The method for preparing the lithium-mixed slurry of the precursor of the positive electrode material of the present invention may further include: adding an inorganic sol to the lithium-mixed slurry of the precursor of the positive electrode material, mixing evenly, and gelling the mixture to obtain the second positive electrode material Precursor mixed lithium slurry. In the present invention, the concentration of the inorganic sol is preferably 5-25wt%, such as 10wt%, 20wt%. The amount of inorganic sol is preferably that the amount of inorganic sol is 0.5%-10% of the mass of the positive electrode material precursor, such as 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%. This facilitates the gelation of the mixture. In a preferred embodiment, a kneader is used to knead the first cathode material precursor mixed lithium slurry and the inorganic sol. The time for kneading the first cathode material precursor mixed with lithium slurry and aluminum sol is preferably 10-30 minutes, for example, 15 minutes or 20 minutes, which is conducive to the gelation of the slurry. In some embodiments of preparing lithium iron phosphate cathode material precursor mixed lithium slurry, iron phosphate, water, lithium salt and optional carbon source are uniformly mixed to obtain lithium iron phosphate cathode material precursor mixed lithium slurry . For example, the ferric phosphate can be uniformly mixed with water or an aqueous solution of carbon source, optionally ground, and then added with lithium salt to disperse uniformly. Optionally or preferably, the lithium iron phosphate cathode material precursor mixed lithium slurry can be properly dried to reduce the water content, so as to facilitate granulation. The present invention includes the positive electrode material precursor lithium mixed slurry prepared by the method for preparing the positive electrode material precursor lithium mixed slurry. The cathode material precursor lithium-mixed slurry prepared by the method for preparing the cathode material precursor lithium-mixed slurry of the present invention can have the characteristics of the cathode material precursor lithium-mixed slurry described above. Microsphere Forming The pretreatment step of the positive electrode material preparation method of the present invention may include microsphere forming. In the present invention, the microsphere molding is to prepare the first slurry into microspheres to provide precursor particle microspheres with excellent gas-solid flow effect for the subsequent stages. In the present invention, microspheres refer to particles with a particle size ≥ 20 μm. In some preferred embodiments, the particle size of the microspheres is 20-300 μm, such as 50 μm, 80 μm, 100 μm, 125 μm, 150 μm, 180 μm, 200 μm, 220 μm, 250 μm, 270 μm. Controlling the particle size of the particles obtained by microsphere molding within this range is beneficial to the fluidization of the particles. If the particle size is too small, the particles cannot be effectively fluidized; if the particle size is too large, the particles can only spray locally while other parts are in a non-fluidized state. Within the preferred particle size range of the present invention, the particles can exhibit a reasonable fluidization curve. Microspheres may contain a certain amount of liquid components. Microsphere molding can be carried out by spraying. In these embodiments, the microspheres are formed by contacting the atomized slurry with a high temperature gas to form the slurry into microspheres during the drying process. The pH of the first slurry used for microsphere formation is preferably 4-12, such as 5, 6, 7, 8, 9, 10, 11, which is conducive to ensuring the stable atmosphere of the positive electrode material. The solid content of the first slurry is preferably 5~75wt%, such as 10wt%, 15wt%, 20wt%, 25wt%, 30wt%, 35wt%, 40wt%, 45wt%, 50wt%, 55wt%, 60wt%, 65wt% %, 70wt%, which is conducive to microsphere spray molding. Within the preferred pH and solid content ranges of the first slurry in the present invention, the slurry is suitable for forming the microspheres of the present invention. If the pH and solid content of the first slurry are too high or too low, the slurry cannot be effectively ejected or formed. As shown in FIG. 1 , the first slurry can be coarsely sanded before forming the microspheres. Coarse sand grinding is to crush the large particles returned by the subsequent sections (such as sieving after microsphere forming and sintering), and mix the powder obtained by crushing the large particles with the first slurry. Coarse sanding can be done with a sander. After the microspheres are formed, the particles can be sieved to obtain particles that meet the requirements of a certain particle size range. The unsatisfactory particles (such as large particles) left by the screening can be returned to the coarse sand grinding section. For example, in some embodiments, after the microspheres are formed, they are sieved, and particles with a particle size of 20-300 μm are screened to enter the subsequent process (such as a multi-stage counter-current swirl preheating section), and other particles that do not meet the particle size range are returned to the next process. Go to the coarse sand grinding section, and then mix with the first slurry. It can be sieved by using a sieving machine, or can be sieved by preheating in a multi-stage countercurrent swirl. Microsphere formation can be performed using the microsphere formation apparatus of the present invention. The microsphere molding device of the present invention is a specially designed gas-solid contact device. The gas (such as hot air, hot oxygen) in the subsequent process (such as the multi-stage counter-current swirl preheating section) can be passed into the microsphere forming device to realize multiple utilization of energy. The specially designed symmetrical ring-nuclear gas distribution device can realize the uniform distribution of gas, and then realize the narrow particle size distribution. The first slurry can be dispersed into a uniform gas (eg hot air, hot oxygen) using a specially designed reverse Laval nozzle. As shown in Figure 2, in some embodiments, the microsphere forming device of the present invention includes: a microsphere forming tower body 26, a symmetrical ring-nuclear gas distribution device 20, at least one slurry input mechanism 25, a microsphere forming tower Bottom cone 29, gas outlet mechanism 27 and solid particle outlet 28. Wherein, the microsphere forming tower body 26 is cylindrical, and is a place where the first slurry contacts with the gas. The symmetrical ring-nuclear gas distribution device 20 is located above the microsphere forming tower body 26 and is used to provide evenly distributed gas to the microsphere forming tower body 26 . The symmetrical ring-nuclear gas distribution device 20 includes at least two gas inlet pipes 21 . The at least two intake pipes 21 are preferably arranged symmetrically and tangentially on the side wall of the symmetrical ring-nuclear gas distribution device 20 . The lower part of the symmetrical ring-nuclear gas distribution device 20 is provided with a pre-distributor 24 for distributing the gas entering the microsphere forming tower cylinder 26 . The bottom of the symmetrical ring-nuclear gas distribution device 20 has an opening communicating with the top of the microsphere forming tower body 26 . The slurry input mechanism 25 includes a spray pipe with a nozzle protruding into the microsphere forming tower body 26 for providing the first slurry to the microsphere forming tower body 26 . When the number of slurry input mechanisms 25 is more than one, each slurry input mechanism 25 is preferably symmetrically distributed on the microsphere forming tower body 26 . The height (d1) of the nozzle of the slurry input mechanism 25 from the symmetrical ring-nuclear gas distribution device 20 is preferably 1/50~1/25 of the diameter (d2) of the microsphere forming tower cylinder body 26, such as 1/45, 1/25 40, 1/35, 1/30. This can prevent the slurry from sticking to the bottom of the symmetrical ring-core gas distribution device 20 after being disturbed by the gas flow. The bottom cone 29 of the microsphere forming tower is in the shape of an inverted cone. The top of the microsphere forming tower bottom cone 29 communicates with the bottom of the microsphere forming tower cylinder body 26 . The cone angle of the microsphere forming tower bottom cone 29 is preferably 15 degrees to 50 degrees, such as 20 degrees, 25 degrees, 30 degrees, 35 degrees, 40 degrees, 45 degrees. This facilitates the collection of microsphere particles obtained by spraying. The cone angle of the microsphere forming tower bottom cone 29 can be designed according to the particle accumulation angle obtained from the experimental results of the microsphere particle friction angle. The solid particle outlet 28 is located at the bottom of the bottom cone 29 of the microsphere forming tower, which can be a circular pipe or a rectangular pipe, and is used to discharge the microspheres out of the microsphere forming device. The gas outlet mechanism 27 includes a gas outlet arranged on the side of the bottom cone 29 of the microsphere forming tower, which is used to discharge the gas out of the microsphere forming device. The gas outlet may be a pipe. In some embodiments, the gas outlet mechanism includes a gas outlet pipe extending into the microsphere forming tower through the side of the bottom cone of the microsphere forming tower. The gas outlet pipe can be a circular pipe or a rectangular pipe. In some embodiments, the opening of the gas outlet pipe in the bottom cone of the microsphere forming tower is upward, and the gas outlet mechanism further includes a microsphere barrier arranged around the opening of the gas outlet pipe in the bottom cone of the microsphere forming tower structure to prevent microspheres from entering the gas outlet tube. The microsphere barrier structure can comprise the microsphere barrier structure cone that is arranged on the opening of the gas outlet pipe in the bottom cone of the microsphere forming tower, the apex of the microsphere barrier structure cone faces upward, and the microsphere barrier structure cone The bottom is connected with the bottom cone of the microsphere forming tower, so that the gas can enter the gas outlet pipe but the microspheres will not fall into the gas outlet pipe. The microsphere barrier structure can also include the microsphere barrier structure column arranged around the opening of the gas outlet pipe in the bottom cone of the microsphere forming tower, the top of the microsphere barrier structure column and the microsphere barrier structure cone The bottom of the column of the microsphere blocking structure communicates with the bottom cone of the microsphere forming tower to better ensure that the microspheres will not fall into the gas outlet pipe. The cone angle of the microsphere blocking structure cone can be designed according to the particle accumulation angle obtained from the experimental results of the microsphere particle friction angle. As shown in Figure 3, the symmetric ring-nuclear gas distribution device in the microsphere forming device of the present invention is specially designed, including at least two inlet pipes 31, an annular gas pre-distribution chamber 32, an outlet pipe 33 and at least one pre-distribution chamber. Distributor 34. Wherein, the annular gas pre-distribution chamber 32 is in the shape of a conical cone. The pre-distributor 34 is located below the symmetrical ring-nuclear gas distribution device. The pre-distributor 34 communicates with the annular gas pre-distribution chamber 32 through the outlet pipe 33 provided in the annular gas pre-distribution chamber 32 . The at least two intake pipes 31 are symmetrically and tangentially distributed on the side wall of the annular gas pre-distribution chamber 32 . The outlet pipe 33 is at least one vertical pipe, located in the center of the annular gas pre-distribution chamber 32 , so that the annular gas pre-distribution chamber 32 communicates with the pre-distributor 34 . The gas intake pipe 31 , the annular gas pre-distribution chamber 32 and the outlet pipe 33 form a gas turnback structure, so that the gas turns back in the annular gas predistribution chamber 32 . In some embodiments, there is one outlet pipe 33 . In some embodiments, the distance (d3) between the upper end opening of the outlet pipe 33 and the top of the annular gas pre-distribution chamber 32 is smaller than the distance (d4) between the upper edge of the inlet pipe 31 and the top of the annular gas pre-distribution chamber 32 ), so that the gas turns back and leaves the annular gas pre-distribution chamber 32 through the outlet pipe 33. Multiple predistributors 34 may be connected in series. The predistributor 34 may be a known gas distributor suitable for gas-solid fluidized beds. The above-mentioned design of the symmetrical ring-nuclear gas distribution device is conducive to the uniform distribution of gases (such as hot air, hot oxygen) in the tower, thereby helping to achieve a narrow particle size distribution of particles. In some embodiments, as shown in FIG. 4 , the nozzle of the slurry input mechanism of the microsphere forming device is designed based on a reverse Laval nozzle and a rotating jet. The lance includes a nozzle 41 and a lance duct 42 . The ratio of the diameter (d5) of the nozzle pipe 42 to the diameter (d6) of the nozzle 41 is preferably 1:1˜1:4. Preferably, the opening angle (∠α) of the nozzle 41 is 15°-60°, so as to effectively atomize and disperse the slurry. The nozzle 41 can adopt the combination of central hot gas injection annulus rotating slurry jet or the central slurry jet annulus hot gas swirling injection protection combination. By adjusting the line speed of the input mechanism and the pressure drop between the bottom and the top (the pressure drop before and after passing through the nozzle), it is ensured that the particles are not worn and the sprayed material is uniform. When using the microsphere forming device of the present invention to form microspheres, the high-temperature gas enters the symmetrical ring-nuclear gas distribution device symmetrically through the tangential inlet pipe 31, and the swirl flows from the outlet pipe 33 along the axial direction after turning back from bottom to top. Leaving the annular gas pre-distribution chamber 32, contacting the slurry from the slurry input mechanism after passing through the pre-distributor 34; completing the microsphere forming process in the microsphere forming tower cylinder; the gas and precursor forming particles are separated from the microsphere forming tower The gas outlet mechanism of the bottom cone and the solid particle outlet are discharged. The operating conditions for microsphere molding can be: operating temperature 50~500°C, preferably 75~300°C, such as 100°C, 150°C, 200°C, 250°C, 275°C; operating pressure 0.5~5bar, such as 1bar, 2bar, 3bar, 4bar, 4.5bar; operating solid-gas ratio is 0.001~10kg/kg, such as 0.01kg/kg, 0.05kg/kg, 0.1kg/kg, 0.5kg/kg, 1kg/kg, 2kg/kg, 3kg/kg , 4kg/kg, 5kg/kg, 6kg/kg, 7kg/kg, 8kg/kg, 9kg/kg. In some embodiments, the first slurry used for forming microspheres is the positive electrode material precursor mixed lithium slurry described in the present invention, and the obtained first slurry particles are positive electrode material precursor mixed lithium particles. Preferably, the positive electrode material precursor mixed lithium slurry used as the first slurry is the second positive electrode material precursor mixed lithium slurry described in any embodiment herein. The present invention includes microsphere molding (ie granulation) of the positive electrode material precursor mixed lithium slurry described in the present invention by using the microsphere forming process described in the present invention, and the positive electrode material precursor mixed lithium particles obtained thereby. Optionally, the positive electrode material precursor mixed lithium slurry can be pretreated before microsphere molding, for example, the positive electrode material precursor mixed lithium slurry of the present invention is mixed with other positive electrode material raw materials or semi-finished products, and the slurry is processed. Sieving, coarse sanding, drying, preheating, etc. The positive electrode material precursor mixed lithium particles (abbreviated as precursor mixed lithium particles) of the present invention include positive electrode material precursor particles, lithium salt, water and inorganic nanoparticles, and the surface of the positive electrode material precursor particle is coated with lithium salt. In some embodiments, in the precursor-mixed lithium particles, the cathode material precursor particles are permeated with lithium salts. The infiltrated or coated lithium salt is in the form of nanoparticles. In the cathode material precursor mixed lithium particles of the present invention, the precursor and the lithium salt are combined in a dense manner, thereby improving the mass transfer reaction of the lithium salt in the precursor, reducing porosity, and improving heat conduction efficiency. In the positive electrode material precursor of the present invention, the following features can be as described in any embodiment of the aforementioned positive electrode material precursor mixed with lithium slurry of the present invention: the type, particle size, shape, and structure of the positive electrode material precursor, lithium salt The type, particle size, shape, the ratio of cathode material precursor and lithium, the ratio of cathode material precursor and inorganic nanoparticles. The cathode material precursor mixed lithium particles of the present invention may contain a small amount of water, preferably no more than 10wt%, such as 0.5wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%. The D50 particle size of the positive electrode material precursor mixed lithium particles is preferably 100-500 μm, such as 200 μm, 210 μm, 230 μm, 240 μm, 250 μm, 300 μm, 350 μm, 400 μm, and the angle of repose is preferably 30-60°, such as 35°, 38°, 40°, 45°, 50°, 55°. This facilitates subsequent sintering. Multi-stage counter-current swirl preheating The pretreatment step of the positive electrode material preparation method of the present invention may include multi-stage counter-current swirl preheating. In the present invention, multi-stage countercurrent swirling preheating is to heat the positive electrode material raw material particles, positive electrode material semi-finished particles or first slurry particles (which can be regarded as preheating before fluidized bed sintering and/or coating), and at the same time Particle size is screened. The multi-stage counter-current cyclone preheating realizes the dilute phase gas-solid multi-stage counter-current cyclone contact and realizes the screening of solid particles. As shown in FIG. 1 , in some embodiments, the present invention directly performs multi-stage countercurrent cyclone preheating on the particles obtained through microsphere molding. It is also possible to sieve the particles obtained by forming microspheres first, and then perform multi-stage countercurrent swirl preheating. The heat source for heating in multi-stage counter-current swirl preheating can be high-temperature gas (such as hot air, hot oxygen) in subsequent processes (such as fluidized bed sintering and/or cladding), so as to achieve better preheating. The unsatisfactory particles (such as small particles) remaining after multi-stage countercurrent cyclone preheating and screening can be transported back to the previous process (such as coarse sand grinding). The multistage countercurrent cyclone preheating device of the present invention can be used for multistage countercurrent cyclone preheating. As shown in Fig. 5, the multi-stage counter-current cyclone preheating device of the present invention includes at least two stages of cyclones and pipes connecting the cyclones. Wherein, the at least two-stage cyclones (such as two-stage, three-stage, four-stage, five-stage, six-stage, seven-stage, eight-stage, nine-stage, ten-stage or more than ten-stage cyclones) are connected in series up and down, It is preferred to connect up and down in series in the form of a ladder connection. The first-stage cyclone in the at least two-stage cyclone (that is, the cyclone located at the bottom of the multi-stage counter-current cyclone preheating device) is used to receive high-temperature gas, such as from fluidized bed sintering and/or cladding The hot air and hot oxygen in the covering section, and part of the high-temperature gas are sent to the upper-stage cyclone (second-stage cyclone). The highest-level cyclone in the at least two-stage cyclone (that is, the cyclone at the top of the multi-stage counter-current cyclone preheating device) is used to receive particles, such as particles transported from the microsphere forming section, and Part of the particles are sent to the next stage cyclone. Each cyclone between the first-stage cyclone and the highest-stage cyclone is used to receive the particles delivered by the upper-stage cyclone and the gas delivered by the next-stage cyclone, and deliver part of the gas to the upper-stage cyclone The device transports part of the particles to the next stage cyclone. The cyclone regulates the gas reactant to carry the solid particles existing inside itself to generate vortex, and realizes the separation after gas-solid heat exchange based on the difference in centrifugal force between gas and solid particles and simultaneously realizes the screening of the particle size distribution of solid particles. The multi-stage counter-current cyclone preheating device of the present invention may also include a screening program. The screening program can be connected with the top-level cyclone to filter the gas discharged from the top-level cyclone. As shown in Figure 6, in some embodiments, the cyclone is a specially designed centrifugal gas-solid separation device, including: a cyclone inlet 61, a main body cylinder 62, a gas outlet 63, a swirl vane 64 and particles Exit 65. The cyclone inlet 61 is arranged on the top of the main cylinder 62 for gas and particles to enter into the cyclone. The gas outlet 63 is arranged on the side wall of the main cylinder 62 for gas to leave the cyclone. The gas outlet 63 may be tubular. The number of gas outlets 63 may be two or more, preferably symmetrically and tangentially distributed on the side wall of the main cylinder 62 . The swirl blades 64 are disposed inside the main cylinder 62 for generating swirl. The particle outlet 65 is arranged at the bottom of the main cylinder 62 for the particles to leave the cyclone. The cyclone uses the generated centrifugal force to throw the adsorbent present inside to the side wall of the main cylinder 62, so that the particles present inside can enter through the bottom particle outlet 65 and the connecting pipeline under the action of gravity. The next-stage cyclone; the gas after heat exchange enters the corresponding upper-stage cyclone through the gas outlet 63 . When multi-stage cyclones are connected in series up and down in the form of trapezoidal connection, the cyclone inlet of each stage of cyclone is connected to the gas outlet of the next stage of cyclone through pipelines, and the particle outlet of each stage of cyclone is connected to the gas outlet of the next stage of cyclone. The cyclone inlet of the device is connected by a pipeline. . For example, as shown in Figure 5, when the three-stage cyclone is connected in series up and down in the form of trapezoidal connection, the cyclone inlet of the third-stage cyclone is connected with the gas outlet of the second-stage cyclone through a pipeline, and the third-stage cyclone The particle outlet of the first-stage cyclone is connected with the cyclone inlet of the second-stage cyclone through a pipeline, and the cyclone inlet of the second-stage cyclone is connected with the gas outlet of the first-stage cyclone through a pipeline. The particle outlet of the first-stage cyclone is connected with the cyclone inlet of the first-stage cyclone through a pipeline. The particle size control of solid particles can be realized by adjusting the ratio of the diameter of the gas outlet (d7) to the diameter of the main body of the cyclone (d8). In the present invention, the ratio of the diameter of the gas outlet to the diameter of the main body of the cyclone is preferably 0.25 to 0.75, such as 0.3, 0.4, 0.5, 0.6, and 0.7. The range of the ratio can control the particle size of the collected solid particles. In the range of 25~350μm, the fluidization quality of particles in this particle size range is the best. In one embodiment, the collected solid particles have a particle size of 50 μm, 75 μm, 100 μm, 125 μm, 150 μm, 175 μm, 200 μm, 225 μm, 250 μm, 275 μm, 300 μm, 325 μm. Herein, unless otherwise specified, the particle size is the median particle size. The median particle size of the particles can be determined using microscopy. The operating temperature of the multi-stage counter-current cyclone preheating can be 500-1200°C, such as 600°C, 700°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1100°C. Fluidized bed sintering and optional further coating Fluidized bed sintering and optional further coating is to enter the pretreated particles into a fluidized bed reactor for sintering and optional further coating. As shown in FIG. 1 , in some embodiments, the present invention provides particles obtained from multi-stage countercurrent cyclone preheating to a fluidized bed reactor for sintering and optional further coating. In other embodiments, the present invention provides the positive electrode material precursor mixed lithium particles obtained by microsphere molding directly to the fluidized bed reactor for sintering and optional further coating, or the positive electrode material precursor obtained by microsphere molding The bulk-mixed lithium particles are preheated by multi-stage counter-current cyclone before being supplied to the fluidized bed reactor for sintering and optional further coating. Fluidized bed sintering and/or cladding is preferably multistage fluidized bed sintering and optional further cladding. Multi-stage fluidized bed sintering and optional further cladding can be carried out using the fluidized bed reactor of the present invention. The fluidized bed reactor of the present invention is a multi-stage dense-phase gas-solid contact device, which can realize multi-reaction condition control in a single device to complete multiple functions such as sintering and cladding. As shown in Figure 7, the fluidized bed reactor of the present invention includes a fluidized bed reactor body 101, at least one perforated plate or umbrella baffle 102, an overflow pipe 103, a particle input mechanism 104, a fluid inlet 106, an optional The fluid distributor 105 and the optional cladding material input mechanism (not shown in FIG. 7 ). Wherein, the porous plate or umbrella-shaped baffle 102 is arranged on the bed height in the fluidized bed reactor body 101, and each porous plate or umbrella-shaped baffle 102 divides the interior of the fluidized bed reactor body 101 into upper and lower adjacent two-stage bed. At least two overflow pipes 103 with different overflow heights are arranged between every two adjacent beds, and are used to transfer the particles in the upper bed of the two adjacent beds to the lower section of the two adjacent beds Bed layer, to avoid particles from entering the lower bed layer due to large gas volume. The particle input mechanism 104 is arranged on the side wall of the fluidized bed reactor body 101 corresponding to the uppermost bed layer, and is used for inputting particle materials into the fluidized bed reactor. The fluid inlet 106 is arranged at the bottom of the fluidized bed reactor body 101 for gas to enter the fluidized bed reactor. Different temperature control can be achieved in each section of the bed to achieve sintering and/or cladding respectively. The residence time in each section of the bed can be adjusted through the operating conditions and the structural parameters of the perforated plate or umbrella-shaped baffle. Optionally or preferably, a fluid distributor 105 is disposed at the bottom of the fluidized bed reactor body for distributing the gas entering the fluidized bed reactor body 101 through the fluid inlet 106 . The fluid distributor may be a known gas distributor suitable for gas-solid fluidized beds. The present invention improves coating uniformity through the above-mentioned optimized fluidized bed reactor component connection relationship and further preferably adopting a fluid distributor. In some embodiments, the particle input mechanism 104 includes a loosely open particle delivery conduit and a side-slotted particle distribution cylinder to avoid particle clogging in the particle input mechanism. In some embodiments, the cladding material input mechanism includes a nozzle, which is preferably designed based on a reverse Laval nozzle and a rotating jet. The nozzle includes nozzles and nozzle pipes. The diameter ratio of the nozzle pipe to the nozzle is preferably 1:1~1:4. Preferably, the opening angle of the nozzle is 15°-60° to effectively atomize and disperse the slurry. The nozzle can adopt the combination of central hot gas injection annulus rotating slurry jet or the central slurry jet annulus hot gas swirling injection protection combination. By adjusting the line speed of the input mechanism and the pressure drop between the bottom and the top to ensure that the particles are not worn and the sprayed material is uniform. The invention improves the coating uniformity through the structural design of the optimized coating material input mechanism. Post-processing In the present invention, post-processing is optionally performed. The post-treatment is mainly to control the fineness distribution of the material obtained by fluidized bed sintering and/or coating (such as microspherical positive electrode material) within the required range. The material obtained by fluidized bed sintering and/or cladding may be subjected to one or more post-treatments selected from the following: fine sand grinding, screening and packaging. By adopting the method of the present invention, positive electrode materials with grain sizes ranging from 1000 to 5000 nm can be prepared. The grain size range of the positive electrode material can be controlled within a narrow range such as 1500-5000nm, 1000-2500nm, 1300-2300nm, 1500-2500nm, 1500-2000nm, and the particle size is consistent Good properties, there is no or almost no crystal grains with a particle size of less than 100nm. In some embodiments, the positive electrode material is free or substantially free of crystal grains with a particle size of less than 500 nm. Herein, when the positive electrode material particles are secondary particles composed of primary particles, the grain size refers to the particle size of the primary particles constituting the secondary particles. At the same time, the positive electrode material has good consistency in chemical composition, tap density, specific surface area and other qualities, and has improved initial discharge capacity and first Coulombic efficiency. In the existing dynamic sintering process, it is difficult to ensure sufficient flow of the positive electrode powder material, and local or even global bonding loss is prone to occur. In order to obtain excellent and stable flow and mixing effects, the present invention has undergone a large number of experiments to obtain the range of particle size and density, and proposes a new positive electrode material preparation method, device and system including one or more of the following designs: In pretreatment, it can be Perform microsphere molding on the first slurry to obtain particles with larger particle sizes and better fluidity, which reduces the additional steps of preparing precursor particles, and can precisely control the particle size of the powder without using a binder; use The microsphere molding device of the present invention can improve the uniformity of heating, realize the narrow particle size distribution of the particles, and utilize the countercurrent heat exchange between the hot gas and the cold powder at the same time, which increases the energy utilization rate and reduces the cost; The slurry input mechanism designed by the nozzle and the rotating jet can ensure that the particles are not worn and the material is sprayed evenly; The particles obtained by molding) are preheated by multi-stage counter-current swirling, so that the size of the particles is suitable for fluidized bed sintering, and at the same time, the preheating of the particles is realized, and the multi-stage counter-current swirling heat exchange between hot gas and cold powder is used to increase the energy. Utilization rate reduces cost; In fluidized bed sintering and/or cladding, using the fluidized bed reactor of the present invention can achieve stable and excellent flow and mixing, shorten sintering time consumption, improve heating uniformity, and improve heating uniformity during sintering Part of the coating can be introduced inside the fluidized bed, and further use of the coating material input mechanism based on the anti-Laval nozzle and rotating jet design can ensure that the particles are not worn and the spray material is uniform, and the coating uniformity is improved. The present invention can achieve the following beneficial technical effects: the present invention provides a low-carbon process technology for preparing positive electrode materials, and realizes the comprehensive utilization of heat energy. The hot air/oxygen in the subsequent process realizes the cyclic utilization of oxygen/air; the fluidized bed reactor provided by the invention realizes the dynamic uniform sintering and rapid sintering of the positive electrode material; the present invention provides an efficient positive electrode material preparation method, Short time consumption, can effectively reduce the probability of impurity contamination, high process integration, energy and materials can be effectively recycled, high mass transfer/heat transfer consistency, so that the product has excellent consistency and coating uniformity; The invention can use undried or reduced-dried positive electrode material precursors for pretreatment and subsequent sintering, which reduces the drying process of positive electrode material precursors and saves costs; the invention is easy to scale up. The present invention will be described below in the form of specific examples. It should be understood that these examples are illustrative only and do not limit the scope of the present invention. For the reagents, methods, conditions, etc. used herein and in the examples, unless otherwise stated, they are conventional reagents, methods and conditions. For the experimental methods without specific conditions indicated in the following examples, the conventional conditions or the conditions suggested by the manufacturer are usually followed. Equipment example 1: Microsphere forming device As shown in Figure 2, the microsphere forming device of this equipment example includes: microsphere forming tower cylinder body 26, symmetrical ring-nuclear gas distribution device 20, slurry input mechanism 25, microsphere forming Tower bottom cone 29, gas outlet mechanism 27 and solid particle outlet 28. The microsphere forming tower body 26 is cylindrical and is the place where the first slurry contacts with the gas. The symmetrical ring-nuclear gas distribution device 20 is located above the microsphere forming tower body 26 and is used to provide evenly distributed gas to the microsphere forming tower body 26 . Two intake pipes 21 are arranged symmetrically and tangentially on the side wall of the symmetrical ring-nuclear gas distribution device 20 . The lower part of the symmetrical ring-nuclear gas distribution device 20 is provided with a pre-distributor 24 . The bottom of the symmetrical ring-nuclear gas distribution device 20 has an opening communicating with the top of the microsphere forming tower body 26 . The slurry input mechanism 25 includes a spray pipe with a nozzle protruding into the microsphere forming tower body 26 for providing the first slurry to the microsphere forming tower body 26 . The number of slurry input mechanism 25 is one. The height (d1) of the nozzle of the slurry input mechanism 25 from the symmetrical ring-nuclear gas distribution device 20 is 1/30 of the diameter (d2) of the microsphere forming tower cylinder body 26. The bottom cone 29 of the microsphere forming tower is in the shape of an inverted cone. The top of the microsphere forming tower bottom cone 29 communicates with the bottom of the microsphere forming tower cylinder body 26 . The cone angle of the microsphere forming tower bottom cone 29 is 30 degrees. The solid particle outlet 28 is located at the bottom of the bottom cone 29 of the microsphere forming tower, and is a circular pipe for discharging the microspheres from the microsphere forming device. The gas outlet mechanism 27 includes a gas outlet pipe extending into the microsphere forming tower through the side of the bottom cone of the microsphere forming tower. The gas discharge pipe is a circular pipe. The opening of the gas outlet pipe in the bottom cone of the microsphere forming tower is upward, and the gas outlet mechanism further includes a microsphere barrier structure arranged around the opening of the gas outlet pipe in the bottom cone of the microsphere forming tower. The microsphere barrier structure includes a microsphere barrier structure cone arranged above the opening of the gas outlet pipe in the bottom cone of the microsphere forming tower, the apex of the microsphere barrier structure cone faces upward, and the bottom of the microsphere barrier structure cone It communicates with the bottom cone of the microsphere forming tower, so that the gas can enter the gas outlet pipe but the microspheres will not fall into the gas outlet pipe. The microsphere barrier structure also includes a microsphere barrier structure cylinder arranged around the opening of the gas outlet pipe in the bottom cone of the microsphere forming tower, the top of the microsphere barrier structure cylinder communicates with the microsphere barrier structure cone, and the microsphere barrier structure The bottom of the column body of the ball blocking structure communicates with the bottom cone of the microsphere forming tower. As shown in FIG. 3 , the symmetrical ring-nuclear gas distribution device in the microsphere molding device of this equipment example includes two inlet pipes 31 , an annular gas pre-distribution chamber 32 , an outlet pipe 33 and a pre-distributor 34 . The annular gas pre-distribution chamber 32 is in the shape of a conical cone. The predistributor 34 is located below the annular gas predistribution chamber 32 . The pre-distributor 34 communicates with the annular gas pre-distribution chamber 32 through the outlet pipe 33 arranged in the annular gas pre-distribution chamber 32 . Two intake pipes 31 are symmetrically and tangentially distributed on the side wall of the annular gas pre-distribution chamber 32 . The outlet pipe 33 is a vertical pipe, located in the center of the annular gas pre-distribution chamber 32 , so that the annular gas pre-distribution chamber 32 communicates with the pre-distributor 34 . The distance (d3) between the upper opening of the outlet pipe 33 and the top of the annular gas pre-distribution chamber 32 is smaller than the distance (d4) between the upper edge of the inlet pipe 31 and the top of the annular gas pre-distribution chamber 32 . The nozzle of the slurry input mechanism in the microsphere forming device of this equipment example is designed based on the anti-Laval nozzle and the rotating jet. The ratio of the diameter (d5) of the nozzle pipe to the diameter (d6) of the nozzle is 1:2, the opening angle of the nozzle is 25°, and the nozzle adopts the combination of central hot gas injection annular space rotating slurry jet. Equipment example 2: Multi-stage counter-current cyclone preheating device As shown in Figure 5, the multi-stage counter-current cyclone pre-heating device in this equipment example includes three-stage cyclones, pipelines connecting each cyclone, screening programs, and Pipes connecting the tertiary cyclone and the screening program. The three-stage cyclone is connected in series up and down in the form of trapezoidal connection. The first-stage cyclone (that is, the cyclone at the bottom of the multi-stage counter-current cyclone preheating device) is used to receive high-temperature gas and deliver part of the high-temperature gas to the upper-stage cyclone (second-stage cyclone). The third-stage cyclone (that is, the cyclone at the top of the multi-stage counter-current cyclone preheating device) is used to receive the raw material particles of the positive electrode material, the semi-finished particles of the positive electrode material or the first slurry particles, and transport part of the particles to the next step. Primary cyclone (secondary cyclone). The second-stage cyclone is used to receive the particles delivered by the upper-stage cyclone (third-stage cyclone) and the gas delivered by the next-stage cyclone (second-stage cyclone), and deliver part of the gas to the upper stage Cyclone, transport part of the particles to the next stage cyclone. The cyclone inlet of the third-stage cyclone is connected to the gas outlet of the second-stage cyclone through a pipeline, and the particle outlet of the third-stage cyclone is connected to the cyclone inlet of the second-stage cyclone through a pipeline. The cyclone inlet of the second-stage cyclone is connected with the gas outlet of the first-stage cyclone through a pipe, and the particle outlet of the second-stage cyclone is connected with the cyclone inlet of the first-stage cyclone through a pipe. The gas outlet of the third-stage cyclone is connected to the screening program through a pipeline. As shown in Figure 6, the cyclone in the multi-stage countercurrent cyclone preheating device of this equipment example is a centrifugal gas-solid separation device, including: cyclone inlet 61, main cylinder 62, gas outlet 63, cyclone vane 64 and particle outlet 65 . The cyclone inlet 61 is arranged at the top of the main cylinder 62 for gas and particles to enter the cyclone. A gas outlet 63 is provided on the side wall of the body cylinder 62 for gas to leave the cyclone. The swirl blades 64 are disposed inside the main cylinder 62 for generating swirl. A particle outlet 65 is located at the bottom of the body barrel 62 for particles to exit the cyclone. The ratio of the diameter (d7) of the gas outlet 63 to the diameter (d8) of the main cylinder 62 is 0.5. Equipment Example 3: Fluidized bed reactor As shown in Figure 7, the fluidized bed reactor of this equipment example includes a fluidized bed reactor body 101, two perforated plates 102, an overflow pipe 103, a particle input mechanism 104, a fluid Inlet 106 and fluid distributor 105 . The porous plate 102 is arranged at the height of the bed in the fluidized bed reactor body 101 , and the two porous plates 102 divide the interior of the fluidized bed reactor body 101 into three adjacent bed layers up and down. Four overflow pipes 103 with different overflow heights are arranged between the uppermost bed and the middle bed. Three overflow pipes 103 with different overflow heights are arranged between the middle bed and the lowermost bed. The particle input mechanism 104 is arranged on the side wall of the fluidized bed reactor body 101 corresponding to the uppermost bed. The fluid inlet 106 is arranged at the bottom of the fluidized bed reactor body 101 for gas to enter the fluidized bed reactor. Different temperature control can be achieved in each section of the bed to achieve sintering and/or cladding respectively. The fluid distributor 105 is arranged at the bottom of the fluidized bed reactor body 101 for distributing the gas entering the fluidized bed reactor body 101 through the fluid inlet 106 . The particle input mechanism 104 includes a particle conveying pipe with a loose opening and a particle distribution cylinder with side slots, so as to avoid blockage of the particles in the particle input mechanism. The nozzle of the coating material input mechanism in the fluidized bed reactor of this equipment example is designed based on the anti-Laval nozzle and the rotating jet. The ratio of the diameter of the nozzle pipe to the nozzle is 1:2, and the nozzle adopts central hot gas injection Annulus rotating slurry jet combination. Example 1 According to the process shown in Figure 1, Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 slurry was mixed with pulverized LiOH to form the first slurry, the solid content of the first slurry was controlled to 45wt%, and the pH With a control of 8.5, the appearance of this slurry is shown in Figure 8 (left). The first slurry is mixed with the unqualified small particles screened by the subsequent multi-stage counter-current cyclone preheating device, and after coarse grinding, it enters the microsphere forming device of Equipment Example 1. The operating temperature is 250 °C, the operating pressure is 1 bar, solid gas The ratio is 5kg/kg, forming particles with a median particle size of 100 μm. The particles have good fluidity (the contact angle is about 40 o ), and their fluidization curves are shown in Figure 9. There is a bulge between the two curves from large to small speeds, indicating that the particles can be effectively fluidized; the particles are preheated to 900°C in the multi-stage counter-current cyclone preheating device of Equipment Example 2, and the median particle size of the screened particles is The diameter is 125 μm; then enter the fluidized bed reactor of equipment example 3 for sintering, the fluidized state in the fluidized bed is good, and the gas-solid contact is uniform; the final product is obtained through the post-processing section, and the following tests are carried out. The results are as follows: (1) Product composition consistency: measured by inductively coupled plasma spectrometer (ICP), 5 different areas were selected for measurement, the variance of Ni quality fraction was 1.0%, the variance of Co quality fraction was 2.5%, the variance of Mn quality fraction was 2%, and the variance of Li quality fraction The variance is 1.5%; (2) Consistency of product particle size: measured by scanning electron microscope (SEM), 10 different areas are selected for measurement, the primary particle grains that make up the secondary particles are distributed in a narrow area of 1500~5000nm, The SEM photo of one of the areas is shown in Figure 10; (3) tap density: select 5 different areas for measurement, and the variance is 13%; (4) specific surface area: use a physical adsorption instrument to measure, select 5 different areas for measurement Measurement, the variance is 1.8%; (5) Button electricity (4.3V/0.1C): Mix the positive electrode material obtained by sintering, the conductive agent SP and the binder PVDF at a mass ratio of 95:2.5:2.5, and then add it to NMP , to prepare the positive electrode slurry, coat the positive electrode slurry on the aluminum foil, dry, and roll to obtain the positive electrode sheet with a loading capacity of 12 mg/cm 2 , using Zhuhai Saiwei SWSD006 electrolyte and Kejing 16 μm separator, assembled into The button battery was charged and discharged at 0.1C at 25°C to test the initial discharge capacity and first coulombic efficiency. The results showed that the initial discharge capacity was 210mAh/g, and the first coulombic efficiency was 89%. Example 2 According to the process shown in Figure 1, Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 slurry was mixed with pulverized LiOH to form the first slurry, the solid content of the first slurry was controlled at 45wt%, and the pH Control is 8.5. The first slurry is mixed with the unqualified particles screened by the subsequent multi-stage counter-current cyclone preheating device, and after coarse grinding, it enters the microsphere forming device of Equipment Example 1. The operating temperature is 250 °C, the operating pressure is 1 bar, and the solid-gas ratio 5kg/kg, forming a particle with a median particle size of 100 μm, the particle has good fluidity (contact angle is about 40 ° ); the particle is preheated to 900° C. , the median particle size of the screened particles is 125 μm; then enter the fluidized bed reactor of the equipment example 3 equipped with a coating material input mechanism for sintering and coating, the coating material is aluminum sol, and the coating material is preheated After reaching 150°C, it is sprayed into the fluidized bed through the coating material input mechanism; the fluidized state in the fluidized bed is good, and the gas-solid contact is uniform; the coated and modified positive electrode material is obtained through the post-processing section, and the following tests are carried out. The results As follows: (1) Consistency of product composition: measured by inductively coupled plasma spectrometer (ICP), 5 different areas were selected for measurement, the variance of Ni mass fraction was 1.0%, the variance of Co mass fraction was 2.5%, and the variance of Mn mass fraction was 2 %, the variance of Li mass fraction is 1.5%, and the variance of Al mass fraction is 1.25%; (2) Consistency of product particle size: measured by scanning electron microscope (SEM), 10 different areas are selected for measurement, and the primary Particles and grains are distributed in a narrow area of 1500~5000nm; (3) Tap density: 5 different areas are selected for measurement, and the variance is 13%; (4) Specific surface area: Measured using a physical adsorption instrument, 5 different areas are selected Measured, the variance is 1.8%; (5) button charge (4.3V/0.1C): the test method is the same as in Example 1, the initial discharge capacity is 210mAh/g, and the first coulombic efficiency is 89%. Example 3 2mol/L metal salt solution (molar ratio Ni:Co:Mn=5:2:3), 5mol/L liquid alkali and 5mol/L ammonia water were pumped into the reaction through 3 feed pipes production in the kettle; control the pH of the reaction kettle to 11, and the reaction temperature to 55°C, the obtained precursor overflows to the aging tank, the aging time is 4h, and then centrifuged to obtain the hydroxide precursor of 523 nickel cobalt manganese, the The precursor is a secondary spherical powder with a D50 of 10-11 μm formed by agglomerating flake nanoparticles of 150nm-200nm. The molar ratio of the sum of lithium atoms and (Ni+Co+Mn) atoms is 1.03:1.00. Weigh 4.3kg monohydrate lithium hydroxide (D50 irregular powder around 7 μm) and 2.5kg deionized water, and disperse at high speed to form lithium hydroxide slurry; 10.1kg 523 nickel cobalt manganese hydroxide precursor ( The dry matter mass fraction is 90%) into the kneader, start stirring, add the lithium hydroxide slurry into the kneader, stir evenly to obtain the first precursor mixed lithium slurry, and use a viscometer (No. 4 rotor ) measured an apparent viscosity of about 3000cps, and observed under an electron microscope, lithium salt particles were uniformly coated on the surface of the precursor. According to the process shown in Figure 1, the first precursor mixed with lithium slurry is used as the first slurry, and the first slurry is mixed with the unqualified small particles screened by the subsequent multi-stage countercurrent swirling preheating device after coarse grinding, Enter the microsphere forming device of equipment example 1, the operating temperature is 250 ° C, the operating pressure is 1 bar, and the solid-gas ratio is 5 kg/kg to form particles, which have good fluidity; make the particles enter the multistage countercurrent cyclone of equipment example 2 The flow preheating device is preheated to 900 ° C, and the median particle size of the screened particles is about 125 μm; then enters the fluidized bed reactor of Equipment Example 3 for sintering, the fluidized state in the fluidized bed is good, and the gas-solid contact is uniform; The final product was obtained after the post-processing section, and the following tests were carried out, and the results are as follows: (1) Product composition consistency: measured by inductively coupled plasma spectrometer (ICP), 5 different areas were selected for measurement, the variance of Ni quality fraction was 1.0%, and the variance of Co The variance of quality fraction is 2.5%, the variance of Mn quality fraction is 2%, and the variance of Li quality fraction is 1.5%; (2) Product particle size consistency: use scanning electron microscope (SEM) to measure, select 10 different areas for measurement, composition The primary particle grains of the secondary particles are distributed in a narrow area of 1500~5000nm; (3) Tap density: 5 different areas are selected for measurement, and the variance is 13%; (4) Specific surface area: Measured using a physical adsorption instrument, Five different areas were selected for measurement, and the variance was 1.8%; (5) Charge (4.3V/0.1C): The test method was the same as in Example 1, the initial discharge capacity was 172Ah/g, and the first Coulombic efficiency was 89%. Example 4 2mol/L metal salt solution (molar ratio Ni:Co:Mn=8:1:1), 5mol/L liquid alkali and 5mol/L ammonia water were pumped into the reaction through 3 feeding pipes production in the kettle; the pH of the reaction kettle is controlled to be 11, and the reaction temperature is 55°C, the obtained precursor overflows to the aging tank, the aging time is 5h, and then centrifuged to obtain the hydroxide precursor of 811 nickel cobalt manganese, the The precursor is a secondary spherical powder with a D50 of 3-4 μm formed by agglomerating flake nanoparticles of 150nm-200nm. According to the molar ratio of lithium atoms, the sum of (Ni+Co+Mn) atoms, and aluminum atoms is 1.03:1.00:0.001. Take by weighing 4.3kg lithium hydroxide monohydrate (D50 irregular powder around 7 μm) and 3.0kg deionized water, and disperse at a high speed to form a lithium hydroxide slurry; 10.4kg of the precursor filter cake ( Among them, the dry matter mass fraction is 89%) into the kneader, start stirring, add the lithium hydroxide slurry into the kneader, stir evenly to obtain the first precursor mixed lithium slurry, and use a viscometer (No. 4 rotor ) measured an apparent viscosity of about 3500cps, and observed under an electron microscope, lithium salt particles were uniformly coated on the surface of the precursor. Put the first precursor mixed lithium slurry and 260g aluminum sol (the mass concentration of Al 2 O 3 is 20%) into the kneader, start stirring for 15 minutes, make the mixture body gel, turn off the stirring after 15 minutes , the resulting gelled mixture is the second precursor-mixed lithium slurry. According to the process shown in Figure 1, the second precursor mixed lithium slurry is used as the first slurry, and the first slurry is mixed with the unqualified small particles screened by the subsequent multi-stage counter-current swirling preheating device after coarse grinding, Enter the microsphere forming device of equipment example 1, the operating temperature is 250 ° C, the operating pressure is 1 bar, and the solid-gas ratio is 5 kg/kg to form particles, which have good fluidity; make the particles enter the multistage countercurrent cyclone of equipment example 2 The flow preheating device is preheated to 900 ° C, and the median particle size of the screened particles is about 125 μm; then enters the fluidized bed reactor of Equipment Example 3 for sintering, the fluidized state in the fluidized bed is good, and the gas-solid contact is uniform; The final product was obtained after the post-processing section, and the following tests were carried out, and the results are as follows: (1) Product composition consistency: measured by inductively coupled plasma spectrometer (ICP), 5 different areas were selected for measurement, the variance of Ni quality fraction was 1.0%, and the variance of Co The quality fraction variance is 2.5%, the Mn quality fraction variance is 2%, the Li quality fraction variance is 1.5%, and the Al quality fraction variance is 1.25%; 10 different areas were measured, and the primary particle grains that make up the secondary particles were distributed in a narrow area of 1500-5000nm; (3) Tap density: 5 different areas were selected for measurement, and the variance was 13%; (4) Compared with Surface area: use physical adsorption instrument to measure, select 5 different areas to measure, and the variance is 1.8%; (5) Button electricity (4.3V/0.1C): The test method is the same as that of Example 1, the initial discharge capacity is 210Ah/g, the first time Coulombic efficiency is 89%. Comparative Example 1 According to the process shown in Figure 1, the difference from Example 1 is that microsphere molding is not carried out, that is, Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 slurry is mixed with pulverized LiOH to form the first slurry ( The solid content rate is 45wt%, and the pH value is 8.5) and directly enters the multi-stage countercurrent cyclone preheating device of equipment example 2. At this time, the particle size of the precursor particles is only 3 ~ 10 μm, and the fluidity is poor (the contact angle is about 60° ), it is easy to block the material leg of the cyclone of the multistage countercurrent cyclone preheating device; the particles are preheated to 900 ° C by the multistage countercurrent cyclone preheating device, and enter the fluidized bed reactor of equipment example 3 for sintering , at this time, due to the small windward area of the particles and the excessive van der Waals force between the particles, the fluidized gas at the bottom cannot effectively hold up the particles, the gas-solid contact efficiency is low, and the uneven gas-solid contact will cause local agglomeration and loss of flow; The final product was obtained after the post-processing section, and the following tests were carried out. The results are as follows: (1) Consistency of product composition: using ICP measurement, 5 different areas were selected for measurement, the variance of Ni quality score was 5%, and the variance of Co quality score was 10%. , the variance of Mn mass fraction is 12%, and the variance of Li mass fraction is 10%; (2) Consistency of product particle size: SEM measurement is used, and 10 different areas are selected for measurement. 2000nm wide area distribution; (3) Tap density: 5 different areas were selected for measurement, with a variance of 15%; (4) Specific surface area: measured using a physical adsorption instrument, 5 different areas were selected for measurement, with a variance of 7 %; (5) Button electricity (4.3V/0.1C): The test method is the same as in Example 1, the initial discharge capacity is 197 mAh/g, and the first Coulombic efficiency is 78%. Comparative Example 2 According to the process shown in Figure 1, the difference from Example 1 is that no multi-stage countercurrent swirl preheating is performed, that is, Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 slurry is mixed with pulverized LiOH to form the second One slurry (solid content rate 45wt%, pH value 8.5), enters the microsphere forming device of equipment example 1, operating temperature is 250 ℃, operating pressure is 1bar, solid-gas ratio is 5kg/kg, forms median particle The particles with a diameter of 100 μm have good fluidity (the contact angle is about 40°); the particles obtained by molding the microspheres directly enter the fluidized bed reactor of Equipment Example 3 for sintering. The thermal device cannot carry out effective fine screening, the particle distribution is wide, and the particles are in a low temperature state of 150°C. After entering the fluidized bed, the cold particles are in contact with the high temperature oxygen atmosphere and the sintering rates of particles of different particle sizes are different, resulting in The uniformity of the positive electrode material becomes worse; the final product is obtained through the post-processing section, and the following tests are carried out. The results are as follows: (1) Product composition consistency: ICP measurement is used, and 5 different areas are selected for measurement. The variance of the Ni quality fraction is 5%. The variance of Co mass fraction is 10%, the variance of Mn mass fraction is 12%, and the variance of Li mass fraction is 10%; (2) Product particle size consistency: SEM measurement is used, and 10 different areas are selected for measurement to form the secondary particles. The primary particle grains are distributed in a wide area of 50nm~2000nm; (3) Tap density: select 5 different areas for measurement, and the variance is 15%; (4) Specific surface area: use a physical adsorption instrument to measure, select 5 different The area was measured, and the variance was 7%; (5) Button charging (4.3V/0.1C): The test method was the same as in Example 1, the initial discharge capacity was 187 mAh/g, and the first Coulombic efficiency was 75%. From the experimental results of Example 1 and Comparative Examples 1-2, it can be seen that the positive electrode material prepared by the preparation method of the present invention has a higher chemical composition than that without microsphere molding or multi-stage countercurrent swirl preheating. , tap density, specific surface area and other quality consistency, the grain size is distributed in a narrow area of 1500~5000nm, there is no grain with a particularly small grain size, and it has better initial discharge capacity and first Coulombic efficiency. Comparative example 3 uses Ni 0.8 Co 0.1 Mn 0.1 (OH) 2 slurry mixed with pulverized LiOH to form the first slurry, the solid content is controlled to 80%, the pH is controlled to 3, the appearance of the slurry is shown in Figure 8 (right figure) shown. The slurry cannot be sprayed into the microsphere molding device of Equipment Example 1 through the slurry input mechanism 25 .