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CN114039031A - Tungsten single-coating anode material and preparation method and application thereof - Google Patents

Tungsten single-coating anode material and preparation method and application thereof Download PDF

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Publication number
CN114039031A
CN114039031A CN202111289901.3A CN202111289901A CN114039031A CN 114039031 A CN114039031 A CN 114039031A CN 202111289901 A CN202111289901 A CN 202111289901A CN 114039031 A CN114039031 A CN 114039031A
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source
manganese
cobalt
nickel
sintering
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莫方杰
朱呈岭
李岚
杨元婴
杨文龙
孙化雨
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Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai Co Ltd
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Envision Power Technology Jiangsu Co Ltd
Envision Ruitai Power Technology Shanghai Co Ltd
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Priority to CN202111289901.3A priority Critical patent/CN114039031A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/131—Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/04—Processes of manufacture in general
    • H01M4/0471—Processes of manufacture in general involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/139—Processes of manufacture
    • H01M4/1391—Processes of manufacture of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/10—Energy storage using batteries

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Abstract

The invention provides a tungsten single-coated anode material and a preparation method and application thereof, wherein the tungsten single-coated anode material comprises an anode material and a tungsten compound; the chemical formula of the anode material is LiNixCoyMn1‑x‑yO2Wherein x is more than or equal to 0.5 and less than or equal to 0.9, and y is more than or equal to 0 and less than or equal to 0.13; the tungsten compound is coated on the surface of the positive electrode material;according to the invention, the tungsten single-coated anode material is prepared by adopting one-time co-sintering or the tungsten compound is coated on the surface of the anode material by adopting two-time sintering, so that the conductivity of the surface of the material can be effectively improved; the method is used for preparing the positive pole piece of the lithium ion battery, can reduce the internal resistance of the battery, and improves the capacity retention rate of the battery under the low-temperature condition.

Description

Tungsten single-coating anode material and preparation method and application thereof
Technical Field
The invention belongs to the field of battery material preparation, and particularly relates to a tungsten single-coated anode material as well as a preparation method and application thereof.
Background
Ternary positive electrode material LiNixCoyMn1-x-yO2The high-capacity power battery system has the advantages that the theoretical specific capacity is 274mAh/g, and the reaction platform voltage is 3.0V-4.3V. However, the widely used ternary positive electrode material has high cobalt content and LiNixCoyMn1-x-yO2Wherein y is more than 0.15, and cobalt ore is increasingly in short supply as a rare mineral resource.
The prior art solves the problems of material cost and limited cobalt ore resources by reducing the content of cobalt in the ternary cathode material, and develops the low-cobalt cathode material LiNixCoyMn1-x-yO2Wherein x is more than or equal to 0.5 and less than or equal to 0.9, and y is more than or equal to 0 and less than or equal to 0.13.
In the low-cobalt cathode material, the decrease of the cobalt content can reduce the overall conductivity of the material and improve the diffusion barrier of lithium ions in crystal lattices, thereby bringing about a serious reaction kinetics retardation problem and influencing the capacity exertion of the battery. Particularly, under the condition of low temperature of less than-20 ℃, the direct current internal resistance and the capacity retention rate of the lithium ion battery are obviously deteriorated. This will result in the energy density reduction of the low cobalt cathode material, and will affect the development and application of the material.
Therefore, development of a positive electrode material having a high energy density under low temperature conditions is in demand.
Disclosure of Invention
The invention aims to provide a tungsten single-coated anode material and a preparation method and application thereof, wherein the tungsten single-coated anode material comprises an anode material and a tungsten compound; the chemical formula of the anode material is LiNixCoyMn1-x-yO2Wherein x is more than or equal to 0.5 and less than or equal to 0.9, and y is more than or equal to 0 and less than or equal to 0.13; the tungsten compound is coated on the surface of the positive electrode material; according to the invention, the tungsten compound is coated on the surface of the low-cobalt cathode material, so that the conductivity of the surface of the material is effectively improved; the method is used for preparing the positive pole piece of the lithium ion battery, can reduce the internal resistance of the battery, and improves the capacity retention rate of the battery under the low-temperature condition.
In order to achieve the purpose, the invention adopts the following technical scheme:
one of the objectives of the present invention is to provide a tungsten single-clad cathode material, which includes a cathode material and a tungsten compound, wherein:
the chemical formula of the anode material is LiNixCoyMn1-x-yO2Wherein x is more than or equal to 0.5 and less than or equal to 0.9, and y is more than or equal to 0 and less than or equal to 0.13;
the tungsten compound is coated on the surface of the positive electrode material.
According to the invention, the surface of the anode material is coated with the tungsten compound, so that the conductivity of the surface is effectively improved, and the anode pole piece prepared by using the tungsten compound has high energy density, so that the reduction of the battery performance caused by low cobalt content is compensated.
Note that the chemical coefficient of Co in the positive electrode material may be 0, that is, y is 0, and means that Co may not be contained in the positive electrode material coated with the tungsten compound.
In a preferred embodiment of the present invention, the positive electrode material is in a secondary sphere form and/or a single crystal form.
Preferably, the particle size of the secondary sphere form of D50 is 9 μm to 25 μm, and may be, for example, 9 μm, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, etc., but is not limited to the values listed, and other values not listed in this range of values are also applicable.
Preferably, the grain size of the single crystal form of D50 is 2 μm to 6 μm, and may be, for example, 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, etc., but not limited to the values listed, and other values not listed in the numerical range are also applicable.
Another object of the present invention is to provide a method for preparing a tungsten single-clad positive electrode material, the method comprising:
carrying out primary co-sintering on a lithium source, a nickel source, a manganese source, a cobalt source and a tungsten source at the temperature of 350-600 ℃ to obtain a tungsten single-coated positive electrode material;
or
The method comprises the steps of sintering a lithium source, a nickel source, a manganese source and a cobalt source for the first time to obtain a positive electrode material, and sintering a tungsten source and the positive electrode material for the second time at a temperature of 300-550 ℃ to obtain a tungsten single-coated positive electrode material.
The invention adopts two methods to prepare the tungsten single-coating anode material, the two methods can ensure that the tungsten compound is coated on the surface of the anode material, the coating effect is not greatly different, and the coating layer is more stable; the tungsten single-coating anode material prepared by adopting the primary co-sintering has deeper embedding depth of the tungsten compound positioned on the surface than that of the tungsten compound prepared by adopting the secondary sintering.
It is worth to be noted that, when the cathode material does not contain Co, the corresponding preparation method may omit the cobalt source.
The temperature of the primary co-sintering in the primary co-sintering of the present invention is preferably 350 ℃ to 600 ℃, and may be, for example, 350 ℃, 360 ℃, 370 ℃, 380 ℃, 390 ℃, 400 ℃, 420 ℃, 440 ℃, 460 ℃, 480 ℃, 500 ℃, 520 ℃, 540 ℃, 560 ℃, 580 ℃, 600 ℃, etc., but not limited to the recited values, and other values not recited in the range of the values are also applicable; if the temperature is higher than 600 ℃, the volatilization of the lithium source is serious, and the gram capacity of the material is reduced; if the temperature is lower than 350 ℃, the phase inversion is insufficient, and a phase-pure layered material cannot be obtained.
The temperature of the secondary sintering in the secondary sintering of the present invention is preferably 300 ℃ to 550 ℃, and may be, for example, 300 ℃, 320 ℃, 340 ℃, 360 ℃, 380 ℃, 400 ℃, 420 ℃, 440 ℃, 460 ℃, 480 ℃, 500 ℃, 520 ℃, 540 ℃, 550 ℃ or the like, but is not limited to the recited values, and other values not recited in the range of the values are also applicable; if the temperature is higher than 550 ℃, the lithium source can be seriously volatilized, and the gram capacity of the material is reduced; if the temperature is lower than 300 ℃, the coating effect is poor, the adhesion of the coating agent is low, and the coating agent is easy to fall off.
As a preferred embodiment of the present invention, in the primary co-sintering, the lithium source includes any one of anhydrous lithium hydroxide, lithium hydroxide monohydrate, or lithium carbonate, or a combination of at least two of them, and typical but non-limiting examples of the combination include a combination of anhydrous lithium hydroxide and lithium hydroxide monohydrate, a combination of anhydrous lithium hydroxide and lithium carbonate, and a combination of lithium hydroxide monohydrate and lithium carbonate.
Preferably, in the primary co-sintering, the nickel source comprises any one of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride or a combination of at least two thereof, typical but non-limiting examples of which include a combination of nickel sulfate and nickel carbonate, a combination of nickel sulfate and nickel nitrate, a combination of nickel sulfate and nickel chloride, a combination of nickel carbonate and nickel nitrate, a combination of nickel carbonate and nickel chloride, a combination of nickel nitrate and nickel chloride.
Preferably, in the primary co-sintering, the manganese source comprises any one of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride or a combination of at least two of the same, typical but non-limiting examples of which include a combination of manganese sulfate and manganese carbonate, a combination of manganese sulfate and manganese nitrate, a combination of manganese sulfate and manganese chloride, a combination of manganese carbonate and manganese nitrate, a combination of manganese carbonate and manganese chloride, a combination of manganese nitrate and manganese chloride.
Preferably, in the primary co-sintering, the cobalt source comprises any one of cobalt sulfate, cobalt carbonate, cobalt nitrate, or cobalt chloride, or a combination of at least two thereof, typical but non-limiting examples of which include a combination of cobalt sulfate and cobalt carbonate, a combination of cobalt sulfate and cobalt nitrate, a combination of cobalt sulfate and cobalt chloride, a combination of cobalt carbonate and cobalt nitrate, a combination of cobalt carbonate and cobalt chloride, and a combination of cobalt nitrate and cobalt chloride.
Preferably, in the primary co-sintering, the tungsten source comprises H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of the above, typical but non-limiting examples of which include H4W and H2W2O7Combination of (1), H2W2O7And WO3Combination of (1), H2W2O7And WO2Combination of (1), H2W2O7And BW combination, H2W2O7And B2Combination of W, H2W2O7And WF6Combination of (1), H2W2O7And WOF4BW and WF6Combinations of (a) and (b).
As a preferable technical scheme of the invention, in the primary co-sintering, the molar ratio of lithium atoms in the lithium source, nickel atoms in the nickel source, cobalt atoms in the cobalt source and manganese atoms in the manganese source is (3 to 12) to (1.35 to 9) to (0 to 1.3) 1, and may be, for example, 3:1.35:0:1, 3:9:0:1, 3:1.35:1.3:1, 3:9:1.3:1, 12:1.35:0:1, 12:9:0:1, 12:1.35:1.3:1, 12:9:1.3:1, 5:1.35:0:1, 5:9:0:1, 8:1.35:1.3:1, 8:9:1.3:1, 10:1.35:0:1, 10:9:0:1, 12:1.35:1.3:1, 12: 1.3:1, 3:1.3:1, 3:1.3:1, 3:1, 3: 1: 3:1, 3: 1: 3:1, 3:1, 3:1, 12:1, 3: 1: 3:1, 3: 1: 3:1, 3:1, 3: 1: 3:1, 3: 1: 3:1, 3:1, 3:1, 3: 1: 3:1, 3: 1: 2:3: 2:1, 3: 1: 3: 1: 3:1, 3:1, 3:1, 3:1, 3:1, 3:1, 3:1, 2, 3:4.5:1.3:1, 12:5:0:1, 12:5.5:1.3:1, 12:6:0:1, 3:6.5:0:1, 3:7:1.3:1, 12:7.5:0:1, 12:8:1.3:1, 12:8.5:0:1, 3:1.35:0.1:1, 3:9:0.2:1, 12:9:0.3:1, 12:1.35:0.4:1, 12:1.35:0.5:1, 12:9:0.6:1, 3:9,0.7:1, 12:9:0.8:1, 3:1.35:0.9:1, 12:9:1:1, 3:1.35:1.1:1, 3:9:1.2:1, etc., but the same values are not limited to the recited herein.
Preferably, in the primary co-sintering, the ratio of the tungsten source mass to the total charge amount is 0.01 wt% to 2 wt%, for example, 0.01 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, etc., further preferably 1.2 wt% to 1.4 wt%, for example, 1.2 wt%, 1.22 wt%, 1.25 wt%, 1.28 wt%, 1.3 wt%, 1.33 wt%, 1.35 wt%, 1.37 wt%, 1.4 wt%, etc., but not limited to the recited values are not limited to other values within the same range.
Preferably, in the primary co-sintering, the time of the primary co-sintering is 12h to 24h, and may be, for example, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h, etc., but is not limited to the enumerated values, and other unrecited values in the numerical range are also applicable.
As a preferred embodiment of the present invention, in the primary sintering, the lithium source includes any one or a combination of at least two of anhydrous lithium hydroxide, lithium hydroxide monohydrate, and lithium carbonate, and typical but non-limiting examples of the combination include a combination of anhydrous lithium hydroxide and lithium hydroxide monohydrate, a combination of anhydrous lithium hydroxide and lithium carbonate, and a combination of lithium hydroxide monohydrate and lithium carbonate.
Preferably, in the primary sintering, the nickel source includes any one of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride or a combination of at least two thereof, and typical but non-limiting examples of the combination include a combination of nickel sulfate and nickel carbonate, a combination of nickel sulfate and nickel nitrate, a combination of nickel sulfate and nickel chloride, a combination of nickel carbonate and nickel nitrate, a combination of nickel carbonate and nickel chloride, and a combination of nickel nitrate and nickel chloride.
Preferably, in the primary sintering, the manganese source includes any one of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride or a combination of at least two thereof, typical but non-limiting examples of which include a combination of manganese sulfate and manganese carbonate, a combination of manganese sulfate and manganese nitrate, a combination of manganese sulfate and manganese chloride, a combination of manganese carbonate and manganese nitrate, a combination of manganese carbonate and manganese chloride, and a combination of manganese nitrate and manganese chloride.
Preferably, in the primary sintering, the cobalt source includes any one of cobalt sulfate, cobalt carbonate, cobalt nitrate, or cobalt chloride or a combination of at least two thereof, and typical but non-limiting examples of the combination include a combination of cobalt sulfate and cobalt carbonate, a combination of cobalt sulfate and cobalt nitrate, a combination of cobalt sulfate and cobalt chloride, a combination of cobalt carbonate and cobalt nitrate, a combination of cobalt carbonate and cobalt chloride, and a combination of cobalt nitrate and cobalt chloride.
Preferably, in the primary sintering, the molar ratio of lithium atoms in the lithium source, nickel atoms in the nickel source, cobalt atoms in the cobalt source and manganese atoms in the manganese source is (3 to 12) to (1.35 to 9) to (0 to 1.3) 1, and may be, for example, 3:1.35:0:1, 3:9:0:1, 3:1.35:1.3:1, 3:9:1.3:1, 12:1.35:0:1, 12:9:0:1, 12:1.35:1.3:1, 12:9:1.3:1, 5:1.35:0:1, 5:9:0:1, 8:1.35:1.3:1, 8:9:1.3:1, 10:1.35:0:1, 10:9:0:1, 12:1.35:1.3:1, 12: 1.3:1, 3:1.3:1, 12: 1.3:1, 3:1.3:1, 3:1.3:1, 3:1, 3:1, 12:1, 3:1, 3:1, 3:1, 12:1, 3:1, 3: 1: 3:1, 12:1, 3:1, 12:1, 3:1, 12:1, 3:1, 3:1, 12:1, 3: 1: 3: 1: 3:1, 12:1, 3:1, 12:1, 3:1, 3:1, 12:3:1, 3: 1: 3:1, 12:5.5:1.3:1, 12:6:0:1, 3:6.5:0:1, 3:7:1.3:1, 12:7.5:0:1, 12:8:1.3:1, 12:8.5:0:1, 3:1.35:0.1:1, 3:9:0.2:1, 12:9:0.3:1, 12:1.35:0.4:1, 12:1.35:0.5:1, 12:9:0.6:1, 3:9,0.7:1, 12:9:0.8:1, 3:1.35:0.9:1, 12:9:1:1, 3:1.35:1.1:1, 3:9:1.2:1, etc., but not only to the recited values are not limited to the same values as those stated, and other values in this range apply.
Preferably, in the secondary sintering, the tungsten source includes H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of the above, typical but non-limiting examples of which include H4W and H2W2O7Combination of (1), H2W2O7And WO3Combination of (1), H2W2O7And WO2Combination of (1), H2W2O7And BW combination, H2W2O7And B2Combination of W, H2W2O7And WF6Combination of (1), H2W2O7And WOF4BW and WF6Combinations of (a) and (b).
Preferably, in the secondary sintering, the ratio of the mass of the tungsten source to the total charge amount in the secondary sintering is 0.01 wt% to 2 wt%, for example, 0.01 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, 1 wt%, 1.1 wt%, 1.2 wt%, 1.3 wt%, 1.4 wt%, 1.5 wt%, 1.6 wt%, 1.7 wt%, 1.8 wt%, 1.9 wt%, 2 wt%, etc., further preferably 1.2 wt% to 1.4 wt%, for example, 1.2 wt%, 1.22 wt%, 1.25 wt%, 1.28 wt%, 1.3 wt%, 1.33 wt%, 1.35 wt%, 1.37 wt%, 1.4 wt%, etc., but not limited to the other numerical values recited in the same range.
In a preferred embodiment of the present invention, the temperature of the primary sintering is 400 to 700 ℃, and may be, for example, 400 ℃, 420 ℃, 440 ℃, 460 ℃, 480 ℃, 500 ℃, 520 ℃, 540 ℃, 560 ℃, 580 ℃, 600 ℃, 620 ℃, 640 ℃, 660 ℃, 680 ℃, 700 ℃, or the like, but the primary sintering is not limited to the above-mentioned values, and other values not listed in the above-mentioned range of values are also applicable.
Preferably, the time for the primary sintering is 12h to 24h, and may be, for example, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h, 24h, etc., but is not limited to the recited values, and other values not recited in the range of the values are also applicable.
Preferably, the time for the secondary sintering is 9h to 16h, and may be, for example, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, etc., but is not limited to the recited values, and other values not recited in the range of the recited values are also applicable.
As a preferred technical solution of the present invention, the preparation method comprises:
carrying out primary co-sintering on a lithium source, a nickel source, a manganese source, a cobalt source and a tungsten source at the temperature of 350-600 ℃ for 12-24 h to obtain a tungsten single-coated positive electrode material;
wherein the lithium source comprises any one of anhydrous lithium hydroxide, lithium hydroxide monohydrate or lithium carbonate or a combination of at least two of the anhydrous lithium hydroxide, the lithium hydroxide monohydrate or the lithium carbonate; the nickel source comprises any one or the combination of at least two of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride; the manganese source comprises any one or a combination of at least two of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride; the cobalt source comprises any one or combination of at least two of cobalt sulfate, cobalt carbonate, cobalt nitrate or cobalt chloride; the tungsten source comprises H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of; the molar ratio of lithium atoms in the lithium source, nickel atoms in the nickel source, cobalt atoms in the cobalt source and manganese atoms in the manganese source is (3-12): 1.35-9): 0-1.3): 1; the mass of the tungsten source accounts for 0.01-2 wt% of the total feeding amount;
or
The method comprises the following steps of sintering a lithium source, a nickel source, a manganese source and a cobalt source for the first time to obtain a positive electrode material, and sintering a tungsten source and the positive electrode material for the second time at a temperature of 300-550 ℃, wherein the sintering comprises the following steps: performing primary sintering on a lithium source, a nickel source, a manganese source and a cobalt source at 400-700 ℃ for 12-24 h to obtain a positive electrode material, and performing secondary sintering at 300-550 ℃ for 9-16 h to obtain a tungsten single-coated positive electrode material;
wherein the lithium source comprises any one of anhydrous lithium hydroxide, lithium hydroxide monohydrate or lithium carbonate or a combination of at least two of the anhydrous lithium hydroxide, the lithium hydroxide monohydrate or the lithium carbonate; the nickel source comprises any one or the combination of at least two of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride; the manganese source comprises any one or a combination of at least two of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride; the cobalt source comprises any one or combination of at least two of cobalt sulfate, cobalt carbonate, cobalt nitrate or cobalt chloride; the mole of lithium atoms in the lithium source, nickel atoms in the nickel source, cobalt atoms in the cobalt source and manganese atoms in the manganese sourceThe molar ratio is (3 to 12): 1.35 to 9): 0 to 1.3): 1; the tungsten source comprises H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of; the mass of the tungsten source accounts for 0.01 wt% to 2 wt% of the total feeding amount of the secondary sintering.
The invention also aims to provide an application of the tungsten single-coated positive electrode material, and the tungsten single-coated positive electrode material is used for preparing a positive electrode plate of a lithium ion battery.
The fourth object of the present invention is to provide an application method of the above-mentioned third object, wherein the application method comprises:
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate;
wherein the mass ratio of the tungsten single coating anode material, the conductive carbon black, the conductive carbon tube, the nitrogen methyl pyrrolidone solvent and the polyvinylidene fluoride is (90-99) to 1:0.5:40: 1.
The recitation of numerical ranges herein includes not only the above-recited numerical values, but also any numerical values between non-recited numerical ranges, and is not intended to be exhaustive or to limit the invention to the precise numerical values encompassed within the range for brevity and clarity.
Compared with the prior art, the invention has the following beneficial effects:
according to the invention, the tungsten single-coating anode material is prepared by coating the tungsten compound on the surface of the low-cobalt anode material, so that the conductivity of the surface of the material is effectively improved, and the diffusion of lithium ions is promoted; the method is used for preparing the positive pole piece of the lithium ion battery, can effectively reduce the direct current resistance of the battery, reduces the low-temperature direct current resistance of the battery and improves the capacity retention rate of the battery under the low-temperature condition.
Drawings
FIG. 1 shows DC resistance values of different states of charge of the positive electrode sheets obtained in example 1 and comparative example 1 at 25 ℃;
FIG. 2 shows DC resistance values of the positive electrode sheets obtained in example 1 and comparative example 1 at-20 ℃ and different charge states;
FIG. 3 shows the capacity retention of the positive electrode sheets obtained in example 1 and comparative example 1 at-20 ℃.
Detailed Description
The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.
In the prior art, one technical scheme provides a preparation method of a carbon-coated ternary cathode material and the carbon-coated ternary cathode material, and the preparation method comprises the following steps: s1, preparing a ternary positive electrode material precursor by taking nickel salt, cobalt salt and manganese salt as raw materials; s2, preparing a conductive carbon dispersion system: dispersing conductive carbon in water containing an organic carbon source; s3, adding the ternary positive electrode material precursor and the lithium compound into the conductive carbon dispersion system, and uniformly mixing to obtain a mixture; s4, drying the mixture under a vacuum condition; and S5, carrying out high-temperature treatment on the dried mixture under a sealed condition or in an atmosphere protected by inert gas to obtain the carbon-coated ternary cathode material. The technical scheme has the advantages of uniform coating, simple operation, low cost and high efficiency, wherein the conductive carbon and the ternary cathode material are simultaneously coated in the reticular amorphous carbon, and the amorphous carbon serves as a conductive medium or a channel of the conductive carbon and the ternary cathode material, so that the rate capability of the ternary cathode material is greatly improved.
The other scheme provides a ternary cathode material coated with lithium tungstate and a preparation method thereof, wherein the preparation method comprises the steps of calcining a nickel-cobalt-manganese hydroxide precursor to obtain a porous nickel-cobalt-manganese oxide precursor; dissolving a tungsten source in a solvent to form a tungsten source solution; dispersing the porous nickel-cobalt-manganese oxide precursor in a tungsten source solution, and then stirring, dipping and evaporating to dryness to obtain a powder product; mixing the powder product and a lithium source according to a molar ratio of 1: 1.03-1.05, and sintering to obtain a lithium tungstate-coated ternary positive electrode material; the capacity retention rate and the cycle performance of the obtained cathode material are effectively improved.
However, the above technical solutions are all directed to modification of a ternary cathode material with a conventional cobalt content, and when the cobalt content is low, the overall conductivity of the material is reduced, and the diffusion barrier of lithium ions in crystal lattices is improved, so that a serious reaction kinetics lag problem is caused, and the capacity exertion of a battery is affected, and particularly under a low-temperature condition below-20 ℃, the direct-current internal resistance and the capacity retention rate are obviously reduced; the technical scheme does not verify whether the method can be applied to the low-cobalt cathode material.
According to the embodiment of the disclosure, a small amount of tungsten compound is coated on the surface of the low-cobalt cathode material with the cobalt content of less than 0.13 through primary co-sintering or secondary sintering, so that the ionic and electronic conductivity of the surface of the material is effectively improved, the internal resistance of the battery is reduced, and the low-temperature performance is improved.
Example 1
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
mixing 98.9 wt% anhydrous lithium hydroxide, nickel sulfate, cobalt sulfate and manganese sulfate with 1.1 wt% H2W2O7Co-sintering at 480 ℃ for 18h at one time to obtain LiNi with the chemical formula0.66Co0.06Mn0.28O2The tungsten single-coating anode material comprises lithium atoms, nickel atoms, cobalt atoms and manganese atoms, wherein the molar ratio of the lithium atoms to the nickel atoms to the cobalt atoms to the manganese atoms is 5:2.35:0.22: 1;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 97.5:1:0.5:40: 1.
Example 2
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
98 wt% of lithium carbonate, nickel nitrate and manganese carbonate and 2 wt% of H2W2O7Co-sintering at 350 ℃ for 24h to obtain LiNi0.9Mn0.1O2The tungsten single-coating anode material of (1), wherein the molar ratio of lithium atoms to nickel atoms to manganese atoms is 12:9: 1;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 90:1:0.5:40: 1.
Example 3
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
99.99 wt% of anhydrous lithium hydroxide, nickel carbonate, cobalt chloride and manganese nitrate and 0.01 wt% of H2W2O7Co-sintering at 600 ℃ for 12h to obtain LiNi0.5Co0.13Mn0.37O2The tungsten single-coating anode material comprises lithium atoms, nickel atoms, cobalt atoms and manganese atoms, wherein the molar ratio of the lithium atoms to the nickel atoms to the cobalt atoms to the manganese atoms is 3:1.35:0.35: 1;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 99:1:0.5:40: 1.
Example 4
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
99 wt% of anhydrous lithium hydroxide, nickel carbonate, cobalt chloride and manganese nitrate and 1 wt% of H2W2O7Co-sintering at 480 ℃ for 18h at one time to obtain LiNi with the chemical formula0.5Co0.13Mn0.1O2The tungsten single-coating anode material comprises lithium atoms, nickel atoms, cobalt atoms and manganese atoms, wherein the molar ratio of the lithium atoms to the nickel atoms to the cobalt atoms to the manganese atoms is 11:5:1.3: 1;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 95:1:0.5:40: 1.
Example 5
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
anhydrous lithium hydroxide, nickel carbonate, cobalt chloride and manganese nitrate are sintered for 18 hours at 550 ℃ once to obtain LiNi with the chemical formula0.66Co0.06Mn0.28O2The positive electrode material of (1), wherein the molar ratio of lithium atoms, nickel atoms, cobalt atoms and manganese atoms is 5:2.35:0.22: 1; 1.1 wt% of WF6Sintering the tungsten single-coated anode material and 98.9 wt% of the anode material for 12 hours at 420 ℃ to obtain a tungsten single-coated anode material;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 97.5:1:0.5:40: 1.
Example 6
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
sintering lithium carbonate, nickel nitrate and manganese carbonate at 400 ℃ for 24 hours at one time to obtain LiNi with the chemical formula0.9Mn0.1O2The positive electrode material of (1), wherein the molar ratio of lithium atoms, nickel atoms and manganese atoms is 12:9: 1; 2 wt% of H2W2O7Sintering the tungsten single-coated anode material and 98 wt% of the anode material for 9 hours at 550 ℃ to obtain a tungsten single-coated anode material;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 99:1:0.5:40: 1.
Example 7
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
anhydrous lithium hydroxide, nickel carbonate, cobalt chloride and manganese nitrate are sintered for 12 hours at 700 ℃ for one time to obtain LiNi with the chemical formula0.5Co0.13Mn0.37O2The positive electrode material of (1), wherein, lithium atom, nickel atom, cobalt atom and manganese atomThe molar ratio is 3:1.35:0.35: 1; 0.01 wt% of WF6Sintering the tungsten single-coated anode material and 99.99 wt% of the anode material for 16h at 300 ℃ to obtain a tungsten single-coated anode material;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 90:1:0.5:40: 1.
Example 8
The embodiment provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method comprises the following steps:
lithium hydroxide monohydrate, nickel carbonate, cobalt chloride and manganese nitrate are sintered for 18 hours at 550 ℃ once to obtain LiNi with the chemical formula0.5Co0.13Mn0.1O2The positive electrode material of (1), wherein the molar ratio of lithium atoms, nickel atoms, cobalt atoms and manganese atoms is 11:5:1.3: 1; 1 wt% of WF6Sintering the tungsten single-coated anode material and 99 wt% of anode material for 12 hours at 420 ℃ to obtain a tungsten single-coated anode material;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a tungsten single-coated positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the tungsten single-coating positive electrode material to the conductive carbon black to the conductive carbon tube to the nitrogen methyl pyrrolidone solvent to the polyvinylidene fluoride is 95:1:0.5:40: 1.
Comparative example 1
The comparative example provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, and the preparation method refers to the example1, differing only in that: omit H2W2O7Namely, the preparation method comprises:
co-sintering anhydrous lithium hydroxide, nickel sulfate, cobalt sulfate and manganese sulfate at 480 ℃ for 18h to obtain LiNi0.66Co0.06Mn0.28O2The positive electrode material of (1), wherein the molar ratio of lithium atoms, nickel atoms, cobalt atoms and manganese atoms is 5:2.35:0.22: 1;
mixing conductive carbon black, a conductive carbon tube, a nitrogen methyl pyrrolidone solvent and polyvinylidene fluoride, and dispersing and stirring at a high speed for 2 hours to obtain conductive slurry; mixing a positive electrode material with the conductive slurry to obtain positive electrode slurry; uniformly coating the positive electrode slurry on an aluminum foil by using a scraper, placing the aluminum foil in a blast drying oven, drying the aluminum foil for 20 minutes at 120 ℃, and rolling and cutting the aluminum foil to prepare a positive electrode plate; the mass ratio of the positive electrode material, the conductive carbon black, the conductive carbon tube, the N-methyl pyrrolidone solvent and the polyvinylidene fluoride is 97.5:1:0.5:40: 1.
Comparative example 2
The comparative example provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, except that the temperature of the primary co-sintering is changed from 480 ℃ to 650 ℃, and the other conditions are completely the same as those in example 1.
Comparative example 3
The comparative example provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, except that the temperature of the primary co-sintering is changed from 480 ℃ to 300 ℃, and the other conditions are completely the same as those in example 1.
Comparative example 4
The comparative example provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, except that the temperature of the secondary sintering is changed from 420 ℃ to 600 ℃, and the other conditions are completely the same as those in example 5.
Comparative example 5
The comparative example provides a tungsten single-coated positive electrode material and a positive electrode plate prepared by using the same, except that the temperature of the secondary sintering is changed from 420 ℃ to 250 ℃, and the other conditions are completely the same as those in example 5.
The positive electrode plates obtained in the above examples and comparative examples were tested for their dc resistance at 25 ℃, dc resistance at-20 ℃ and battery capacity retention at-20 ℃ while maintaining the state of charge at 50% SOC, according to the following test methods:
25 ℃ DC resistance value: 25 ℃ DC resistance value: charging to 4.3V voltage at 25 deg.C with 0.33C rate, discharging to 2.8V with 0.33C rate to obtain battery capacity C0(ii) a Then adjusting the state of charge of the battery to 50% SOC, then discharging the battery for 30s at a current density of 4C, wherein the voltage difference value before and after the discharge is divided by the current density to obtain a direct current resistance value of the battery in the state of charge; the DC resistance values of 70% SOC and 20% SOC at 25 deg.C can be obtained by this method;
-20 ℃ low temperature dc resistance value: charging to 4.3V voltage at-20 deg.C with 0.33C rate, discharging to 2.8V with 0.33C rate to obtain battery capacity C1(ii) a Then adjusting the state of charge of the battery to 50% SOC, then discharging the battery for 30s at a current density of 4C, wherein the voltage difference value before and after the discharge is divided by the current density to obtain a direct current resistance value of the battery in the state of charge; the DC resistance value of 70% SOC and 20% SOC can be obtained by the method under-20 ℃;
a retention rate of a battery capacity at-20 ℃ of C1/C0X 100%, wherein C0A battery capacity of 25 ℃; c1The cell capacity was-20 ℃.
The test results of the above examples and comparative examples are shown in Table 1.
TABLE 1
Figure BDA0003334523130000171
The following points can be derived from table 1:
(1) comparing examples 1, 5 with comparative example 1, it can be seen that H is omitted since comparative example 12W2O7The surface conductivity of the positive electrode material is deteriorated, and further, when the charge state is 50% SOC, the direct current resistance values at 25 ℃ and-20 ℃ are obviously increased, and the capacity retention rate of the battery at-20 ℃ is reduced.
(2) Will be provided withWhen the temperature of the primary co-sintering in the comparative example 2 is 650 ℃, which exceeds the 350 ℃ to 600 ℃ preferred in the invention, the example 1 is compared with the comparative examples 2 and 3, and the lithium source is seriously volatilized, the gram capacity of the material is reduced, the content of lithium element in the structural formula of the positive electrode material is reduced, and the chemical formula of the lithium element is changed into Li0.91Ni0.66Co0.11Mn0.23O2Further, when the charge state is 50% SOC, the direct current resistance values at 25 ℃ and-20 ℃ are increased, and the capacity retention rate of the battery at-20 ℃ is reduced; since the temperature of the primary co-sintering in the comparative example 3 is 300 ℃ which is lower than the preferred temperature of 350 ℃ to 600 ℃ in the invention, the phase inversion is insufficient, a pure-phase cathode material cannot be obtained, and a tungsten source cannot be successfully coated on the surface of the cathode material, namely, a tungsten compound does not exist in the tungsten single-coated cathode material, so that the direct current resistance values at 25 ℃ and-20 ℃ are increased when the charge state is 50% SOC, and the capacity retention rate of a battery at-20 ℃ is reduced;
(3) comparing example 5 with comparative examples 4 and 5, it can be seen that since the temperature of the secondary sintering in comparative example 4 is 600 ℃ which is higher than the preferred temperature of 300 ℃ to 550 ℃ of the present invention, the volatilization of the lithium source is serious, the gram volume of the material is reduced, the content of lithium element in the structural formula of the positive electrode material is reduced, and the chemical formula is changed into Li0.98Ni0.66Co0.11Mn0.23O2Further, when the charge state is 50% SOC, the direct current resistance values at 25 ℃ and-20 ℃ are increased, and the capacity retention rate of the battery at-20 ℃ is reduced; since the temperature of secondary sintering in the comparative example 5 is 250 ℃ which is lower than the preferred temperature of 300 ℃ to 550 ℃ in the invention, insufficient phase transformation can be caused, a pure-phase cathode material cannot be obtained, and a tungsten source cannot be successfully coated on the surface of the cathode material, namely, a tungsten compound does not exist in the tungsten single-coated cathode material, so that the direct current resistance values at 25 ℃ and-20 ℃ are increased when the charge state is 50% SOC, and the capacity retention rate of a battery at-20 ℃ is reduced;
(4) comparing comparative example 1 with comparative examples 2 to 5, it can be found that the dc resistance at 25 ℃ and the dc resistance at-20 ℃ of comparative example 2 and comparative example 4 are both higher than that of comparative example 1, because the temperature of the primary co-sintering in comparative example 2 is too high and the temperature of the secondary sintering in comparative example 4 is too high, the volatilization of the lithium source is serious due to the too high temperature during sintering, the structural formula of the positive electrode material is changed, smaller particles in the positive electrode material are aggregated into large particles, the structure of the positive electrode material is changed, the dc resistance is higher than that of comparative example 1, and the retention rate of the battery capacity at-20 ℃ is lower than that of comparative example 1; the direct current resistance values of the comparative examples 3 and 5 at 25 ℃ and-20 ℃ are higher than those of the comparative example 1, because the temperature of the primary co-sintering in the comparative example 3 is too low and the temperature of the secondary sintering in the comparative example 5 is too low, the tungsten source cannot be combined with the positive electrode material due to the low temperature during sintering, no tungsten compound exists in the obtained tungsten single-coated positive electrode material, the surface conductivity of the positive electrode material is poor, the direct current resistance value is increased, and the capacity retention rate of the battery at-20 ℃ is reduced.
In order to further verify the 25 ℃ direct current resistance value, the-20 ℃ direct current resistance value and the-20 ℃ battery capacity retention rate under different charge states, the test is carried out by taking the example 1 and the comparative example 1 as examples, the 25 ℃ direct current resistance values of the positive pole pieces obtained in the example 1 and the comparative example 1 under different charge states are shown in figure 1, the-20 ℃ direct current resistance values of the positive pole pieces obtained in the example 1 and the comparative example 1 under different charge states are shown in figure 2, the-20 ℃ capacity retention rates of the positive pole pieces obtained in the example 1 and the comparative example 1 under different charge states are shown in figure 3, and specific values of figures 1 to 3 are listed in table 2.
TABLE 2
Figure BDA0003334523130000191
Figure BDA0003334523130000201
From fig. 1-3 and table 2 it can be derived:
the direct current resistance value of the positive pole piece in the embodiment 1 at different charge states and different temperatures is lower than that of the positive pole piece in the comparative example 1, and the capacity retention rate of the battery at-20 ℃ is higher than that of the positive pole piece in the comparative example 1, because the surface of the positive pole piece in the embodiment 1 is coated with the tungsten compound, the conductivity of the surface is effectively improved, and therefore, the energy density of the positive pole piece in the embodiment 1 is higher.
The applicant declares that the above description is only a specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and it should be understood by those skilled in the art that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are within the scope and disclosure of the present invention.

Claims (10)

1. A tungsten single clad positive electrode material, comprising a positive electrode material and a tungsten compound, wherein:
the chemical formula of the anode material is LiNixCoyMn1-x-yO2Wherein x is more than or equal to 0.5 and less than or equal to 0.9, and y is more than or equal to 0 and less than or equal to 0.13;
the tungsten compound is coated on the surface of the positive electrode material.
2. The tungsten single-coated positive electrode material as claimed in claim 1, wherein the positive electrode material is in a secondary sphere form and/or a single crystal form;
preferably, the secondary sphere form has a D50 particle size of 9 to 25 μm;
preferably, the single crystal form has a D50 particle size of 2 to 6 μm.
3. A method for preparing the tungsten single-coated cathode material according to claim 1 or 2, wherein the method comprises the following steps:
carrying out primary co-sintering on a lithium source, a nickel source, a manganese source, a cobalt source and a tungsten source at the temperature of 350-600 ℃ to obtain a tungsten single-coated positive electrode material;
or
The method comprises the steps of sintering a lithium source, a nickel source, a manganese source and a cobalt source for the first time to obtain a positive electrode material, and sintering a tungsten source and the positive electrode material for the second time at a temperature of 300-550 ℃ to obtain a tungsten single-coated positive electrode material.
4. The method of claim 3, wherein in the primary co-sintering, the lithium source comprises any one of anhydrous lithium hydroxide, lithium hydroxide monohydrate, or lithium carbonate, or a combination of at least two thereof;
preferably, in the primary co-sintering, the nickel source comprises any one of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride or a combination of at least two thereof;
preferably, in the primary co-sintering, the manganese source comprises any one of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride, or a combination of at least two thereof;
preferably, in the primary co-sintering, the cobalt source comprises any one of cobalt sulfate, cobalt carbonate, cobalt nitrate or cobalt chloride or a combination of at least two thereof;
preferably, in the primary co-sintering, the tungsten source comprises H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of them.
5. The method for preparing a tungsten single-clad cathode material according to claim 3 or 4, wherein in the primary co-sintering, the molar ratio of lithium atoms in the lithium source, nickel atoms in the nickel source, cobalt atoms in the cobalt source and manganese atoms in the manganese source is (3 to 12): (1.35 to 9): (0 to 1.3): 1;
preferably, in the primary co-sintering, the proportion of the mass of the tungsten source to the total charge is 0.01 wt% to 2 wt%, and more preferably 1.2 wt% to 1.4 wt%.
6. The preparation method of the tungsten single-coated cathode material as claimed in any one of claims 3 to 5, wherein the time of the primary co-sintering is 12 to 24 hours.
7. The method for producing a tungsten single-clad cathode material according to any one of claims 3 to 6, wherein in the primary sintering, the lithium source comprises any one of anhydrous lithium hydroxide, lithium hydroxide monohydrate, or lithium carbonate, or a combination of at least two thereof;
preferably, in the primary sintering, the nickel source includes any one of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride or a combination of at least two thereof;
preferably, in the primary sintering, the manganese source comprises any one of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride or a combination of at least two of the manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride;
preferably, in the primary sintering, the cobalt source comprises any one of cobalt sulfate, cobalt carbonate, cobalt nitrate or cobalt chloride or a combination of at least two of the foregoing;
preferably, in the primary sintering, the molar ratio of lithium atoms in the lithium source, nickel atoms in the nickel source, cobalt atoms in the cobalt source, and manganese atoms in the manganese source is (3 to 12): (1.35 to 9): (0 to 1.3): 1;
preferably, in the secondary sintering, the tungsten source includes H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of;
preferably, in the secondary sintering, the proportion of the mass of the tungsten source to the total charge amount in the secondary sintering is 0.01 wt% to 2 wt%, and more preferably 1.2 wt% to 1.4 wt%.
8. The preparation method of the tungsten single-coated cathode material as claimed in any one of claims 3 to 7, wherein the temperature of the primary sintering is 400 ℃ to 700 ℃;
preferably, the time of the primary sintering is 12 to 24 hours;
preferably, the time of the secondary sintering is 9 to 16 hours.
9. The preparation method of the tungsten single-coated cathode material as claimed in any one of claims 3 to 8, wherein the preparation method comprises the following steps:
carrying out primary co-sintering on a lithium source, a nickel source, a manganese source, a cobalt source and a tungsten source at the temperature of 350-600 ℃ for 12-24 h to obtain a tungsten single-coated positive electrode material;
wherein the lithium source comprises any one of anhydrous lithium hydroxide, lithium hydroxide monohydrate or lithium carbonate or a combination of at least two of the anhydrous lithium hydroxide, the lithium hydroxide monohydrate or the lithium carbonate; the nickel source comprises any one or the combination of at least two of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride; the manganese source comprises any one or a combination of at least two of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride; the cobalt source comprises any one or combination of at least two of cobalt sulfate, cobalt carbonate, cobalt nitrate or cobalt chloride; the tungsten source comprises H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of; the molar ratio of lithium atoms in the lithium source, nickel atoms in the nickel source, cobalt atoms in the cobalt source and manganese atoms in the manganese source is (3-12): 1.35-9): 0-1.3): 1; the mass of the tungsten source accounts for 0.01-2 wt% of the total feeding amount;
or
The method comprises the following steps of sintering a lithium source, a nickel source, a manganese source and a cobalt source for the first time to obtain a positive electrode material, and sintering a tungsten source and the positive electrode material for the second time at a temperature of 300-550 ℃, wherein the sintering comprises the following steps: performing primary sintering on a lithium source, a nickel source, a manganese source and a cobalt source at 400-700 ℃ for 12-24 h to obtain a positive electrode material, and performing secondary sintering at 300-550 ℃ for 9-16 h to obtain a tungsten single-coated positive electrode material;
wherein the lithium source comprises any one of anhydrous lithium hydroxide, lithium hydroxide monohydrate or lithium carbonate or a combination of at least two of the anhydrous lithium hydroxide, the lithium hydroxide monohydrate or the lithium carbonate; the nickel source comprises any one or the combination of at least two of nickel sulfate, nickel carbonate, nickel nitrate or nickel chloride; the manganese source comprises any one or a combination of at least two of manganese sulfate, manganese carbonate, manganese nitrate or manganese chloride; the cobalt source comprises any one or combination of at least two of cobalt sulfate, cobalt carbonate, cobalt nitrate or cobalt chloride; lithium atoms in the lithium source and nickel atoms in the nickel sourceThe molar ratio of the cobalt atoms in the cobalt source to the manganese atoms in the manganese source is (3-12): 1.35-9): 0-1.3): 1; the tungsten source comprises H4W、H2W2O7、WO3、WO2、BW、B2W、W2N3、WF6、WF4Or WOF4Any one or a combination of at least two of; the mass of the tungsten source accounts for 0.01 wt% to 2 wt% of the total feeding amount of the secondary sintering.
10. The application of the tungsten single-coated positive electrode material as claimed in claim 1 or 2, wherein the tungsten single-coated positive electrode material is used for preparing a positive electrode plate of a lithium ion battery.
CN202111289901.3A 2021-11-02 2021-11-02 Tungsten single-coating anode material and preparation method and application thereof Pending CN114039031A (en)

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