A kind of lithium-rich anode material of Li-O adulterated lithium manganate and preparation method thereof
Technical field
The present invention relates to anode material for lithium-ion batteries technical fields, and in particular to a kind of richness of Li-O adulterated lithium manganate
Lithium anode material and preparation method thereof.
Background technology
Lithium ion battery has average output voltage height, energy density height, output power, self discharge is small, does not remember
Effect, cycle performance be superior, can fast charging and discharging, charge efficiency is high, operating temperature range is wide and environmentally friendly etc. excellent
Point, in recent years with the development of electric vehicle and its technology is able to fast development.But the energy of lithium ion battery is close at present
Degree cannot still meet requirement of the electric vehicle for long continuation of the journey, after all or the energy density of lithium ion battery be not achieved will
It asks.In addition to improving the energy density of battery core in core strueture design and manufacturing process, the energy density of battery is improved
Main two approach:First, the discharge platform voltage of positive and negative pole material is improved, second is that the gram volume for improving material plays.
Compared with negative material, positive electrode is in capacity performance, power density, charge-discharge magnification, cycle life and safety
Performance etc. there are serious realistic problem, so, the promotion of power battery performance, particularly energy density raising, very
The development progress of positive electrode is depended in big degree.At present, commercial Li-ion battery positive electrode mainly has cobalt acid lithium, manganese
Sour lithium, nickel-cobalt-manganese ternary composite material and LiFePO4 etc., but they there are the uses that power battery is not achieved in some indexs
It is required that the problem of.So based on above present situation, lithium-rich anode material is up to 300mAh/g, higher because of its specific discharge capacity
Operating voltage, high security and relatively low cost have been a great concern.
Although lithium-rich anode material is unrivaled with other positive electrodes on lithium ion battery energy density is improved
Advantage, but its be applied to lithium-ion-power cell, there are it is serious the problem of:First, discharge capacity is big for the first time, and head effects are relatively low;
Second, high rate performance is poor, mainly thinks this and Li at present2MnO3Poor electric conductivity is related;3rd, cyclic process there is
Voltage drop, while cycle performance is also poor, is mainly considered that in charge and discharge process transition metal ions is moved from transition metal layer
Lithium layer position is moved to, so as to cause the change of crystal structure;4th, charging process with oxygen precipitation, this is because
Li2MnO3Material has oxygen atom to take part in charge compensation during de- lithium, causes structure that irreversible change occurs, causes to hold
Measure irreversible attenuation.Meanwhile it discharges oxygen and can produce serious influence to the security performance of battery, generate bulge or even explode etc.
Problem.
The content of the invention
In view of the deficiencies of the prior art, the present invention provides a kind of lithium-rich anode material and its system of Li-O adulterated lithium manganate
Preparation Method, it is intended to which head existing for current lithium-rich anode material is overcome to imitate, and relatively low, high rate performance is poor, there are voltage drop, cycle performances
The problems such as difference and release oxygen, the high rate performance and power that make the lithium-rich anode material of preparation get a promotion, while have charging
The advantages that stable structure and material circulation are stablized in the process.
In order to solve the above technical problems, the present invention provides following technical solution:
On the one hand, the present invention provides a kind of preparation method of the lithium-rich anode material of Li-O adulterated lithium manganate, including such as
Lower step:
1) by manganese source, lithium source and doped chemical lithium compound by it is required proportioning add in high energy ball mill carry out dry ball milling,
D is made in solid-phase sintering50For 1~10 μm of adulterated lithium manganate powder;The addition of the manganese source, lithium source and doped chemical lithium compound
Amount is using molar ratio as Mn:Li:Li-X=1:(1~1.1):(1~1.1) is measured;The doped chemical lithium compound includes
Li doped chemical lithium compounds, O doped chemical lithium compounds or combination;The Li-X is the mixing of doped chemical
Object;
2) adulterated lithium manganate powder obtained by step 1) is subjected to wet method cladding, drying and the doping mangaic acid coated that sieves
Lithium powder;
3) it is the positive electrode powder of the adulterated lithium manganate powder of cladding obtained by step 2) and cladding is fully dispersed uniform
To mixed-powder;The positive electrode powder includes cobalt acid lithium (LiCoO2), nickle cobalt lithium manganate ((Li (NiCoMn) O2, it is denoted as
NCM), nickel cobalt lithium aluminate (Li (NiCoAl) O2, it is denoted as NCA) or LiMn2O4 (LiMn2O4);
4) mixed-powder for obtaining step 3) is calcined to obtain the lithium-rich anode material of Li-O adulterated lithium manganates.
Further, the dry ball milling carries out the parameter of batch mixing:Rotating speed is 350~500r/min, mixing time for 8~
10 it is small when.
Further, the solid-phase sintering is that mixed material is placed in inert atmosphere to carry out, solid-phase sintering parameter:Temperature
For 700~900 DEG C, when sintering time is 20~25 small.
Further, the Li doped chemical lithium compound is selected from Li3N and Li3It is a kind of in P.
Further, the one kind of the O doped chemical lithium compound in LiF and LiCl.
In an embodiment of the present invention doped chemical lithium compound doping requirement be:Li doped chemical lithium compounds and
O doped chemical lithium compounds only adulterate one kind or two kinds while adulterate, but similar doped chemical lithium compound can only select
From one kind therein.The doped chemical X in Li-X is the elements such as N, P, F, Cl in an embodiment of the present invention.
Further , Suo Shu Manganese sources are α-MnO2。
Further, the lithium source is LiOH.
Further, the inert atmosphere is the gaseous mixture atmosphere of nitrogen atmosphere, argon gas atmosphere or both.
Further, the covering material that wet method cladding is carried out in the step 2) is Al2O3、TiO2、ZrO2、CeO2、SiO2、
ZnO、MgO、SnO2、AlPO4、CoPO4In it is one or two kinds of.
Further, wet method cladding is carried out in the step 2) to coat using individual layer wet method, detailed process is as follows:It will
Covering material homogenate adds in adulterated lithium manganate powder to be covered after being uniformly dispersed, stir, and is dried at a temperature of 120 DEG C
4~8 it is small when, at 500~600 DEG C calcine 15~20 it is small when, obtain integral coating amount less than 5% cladding mixed-powder.
Further, the NCM includes NCM111, NCM442, NCM523, NCM622, NCM811 etc..
Further, the positive electrode powder of the cladding is coated, and detailed process is as follows:By covering material homogenate point
Positive electrode powder to be covered is added in after dissipating uniformly, is stirred, when drying 4~8 is small at a temperature of 120 DEG C, 500~
When calcining 15~20 is small at 600 DEG C, the mixed-powder of cladding of the integral coating amount less than 5% is obtained.Preferably, the cladding material
Expect for Al2O3、TiO2、ZrO2、CeO2、SiO2、ZnO、MgO、SnO2、AlPO4、CoPO4In it is one or two kinds of.
Further, the granularity D50 of the adulterated lithium manganate powder of the cladding is the granularity of the positive electrode powder of cladding
D5010%~15%, the doping of the adulterated lithium manganate powder of cladding is 1.5%~5.5%.
Further, fully dispersed uniform use high speed mixer or double-cone mixer carry out batch mixing, batch mixing in step 3)
When time is 3~5 small.
Further, the parameter of calcining is as follows in the step 4):Calcining heat is 650 DEG C~750 DEG C, and calcination time is
8~12 it is small when.
On the other hand, the present invention provides a kind of lithium-rich anode material of the Li-O positions adulterated lithium manganate prepared with the above method
Material.
On the other hand, the present invention provides a kind of lithium battery anode, and the Li-O positions including being prepared with the method for the present invention are mixed
The lithium-rich anode material of miscellaneous LiMn2O4.
The present invention provides a kind of lithium-rich anode material of Li-O adulterated lithium manganate and preparation method thereof, using doped chemical
Lithium compound is doped lithium-rich anode material modification, and Li doped chemical lithium compound therein adulterates N, P at Li, make
It obtains and stronger covalent bond is formed between N, P and O atom, effectively inhibit the oxygen release problem of lithium-rich anode material initial charge process,
Promote the cycle performance of lithium-rich anode material;Since there is more valence electron may be such that part Mn by N, P4+Become Mn3+, inhibit
The Lacking oxygen of disengaging process is formed, and improves the stability for departing from state, while also improves the electron conduction of LiMn2O4, is improved
The high rate performance and power-performance of material;O doped chemical lithium compounds adulterate F, Cl ion at O, and F, Cl therein are more than O
One valence electron, can make part Mn4+Become Mn3+, the structural stability in charging process can be improved, also improves LiMn2O4
Electron conduction, improves the high rate performance and power-performance of material, and cycle performance is also improved.
Beneficial effects of the present invention:
The present invention provides a kind of lithium-rich anode material of Li-O adulterated lithium manganate and preparation method thereof, the Li-O doping
The lithium-rich anode material of LiMn2O4 is coated by solid-phase sintering, wet method, material mixing and calcination process are prepared, by manganese
The Li positions of sour lithium are doped with O, effectively inhibit analysis oxygen, improve high rate performance, and the Lacking oxygen that reservation charging process is formed carries
High efficiency for the first time promotes the security performance of battery, the energy density of material is improved, specifically with following advantage:
The lithium-rich anode material of the Li-O adulterated lithium manganate using doped chemical lithium compound to lithium-rich anode material into
Row doping vario-property, Li doped chemical lithium compound therein adulterate N, P and/or O doped chemical lithium compounds at Li in O
Position doping F, Cl so that form strong covalent bond or reduction part Mn4+, realize that the charge that oxygen atom is reduced in charge and discharge process is mended
It repays, reduces the appearance of Lacking oxygen, effectively inhibit the analysis oxygen problem in charging process, and then improve the security performance of positive electrode;
The reduction of Lacking oxygen so that Li in discharge process+It can be well embedded in, so as to improve discharge capacity, improve and imitate for the first time
Rate;The doping of atom changes the forbidden band structure of material, improves the electric conductivity of material so that high rate performance and power density obtain
To be promoted;Meanwhile the stable structure of the positive electrode of preparation can also improve cycle performance of the battery under high power capacity performance, change
Kind cycle life.
When preparing the lithium-rich anode material of Li-O adulterated lithium manganates, nano level adulterated lithium manganate powder is coated using wet method
End and the positive electrode powder of cladding, the cladding of the two can reduce the loss of Lacking oxygen and the migration of transition metal ions, carry
High discharge capacity for the first time, improves the voltage drop problem in cyclic process;In addition cladding can reduce the reaction of material and electrolyte,
The thermal stability of material is improved, improves security performance.
When preparing the lithium-rich anode material of Li-O adulterated lithium manganates, the grain size and anode of the adulterated lithium manganate powder of mixing
The proper ratio of the grain size of material powder and suitable mixing proportion can improve the tap density of powder well, further carry
The compacted density of high anode pole piece, and then promote the energy density of the battery of material.
When preparing the lithium-rich anode material of Li-O adulterated lithium manganates, by being calcined to mixed-powder, it can make
Grain surface passivation, reduces the destruction of particle surface that process is brought early period;It can also be released particle internal stress, make body
It is more stable.
The lithium-rich anode material of Li-O positions adulterated lithium manganate prepared by the present invention discharges for the first time reaches 290~295.5mAh/
G, head effect reach 90%, 0.5C/0.5C Xun Huans, 800 circle, keep more than 95.5%~96.5%, voltage drop is apparent in cyclic process
Reduce, while particle is mashed up so that mass energy density improves 19.5%~21% or so.
Specific embodiment
With specific embodiment, the present invention is further illustrated below, but the present invention is from the restriction of following embodiments.
Embodiment one
(1)α-MnO2, LiOH and Li3N is using molar ratio as Mn:Li:Li=1.0:1.05:0.34Ratio carry out dispensing, adopt
Dry ball milling batch mixing (control rotating speed 400r/min, when mixing time 8 is small) is carried out with high energy ball mill, it is uniformly mixed and is no different
Often occur as, then mixture is put into agate crucible, be placed in atmosphere protection stove carry out high temperature solid-phase sintering, be sintered under a nitrogen,
750 DEG C of sintering temperature is controlled, when sintering time 20 is small, generates nano level doping Li2MnO3Powder;
(2) Al is used2O3Wet method individual layer coats nano level doping Li2MnO3Powder enrobing process:Al2O3Powder exists first
It is homogenized in stirred tank, is dispersed to uniformly, adds in material doped with lithium manganate powder to be covered, stir, it is follow-up to dry
Dry when small (120 DEG C, 4), then when small (500 DEG C, 20) are calcined, integral coating amount is less than 4%, and dries and cross 325 mesh sieves
The adulterated lithium manganate powder coated;
(3) the adulterated lithium manganate powder (being denoted as A powder) of cladding (is denoted as B powder, and is cladding powder, directly with NCM523
Purchase) according to granularity D50(A powder) is granularity D50The doping of 12%, the A powder of (B powder) is 3.5%.It will using double-cone mixer
Two kinds of powder are sufficiently mixed, and when mixing time is 4.5 small, particle are made to be uniformly dispersed;
(4) mixed-powder is calcined under oxygen atmosphere, crushed, is classified, except magnetic, so as to which Li-O doping be prepared
The lithium-rich anode material of LiMn2O4 controls calcining heat as 650 DEG C, when calcination time is 10 small.
Compared to the research level of current rich lithium material, the Li positions prepared using the above method and O doping Li2MnO3Fu Li
The electric discharge for the first time of positive electrode reaches 290mAh/g, and head effects reach 90%, 0.5C/0.5C Xun Huans, 800 circle, keep more than 96%,
Voltage drop is obviously reduced in cyclic process, while particle is mashed up so that mass energy density improves 20% or so.
Embodiment two
(1)α-MnO2, LiOH and LiF be using molar ratio as Mn:Li:Li=1.0:1.0:1.1 ratio carries out dispensing, uses
High energy ball mill carries out dry ball milling batch mixing (control rotating speed 450r/min, when mixing time 8.5 is small), is uniformly mixed it and is no different
Often occur as, then mixture is put into agate crucible, be placed in atmosphere protection stove carry out high temperature solid-phase sintering, be sintered under a nitrogen,
800 DEG C of sintering temperature is controlled, when sintering time 22 is small, generation nanoscale doping Li2MnO3Powder;
(2) TiO is used2Wet method individual layer coats nano level doping Li2MnO3Powder coats process:TiO2Powder exists first
It is homogenized in stirred tank, is dispersed to uniformly, adds in material doped with lithium manganate powder to be covered, stir, it is follow-up to dry
Dry when small (120 DEG C, 4), then calcined when small (550 DEG C, 20), integral coating amount is less than 4.5%, and dries and sieving obtains
The adulterated lithium manganate powder of cladding;
(3) above-mentioned cladding powder (being denoted as A powder) and NCM622 (be denoted as B powder, and be cladding powder, is commercially available) according to
Granularity D50(A powder) is granularity D50The doping of 13%, the A powder of (B powder) is 4.5%.Two kinds of powder are filled using double-cone mixer
Divide mixing, when mixing time is 3 small, particle is made to be uniformly dispersed;
(4) mixed-powder is calcined under oxygen atmosphere, crushed, is classified, except magnetic, so as to which Li-O doping be prepared
The lithium-rich anode material of LiMn2O4 controls calcining heat as 700 DEG C, when calcination time is 8 small.
Compared to the research level of current rich lithium material, the Li positions prepared using the above method and O doping Li2MnO3Fu Li
The electric discharge for the first time of positive electrode reaches 291mAh/g, and head effects reach 90%, 0.5C/0.5C cycles, 800 circle, keep 96.5% with
On, voltage drop is obviously reduced in cyclic process, while particle is mashed up so that mass energy density improves 19.5% or so.
Embodiment three
(1)α-MnO2, LiOH and LiF, Li3N is using molar ratio as Mn:Li:Li:Li=1.0:1.0:0.23:0.29 ratio
Dispensing is carried out, dry ball milling batch mixing (control rotating speed 500r/min, when mixing time 9.5 is small) is carried out using high energy ball mill, is made
It is uniformly mixed phenomenon without exception, and then mixture is put into agate crucible, is placed in atmosphere protection stove and carries out high temperature solid-phase sintering,
It is sintered under a nitrogen, controls 900 DEG C of sintering temperature, when sintering time 24 is small, generate nano level doping Li2MnO3Powder;
(2) ZrO is used2Wet method individual layer coats above-mentioned Li2MnO3Powder coats process:ZrO2Powder is first in stirred tank
Homogenate is dispersed to uniformly, adds in material doped with lithium manganate powder to be covered, stir, subsequently dry (120 DEG C,
6 it is small when), then calcined when small (600 DEG C, 18), integral coating amount is less than 4.8%, and dries and sieve;
(3) above-mentioned cladding powder (being denoted as A powder) and LiCoO2(be denoted as B powder, and be cladding powder, is commercially available) according to
Granularity D50(A powder) is granularity D50The doping of 14%, the A powder of (B powder) is 4.8%.Two kinds of powder are filled using high speed mixer
Divide mixing, when mixing time is 4 small, particle is made to be uniformly dispersed;
(4) mixed-powder is calcined under oxygen atmosphere, crushed, is classified, except magnetic, so as to which Li-O doping be prepared
The lithium-rich anode material of LiMn2O4 controls calcining heat as 750 DEG C, when calcination time is 12 small.
Compared to the research level of current rich lithium material, the Li positions prepared using the above method and O doping Li2MnO3Fu Li
The electric discharge for the first time of positive electrode reaches 295.5mAh/g, and head effects reach 90%, 0.5C/0.5C cycles, 800 circle, keep 95.5% with
On, voltage drop is obviously reduced in cyclic process, while particle is mashed up so that mass energy density improves 21% or so.
The foregoing is only a preferred embodiment of the present invention, is not intended to limit the invention, for the skill of this field
For art personnel, the invention may be variously modified and varied.Within the spirit and principles of the invention, that is made any repaiies
Change, equivalent substitution, improvement etc., should all be included in the protection scope of the present invention.