CN109786721A - A kind of positive electrode, and its preparation method and application - Google Patents
A kind of positive electrode, and its preparation method and application Download PDFInfo
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- CN109786721A CN109786721A CN201910117166.4A CN201910117166A CN109786721A CN 109786721 A CN109786721 A CN 109786721A CN 201910117166 A CN201910117166 A CN 201910117166A CN 109786721 A CN109786721 A CN 109786721A
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Abstract
The present invention relates to a kind of positive electrode, and its preparation method and application, the preparation method of the positive electrode includes the following steps: that block copolymer solution is added in the mixed solution containing manganese salt, lithium salts and transition metal salt in (1), obtains precursor solution；(2) precursor solution is precipitated, positive electrode is obtained after calcining.The both ends of block copolymer of the present invention have different groups, one side hydrophilic radical is conducive to its dissolution in precursor solution, and then the carbon coating layer formed and the carbon material being distributed between primary particle are functional, are conducive to the electric conductivity for improving positive electrode；On the other hand, being selected by the other end in block copolymer can the mineralising group that is regulated and controled of structure, size and pattern to crystal, the positive electrode made has specific pattern and size, and then be more conducive to the crystal face of lithium ion transport by exposure, the diffusion rate of lithium ion is improved, chemical property is improved.
Description
Technical field
The invention belongs to field of lithium ion battery material, and in particular to a kind of positive electrode, and its preparation method and application.
Background technique
" energy conservation and new-energy automobile national planning (2012-2020) " proposes to arrive the year two thousand twenty, the quality of battery module in China
Density reaches 300Wh/kg or more, and cost is down to 1.5 yuan/Wh.The anode material for lithium-ion batteries of mainstream is main currently on the market
There are LiMn2O4, LiFePO4, ternary material high-voltage lithium nickel manganate etc., the specific capacity of these lithium electricity positive electrodes exists
200mAh/g hereinafter, operating voltage in 4V hereinafter, being unable to satisfy Future New Energy Source automobile power cell high voltage, high capacity, low
The demand for development of cost.
Lithium-rich manganese-based anode material specific capacity can reach 4.5V or more in 280mAh/g or more, operating voltage, it is considered to be
The ideal chose of next-generation anode material for lithium-ion batteries, but the voltage attenuation of lithium-rich manganese-based anode material is fast, and high rate performance is poor,
The problems such as phase transition occurs in cyclical stability difference and cyclic process, limits its Commercialization application.
CN106058203B disclose it is a kind of covered using basic zirconium phosphate as the double-contracting that outer cladding, calcirm-fluoride are interior cladding it is lithium-rich manganese-based
The preparation method of material.The preparation method comprises the following steps: dripping ammonium hydroxide and sodium hydroxide mixed solution under stirring condition
It is added in the mixed solution containing manganese salt, cobalt salt and nickel salt, obtains hydroxyl presoma；Then by the hydroxyl presoma with
Lithium source reacts to arrive manganese base shape richness oxidate for lithium；Manganese base shape richness oxidate for lithium obtained is added to calcium salt soln again
In, and fluoride aqueous solution is instilled, it filters calcining and obtains the manganese base shape richness oxidate for lithium of calcirm-fluoride cladding；Then fluorine after calcining
The manganese base shape richness oxidate for lithium for changing calcium cladding is added in the basic zirconium phosphate suspension that pH value is 7~7.5, after being sufficiently mixed,
It filters calcining and obtains final product, i.e., using basic zirconium phosphate as outer cladding, calcirm-fluoride is that lithium-rich manganese base material is covered in the double-contracting of interior cladding.Institute
Preparation process complex process is stated, it can not industrialized production.
CN102751480B discloses a kind of preparation method of cladded type lithium-rich manganese base material, and the preparation method includes such as
Lower step: (1) soluble nickel, cobalt, manganese salt is made into mixed solution；(2) aqueous slkali is prepared；(3) alkali soluble is added in a kettle
Liquid, nickel, cobalt, manganese mixed solution after stirring to get co-precipitation strongly, then are pumped into nickel, manganese mixing salt solution and aqueous slkali, by altogether
Cladded type presoma is obtained after precipitation reaction, ageing, centrifuge, drying；(4) presoma and lithium source homogeneous mixture are divided
Section sintering, then lithium-rich manganese base material can be obtained in sieving.The cladded type lithium-rich manganese base material surface alkalinty that the method obtains
Higher, chemical property is poor.
CN107834061 discloses a kind of method of modifying for improving lithium-rich manganese base material chemical property, the method packet
It includes following steps: (1) dispersing a certain amount of two-dimentional conductive agent and/or one-dimensional electric agent, lithium-rich manganese base material in a solvent respectively
Uniformly, conductive agent solution and lithium-rich manganese base material solution are obtained；(2) that lithium-rich manganese base material is added dropwise in the conductive agent solution is molten
It in liquid, is uniformly mixed, obtains slurry, dry to get the active substances in cathode materials with three-dimensional conductive network.The method is made
The active substances in cathode materials surface with three-dimensional conductive network have good electric conductivity, but its inner conductive performance compared with
Difference, and then cycle performance is poor.
Therefore, this field needs to develop a kind of preparation method of novel lithium-rich manganese-based anode material, and preparation process letter
It is single, can industrialized production, the positive electrode being prepared has good chemical property.
Summary of the invention
One of the objects of the present invention is to provide a kind of preparation method of positive electrode, the preparation method includes following step
It is rapid:
(1) block copolymer solution is added in the mixed solution containing manganese salt, lithium salts and transition metal salt, obtains forerunner
Liquid solution；
(2) precursor solution is precipitated, positive electrode is obtained after calcining.
The both ends of block copolymer of the present invention have different groups, and one side hydrophilic radical is conducive to it preceding
The dissolution in liquid solution is driven, and then reacts more abundant with the material component in mixed solution, the surface of material and primary
The dispersion of intergranular is more uniform, and the carbon material performance between carbon coating layer and primary particle formed on the surface of the material after calcining is good
It is good, be conducive to the electric conductivity for improving positive electrode；It on the other hand, can be to crystal by the other end selection in block copolymer
The group that is regulated and controled of structure, size and pattern, the positive electrode made has specific pattern and size, and then passes through
Exposure is more conducive to the crystal face of lithium ion transport, improves the diffusion rate of lithium ion, improves chemical property, close in 2C electric current
Under degree, first discharge specific capacity >=283.2mAh/g, coulombic efficiency >=91.6%, 200 week capacity retention ratio >=94.3% for the first time,
200 weeks voltage attenuation≤0.11V.
Sol-gel method is mostly used to prepare greatly in compared with the existing technology, preparation method of the invention can regulate and control crystal
Size and specific surface area, and then solve sol-gel method preparation positive electrode large specific surface area, it is more with electrolyte side reaction
The problem of；The prior art is mainly distributed on material secondary particle surface using the carbon encapsulated material that method for coating obtains, for two
The rupture of secondary particle does not have the effect of inhibition, while electric conductivity promotes smaller, the carbon material that preparation method of the invention obtains
It can be distributed between positive electrode primary particle, larger to the electric conductivity promotion of positive electrode, preparation method of the present invention is simple, can
Industrialized production.
Preferably, the relative molecular mass of step (1) described block copolymer is 500~20000g/mol, such as
1000g/mol, 3000g/mol, 5000g/mol, 10000g/mol, 15000g/mol etc..
Preferably, the mass concentration of the block copolymer solution is 0.01~3g/L, such as 0.3g/L, 0.8g/L, 1g/
L, 1.5g/L, 2g/L, 2.3g/L, 2.5g/L etc..
Preferably, one end of the block copolymer is mineralising group block, and the other end is to contain the embedding of hydrophilic radical
Section.
It is molten in precursor solution that block of the present invention containing hydrophilic radical can be conducive to block copolymer
Solution, mineralising group block can structure, size and pattern to crystal regulate and control.
Mineralising group of the present invention is by the way that mineralization, the base regulated and controled to the structure size pattern of crystal occurs
Group, the mineralization is the interaction by the ion in organic macromolecule and precursor solution in interface, Jin Ercong
Crystallization, the growth that positive electrode is controlled on molecular level, to make positive electrode that there is special structure and assembling mode.
Preferably, the mineralising group block includes in polyethylene oxide, polyvinyl acetate and polymethyl acrylate
Any one or at least two combination.
Preferably, the hydrophilic radical includes any one in carboxyl, amido, hydroxyl and polypeptide or at least two
Combination, further preferably, the block containing hydrophilic radical includes polyacrylamide, 2- [4- dihydroxyphosphoryl] -2-
The poly- acetic acid of oxa- butyl acrylate, hexa, polyacrylic acid, polyethyleneimine, polyethyleneimine-, polyethylene
Imines-polysulfonate acid, sulfonated polyethylene imines, poly epihydric alcohol, polyglutamic acid, poly- [2- (2- ethoxy)] ethylene, poly- 1,4,7,
10,13,16- hexanitrogen heterocycle octadecane ethylenimine, polymethylacrylic acid, alkylation methacrylic acid and polystyrolsulfon acid
In any one or at least two combination.
Preferably, the solvent in the block copolymer solution includes any one in water, surfactant and polypeptide
Or at least two combination.
Preferably, the surfactant includes cetyl trimethylammonium bromide and/or lauryl sodium sulfate.
Preferably, the polypeptide includes n,N-Dimethylformamide.
Preferably, the mass ratio of block copolymer and transition metal salt is 0.5~5:1 in the precursor solution, such as
1:1,1.5:1,2:1,2.5:1,3:1,3.5:1,4:1,4.5:1 etc..
When the mass ratio of block copolymer and transition metal salt is less than 0.5:1 in precursor solution of the present invention, forerunner
The content of block copolymer is too low in liquid solution, and then the content of the carbon material between carbon coating layer and primary particle is too low, right
It is smaller in the electric conductivity and structural stability castering action of positive electrode, and the insulating of positive electrode and electrolyte is poor, leads
Coulombic efficiency and cycle performance are poor for the first time for cause, and discharge platform voltage is easily decayed；In the precursor solution block copolymer with
When the mass ratio of transition metal salt is greater than 5:1, the too high levels of block copolymer in precursor solution, and then carbon coating layer and one
The too high levels of carbon material between secondary particle, the active capacity that electrochemical reaction occurs is lower, leads to the electric discharge of positive electrode
Specific capacity is lower.
Preferably, the process of step (2) described precipitating are as follows:, with precipitant mix, will be adjusted anti-in the precursor solution
The pH value and temperature for answering system are precipitated.
Preferably, the hybrid mode of the precursor solution and precipitating reagent is to be stirred, and preferably mechanical stirring, magnetic force stir
Mix and stir ultrasonic wave dispersion in any one or at least two combination.
Preferably, the pH value is 2~11, preferably 3~10, such as 3,4,5,6,7,8,9,10 etc..
Preferably, the temperature of the reaction system be 10~50 DEG C, preferably 20~35 DEG C, for example, 20 DEG C, 25 DEG C, 30 DEG C,
35 DEG C, 40 DEG C, 45 DEG C etc..
When the temperature of reaction system of the present invention is less than 10 DEG C, block copolymer is between the surface and primary particle of material
Dispersibility it is poor；When the temperature of reaction system is greater than 50 DEG C, reaction system nucleation is very fast, and it is more difficult to control to obtain product morphology.
Preferably, the precipitating reagent includes sodium hydroxide, sodium carbonate, sodium oxalate, sodium acetate, potassium hydroxide, potassium oxalate, hydrogen
In potassium oxide and potassium acetate any one or at least two combination.
Preferably, the molar concentration of the precipitating reagent be 0.01~2mol/L, such as 0.1mol/L, 0.5mol/L,
0.8mol/L, 1mol/L, 1.2mol/L, 1.5mol/L, 1.8mol/L etc..
Preferably, the molar ratio of manganese salt, lithium salts and transition metal salt is 0.64:1.2 in step (1) described mixed solution:
0.08~0.18, such as 0.64:1.2:0.08,0.64:1.2:0.1,0.64:1.2:0.12,0.64:1.2:0.14,0.64:
1.2:0.15,0.64:1.2:0.16 etc..
Preferably, the molar concentration of metal ion is 0.1~2mol/L in step (1) described mixed solution, such as
0.2mol/L, 0.5mol/L, 1mol/L, 1.2mol/L, 1.5mol/L etc..
Preferably, the manganese salt includes any one in manganese sulfate, manganese chloride, manganese nitrate and manganese acetate or at least two
Combination.
Preferably, the lithium salts includes lithium chloride, lithium nitrate, lithium sulfate, lithium acetate, lithium carbonate, lithium hydroxide and oxalic acid
In lithium any one or at least two combination.
Preferably, the transition metal salt includes cobalt salt, nickel salt, molysite, chromic salts, zirconates, strontium salt, titanium salt, yttrium salt and ruthenium
In salt any one or at least two combination.
It preferably, further include being washed to obtained sediment after step (2) precipitates the precursor solution
With dry process.
Preferably, the drying includes any one in forced air drying, vacuum drying and freeze-drying or at least two
Combination.
Preferably, the drying is forced air drying, the temperature of the drying be 50~100 DEG C (such as 60 DEG C, 70 DEG C, 80
DEG C, 90 DEG C etc.), the time of the drying is 1~5h (such as 2h, 3h, 4h etc.).
Preferably, the process of the calcining includes: that the product obtained after the drying is first warming up to 300~650 DEG C of (examples
Such as 350 DEG C, 400 DEG C, 500 DEG C, 600 DEG C) sintering 2~10h (such as 3h, 4h, 5h, 6h, 7h, 8h, 9h etc.), then heats up again
To 700~900 DEG C (such as 750 DEG C, 800 DEG C, 850 DEG C etc.) 1~20h of sintering (such as 3h, 5h, 8h, 10h, 12h, 15h, 18h
Deng).
As optimal technical scheme, a kind of preparation method of positive electrode of the present invention, the preparation method includes such as
Lower step:
(1) by manganese salt, lithium salts and transition metal salt molar ratio be 0.64:1.2:0.08~0.18, by manganese salt, lithium salts and
Transition metal salt mixing is soluble in water, and the molar concentration for obtaining metal ion is the mixed solution of 0.1~2mol/L；
(2) it is 0.5~5:1 by the mass ratio of block copolymer and transition metal salt, matter is added in the mixed solution
The block copolymer solution that concentration is 0.01~3g/L is measured, is stirred to obtain precursor solution；
(3) precipitating reagent that molar concentration is 0.01~2mol/L is added in the precursor solution, adjusts reaction system
PH value be 3~10, temperature be 20~35 DEG C, obtained sediment is washed, 50~100 DEG C of 1~5h of forced air drying, so
The product obtained after the drying is first warming up to 300~650 DEG C of 2~10h of sintering afterwards, is then warming up to 700~900 DEG C of burnings again
1~20h of knot, obtains positive electrode.
The second object of the present invention is to provide a kind of positive electrode, the positive electrode passes through anode material described in the first purpose
The preparation method of material obtains.
Preferably, the positive electrode includes lithium-rich manganese-based anode material, is set to the lithium-rich manganese-based anode material table
The carbon coating layer in face and the carbon material being present between the lithium-rich manganese-based anode material primary particle.
The present invention is dispersed between primary particle using carbon material, and carbon material has good electric conductivity, and then can assign
The good chemical property of positive electrode, while carbon material is filled between primary particle, enhances the connection between primary particle
To inhibit the fragmentation of second particle.
In the present invention carbon coating layer can contact with physical isolation positive electrode active materials with electrolyte, to reduce surface pair
Reaction and reacting metal ion dissolution, while carbon coating layer be also possible to prevent material in charge and discharge cycles because of volume repeatedly
Telescopic variation causes the problem of electrode dusting, and then improves the cycle performance of positive electrode.
Preferably, the chemical formula of the lithium-rich manganese-based anode material is xLi2MnO3·(1-x)LiMO2, the x is 0.45
~0.55, the M are metal.
Preferably, the M include in cobalt, nickel, iron, chromium, zirconium, strontium, titanium, yttrium and ruthenium any one or at least two group
It closes.
Preferably, in the positive electrode carbon mass percentage be 5~10wt%, such as 6wt%, 7wt%,
8wt%, 9wt% etc..
Preferably, the average grain diameter of the positive electrode be 0.1~30 μm, such as 0.5 μm, 1 μm, 5 μm, 10 μm, 15 μm,
20 μm, 22 μm, 25 μm etc..
Preferably, surface residual alkali amount≤300ppm of the positive electrode, for example, 50ppm, 100ppm, 150ppm,
200ppm, 250ppm etc..
The three of the object of the invention are to provide a kind of purposes of positive electrode as described in the second purpose, the positive electrode application
In field of batteries, it is preferred for field of lithium ion battery anode.
The fourth object of the present invention is to provide a kind of lithium ion battery, and the lithium ion battery includes described in the second purpose
Positive electrode.
Preferably, positive electrode described in two for the purpose of the anode material for lithium-ion batteries.
Compared with prior art, the invention has the following beneficial effects:
(1) both ends of block copolymer of the present invention have different groups, and one side hydrophilic radical is conducive to it
Dissolution in precursor solution, and then react more abundant with the material component in mixed solution, on the surface of material and one
More uniform, the carbon material between carbon coating layer and primary particle formed on the surface of the material after calcining of secondary intergranular dispersion
Can be good, be conducive to the electric conductivity for improving positive electrode；It on the other hand, can be right by the other end selection in block copolymer
The group that structure, size and the pattern of crystal are regulated and controled, the positive electrode made have specific pattern and size, in turn
The crystal face for being more conducive to lithium ion transport by exposure, improves the diffusion rate of lithium ion, improves chemical property, in 2C electricity
Under current density, first discharge specific capacity >=283.2mAh/g, for the first time coulombic efficiency >=91.6%, 200 week capacity retention ratio >=
94.3%, 200 weeks voltage attenuation≤0.11V.
(2) compared with the existing technology in mostly use sol-gel method to prepare greatly, preparation method of the invention can regulate and control crystalline substance
The size and specific surface area of body, and then the positive electrode large specific surface area of sol-gel method preparation is solved, with electrolyte side reaction
More problems；The prior art is mainly distributed on material secondary particle surface using the carbon encapsulated material that method for coating obtains, for
The rupture of second particle does not have the effect of inhibition, while electric conductivity promotes smaller, the carbon materials that preparation method of the invention obtains
Material can be distributed between positive electrode primary particle, larger to the electric conductivity promotion of positive electrode, and preparation method of the present invention is simple,
It can industrialized production.
(3) present invention is dispersed between primary particle using carbon material, and carbon material has good electric conductivity, and then can assign
The good chemical property of positive electrode is given, while carbon material is filled between primary particle, enhances the connection between primary particle
System is to inhibit the fragmentation of second particle；Carbon coating layer can be with physical isolation positive electrode active materials and electrolyte in the present invention
Contact, to reduce the dissolution of surface side reaction and reacting metal ion, while carbon coating layer is also possible to prevent material in charge and discharge
The problem of leading to electrode dusting because of the telescopic variation repeatedly of volume in electricity circulation, and then improve the cycle performance of positive electrode.
Specific embodiment
The technical scheme of the invention is further explained by means of specific implementation.Those skilled in the art should be bright
, the described embodiments are merely helpful in understanding the present invention, should not be regarded as a specific limitation of the invention.
Embodiment 1
A kind of preparation method of positive electrode includes the following steps:
(1) molecular formula Li is pressed1.2Mn0.64Ni0.08Co0.08O2Molar ratio weighing lithium chloride, manganese chloride, nickel chloride and chlorination
Cobalt is added deionized water dissolving and is configured to the mixed solution that the molar concentration of metal ion is 0.2mol/L；
(2) it is 1:1 by the mass ratio of block copolymer and transition metal salt, mass concentration is added in the mixed solution
It is 6000g/ that for the block copolymer solution of 0.1g/L, in the block copolymer solution, block copolymer, which is relative molecular mass,
The poly- Isosorbide-5-Nitrae of the polyethylene oxide-of mol, 7,10,13,16- hexanitrogen heterocycle octadecane ethylenimines, the wherein phase of polyethylene oxide
It is 5000g/mol, poly- Isosorbide-5-Nitrae, the relative molecular mass of 7,10,13,16- hexanitrogen heterocycle octadecane ethylenimines to molecular mass
For 1000g/mol, the solvent in the block copolymer solution is cetyl trimethylammonium bromide, is stirred to obtain forerunner
Liquid solution；
(3) precipitating reagent that molar concentration is 0.5mol/L is added in the precursor solution, adjusts the pH of reaction system
Value is 9.5, and temperature is 25 DEG C, obtained sediment is washed, 80 DEG C of forced air drying 4h, then will be obtained after the drying
Product be first warming up to 350 DEG C of sintering 4h, be then warming up to 800 DEG C of sintering 5h again, obtain positive electrode.
Embodiment 2
The difference from embodiment 1 is that the mass ratio of block copolymer and transition metal salt is 0.5:1 in step (2).
Embodiment 3
The difference from embodiment 1 is that the mass ratio of block copolymer and transition metal salt is 5:1 in step (2).
Embodiment 4
The difference from embodiment 1 is that the mass ratio of block copolymer and transition metal salt is 0.4:1 in step (2).
Embodiment 5
The difference from embodiment 1 is that the mass ratio of block copolymer and transition metal salt is 6:1 in step (2).
Embodiment 6
The difference from embodiment 1 is that block copolymer is polyethylene oxide-polymethylacrylic acid in step (2), wherein
The relative molecular mass of polyethylene oxide is 5000g/mol, and the relative molecular mass of polymethylacrylic acid is 1000g/mol.
Embodiment 7
The difference from embodiment 1 is that block copolymer is polyethylene oxide-polyvinyl acetate in step (2), wherein
The relative molecular mass of polyethylene oxide is 5000g/mol, and the relative molecular mass of polyvinyl acetate is 1000g/mol.
Embodiment 8
The difference from embodiment 1 is that block copolymer is poly- Isosorbide-5-Nitrae, 7,10,13,16- hexanitrogen heterocycles ten in step (2)
Eight alkane ethylenimines-polymethylacrylic acid, wherein polymers is poly- Isosorbide-5-Nitrae, and 7,10,13,16- hexanitrogen heterocycle octadecane ethylidene are sub-
The relative molecular mass of amine is 5000g/mol, and the relative molecular mass of polymethylacrylic acid is 1000g/mol.
Embodiment 9
A kind of preparation method of positive electrode includes the following steps:
(1) molecular formula Li is pressed1.2Mn0.64Ni0.04Co0.04O2Molar ratio weighing lithium sulfate, manganese sulfate, nickel sulfate and sulfuric acid
Cobalt is added deionized water dissolving and is configured to the mixed solution that the molar concentration of metal ion is 0.1mol/L；
(2) it is 1:1 by the mass ratio of block copolymer solution and precursor solution, quality is added in the mixed solution
Concentration is the block copolymer solution of 0.01g/L, and block copolymer is that relative molecular mass is in the block copolymer solution
The poly- Isosorbide-5-Nitrae of the polyethylene oxide-of 6000g/mol, 7,10,13,16- hexanitrogen heterocycle octadecane ethylenimines, wherein polycyclic oxygen second
The relative molecular mass of alkane is 5000g/mol, poly- Isosorbide-5-Nitrae, opposite point of 7,10,13,16- hexanitrogen heterocycle octadecane ethylenimines
Protonatomic mass is 1000g/mol, and the solvent in the block copolymer solution is lauryl sodium sulfate, is stirred to obtain forerunner
Liquid solution；
(3) precipitating reagent that molar concentration is 0.01mol/L is added in the precursor solution, adjusts the pH of reaction system
Value is 3, and temperature is 20 DEG C, obtained sediment is washed, 50 DEG C of forced air drying 5h, then will be obtained after the drying
Product is first warming up to 300 DEG C of sintering 10h, is then warming up to 700 DEG C of sintering 20h again, obtains positive electrode.
Embodiment 10
A kind of preparation method of positive electrode includes the following steps:
(1) molecular formula Li is pressed1.2Mn0.64Ni0.09Co0.09O2Molar ratio weighing lithium sulfate, manganese sulfate, nickel sulfate and sulfuric acid
Cobalt is added deionized water dissolving and is configured to the mixed solution that the molar concentration of metal ion is 2mol/L；
(2) it is 1:1 by the mass ratio of block copolymer solution and precursor solution, quality is added in the mixed solution
Concentration is the block copolymer solution of 3g/L, and block copolymer is that relative molecular mass is in the block copolymer solution
The poly- Isosorbide-5-Nitrae of the polyethylene oxide-of 6000g/mol, 7,10,13,16- hexanitrogen heterocycle octadecane ethylenimines, wherein polycyclic oxygen second
The relative molecular mass of alkane is 5000g/mol, poly- Isosorbide-5-Nitrae, opposite point of 7,10,13,16- hexanitrogen heterocycle octadecane ethylenimines
Protonatomic mass is 1000g/mol, and the solvent in the block copolymer solution is n,N-Dimethylformamide, is stirred before obtaining
Drive liquid solution；
(3) precipitating reagent that molar concentration is 2mol/L is added in the precursor solution, adjusts the pH value of reaction system
It is 10, temperature is 35 DEG C, obtained sediment is washed, 100 DEG C of forced air drying 1h, then will be obtained after the drying
Product is first warming up to 650 DEG C of sintering 2h, is then warming up to 900 DEG C of sintering 1h again, obtains positive electrode.
Comparative example 1
The difference from embodiment 1 is that block copolymer is replaced with graphene in step (2).
Comparative example 2
The difference from embodiment 1 is that not adding block copolymer in step (2).
Performance test:
The positive electrode being prepared is performed the following performance tests:
(1) battery assembly: anode pole piece is made in positive electrode produced by the present invention, cathode is metal lithium sheet, and diaphragm is
Celgard2400, electrolyte are the LiPF6/DMC+DEC of 1mol/L, are assembled into CR2025 type button cell.The system of anode pole piece
Standby process includes: the positive electrode that will be prepared, conductive agent acetylene black, binder PVDF (Kynoar) according to 8:1:1
Mass ratio, with N-Methyl pyrrolidone NMP as solvent be mixed and made into slurry after be coated in aluminium foil on, 120 DEG C drying 12 hours
Afterwards, roll and be punched into diameter be 8.4mm disk as anode pole piece.
(2) electro-chemical test: in normal temperature condition, button cell obtained is surveyed on LAND battery test system
Examination, charging/discharging voltage section are 2.0~4.8V, and charge-discharge test, 200 weeks conservation rate=circulations are carried out under 2C current density
200 weeks specific discharge capacity/first discharge specific capacities, coulombic efficiency=first discharge specific capacity/initial charge specific capacity for the first time,
Discharge platform voltage-discharge platform the voltage of circulation 200 weeks of 200 weeks voltage attenuations=for the first time.
Table 1
It can be seen from Table 1 that the positive electrode chemical property that Examples 1 to 10 obtains is good, in 2C current density
Under, first discharge specific capacity >=283.2mAh/g, coulombic efficiency >=91.6%, 200 week capacity retention ratio >=94.3% for the first time,
200 weeks voltage attenuation≤0.11V.
It can be seen from Table 1 that embodiment 4 is relative to embodiment 1, under 2C current density, coulombic efficiency and 200 for the first time
All capacity retention ratios are lower, and 200 weeks voltage attenuations are higher, it may be possible to because the content of block copolymer is too low in embodiment 4,
And then the content of the carbon material between carbon coating layer and primary particle is too low, for the electric conductivity and structural stability of positive electrode
Castering action is smaller, and the insulating of positive electrode active materials and electrolyte is poor, cause coulombic efficiency for the first time and cycle performance compared with
Difference, discharge platform voltage are easily decayed, so embodiment 4 is relative to embodiment 1, under 2C current density, for the first time coulombic efficiency and
Capacity retention ratio is lower within 200 weeks, and 200 weeks voltage attenuations are higher.
It can be seen from Table 1 that embodiment 5 is relative to embodiment 1, under 2C current density, first discharge specific capacity compared with
It is low, it may be possible to because in embodiment 5 block copolymer too high levels, and then the carbon material between carbon coating layer and primary particle
Too high levels, cause the active capacity that electrochemical reaction occurs lower, and then embodiment 5 is relative to embodiment 1, in 2C electric current
Under density, first discharge specific capacity is lower.
It can be seen from Table 1 that embodiment 7 is relative to embodiment 1, under 2C current density, first discharge specific capacity, head
Secondary coulombic efficiency and 200 weeks capacity retention ratios are lower, and 200 weeks voltage attenuations are higher, it may be possible to because block is total in embodiment 7
The both ends of polymers are all the block containing hydrophilic radical, without mineralising group block, and then positive electrode during the preparation process
Can not self assembly exposure be more conducive to the crystal faces of lithium ion transport, and the structural stability of positive electrode is promoted it is smaller,
Embodiment 7 is relative to embodiment 1 in turn, under 2C current density, first discharge specific capacity, for the first time coulombic efficiency and 200 weeks appearances
It is lower to measure conservation rate, and 200 weeks voltage attenuations are higher.
It can be seen from Table 1 that embodiment 8 is relative to embodiment 1, under 2C current density, first discharge specific capacity, head
Secondary coulombic efficiency and 200 weeks capacity retention ratios are lower, and 200 weeks voltage attenuations are higher, it may be possible to because block is total in embodiment 8
The both ends of polymers are all mineralising group block, and not containing the block of hydrophilic radical, and then block copolymer is in the table of material
Dispersed poor, the carbon materials between carbon coating layer and primary particle formed on the surface of the material after calcining between face and primary particle
Expect that performance is poor, obtained positive electrode electric conductivity is poor, and smaller for the promotion of the structural stability of positive electrode, so real
Example 8 is applied relative to embodiment 1, under 2C current density, first discharge specific capacity, for the first time coulombic efficiency and 200 weeks capacity are kept
Rate is lower, and 200 weeks voltage attenuations are higher.
It can be seen from Table 1 that comparative example 1 is relative to embodiment 1, under 2C current density, first discharge specific capacity, head
Secondary coulombic efficiency and 200 weeks capacity retention ratios are lower, and 200 weeks voltage attenuations are higher, it may be possible to because by block in comparative example 1
Copolymer replaces with graphene, and graphene can not be dispersed between positive electrode primary particle, and for positive electrode active materials with
The insulating of electrolyte is poor, and side reaction and digestion of metallic ion are more, and cathode material structure stability is poor, so comparative example
1 relative to embodiment 1, under 2C current density, first discharge specific capacity, for the first time coulombic efficiency and 200 weeks capacity retention ratios compared with
It is low, and 200 weeks voltage attenuations are higher.
It can be seen from Table 1 that comparative example 2 is relative to embodiment 1, under 2C current density, first discharge specific capacity, head
Secondary coulombic efficiency and 200 weeks capacity retention ratios are lower, and 200 weeks voltage attenuations are higher, it may be possible to because not adding in comparative example 2
Block copolymer, and then side reaction is more when generation electrochemical reaction, cathode material structure stability is poor, so comparative example 2
Relative to embodiment 1, under 2C current density, first discharge specific capacity, for the first time coulombic efficiency and 200 weeks capacity retention ratios compared with
It is low, and 200 weeks voltage attenuations are higher.
Method detailed of the invention that the present invention is explained by the above embodiments, but the invention is not limited to it is above-mentioned in detail
Method, that is, do not mean that the invention must rely on the above detailed methods to implement.Person of ordinary skill in the field should
It is illustrated, any improvement in the present invention, addition, the concrete mode of equivalence replacement and auxiliary element to each raw material of product of the present invention
Selection etc., all of which fall within the scope of protection and disclosure of the present invention.
Claims (10)
1. a kind of preparation method of positive electrode, which is characterized in that the preparation method includes the following steps:
(1) block copolymer solution is added in the mixed solution containing manganese salt, lithium salts and transition metal salt, it is molten obtains presoma
Liquid；
(2) precursor solution is precipitated, positive electrode is obtained after calcining.
2. preparation method as described in claim 1, which is characterized in that the average molecular matter of step (1) described block copolymer
Amount is 500~20000g/mol；
Preferably, the mass concentration of the block copolymer solution is 0.01~3g/L；
Preferably, one end of the block copolymer is mineralising group block, and the other end is the block containing hydrophilic radical；
Preferably, the mineralising group block includes any in polyethylene oxide, polyvinyl acetate and polymethyl acrylate
It is a kind of or at least two combination；
Preferably, the hydrophilic radical include in carboxyl, amido, hydroxyl and polypeptide any one or at least two group
It closes, further preferably, the block containing hydrophilic radical includes polyacrylamide, 2- [4- dihydroxyphosphoryl] -2- oxygen
The poly- acetic acid of miscellaneous butyl acrylate, hexa, polyacrylic acid, polyethyleneimine, polyethyleneimine-, polyethyleneimine
Amine-polysulfonate acid, sulfonated polyethylene imines, poly epihydric alcohol, polyglutamic acid, poly- [2- (2- ethoxy)] ethylene, poly- 1,4,7,10,
In 13,16- hexanitrogen heterocycle octadecane ethylenimine, polymethylacrylic acid, alkylation methacrylic acid and polystyrolsulfon acid
Any one or at least two combination；
Preferably, the solvent in the block copolymer solution include in water, surfactant and polypeptide any one or extremely
Few two kinds of combination；
Preferably, the surfactant includes cetyl trimethylammonium bromide and/or lauryl sodium sulfate；
Preferably, the polypeptide includes n,N-Dimethylformamide；
Preferably, the mass ratio of block copolymer and transition metal salt is 0.5~5:1 in the precursor solution.
3. preparation method as claimed in claim 1 or 2, which is characterized in that the process of step (2) described precipitating are as follows: will be described
With precipitant mix in precursor solution, the pH value and temperature for adjusting reaction system are precipitated；
Preferably, the hybrid mode of the precursor solution and precipitating reagent be stirred, preferably mechanical stirring, magnetic agitation and
Ultrasonic wave dispersion in any one or at least two combination；
Preferably, the pH value is 2~11, preferably 3~10；
Preferably, the temperature of the reaction system is 10~50 DEG C, preferably 20~35 DEG C；
Preferably, the precipitating reagent includes sodium hydroxide, sodium carbonate, sodium oxalate, sodium acetate, potassium hydroxide, potassium oxalate, hydroxide
In potassium and potassium acetate any one or at least two combination；
Preferably, the molar concentration of the precipitating reagent is 0.01~2mol/L.
4. the preparation method as described in one of claim 1-3, which is characterized in that manganese salt, lithium in step (1) described mixed solution
The molar ratio of salt and transition metal salt is 0.64:1.2:0.08~0.18；
Preferably, the molar concentration of metal ion is 0.1~2mol/L in step (1) described mixed solution；
Preferably, the manganese salt include in manganese sulfate, manganese chloride, manganese nitrate and manganese acetate any one or at least two group
It closes；
Preferably, the lithium salts includes in lithium chloride, lithium nitrate, lithium sulfate, lithium acetate, lithium carbonate, lithium hydroxide and lithium oxalate
Any one or at least two combination；
Preferably, the transition metal salt includes in cobalt salt, nickel salt, molysite, chromic salts, zirconates, strontium salt, titanium salt, yttrium salt and ruthenium salt
Any one or at least two combination.
5. the preparation method as described in one of claim 1-4, which is characterized in that step (2) carries out the precursor solution
It further include the process that obtained sediment is washed and dried after precipitating；
Preferably, the drying include in forced air drying, vacuum drying and freeze-drying any one or at least two group
It closes；
Preferably, the drying is forced air drying, and the temperature of the drying is 50~100 DEG C, the time of the drying is 1~
5h；
Preferably, the process of the calcining include: by the product obtained after the drying be first warming up to 300~650 DEG C sintering 2~
Then 10h is warming up to 700~900 DEG C of 1~20h of sintering again.
6. the preparation method of positive electrode as described in one of claim 1-5, which is characterized in that the preparation method includes as follows
Step:
It (1) is 0.64:1.2:0.08~0.18 by the molar ratio of manganese salt, lithium salts and transition metal salt, by manganese salt, lithium salts and transition
Metal salt mixing is soluble in water, and the molar concentration for obtaining metal ion is the mixed solution of 0.1~2mol/L；
(2) it is 0.5~5:1 by the mass ratio of block copolymer and transition metal salt, it is dense that quality is added in the mixed solution
Degree is the block copolymer solution of 0.01~3g/L, is stirred to obtain precursor solution；
(3) precipitating reagent that molar concentration is 0.01~2mol/L is added in the precursor solution, adjusts the pH of reaction system
Value is 3~10, and temperature is 20~35 DEG C, obtained sediment is washed, 50~100 DEG C of 1~5h of forced air drying, then will
The product obtained after the drying is first warming up to 300~650 DEG C of 2~10h of sintering, is then warming up to 700~900 DEG C of sintering 1 again
~20h, obtains positive electrode.
7. a kind of positive electrode, which is characterized in that the system that the positive electrode passes through positive electrode described in one of claim 1-6
Preparation Method obtains.
8. positive electrode as claimed in claim 7, which is characterized in that the positive electrode include lithium-rich manganese-based anode material,
It is set to the carbon coating layer on the lithium-rich manganese-based anode material surface and is present in the lithium-rich manganese-based anode material primary particle
Between carbon material；
Preferably, the chemical formula of the lithium-rich manganese-based anode material is xLi2MnO3·(1-x)LiMO2, the x be 0.45~
0.55, the M are metal；
Preferably, the M include in cobalt, nickel, iron, chromium, zirconium, strontium, titanium, yttrium and ruthenium any one or at least two combination；
Preferably, the mass percentage of carbon is 5~10wt% in the positive electrode；
Preferably, the average grain diameter of the positive electrode is 0.1~30 μm；
Preferably, surface residual alkali amount≤300ppm of the positive electrode.
9. a kind of purposes of the positive electrode as described in claim 7 or 8, which is characterized in that the positive electrode is applied to battery
Field is preferred for field of lithium ion battery anode.
10. a kind of lithium ion battery, which is characterized in that the lithium ion battery includes positive material described in claim 7 or 8
Material；
Preferably, the anode material for lithium-ion batteries is positive electrode described in claim 7 or 8.
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| CN111640923A (en) * | 2020-06-01 | 2020-09-08 | 广州大学 | Lithium nickel manganese oxide positive electrode material and preparation method thereof |
| CN112436135A (en) * | 2020-11-20 | 2021-03-02 | 国联汽车动力电池研究院有限责任公司 | Positive electrode material and preparation method and application thereof |
| CN112436142A (en) * | 2020-10-23 | 2021-03-02 | 江苏同科蓄电池股份有限公司 | Positive electrode slurry of lithium iron phosphate battery and preparation method thereof |
| CN114843498A (en) * | 2022-03-30 | 2022-08-02 | 北京当升材料科技股份有限公司 | Sodium-containing oxide positive electrode material, preparation method and application thereof, positive electrode plate and application thereof |
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| CN110247039A (en) * | 2019-06-17 | 2019-09-17 | 启东启澳新材料科技发展有限公司 | A kind of nickel lithium manganate cathode material preparation method coating strontium titanate base conductive coating |
| CN111640923A (en) * | 2020-06-01 | 2020-09-08 | 广州大学 | Lithium nickel manganese oxide positive electrode material and preparation method thereof |
| CN112436142A (en) * | 2020-10-23 | 2021-03-02 | 江苏同科蓄电池股份有限公司 | Positive electrode slurry of lithium iron phosphate battery and preparation method thereof |
| CN112436135A (en) * | 2020-11-20 | 2021-03-02 | 国联汽车动力电池研究院有限责任公司 | Positive electrode material and preparation method and application thereof |
| TWI788041B (en) * | 2021-10-05 | 2022-12-21 | 芯量科技股份有限公司 | Battery positive electrode material and manufacturing method thereof |
| CN114843498A (en) * | 2022-03-30 | 2022-08-02 | 北京当升材料科技股份有限公司 | Sodium-containing oxide positive electrode material, preparation method and application thereof, positive electrode plate and application thereof |
| US11984591B1 (en) | 2022-03-30 | 2024-05-14 | Beijing Easpring Material Technology Co., Ltd. | Sodium-containing oxide positive electrode material and preparation method therefor and use thereof, and positive electrode plate and use thereof |
| CN115108589A (en) * | 2022-07-21 | 2022-09-27 | 广东邦普循环科技有限公司 | Carbon-coated lithium-rich oxide and preparation method and application thereof |
| CN115108589B (en) * | 2022-07-21 | 2024-05-10 | 广东邦普循环科技有限公司 | Carbon-coated lithium-rich oxide and preparation method and application thereof |
| WO2024066188A1 (en) * | 2022-09-26 | 2024-04-04 | 广东邦普循环科技有限公司 | Spinel-phase lithium nickel manganate positive electrode material, preparation method therefor, and battery |
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