Method for reducing surface alkalinity of high-nickel positive electrode material, positive electrode material and lithium battery

A positive electrode material, surface alkaline technology, applied in the direction of battery electrodes, secondary batteries, circuits, etc., can solve the problems of affecting the electrochemical performance of materials, destroying the crystal structure of materials, and having no electrochemical activity, so as to improve the electrochemical performance of cycles. Performance, simple process, and the effect of improving processing performance

Active Publication Date: 2020-02-21
TIANMU LAKE INST OF ADVANCED ENERGY STORAGE TECH CO LTD
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AI Technical Summary

Problems solved by technology

However, the above scheme still has the following defects: (1) Since high-nickel materials, especially NCM or NCA materials with a Ni content greater than 85%, are sensitive to water, even if they are directly washed with water for a short period of time, some materials in the lattice may be removed. Li + Dissolution produces cubic phase NiO-like species with no electrochemical activity, which destroys the crystal structure of the material, thus affecting the electrochemical performance of the material, such as the reduction of reversible capacity and poor cycle performance; (2) After washing, the material needs to be dehydrated, re- Drying and other multi-step processes will cause loss of raw materials

Method used

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  • Method for reducing surface alkalinity of high-nickel positive electrode material, positive electrode material and lithium battery

Examples

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Embodiment 1

[0021] (1) Add a certain mass of manganese acetate to 100g of propylene glycol, stir at a speed of 2m / s to dissolve it, and form a manganese acetate solution;

[0022] (2) Add 200g Li to the manganese acetate solution 1.01 (Ni 0.85 co 0.10 mn 0.04 Al 0.01 ) 0.99 o 2 powder, continue to stir for 10 minutes; then stir and evaporate at a linear speed of 8m / s under vacuum at 80°C for 4h to obtain the dried material;

[0023] (3) The dried mixture was calcined at 500°C in an oxygen atmosphere for 2 hours to obtain Li x MnO 2 Coated high-nickel ternary cathode material.

[0024] The lithium ion battery of the present embodiment is to mix the above-mentioned high-nickel ternary positive electrode material coated, the binder polyvinylidene fluoride PVDF, and the conductive agent carbon black Super P Li in a weight ratio of 94:3:3, and use N- Methylpyrrolidone was used as a solvent to prepare positive electrode slurry. The positive electrode slurry was coated on battery-grade...

Embodiment 2

[0026] (1) Add a certain mass of lithium nitrate and manganese acetate to 400g of ethanol, stir at a speed of 5m / s to dissolve them, and form a mixed solution of lithium nitrate and manganese acetate;

[0027] (2) Add 400g Li to the mixed solution 1.05 (Ni 0.90 co 0.05 mn 0.04 W 0.01 ) 0.95 o 2 powder, continue to stir for 8 minutes; then stir and evaporate at a linear speed of 8m / s for 4h under vacuum at 40°C to obtain the dried material;

[0028] (3) The dried material was calcined in an oxygen atmosphere at 600°C for 2 hours to obtain Li x MnO 2 Coated high-nickel ternary cathode material.

[0029] The lithium-ion battery of this embodiment uses the positive electrode material of this embodiment, and is prepared and tested with reference to the method of Embodiment 1.

Embodiment 3

[0031] (1) Add a certain mass of lithium hydroxide and manganese acetate to 400g of methanol, stir at a speed of 2m / s to dissolve them, and form a mixed solution of lithium hydroxide and manganese acetate;

[0032] (2) Add 100g Li to the mixed solution 0.97 (Ni 0.95 co 0.02 mn 0.01 Al 0.02 ) 1.03 o 2 powder, continue to stir for 9 minutes; then, under vacuum conditions at 20°C, stir and evaporate at a linear speed of 8m / s for 2h to obtain the dried material;

[0033] (3) The dried material was calcined in an oxygen atmosphere at 700°C for 2 hours to obtain Li x MnO 2 Coated high-nickel ternary cathode material.

[0034] The lithium-ion battery of this embodiment uses the positive electrode material of this embodiment, and is prepared and tested with reference to the method of Embodiment 1.

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Abstract

The invention belongs to the lithium ion battery technology field, and relates to a method for reducing surface alkalinity of a high-nickel positive electrode material, the positive electrode materialand a lithium battery. The method for reducing the surface alkalinity of the high-nickel positive electrode material comprises the step of mixing an alcohol solution of lithium salt and manganese salt mixed according to a certain molar ratio with a high-nickel ternary, drying and sintering to obtain the high-nickel positive electrode material coated with LixMnO2. By using the method of the invention, a damage to a surface structure of the material and losses of raw materials due to long-time washing of a large amount of water can be avoided, and electrochemical properties such as material circulation and the like are greatly improved. In addition, a residual alkali amount on the material surface can be effectively reduced, a technology is simple, a process is easy to control and the method is suitable for large-scale production.

Description

technical field [0001] The invention belongs to the field of lithium batteries, and in particular relates to a method for reducing the surface alkalinity of a high-nickel positive electrode material, the positive electrode material and a lithium battery. Background technique [0002] Lithium battery cathode materials, especially high-nickel ternary NCM / NCA materials, due to the residual LiOH and Li 2 CO 3 The high impurity content (>0.7wt%) will seriously affect the pulping and coating process of the positive electrode of the battery, and will also affect the safety and cycle performance of the battery. The existing standard process: water washing or water washing + coating has a more obvious effect in removing alkaline lithium-containing impurities, but there are also obvious disadvantages. For example, the existing water washing and coating process will sacrifice the electrochemical performance of the material (capacity reduction , cycle becomes worse), especially for...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/485H01M4/505H01M4/525H01M4/62H01M10/0525
CPCH01M4/366H01M4/485H01M4/505H01M4/525H01M4/62H01M10/0525Y02E60/10
Inventor 任瑜许国干吕焱
Owner TIANMU LAKE INST OF ADVANCED ENERGY STORAGE TECH CO LTD
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