Graft copolymer coated silicon-based material and preparation method thereof

A graft copolymer, silicon-based material technology, applied in structural parts, electrical components, battery electrodes, etc., can solve the problems of poor cycle performance and low first charge and discharge efficiency of lithium-ion batteries, and achieve the effect of inhibiting volume expansion

Active Publication Date: 2021-06-29
ZHUHAI COSMX BATTERY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The invention provides a graft copolymer-coated silicon-based material and a preparation method thereof. In the graft copolymer-coated silicon-based material, the graft copolymer is coated on the surface of the silicon-based material. Coating can improve the conductivity of silicon-based materials to lithium ions and provide mechanical support for the matrix. The graft copolymer coated silicon-based materials can be used to solve the first charge and discharge of lithium-ion batteries caused by the volume expansion of silicon-based materials Problems of low efficiency and poor cycle performance

Method used

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  • Graft copolymer coated silicon-based material and preparation method thereof
  • Graft copolymer coated silicon-based material and preparation method thereof
  • Graft copolymer coated silicon-based material and preparation method thereof

Examples

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[0066] The preparation method of the present invention will be further described in detail in conjunction with specific examples below. It should be understood that the following examples are only for illustrating and explaining the present invention, and should not be construed as limiting the protection scope of the present invention. All technologies realized based on the above contents of the present invention are covered within the scope of protection intended by the present invention.

[0067] The experimental methods used in the following examples are conventional methods unless otherwise specified; the reagents and materials used in the following examples can be obtained from commercial sources unless otherwise specified.

Embodiment 1

[0083] Preparation of PAA-g-mPBI coated silica material:

[0084] 0.003 parts by mass of mPBI (viscosity average molecular weight=250kDa) and 0.027 parts by mass of PAA (Mn=450,000) were dissolved in 1 part by mass of DMAc, and reacted at 150°C for 8h. Then add 99 parts by mass of DMAc and 100 parts by mass of irregular granular silicon oxide (D 50 10 μm) vigorously stirred for 4h. Then spray drying to obtain PAA 90 -g-mPBI 10 Coated silicon oxide negative electrode material (the total polymer mass (mPBI and PAA) is 0.03% of the silicon oxide mass).

[0085] Preparation of negative electrode sheet:

[0086] With the above-mentioned negative electrode material of 20 mass parts, the graphite of 74 mass parts, the conductive agent carbon black of 2.0 mass parts, the conductive agent carbon nanotube of 1.0 mass parts, the binding agent SBR of 2.5 mass parts, the carboxymethyl group of 0.5 mass parts Cellulose and 100 parts by mass of water are fully mixed to make negative ele...

Embodiment 2

[0092] Preparation of PAA-g-mPBI-coated silicon oxide material: the same as in Example 1, except that the total mass of the polymer is 0.06% of the mass of silicon oxide.

[0093] Negative electrode sheet, positive electrode sheet and battery preparation are the same as in Example 1.

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Abstract

According to a graft copolymer coated silicon-based material and a preparation method thereof provided by the invention, a polyacrylic acid grafted benzimidazole copolymer coats the surface of the silicon-based material, and the polyacrylic acid and the benzimidazole copolymer have strong covalent bonds so as to ensure the compatibility of the two substances; the copolymer has certain strength so that the volume expansion of the silicon material can be effectively inhibited; a hydrogen bond formed by PAA in the copolymer and a silicon substrate, especially SiO, has good coating stability, and PAA-g-PBI has a three-dimensional network structure and an effect of reversible ionic bond reconstruction, and a specific structure can show a high adhesive force, high mechanical strength and self-healing characteristics to silicon, and can effectively adapt to volume expansion and shrinkage of a silicon-based material; and the structural stability can still be maintained after a huge volume change is generated so that the silicon-based material with high cycle stability is obtained.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a graft copolymer-coated silicon-based material and a preparation method. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, long cycle life, and environmental friendliness. Therefore, lithium-ion batteries have been widely used. At present, graphite is the most commonly used negative electrode material in lithium-ion batteries, and its theoretical specific capacity is 372mAh / g, which limits the development of lithium-ion batteries to higher energy density, while the theoretical specific capacity of silicon materials can reach 4200mAh / g , the actual specific capacity is greater than 3000mAh / g, when it replaces graphite as the anode material of lithium-ion batteries, it can significantly increase the energy density of lithium-ion batteries, and is a very promising next-generation anode material. [0003] However, silicon ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62H01M10/0525
CPCH01M4/386H01M4/625H01M10/0525Y02E60/10
Inventor 莫肇华赵伟李素丽
Owner ZHUHAI COSMX BATTERY CO LTD
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