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A kind of silicon-based negative electrode material for lithium ion battery and preparation method thereof

A silicon-based negative electrode material, lithium-ion battery technology, applied in battery electrodes, secondary batteries, circuits, etc., can solve problems such as pole piece processing performance, compaction density limitation, affecting pole piece cell capacity and energy density, etc. Achieve the effect of improving electrochemical performance and relieving contact stress

Active Publication Date: 2021-08-17
BEIJING WELION NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the existence of the cavity structure, the processing performance and compaction density of the material are greatly limited, which seriously affects the capacity and energy density of the pole piece and the battery.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0046] A preparation method of a silicon-based negative electrode material for a lithium ion battery, comprising the following steps:

[0047] A. Take 500g of silicon-based composite material, 0.5g of polyvinylidene fluoride, and 0.5g of carbon nanotubes into a ball mill jar containing 250g of N-methylpyrrolidone, stir evenly, take out and dry, then grind and crush to obtain carbon nanotubes on the surface Silicon-based composite material for cladding;

[0048] B. adding the silicon-based composite material prepared in the above step A into the fluidized bed cavity;

[0049] C. Get 125g polymethyl methacrylate and add in 1250g dimethyl carbonate, stir until the solid dissolves completely;

[0050] D. The polymethyl methacrylate solution prepared in the above step C is pumped into the fluidized bed at a rate of 80 g / min, and the reaction is completed to obtain a silicon-based negative electrode material coated with polymethyl methacrylate.

Embodiment 2

[0052] A preparation method of a silicon-based negative electrode material for a lithium ion battery, comprising the following steps:

[0053] A. Take 500g of silicon-based composite material and add it to the fluidized bed cavity;

[0054] B. Take 5g of sodium carboxymethylcellulose, 50g of carbon nanotubes and graphene and add it to 1500g of deionized water. After stirring evenly, pump it into the fluidized bed at a rate of 50g / min. The inlet temperature is 200°C. After the sample is taken out, it is crushed to obtain a silicon-based composite material coated with a mixture of carbon nanotubes and graphene;

[0055] C. adding the silicon-based composite material obtained in the above step B into the fluidized bed cavity;

[0056] D. Get 200g two (2,3-cycloglycerol carbonate) carbonates and add in 4000g ethylene carbonate, stir until the solid dissolves completely;

[0057] E. The bis(2,3-cycloglycerol carbonate) carbonate solution prepared in the above step D is pumped int...

Embodiment 3

[0059] A preparation method of a silicon-based negative electrode material for a lithium ion battery, comprising the following steps:

[0060] A. Get 500g of the silicon-based composite material and add it to the ethanol solution of nickel nitrate, mix it evenly, dry it, and grind it; then place it in a chemical vapor deposition furnace to grow carbon nanofibers; after the reaction, drop to room temperature, take it out and grind it to obtain A silicon-based composite material with a carbon nanomaterial coating on the surface;

[0061] B. adding the silicon-based composite material prepared in the above step A into the fluidized bed cavity;

[0062] C. Get 25g tetrakis (1,2-glyceryl sulfite) pyromellitic acid ester and add in the mixed solution of ethylene carbonate and dimethyl carbonate of 125g, stir until the solid dissolves completely;

[0063] D. The tetrakis (1,2-cyclosulfite) pyromellitic acid ester solution prepared in the above step C is pumped into the fluidized bed...

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PUM

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Abstract

The invention discloses a silicon-based negative electrode material for lithium ion batteries and a preparation method thereof, belonging to the technical field of lithium ion batteries. The lithium-ion battery silicon-based negative electrode material includes from the inside to the outside: a silicon-based composite material, a carbon nanomaterial coating layer, and a polymer coating layer; wherein, the mass of the polymer coating layer and the silicon-based composite material The ratio is 0.05-0.4:1, and the mass ratio of the carbon nanomaterial coating layer to the silicon-based composite material is 0.001-0.1:1. It is prepared by using raw materials such as silicon-based composite materials, polymers, and carbon nanomaterials through a one-step coating method or a multi-step coating method. The silicon-based negative electrode material of the present invention can effectively release the stress generated by volume expansion under extremely high compaction density of the pole piece, has excellent processing performance, and can effectively improve the cycle performance and energy density of the battery at the same time.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a silicon-based negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] Due to its high energy density, long life, no pollution, and excellent storage performance, lithium-ion batteries have become the preferred battery system for 3C products, electric vehicles, and large-scale energy storage equipment. At present, graphite-based carbon-based anode materials widely used in lithium-ion batteries have low capacity and cannot meet the requirements of high-performance lithium-ion battery anodes. The theoretical capacity of silicon material is as high as 4200mAh / g. At the same time, it has the advantages of low potential, stable and long platform discharge, high safety performance, environmental friendliness and no pollution. It is considered to be one of the most promising high-energy density anode materials ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/48H01M4/62H01M10/0525
CPCH01M4/366H01M4/386H01M4/483H01M4/62H01M4/625H01M10/0525Y02E60/10
Inventor 黄杰王胜彬丁泽鹏张鹏伟李群张超
Owner BEIJING WELION NEW ENERGY TECH CO LTD