Method for making lithium ion battery anode active material

Patent metadata

Field	Value
Publication number	US-2016164081-A1
Application number	US-201414907295-A
Country	US
Kind code	A1
Filing date	Jul 2, 2014
Priority date	Jul 23, 2013
Publication date	Jun 9, 2016
Grant date	—

Abstract

A method for making a lithium ion battery anode active material comprising: providing silicon particles and a silane coupling agent, wherein the silane coupling agent comprises a hydrolysable functional group and an organic functional group; mixing the silicon particles and the silane coupling agent in water to obtain a first mixture; adding a monomer or oligomer to the first mixture to obtain a second mixture, the surfaces of the silicon particles being coated with a polymer layer by in situ polymerization method to obtain silicon polymer composite material, the monomer or the oligomer reacting with the organic functional group of the silane coupling agent in a polymerization, thereby a generated polymer layer being chemically grafted on the surfaces of the silicon particles; and heating the silicon polymer composite material to carbonize the polymer layer to form a carbon layer coated on the surfaces of the silicon particles.

First claim

What is claimed is:

1 . A method for making a lithium ion battery anode active material comprising:
providing silicon particles and a silane coupling agent, wherein the silane coupling agent comprises a hydrolysable functional group and an organic functional group; mixing the silicon particles and the silane coupling agent in water to obtain a first mixture, the hydrolysable functional group of the silane coupling agent being hydrolyzed and chemically grafted on surfaces of the silicon particles; adding a monomer or oligomer to the first mixture to obtain a second mixture, the surfaces of the silicon particles being coated with a polymer layer by in situ polymerization method to obtain silicon polymer composite material, the monomer or the oligomer reacting with the organic functional group of the silane coupling agent in a polymerization, thereby a generated polymer layer being chemically grafted on the surfaces of the silicon particles; and heating the silicon polymer composite material to carbonize the polymer layer to form a carbon layer coated on the surfaces of the silicon particles, thereby achieving silicon carbon composite material.

2 . The method for making a lithium ion battery anode active material of claim 1 , wherein the mixing the silicon particles and the silane coupling agent in water to obtain the first mixture, comprises:
adding the silicon particles into water to form a dispersion liquid; and adding the silane coupling agent into the dispersion liquid to form the first mixture.

3 . The method for making a lithium ion battery anode active material of claim 2 , wherein an organic solvent is added into the water to form the dispersion liquid, the organic solvent is miscible with the silane coupling agent, and a volume ratio of the water to the organic solvent is in a range from about 1:2 to about 1:10.

4 . The method for making a lithium ion battery anode active material of claim 2 , wherein the silicon particles is etched by hydrofluoric acid before the silane coupling agent is added into the dispersion liquid.

5 . The method for making a lithium ion battery anode active material of claim 2 , wherein the silane coupling agent are added drop by drop to the dispersion liquid at a rate in a range from about 0.2 ml/min to about 1 ml/min.

6 . The method for making a lithium ion battery anode active material of claim 2 , wherein an acid is added to the first mixture to adjust the pH value and maintain the first mixture at an acidic environment, and the pH value is in a range from about 3 to about 4.

7 . The method for making a lithium ion battery anode active material of claim 1 , wherein the mass ratio of the silicon particles to the silane coupling agent is in a range from about 0.1 to about 0.3.

8 . The method for making a lithium ion battery anode active material of claim 1 , wherein the silane coupling agent is selected from the group consisting of vinyltriethoxysilane, methyl trimethoxysilane, tetraethoxysilane, vinyl trimethoxy silane, methyl vinyl dimethyl silane, γ-methacryloxypropyl trimethoxy silane (KH570), methacryloxy propyl methyl dimethoxy silane (KH571), γ-aminopropyltriethoxysilane, γ-mercaptopropyl trimethoxysilane, γ-cyanopropyl trimethoxysilane, γ-glycidoxypropyl trimethoxysilane, β-(3,4-epoxycyclohexyl) ethyl trimethoxysilane, γ-aminopropyltrimethoxysilane, or combinations thereof.

9 . The method for making a lithium ion battery anode active material of claim 1 , wherein the monomer is selected from the group consisting of acrylonitrile, acrylic, phenolic resin, or combinations thereof.

10 . The method for making a lithium ion battery anode active material of claim 1 , wherein the carbon layer is a continuous layer and uniformly coated on the surfaces of the silicon particles.

Assignees

• Jiangsu Huadong Inst Of Li Ion Battery Co Ltd
• Univ Tsinghua

Inventors

• Cui qing-wei
• Li Jian-Jun
• He xiang-ming
• Cao Jiang
• Wang Li
• Dai Zhong-Jia

Classifications

• H01M4/366 Primary

  as layered products · CPC title

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title

• H01M4/587

  for inserting or intercalating light metals · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title