Negative-electrode active material, production process for the same and electric storage apparatus

Patent metadata

Field	Value
Publication number	US-10141563-B2
Application number	US-201414768325-A
Country	US
Kind code	B2
Filing date	Jan 31, 2014
Priority date	Mar 18, 2013
Publication date	Nov 27, 2018
Grant date	Nov 27, 2018

Abstract

A negative-electrode active material is used, the negative-electrode active material including: a nanometer-size silicon material produced by heat treating a lamellar polysilane having a structure in which multiple six-membered rings constituted of a silicon atom are disposed one after another, and expressed by a compositional formula, (SiH)n; and the nanometer-size silicon material including silicon, and a halogen element wherein the halogen element is included in a molar fraction of 11.5 or less to a molar amount of the silicon taken as 100. Since the content of halogen has been reduced, an electric storage apparatus using the negative-electrode active material for one of the negative electrodes has an upgraded capacity maintained rate.

First claim

The invention claimed is:

1. A production process for negative-electrode active material, the production process comprising the steps of:
a reaction step of obtaining a lamellar polysilane by reacting a hydrogen chloride (HCl) aqueous solution with calcium disilicide;
an impurity removal step of turning the lamellar polysilane into an impurity-reduced lamellar polysilane by removing halogen elements from the lamellar polysilane; and
a calcination step of obtaining a nanometer-size silicon powder by heat treating the impurity-reduced lamellar polysilane at a temperature exceeding 100° C. under a nonoxidizing atmosphere,
wherein said impurity removal step is carried out by neutralizing a reaction solution including said lamellar polysilane with a base after said reaction step.

2. The production process for negative-electrode active material as set forth in claim 1 , wherein said reaction step is carried out by reacting a mixture of a hydrogen chloride (HCl) aqueous solution and a hydrogen fluoride (HF) aqueous solution with calcium disilicide.

3. The production process for negative-electrode active material as set forth in claim 1 , wherein said impurity removal step is carried out so as to make a pH of a post-neutralization filtrate from 0.5 to 8.0.

4. The production process for negative-electrode active material as set forth in claim 1 , wherein said impurity removal step is carried out so as to make a pH of a post-neutralization filtrate from 0.5 to 7.0.

5. The production process for negative-electrode active material as set forth in claim 1 , wherein said calcination step is a step of heat treating at 400° C. or more.

Assignees

• Toyota Jidoshokki Kk

Inventors

• Yukawa Kayoko

Classifications

• H01M4/386

  Silicon or alloys based on silicon · CPC title

• H01M4/582

  Halogenides · CPC title

• H01M4/1395

  of electrodes based on metals, Si or alloys · CPC title

• H01M4/134 Primary

  Electrodes based on metals, Si or alloys · CPC title

• H01M2004/027

  Negative electrodes · CPC title