Energy storage device and method for manufacturing the same

Patent metadata

Field	Value
Publication number	US-2015357640-A1
Application number	US-201514827444-A
Country	US
Kind code	A1
Filing date	Aug 17, 2015
Priority date	Jun 30, 2010
Publication date	Dec 10, 2015
Grant date	—

Abstract

Provided are an energy storage device including an electrode in which lithium is introduced into a silicon layer and a method for manufacturing the energy storage device. A silicon layer is formed over a current collector, a solution including lithium is applied on the silicon layer, and heat treatment is performed thereon; thus, at least lithium can be introduced into the silicon layer. By using the solution including lithium, even when the silicon layer includes a plurality of silicon microparticles, the solution including lithium can enter a space between the microparticles and lithium can be introduced into the silicon microparticles which are in contact with the solution including lithium. Moreover, even when the silicon layer is a thin silicon film or includes a plurality of whiskers or whisker groups, the solution can be uniformly applied; accordingly, lithium can be included in silicon easily.

First claim

1 . (canceled)

2 . An electrode comprising:
a current collector; an active material layer comprising silicon over the current collector; and a conductive layer comprising titanium over the active material layer.

3 . The electrode according to claim 2 , wherein the conductive layer is in contact with the active material layer.

4 . The electrode according to claim 2 , wherein the current collector comprises titanium.

5 . The electrode according to claim 2 , wherein a thickness of the conductive layer is greater than or equal to 0.1 nm and less than or equal to 10 nm.

6 . The electrode according to claim 2 , wherein silicide is formed between the active material layer and the conductive layer.

7 . The electrode according to claim 2 ,
wherein the active material layer comprises lithium, and wherein a lithium concentration in a superficial portion of the active material layer is higher than a lithium concentration in a portion of the active material layer which is close to the current collector.

8 . An energy storage device comprising:
a negative electrode comprising:
a negative electrode current collector;
a negative electrode active material layer comprising silicon over the negative electrode current collector; and
a conductive layer comprising titanium over the negative electrode active material layer; and
a positive electrode facing the negative electrode with an electrolyte between the positive electrode and the negative electrode.

9 . The energy storage device according to claim 8 , wherein the conductive layer is in contact with the negative electrode active material layer.

10 . The energy storage device according to claim 8 , wherein the negative electrode current collector comprises titanium.

11 . The energy storage device according to claim 8 , wherein a thickness of the conductive layer is greater than or equal to 0.1 nm and less than or equal to 10 nm.

12 . The energy storage device according to claim 8 , wherein silicide is formed between the negative electrode active material layer and the conductive layer.

13 . The energy storage device according to claim 8 ,
wherein the negative electrode active material layer comprises lithium, and wherein a lithium concentration in a superficial portion of the negative electrode active material layer is higher than a lithium concentration in a portion of the negative electrode active material layer which is close to the negative electrode current collector.

14 . An energy storage device comprising:
a negative electrode comprising:
a negative electrode current collector;
a negative electrode active material layer comprising silicon over the negative electrode current collector; and
a conductive layer comprising titanium over the negative electrode active material layer; and
a positive electrode facing the negative electrode with an electrolyte between the positive electrode and the negative electrode, wherein the negative electrode active material layer comprises a plurality of whiskers of crystalline silicon.

15 . The energy storage device according to claim 14 , wherein the conductive layer is in contact with the negative electrode active material layer.

16 . The energy storage device according to claim 14 , wherein the negative electrode current collector comprises titanium.

17 . The energy storage device according to claim 14 , wherein a thickness of the conductive layer is greater than or equal to 0.1 nm and less than or equal to 10 nm.

18 . The energy storage device according to claim 14 , wherein silicide is formed between the negative electrode active material layer and the conductive layer.

19 . The energy storage device according to claim 14 ,
wherein the negative electrode active material layer comprises lithium, and wherein a lithium concentration in a superficial portion of the negative electrode active material layer is higher than a lithium concentration in a portion of the negative electrode active material layer which is close to the negative electrode current collector.

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei

Classifications

• H01M4/386 Primary

  Silicon or alloys based on silicon · CPC title

• H01M4/134 Primary

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/405

  Alloys based on lithium · CPC title

• H01M4/661

  Metal or alloys, e.g. alloy coatings (H01M4/669 take precedence) · CPC title

• H01G11/50

  specially adapted for lithium-ion capacitors, e.g. for lithium-doping or for intercalation · CPC title