Electrode, power storage device, and electronic device

Patent metadata

Field	Value
Publication number	US-10529990-B2
Application number	US-201715668743-A
Country	US
Kind code	B2
Filing date	Aug 4, 2017
Priority date	Jan 23, 2014
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

A power storage device with high capacity or high energy density is provided. A highly reliable power storage device is provided. A long-life power storage device is provided. An electrode includes an active material, a first binder, and a second binder. The specific surface area of the active material is S [m2/g]. The weight of the active material, the weight of the first binder, and the weight of the second binder are a, b, and c, respectively. The solution of {(b+c)/(a+b+c)}×100÷S is 0.3 or more. The electrode includes a first film in contact with the active material. The first film preferably includes a region in contact with the active material. The first film preferably includes a region with a thickness of 2 nm or more and 20 nm or less. The first film contains a water-soluble polymer.

First claim

What is claimed is:

1. An electrode comprising:
an active material comprising an active material particle;
a first film covering the active material particle, the first film comprising a first binder and a second binder;
a second film covering the active material particle and the first film, the second film comprising Li, F, O and C,
wherein a first portion of the second film is in contact with the first film,
wherein a second portion of the second film is in contact with the active material particle,
wherein the first binder is a water-soluble polymer,
wherein a thickness of the first portion of the second film is thinner than a thickness of the second portion of the second film.

2. The electrode according to claim 1 , wherein the second binder comprises a double bond which is capable of reacting with osmium tetroxide.

3. The electrode according to claim 1 , wherein a repeating unit of the second binder comprises a stylene monomer unit.

4. The electrode according to claim 3 , wherein the second binder further comprises a butadiene monomer unit.

5. The electrode according to claim 1 , wherein a material of the active material particle is graphite.

6. The electrode according to claim 1 , wherein the first film comprises a region with a thickness of 2 nm or more and 20 nm or less.

7. The electrode according to claim 1 , wherein the first binder is a cellulose derivative.

8. The electrode according to claim 1 ,

A
=

b
+
c

a
+
b
+
c

×

100
÷
S

[

Mathematical
⁢

⁢
Formula
⁢

⁢
1

]

wherein A defined by Mathematical Formula 1 is 1 or more,
wherein S [m 2 /g] is a specific surface area of the active material
wherein a [g] is a weight of the active material,
wherein b [g] is a weight of the first binder, and
wherein c [g] is a weight of the second binder.

9. The electrode according to claim 8 ,

B
=

b

a
+
b
+
c

×

100
÷
S

[

Mathematical
⁢

⁢
Formula
⁢

⁢
2

]

wherein B defined by Mathematical Formula 2 is 0.3 or more.

10. A power storage device comprising:
a positive electrode;
a negative electrode comprising:
a negative active material comprising an active material particle;
a first film covering the active material particle, the first film comprising a first binder and a second binder;
a second film covering the active material particle and the first film, the second film comprising Li, F, O and C; and

an electrolyte,
wherein a first portion of the second film is in contact with the first film,
wherein a second portion of the second film is in contact with the active material particle,
wherein the first binder is a water-soluble polymer,
wherein a thickness of the first portion of the second film is thinner than a thickness of the second portion of the second film.

11. The power storage device according to claim 10 , wherein the second binder comprises a double bond which is capable of reacting with osmium tetroxide.

12. The power storage device according to claim 10 , wherein the second binder comprises a stylene monomer unit.

13. The power storage device according to claim 10 , wherein the second binder further comprises a butadiene monomer unit.

14. The power storage device according to claim 10 , wherein a material of the active material particle is graphite.

15. The power storage device according to claim 10 , wherein the first film comprises a region with a thickness of 2 nm or more and 20 nm or less.

16. The power storage device according to claim 10 , wherein the first binder is a cellulose derivative.

17. The power storage device according to claim 10 ,

A
=

b
+
c

a
+
b
+
c

×

100
÷
S

[

Mathematical
⁢

⁢
Formula
⁢

⁢
1

]

wherein A defined by Mathematical Formula 1 is 1 or more,
wherein S [m 2 /g] is a specific surface area of the negative active material,
wherein a [g] is a weight of the negative activ

Assignees

• Semiconductor Energy Lab

Inventors

• Kimura Kai
• Kuriki Kazutaka
• Oguni Teppei
• Uchida Aya

Classifications

• H01M4/133

  Electrodes based on carbonaceous material, e.g. graphite-intercalation compounds or CFx · CPC title

• H01M2220/30

  Batteries in portable systems, e.g. mobile phone, laptop · CPC title

• H01M10/0525

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

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title