Lithium-ion secondary battery and electronic device

Patent metadata

Field	Value
Publication number	US-10249876-B2
Application number	US-201815874123-A
Country	US
Kind code	B2
Filing date	Jan 18, 2018
Priority date	May 9, 2014
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A lithium-ion secondary battery with high capacity is provided. Alternatively, a lithium-ion secondary battery with unproved cycle characteristics is provided. To achieve this, an active material including a particle having a cleavage plane and a layer containing carbon covering at least part of the cleavage plane is provided. The particle having the cleavage plane contains lithium, manganese, nickel, and oxygen. The layer containing carbon preferably contains graphene. When a lithium-ion secondary battery is fabricated using an electrode including the particle having the cleavage plane at least part of which is covered with the layer containing carbon as an active material, the discharge capacity can be increased and the cycle characteristics can be improved.

First claim

What is claimed is:

1. A method for forming an active material, comprising the steps of:
forming a mixture of a lithium compound, a manganese compound, and a nickel compound;
heating the mixture and obtaining a secondary particle composed of sintered primary particles;
crushing the secondary particle into a plurality of particles; and
coating the plurality of particles with a layer comprising graphene,
wherein a first cleavage plane of a first particle in the plurality of particles is covered with the layer comprising graphene,
wherein the first cleavage plane is formed by the crushing step,
wherein a second cleavage plane of a second particle in the plurality of particles is covered with the layer comprising graphene, and
wherein the first particle and the second particle are bound with graphene.

2. The method for forming the active material according to claim 1 , wherein the heating step is performed at higher than or equal to 800° C. and lower than or equal to 1000° C.

3. The method for forming the active material according to claim 2 , wherein the crushing step is performed using a bead mill.

4. The method for forming the active material according to claim 3 , wherein a particle size of the plurality of particles is substantially the same as a particle size of the sintered primary particles.

5. A method for forming an active material, comprising the steps of:
forming a mixture of a lithium compound and a cobalt compound;
heating the mixture and obtaining a secondary particle composed of sintered primary particles;
crushing the secondary particle into a plurality of particles; and
coating the plurality of particles with a layer comprising graphene,
wherein a first cleavage plane of a first particle in the plurality of particles is covered with the layer comprising graphene,
wherein the first cleavage plane is formed by the crushing step,
wherein a second cleavage plane of a second particle in the plurality of particles is covered with the layer comprising graphene, and
wherein the first particle and the second particle are bound with graphene.

6. The method for forming the active material according to claim 5 , wherein the heating step is performed at higher than or equal to 800° C. and lower than or equal to 1000° C.

7. The method for forming the active material according to claim 5 , wherein the crushing step is performed using a bead mill.

8. The method for forming the active material according to claim 5 , wherein a particle size of the plurality of particles is substantially the same as a particle size of the sintered primary particles.

9. A method for forming an active material, comprising the steps of:
forming a mixture of a lithium compound, a manganese compound, and a nickel compound;
heating the mixture and obtaining a secondary particle composed of sintered primary particles;
crushing the secondary particle into a plurality of particles;
kneading the plurality of particles and graphene oxide;
reducing the graphene oxide on the plurality of particles and coating the plurality of particles with a layer comprising graphene,
wherein a first cleavage plane of a first particle in the plurality of particles is covered with the layer comprising graphene,
wherein the first cleavage plane is formed by the crushing step,
wherein a second cleavage plane of a second particle in the plurality of particles is covered with the layer comprising graphene, and
wherein the first particle and the second particle are bound with graphene.

10. The method for forming the active material according to claim 9 , wherein the heating step is performed at higher than or equal to 800° C. and lower than or equal to 1000° C.

11. The method for forming the active material according to claim 9 , wherein the crushing step is performed using a bead mill.

12. The method for forming the active material according to claim 9 , wherein a particle size of the plurality of particles is substantially the same as a particle size of the sintered primary particles.

Assignees

• Semiconductor Energy Lab

Inventors

• Kawakami Takahiro
• Ikenuma Tatsuya
• Ochiai Teruaki
• Yoshitomi Shuhei
• Motoyoshi Mako
• Miyake Hiroyuki
• Momma Yohei
• Hirohashi Takuya
• Seo Satoshi

Classifications

• G06F1/163

  Wearable computers, e.g. on a belt · CPC title

• G06F1/1652

  the display being flexible, e.g. mimicking a sheet of paper, or rollable · CPC title

• G06F1/1626

  with a single-body enclosure integrating a flat display, e.g. Personal Digital Assistants [PDAs] · CPC title

• H01M2220/30

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

• G04G21/00

  Input or output devices integrated in time-pieces · CPC title