Graphene oxide, positive electrode for nonaqueous secondary battery using graphene oxide, method of manufacturing positive electrode for nonaqueous secondary battery, nonaqueous secondary battery, and electronic device

Patent metadata

Field	Value
Publication number	US-2016204440-A1
Application number	US-201615075387-A
Country	US
Kind code	A1
Filing date	Mar 21, 2016
Priority date	Apr 10, 2012
Publication date	Jul 14, 2016
Grant date	—

Abstract

A graphene oxide used as a raw material of a conductive additive for forming an active material layer with high electron conductivity with a small amount of a conductive additive is provided. A positive electrode for a nonaqueous secondary battery using the graphene oxide as a conductive additive is provided. The graphene oxide is used as a raw material of a conductive additive in a positive electrode for a nonaqueous secondary battery and, in the graphene oxide, the weight ratio of oxygen to carbon is greater than or equal to 0.405.

First claim

What is claimed is:

1 . A graphene oxide,
wherein a weight ratio of oxygen to carbon in the graphene oxide is 0.405 or more.

2 . The graphene oxide according to claim 1 ,
wherein the graphene oxide is a single layer or a multi-layer comprising 2 or more and 100 or less layers.

3 . The graphene oxide according to claim 1 ,
wherein the graphene oxide comprises one or more groups selected from an epoxy group, a carbonyl group, a carboxyl group, and a hydroxyl group.

4 . The graphene oxide according to claim 1 ,
wherein the graphene oxide is used as a raw material of a conductive additive in a positive electrode for a nonaqueous secondary battery.

5 . A positive electrode for a nonaqueous secondary battery, comprising:
an active material layer over a current collector, the active material layer comprising:
active material particles;
a conductive additive comprising graphenes; and
a binding agent,
wherein, as bonding states of carbon included in the active material layer, a proportion of a C═C bond is 35% or more and a proportion of a C—O bond is 5% or more and 20% or less.

6 . The positive electrode for a nonaqueous secondary battery according to claim 5 ,
wherein at least one of the graphenes is larger than an average particle diameter of each of the active material particles, wherein the graphenes are dispersed in the active material layer such that at least one of the graphenes makes surface contact with one or more graphenes adjacent to the graphene, and wherein at least one of the graphenes makes surface contact with the active material particles in such a way as to wrap part of surfaces of the active material particles.

7 . The positive electrode for a nonaqueous secondary battery according to claim 5 ,
wherein the active material particles are lithium iron phosphate.

8 . The positive electrode for a nonaqueous secondary battery according to claim 5 ,
wherein a compounding ratio of the conductive additive:the active material particles:the binding agent in the active material layer is 1 to 5:90 to 94:1 to 5.

9 . A nonaqueous secondary battery comprising the positive electrode for a nonaqueous secondary battery according to claim 5 .

10 . An electronic device comprising the nonaqueous secondary battery according to claim 9 .

Assignees

• Semiconductor Energy Lab

Inventors

• Todoriki Hiroatsu
• Yukawa Mikio
• Saito Yumiko
• Yamakaji Masaki
• Yatabe Rika
• Ikenuma Tatsuya

Classifications

• H01M4/625 Primary

  Carbon or graphite · CPC title

• H01M4/5825

  Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines · CPC title

• H01M10/052

  Li-accumulators · CPC title

• H01M4/136

  Electrodes based on inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy · CPC title

• H01M4/624

  Electric conductive fillers · CPC title