Electrode, manufacturing method thereof, storage battery, and electronic device

Patent metadata

Field	Value
Publication number	US-11967710-B2
Application number	US-202117152830-A
Country	US
Kind code	B2
Filing date	Jan 20, 2021
Priority date	Aug 27, 2015
Publication date	Apr 23, 2024
Grant date	Apr 23, 2024

Abstract

As a positive electrode active material of a secondary battery, a lithium-manganese composite oxide containing lithium, manganese, and an element represented by M, and oxygen is used, and the lithium-manganese composite oxide is covered with reduced graphene oxide. An active material layer including the active material, graphene oxide, a conductive additive, and a binder is formed and soaked in alcohol, and then heat treatment is performed, whereby an electrode with reduced graphene oxide is fabricated.

First claim

What is claimed is:

1. A method for manufacturing an electrode, comprising:
mixing a first particle and a first piece of graphene oxide to form a second particle, the second particle covered with the first piece of graphene oxide;
reducing the first piece of graphene oxide to form a third particle, the third particle covered with a first piece of graphene oxide being reduced,
forming an active material layer over a current collector, the active material layer comprising the third particle and a second piece of graphene oxide;
impregnating the active material layer with alcohol; and
performing heat treatment on the active material layer after impregnating the active material layer,
wherein the third particle comprises an inner region and a surficial region after the heat treatment,
wherein the inner region comprises a crystal having a layered rock-salt crystal structure,
wherein the surficial region comprises a crystal having a spinel crystal structure, wherein the surficial region is in contact with a second piece of graphene oxide being reduced, and
wherein the heat treatment is performed at a temperature higher than or equal to 250° C. and lower than or equal to 300° C.

2. The method for manufacturing an electrode, according to claim 1 , wherein the third particle has a cleavage plane.

3. The method for manufacturing an electrode, according to claim 1 ,
wherein a composition of the first particle is represented by formula of LiaMnbMcOd,
wherein, in the formula, a/(b+c) is larger than or equal to 0 and less than 2, c is larger than 0, and (b+c)/d is larger than or equal to 0.26 and less than 0.5, and
wherein the element M is any one of chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium, gallium, copper, titanium, niobium, silicon and phosphorus.

4. The method for manufacturing an electrode, according to claim 3 , wherein the element M is nickel.

5. The method for manufacturing an electrode, according to claim 1 , wherein the alcohol is any one of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol and tert-butyl alcohol.

6. A method for manufacturing an active material, comprising:
forming an active material particle covered with a first piece of graphene oxide being reduced;
forming an active material layer over a current collector, the active material layer comprising the active material particle and a second piece of graphene oxide,
impregnating the active material layer with alcohol; and
performing heat treatment on the active material layer after impregnating the active material layer,
wherein the active material particle comprises an inner region and a surficial region after the heat treatment,
wherein the inner region comprises a crystal having a layered rock-salt crystal structure,
wherein the surficial region comprises a crystal having a spinel crystal structure,
wherein the surficial region is in contact with a second piece of graphene oxide being reduced, and
wherein the heat treatment is performed at a temperature higher than or equal to 250° C. and lower than or equal to 300° C.

7. The method for manufacturing an active material, according to claim 6 , wherein the active material particle has a cleavage plane.

8. The method for manufacturing an active material, according to claim 6 ,
wherein a composition of the active material particle is represented by formula of Li a Mn b M c O d ,
wherein, in the formula, a/(b+c) is larger than or equal to 0 and less than 2, c is larger than 0, and (b+c)/d is larger than or equal to 0.26 and less than 0.5, and
wherein the element M is any one of chromium, cobalt, aluminum, nickel, iron, magnesium, molybdenum, zinc, indium, gallium, copper, titanium, niobium, silicon and phosphorus.

9. The method for manufacturing an active material, according to claim 6 , wherein the alcohol is any one of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol and tert-butyl alcohol.

10. The method for manufacturing an active material, according to claim 6 , further comprising:
wherein the first piece of graphene oxide being reduced is formed by reduction of a first piece of graphene oxide, and
wherein the reduction is performed by a reducing agent.

Assignees

• Semiconductor Energy Lab

Inventors

• Ikenuma Tatsuya

Classifications

• H01M4/505 Primary

  of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy · CPC title

• H01M4/0404

  by coating on electrode collectors · CPC title

• H01M4/0471

  involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis · CPC title

• H01M4/131 Primary

  Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title

• H01M4/1391

  of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx · CPC title