Method of producing cathode active material, and method of producing lithium ion battery

Patent metadata

Field	Value
Publication number	US-11728467-B2
Application number	US-202017064132-A
Country	US
Kind code	B2
Filing date	Oct 6, 2020
Priority date	Oct 21, 2019
Publication date	Aug 15, 2023
Grant date	Aug 15, 2023

Abstract

A major object is to provide a method of producing a cathode active material having a high average discharge potential, and a high degree of stability at high potential. The method includes: a step of preparing a Na-doped precursor of making a sodium-containing transition metal oxide having the P2 structure belonging to a space group of P63/mmc; and an ion exchange step of substituting lithium for at least part of sodium contained in the sodium-containing transition metal oxide by the ion exchange method, wherein in the ion exchange step, at least lithium iodide is used as a Li ion source.

First claim

What is claimed is:

1. A method of producing a cathode active material, the method comprising:
a step of preparing a Na-doped precursor of making a sodium-containing transition metal oxide having a P2 structure belonging to a space group of P6 3 /mme; and
an ion exchange step of substituting lithium for at least part of sodium contained in the sodium-containing transition metal oxide by an ion exchange method,
wherein in the ion exchange step, at least lithium iodide is used as a Li ion source, and
O2 structure and O3 structure coexist in a layered direction in a single particle of the cathode active material by the ion exchange step.

2. The method according to claim 1 ,
wherein the sodium-containing transition metal oxide has the composition represented by Na a Ni x Mn y Co z O 2 where 0.5≤a≤1, x+y+z=1, and 3<4x+2y+3z≤3.5.

3. The method according to claim 1 , wherein in the ion exchange step, a mixture of lithium iodide and lithium nitrate is used as the Li ion source.

4. The method according to claim 3 , wherein the ion exchange step is carried out at a temperature of at most 400° C.

5. A method of producing a lithium ion battery, the method comprising:
a step of making a cathode active material layer containing the cathode active material produced by the method according to claim 1 ; and
a step of using the cathode active material layer, an anode active material layer containing an anode active material, and an electrolyte layer containing an electrolyte, to arrange the electrolyte layer between the cathode active material layer and the anode active material layer.

6. The method according to claim 5 , wherein the electrolyte layer is a solid electrolyte layer containing a solid electrolyte.

7. A cathode active material having the composition represented by Li b Na c Mn p Ni q Co r O 2 where 0<b+c≤1, p+q+r=1, and 3≤4p+2q+3r≤3.5, wherein O2 structure and O3 structure coexist in a layered direction in a single particle of the cathode active material.

8. A lithium ion battery comprising:
a cathode active material layer containing the cathode active material according to claim 7 ;
an anode active material layer containing an anode active material; and
an electrolyte layer containing an electrolyte, the electrolyte layer arranged between the cathode active material layer and the anode active material layer.

Assignees

• Toyota Motor Co Ltd

Inventors

• Sugiyama Issei

Classifications

• C01G53/01

  Preparation or separation involving a liquid-liquid extraction, an adsorption or an ion-exchange · CPC title

• H01M4/131 Primary

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

• H01M4/0471

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

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/1391

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