Method for producing cathode, and method for producing oxide solid-state battery

• US 10,950,862 B2
• Filed: 12/11/2017
• Issued: 03/16/2021
• Est. Priority Date: 01/25/2017
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kawakami, Masatsugu, Ohta, Shingo
• Primary Examiner(s): Efta, Alex B
• Application Number:
  US15/837,119
• Publication Number:
  US 20180212246A1
• Time in Patent Office: 1,191 Days
• CPC Class Codes: H01M 10/052 Li-accumulators
• CPC Class Codes: H01M 10/0562 Solid materials
• CPC Class Codes: H01M 10/0585 of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 2300/0071 Oxides
• CPC Class Codes: H01M 4/0471 involving thermal treatment, e.g. firing, sintering, backing particulate active material, thermal decomposition, pyrolysis
• CPC Class Codes: H01M 4/131 Electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/1391 of electrodes based on mixed oxides or hydroxides, or on mixtures of oxides or hydroxides, e.g. LiCoOx
• CPC Class Codes: H01M 4/525 of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
• CPC Class Codes: H01M 4/62 Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

A method for producing a cathode that can lower a sintering temperature is provided. The method comprises: acid-treating particles of a lithium containing composite oxide that has a layered rock-salt structure; obtaining a mixture by mixing the acid-treated particles with a lithium salt whose melting point is lower than that of the lithium containing composite oxide; and heating and sintering the mixture.

Claims

1. A method for producing a cathode, the method comprising:

obtaining a lithium containing composite oxide that has a layered rock-salt structure;

determining the melting point of the lithium containing composite oxide;

acid-treating particles of the lithium containing composite oxide;

obtaining a lithium salt whose melting point is lower than that of the lithium containing composite oxide;

obtaining a mixture by mixing the acid-treated particles with the lithium salt; and

heating and sintering the mixture,

wherein the lithium salt is a combination of lithium formate and lithium acetate.

2. The method according to claim 1,

wherein the lithium salt further comprises lithium nitrate.

3. The method according to claim 1,

wherein in said sintering the mixture, the mixture is heated either while or after pressurized.

4. The method according to claim 1,

wherein a molar ratio of the lithium formate to the lithium acetate (lithium formate/lithium acetate) in the mixture is 1/3 to 3.

5. The method according to claim 1,

wherein an amount of the lithium salt in the mixture is 1 part by mass to 100 parts by mass per 100 parts by mass of the acid-treated particles in the mixture.

6. The method according to claim 1,

wherein the lithium salt has a melting point lower than 250°

C.

7. A method for producing an oxide solid-state battery, the method comprising:

obtaining a lithium containing composite oxide that has a layered rock-salt structure;

determining the melting point of the lithium containing composite oxide,

acid-treating particles of the lithium containing composite oxide;

obtaining a lithium salt whose melting point is lower than that of the lithium containing composite oxide;

obtaining a mixture by mixing the acid-treated particles with the lithium salt;

obtaining a layered body by layering a layer that comprises the mixture, and a layer of an oxide solid electrolyte;

determining a reaction temperature at which the mixture reacts with the oxide solid electrolyte;

selecting a heating temperature that is greater than or equal to the melting point of the lithium salt and lower than the reaction temperature; and

heating the layered body at the temperature, and sintering the mixture on a surface of the layer of the oxide solid electrolyte,

wherein the lithium salt is a combination of lithium formate and lithium acetate.

8. The method according to claim 7, wherein

the oxide solid electrolyte contains garnet type lithium lanthanum zirconate, and

the heating temperature is no less than the melting point of the lithium salt, and lower than 600°

C.

9. The method according to claim 7,

wherein a molar ratio of the lithium formate to the lithium acetate (lithium formate/lithium acetate) in the mixture is 1/3 to 3.

10. The method according to claim 7,

wherein an amount of the lithium salt in the mixture is 1 part by mass to 100 parts by mass per 100 parts by mass of the acid-treated particles in the mixture.

11. The method according to claim 7,

wherein the lithium salt has a melting point lower than 250°

C.