Cathode active material and secondary battery using same

Patent metadata

Field	Value
Publication number	US-11791464-B2
Application number	US-202016847636-A
Country	US
Kind code	B2
Filing date	Apr 13, 2020
Priority date	May 30, 2019
Publication date	Oct 17, 2023
Grant date	Oct 17, 2023

Abstract

Provided is a cathode active material comprising particles each containing a lithium composite oxide; and a coating layer containing an ammonium phosphate compound and coating each of the particles.

First claim

The invention claimed is:

1. A cathode active material comprising:
particles each containing a lithium composite oxide; and
a coating layer containing an ammonium phosphate compound and coating each of the particles,
wherein the ammonium phosphate compound is represented by a formula Li x (NR 4 ) 3-x PO 4 a salt containing a phosphate ion and an ammonium ion, where 0.10≤x≤2.90, each R is independently a hydrogen atom or a saturated aliphatic group represented by a composition formula C α H β F γ , α, β, and γ are integers that satisfy the following relational formulas: α≥1, β≥0, γ≥0, and β+γ=2α+1, and at least one R is the saturated aliphatic group.

2. The cathode active material according to claim 1 , wherein
a weight ratio of the ammonium phosphate compound to the lithium composite oxide is not less than 0.2 wt % and not more than 1.8 wt %.

3. The cathode active material according to claim 2 , wherein
the weight ratio of the ammonium phosphate compound to the lithium composite oxide is not less than 1.0 wt % and not more than 1.8 wt %.

4. The cathode active material according to claim 1 , wherein
the lithium composite oxide contains at least one selected from the group consisting of nickel, cobalt, and manganese.

5. The cathode active material according to claim 1 , wherein
the lithium composite oxide has a crystal structure which belongs to a space group R-3m or C2/m.

6. A secondary battery, comprising:
a cathode comprising the cathode active material according to claim 1 ;
an anode comprising an anode active material capable of occluding and releasing lithium ions; and
a non-aqueous electrolyte containing a non-aqueous solvent and a lithium salt which has been dissolved in the non-aqueous solvent.

7. A secondary battery, comprising:
a cathode containing a cathode mixture layer containing a cathode current collector and the cathode active material according to claim 1 ;
an anode comprising an anode current collector; and
a non-aqueous electrolyte containing a non-aqueous solvent and a lithium salt which has been dissolved in the non-aqueous solvent,
wherein
during charge, a lithium metal is deposited on the anode current collector; and
during discharge, the lithium metal is dissolved in the non-aqueous electrolyte.

8. The secondary battery according to claim 6 , wherein
the lithium salt contains at least one selected from the group consisting of LiBF 4 , LiPF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 , a lithium bis(oxalate) borate, and a lithium difluoro(oxalate) borate.

9. The secondary battery according to claim 7 , wherein
the lithium salt contains at least one selected from the group consisting of LiBF 4 , LiPF 6 , LiN(SO 2 CF 3 ) 2 , LiN(SO 2 F) 2 , a lithium bis(oxalate) borate, and a lithium difluoro(oxalate) borate.

10. The secondary battery according to claim 8 , wherein
the lithium salt in the non-aqueous electrolyte has a concentration of not less than 0.5 mol/L and not more than 3.5 mol/L.

11. The secondary battery according to claim 9 , wherein
the lithium salt in the non-aqueous electrolyte has a concentration of not less than 0.5 mol/L and not more than 3.5 mol/L.

12. The cathode active material according to claim 1 , wherein γ=0.

13. The cathode active material according to claim 1 , wherein
an upper limit of the carbon number of the saturated aliphatic group is three.

14. The cathode active material according to claim 1 , wherein γ>0.

15. The cathode active material according to claim 1 , wherein the coating layer consists of the ammonium phosphate compound.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Suzuki Hirotetsu

Classifications

• H01M4/525 Primary

  of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy · CPC title

• H01M4/134

  Electrodes based on metals, Si or alloys · CPC title

• H01M4/505

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

• H01M4/667

  in the form of layers, e.g. coatings · CPC title

• H01M10/0525

  Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries · CPC title