Positive electrode active material particle including core containing lithium cobalt oxide and coating layer containing boron and fluorine, and preparation method thereof

• US 10,868,309 B2
• Filed: 03/30/2017
• Issued: 12/15/2020
• Est. Priority Date: 03/31/2016
• Status: Active Grant

• Current Assignee: LG Energy Solution Limited (LG Corporation)
• Original Assignee: LG Chem Limited (LG Corporation)
• Inventors: Lee, Bo Ram, Park, Sung Bin, Park, Young Uk, Jo, Chi Ho, Hur, Hyuck, Jung, Wang Mo
• Primary Examiner(s): Raymond, Brittany L
• Application Number:
  US15/770,102
• Publication Number:
  US 20180316015A1
• Time in Patent Office: 1,356 Days
• CPC Class Codes: C01G 51/00 Compounds of cobalt
• CPC Class Codes: C01G 51/42 containing alkali metals, e.g. LiCoO2
• CPC Class Codes: C01P 2004/03 obtained by SEM
• CPC Class Codes: C01P 2004/80 Particles consisting of a mixture of two or more inorganic phases
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/0568 characterised by the solutes
• CPC Class Codes: H01M 10/4235 Safety or regulating additives or arrangements in electrodes, separators or electrolyte H01M10/4242 takes precedence
• CPC Class Codes: H01M 2004/028 Positive electrodes
• CPC Class Codes: H01M 4/36 Selection of substances as active materials, active masses, active liquids
• CPC Class Codes: H01M 4/366 as layered products
• 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 4/628 Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

Provided is a positive electrode active material particle including a core containing lithium cobalt oxide represented by the following Chemical Formula 1; and a coating layer containing boron (B) and fluorine (F), which is coated on the surface of the core:
Li_1+xCo_1−xO₂  (1)

Claims

1. A positive electrode active material particle, comprising

a core including lithium cobalt oxide represented by the following Chemical Formula 1;

and

a coating layer including boron (B) and fluorine (F), which is coated on the surface of the core;

Li_1+xCo<sub>1−

x</sub>O₂ 

 

(1)

wherein −

0.03≤

x≤

0.1, and

wherein lithium in the core is in an excessive amount.

2. The positive electrode active material particle of claim 1, wherein in the coating layer, the boron and fluorine form a chemical bond with lithium.

3. The positive electrode active material particle of claim 1, wherein the boron and fluorine form a chemical bond with lithium of the core.

4. The positive electrode active material particle of claim 1, wherein the boron and fluorine exist in a compound of forming a chemical bond with lithium, independently of the core.

5. The positive electrode active material particle of claim 2, wherein the boron and fluorine, together with lithium, exist as LiBF₄.

6. The positive electrode active material particle of claim 1, wherein a weight of the coating layer is 0.5% by weight to 5% by weight with respect to a weight of the core.

7. The positive electrode active material particle of claim 1, wherein the positive electrode active material particle exhibits a capacity retention rate of 90% or more, as measured in a coin-type half cell at an upper voltage limit of 4.5 V at 45°

C. during 50 cycles.

16. A secondary battery comprising a positive electrode including the positive electrode active material particle of claim 1, a negative electrode, and an electrolyte.

17. The secondary battery of claim 16, wherein the electrolyte includes LiPF₆ as a lithium salt, and PF₅ which is a decomposition product of LiPF₆ reacts with a coating layer of the positive electrode active material particle to be converted into PF₆⁻

which is a less reactive anion than PF₅.

18. The secondary battery of claim 16, wherein at least part of the coating layer of the positive electrode active material particle is dissolved into the electrolyte.

19. A battery pack comprising the secondary battery of claim 16.

20. A device comprising the battery pack of claim 19.

8. A method of preparing a positive electrode active material particle for a secondary battery, the method comprising:

(a) preparing a first lithium cobalt oxide represented by the following Chemical Formula 2;

Li_1+yCo<sub>1−

y</sub>O₂ 

 

(2)

 

(wherein −

0.03≤

y≤

0.1)

(b) dry-mixing the first lithium cobalt oxide and a first compound including all of boron and fluorine, or dry-mixing the first lithium cobalt oxide, a second compound including boron, and a third compound including fluorine; and

(c) heat-treating the mixture after the dry-mixing of (b).

9. The method of claim 8, wherein the first compound is one or more selected from the group consisting of NH₄BF₄, NaBF₄, (CH₃)₃O(BF₄), (C₂H₅)₄N(BF₄), (C₆H₅)₃C(BF₄), (CH₃)₄N(BF₄), (CH₃CH₂CH₂)₄N(BF₄), and C₃H₁₀BF₄P.

10. The method of claim 8, wherein the second compound is one or more selected from the group consisting of B₂O₃, H₃BO₃, (C₆H₅O)₃B, B₂H₄O₄, C₆H₅B(OH)₂, CH₃OC₆H₄B(OH)₂, and C₆H₁₂BNO₃.

11. The method of claim 8, wherein the third compound is one or more selected from the group consisting of NH₄HF₂, NH₄F, (CH₃)₄NF, (CH₃CH₂)₄NF, PVdF (polyvinylidene fluoride), PVdF-HFP (poly(vinylidene fluoride-co-hexafluoropropylene)), PVF (polyvinyl fluoride), PTFE (polytetrafluoroethylene) and ETFE (ethylene tetrafluoroethylene).

12. The method of claim 8, wherein the dry-mixing of (b) is performed by high energy milling.

13. The method of claim 8, wherein the heat-treatment of (c) is performed at 300°

C. to 600°

C.

14. The method of claim 8, wherein the heat-treatment of (c) is performed at 450°

C. to 500°

C.

15. The method of claim 8, wherein the heat-treatment of (c) is performed for 3 hours to 7 hours.

21. A positive electrode active material particle, comprising

a core including lithium cobalt oxide represented by the following Chemical Formula 1;

and

a coating layer including boron (B) and fluorine (F), which is coated on the surface of the core;

Li_1+xCo<sub>1−

x</sub>O₂ 

 

(1)

wherein −

0.03≤

x≤

0.1, and

wherein a weight of the coating layer is 0.5% by weight to 5% by weight with respect to a weight of the core.