Lithium ion battery and cathode active material therefor

Patent metadata

Field	Value
Publication number	US-2020006758-A1
Application number	US-201916444023-A
Country	US
Kind code	A1
Filing date	Jun 18, 2019
Priority date	Jun 27, 2018
Publication date	Jan 2, 2020
Grant date	—

Abstract

Certain embodiments of the disclosure relate to a bimodal-type cathode active material for a lithium ion battery. The cathode active material includes a mixture of layered LiCoO2 large particles and manganese-based olivine structural small particles. The manganese-based olivine structural small particles may be represented by chemical formula LiCoxMnyFezPO4 (0≤x≤1, 0<y≤1, 0≤z≤1, x+y+z=1). An average particle diameter of the large particles may be 16 to 25 μm, and an average particle diameter of the small particles may be 1 to 3 μm. The cathode active material of the disclosure can achieve high energy density and high voltage stability.

First claim

What is claimed is:

1 . A bimodal-type cathode active material for a lithium ion battery, comprising:
a mixture of layered LiCoO 2 large particles and manganese-based olivine structural small particles, wherein the manganese-based olivine structural small particles are represented by chemical formula LiCo x Mn y Fe z PO 4 (0≤x≤1, 0<y≤1, 0≤z≤1, x+y+z=1), and wherein an average particle diameter of the large particles is 16 to 25 μm, and an average particle diameter of the small particles is 1 to 3 μm.

2 . The cathode active material of claim 1 , wherein in the chemical formula LiCo x Mn y Fe z PO 4 of the manganese-based olivine structural small particles, 0.1≤x≤0.4, 0.2≤y≤0.8, and 0.1≤z≤0.6.

3 . The cathode active material of claim 2 , wherein in the chemical formula LiCo x Mn y Fe z PO 4 of the manganese-based olivine structural small particles, 0.7≤y≤0.8.

4 . The cathode active material of claim 1 , wherein the manganese-based olivine structural small particles are secondary particles made from aggregation of primary particles having an average thickness of about 100 nm or less, and wherein the secondary particles have a spherical or plate-like mesocrystal aggregate structure.

5 . The cathode active material of claim 4 , wherein the secondary particles are formed using a solvothermal synthesis technique.

6 . The cathode active material of claim 4 , wherein surfaces of the secondary particles are coated with a carbon-based material.

7 . The cathode active material of claim 1 , wherein a mixing ratio of the large particles to the small particles is 80:20 to 99:1 by weight.

8 . The cathode active material of claim 1 , wherein the cathode active material has an operating voltage ranging from 3.0 V to 4.5 V.

9 . The cathode active material of claim 1 , wherein the cathode active material has a rolling density of 3.8 to 4.4 g/cc.

10 . A method for producing manganese-based olivine structural small particles contained in a bimodal-type cathode active material for a lithium ion battery, the cathode active material comprising a mixture of layered LiCoO 2 large particles having an average particle diameter of 16 to 25 μm and the manganese-based olivine structural small particles having an average particle diameter of 1 to 3 μm, the manganese-based olivine structural small particles are represented by chemical formula LiCo x Mn y Fe z PO 4 (0≤x≤1, 0<y≤1, 0≤z≤1, x+y+z=1), the method comprising:
a) preparing a precursor aqueous solution by mixing Co(CH 3 COO) 2 .4H 2 O, Mn(CH 3 COO) 2 .4H 2 O, and Fe(NO 3 ) 3 .9H 2 O in accordance with a molar ratio;
b) forming a solid solution of Co, Mn, and Fe by mixing and stirring the precursor aqueous solution with N,N-dimethylformamide (DMF);
c) forming LiCo x Mn y Fe z PO 4 primary particles by introducing H 3 PO 4 , lithium hydroxide monohydrate (LiOH.H 2 O), and ascorbic acid (C 6 H 8 O 6 ) into the solid solution; and
d) forming LiCo x Mn y Fe z PO 4 secondary particle aggregation by injecting nitric acid (HNO 3 ) into the LiCo x Mn y Fe z PO 4 primary particles, adjusting pH, and using a solvothermal synthesis technique.

11 . The method of claim 10 , further comprising:
e) coating the secondary particle aggregation with a conductive material.

12 . The method of claim 10 , wherein the LiCo x Mn y Fe z PO 4 primary particles have an average thickness of about 100 nm or less.

13 . The method of claim 10 , wherein the LiCo x Mn y Fe z PO 4 secondary particle aggregation has a spherical structure.

14 . The method of claim 10 , wherein the LiCoMn y Fe z PO 4 secondary particle aggregation has a plate-like structure.

15 . The method of claim 11 , wherein the conductive material is a material capable of forming a carbon coating after heat treatment and is glucose, sucrose, polyethylene glycol, polyvinyl alcohol, polyvinyl chloride, citric acid, or ascorbic acid.

16 . A lithium ion battery comprising a bimodal-type cathode active material including a mixture of layered LiCoO 2 large particles and manganese-based olivine structural small particles,
wherein the manganese-based olivine structural small particles are represented by chemical formula LiCo x Mn y Fe z PO 4 (0≤x≤1, 0<y≤1, 0≤z≤1, x+y+z=1), and wherein an average particle diameter of the large particles is 16 to 25 μm, and an average particle diameter of the small particles is 1 to 3 μm.

17 . An electronic device comprising a lithium ion battery used as a battery module, comprising a bimodal-type cathode active material including a mixture of layered LiCoO 2 large particles and manganese-based olivine structural small particles,
wherein the manganese-based olivine structural small particles are represented by chemical formula LiCo x Mn y Fe z PO 4 (0≤x≤1, 0<y≤1, 0≤z≤1, x+y+z=1), and wherein an average particle diameter of the large particles is 16 to 25 μm, and an average particle diameter of the small particles is 1 to 3 μm.

Assignees

• Samsung Electronics Co Ltd

Inventors

• Wi Sungun
• Oh Bookeun
• Lee Jaeyeon
• Choi Jaeman

Classifications

• H01M4/131

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

• H01M10/0525

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

• H01M2004/021

  Physical characteristics, e.g. porosity, surface area · CPC title

• H01M4/139

  Processes of manufacture · CPC title

• H01M4/364 Primary

  as mixtures · CPC title