Granted Patent B2

US 12,633,536 · App. 19/198,251 · Granted May 19, 2026

Inventors: Mayumi Mikami (Kanagawa, JP); Aya Uchida (Tochigi, JP); Yumiko Yoneda (Kanagawa, JP); Yohei Momma (Kanagawa, JP); Masahiro Takahashi (Kanagawa, JP); Teruaki Ochiai (Kanagawa, JP)

Assignee: Semiconductor Energy Laboratory Co., Ltd.

H01M4/525C01G53/50H01B1/08H01M4/131H01M4/133H01M4/134H01M4/139H01M4/366H01M4/505H01M6/164H01M10/0525C01P2002/74H01M2004/028

Abstract

Claims (27)

1 . A lithium-ion secondary battery comprising a positive electrode,

wherein the positive electrode comprises a positive electrode active material comprising a positive electrode active material particle,

wherein the positive electrode active material particle comprises lithium cobalt oxide,

wherein the positive electrode active material particle comprises magnesium, aluminum, and fluorine,

wherein, in EDX linear analysis of the positive electrode active material particle, a peak of aluminum is located in a deeper region than a peak of magnesium,

when the positive electrode of the lithium-ion secondary battery is subjected to an X-ray diffraction measurement under a measurement condition, an X-ray diffraction pattern shows a first diffraction peak at 2θ=19.3 0 ° ±0.2° and a second diffraction peak at 2θ=45.55° ±0.1°, the measurement condition comprising:

manufacturing a battery using the positive electrode of the lithium-ion secondary battery, a lithium metal as a counter electrode, an electrolyte solution, and a polypropylene separator;

subjecting the battery to constant current charging at 25° C. until a voltage value reaches 4.6 V with a current value of 0.5 C, where 1 C is set to 137 mA/g which is a current value per unit mass of the positive electrode active material;

after the constant current charging, subjecting the battery to constant voltage charging until a current value reaches 0.01 C with the voltage value of 4.6 V:

after the constant voltage charging, taking out the positive electrode from the battery and enclosing the taken-out positive electrode in an air tight container in an argon atmosphere;

performing the X-ray diffraction measurement to the positive electrode active material enclosed in the air tight container using a CuKα1 ray in an argon atmosphere,

wherein the electrolyte solution comprises 1 mol/L lithium hexafluorophosphate as an electrolyte, and a solution in which ethylene carbonate and diethyl carbonate at a volume ratio of 3:7 and vinylene carbonate at 2 wt % are mixed.

2 . A lithium-ion secondary battery comprising a positive electrode,

wherein the positive electrode comprises a positive electrode active material comprising a positive electrode active material particle,

wherein the positive electrode active material particle comprises lithium cobalt oxide,

wherein the positive electrode active material particle comprises magnesium, aluminum, and fluorine,

wherein, in EDX linear analysis of the positive electrode active material particle, a peak of aluminum is located in a deeper region than a peak of magnesium,

when the positive electrode of the lithium-ion secondary battery is subjected to an X-ray diffraction measurement under a measurement condition, an X-ray diffraction pattern shows a first diffraction peak at 2θ=19.30°±0.2° and a second diffraction peak at 2θ=45.55°±0.1°,

the measurement condition comprising:

manufacturing a CR2032 type coin cell using the positive electrode of the lithium-ion secondary battery, a lithium metal as a counter electrode, an electrolyte solution, a polypropylene separator, a positive electrode can, and a negative electrode can;

subjecting the coin cell to constant current charging at 25° C. until a voltage value reaches 4.6 V with a current value of 0.5 C, where 1 C is set to 137 mA/g which is a current value per unit mass of the positive electrode active material;

after the constant current charging, subjecting the coin cell to constant voltage charging until a current value reaches 0.01 C with the voltage value of 4.6 V;

after the constant voltage charging, taking out the positive electrode by disassembling the coin cell in an argon atmosphere;

washing the positive electrode with dimethyl carbonate in an argon atmosphere; and

performing the X-ray diffraction measurement using a CuKα1 ray in an argon atmosphere,

wherein the electrolyte solution comprises 1 mol/L lithium hexafluorophosphate as an electrolyte, and a solution in which ethylene carbonate and diethyl carbonate at a volume ratio of 3:7 and vinylene carbonate at 2 wt % are mixed, and

wherein the positive electrode can and the negative electrode can are formed of stainless steel.

Assignments (1)

Priority Claims (1)

Continuity (3)

References Cited (400)