Method for manufacturing positive electrode active material, and secondary battery

Patent metadata

Field	Value
Publication number	US-2021028456-A1
Application number	US-202017036740-A
Country	US
Kind code	A1
Filing date	Sep 29, 2020
Priority date	Jun 26, 2017
Publication date	Jan 28, 2021
Grant date	—

Abstract

A positive electrode active material has a small difference in a crystal structure between the charged state and the discharged state. For example, the crystal structure and volume of the positive electrode active material, which has a layered rock-salt crystal structure in the discharged state and a pseudo-spinel crystal structure in the charged state at a high voltage of approximately 4.6 V, are less likely to be changed by charging and discharging as compared with those of a known positive electrode active material. In order to form the positive electrode active material having the pseudo-spinel crystal structure in the charged state, it is preferable that a halogen source such as a fluorine and a magnesium source be mixed with particles of a composite oxide containing lithium, a transition metal, and oxygen, which is synthesized in advance, and then the mixture be heated at an appropriate temperature for an appropriate time.

First claim

1 . A lithium ion secondary battery comprising:
a positive electrode active material comprising lithium, cobalt, and oxygen, wherein dQ/dV vs V curve in a range of greater than or equal to 4.0V and less than or equal to 4.8V which is obtained by differentiating capacitance (Q) with voltage (V) does not have a maximum peak in a range of greater than or equal to 4.5V and less than or equal to 4.7 V.

2 . A lithium ion secondary battery comprising:
a positive electrode active material comprising lithium, cobalt, and oxygen, wherein dQ/dV vs V curve which is obtained by differentiating capacitance (Q) with voltage (V) has a peak in a range of greater than or equal to 4.5V and less than or equal to 4.7V, and wherein the peak is not a maximum peak in a range of greater than or equal to 4.0V and less than or equal to 4.8V.

3 . A lithium ion secondary battery comprising:
a positive electrode active material comprising lithium, cobalt, and oxygen, wherein dQ/dV vs V curve which is obtained by differentiating capacitance (Q) with voltage (V) has a peak in a range of greater than or equal to 4.5V and less than or equal to 4.7V, wherein the peak is not a maximum peak in a range of greater than or equal to 4.0V and less than or equal to 4.8V, and wherein the peak which is not the maximum peak is smaller than a peak in the range of greater than or equal to 4.0V and less than 4.5V.

Assignees

• Semiconductor Energy Lab

Inventors

• Takahashi Masahiro
• Mikami Mayumi
• Momma Yohei
• Ochiai Teruaki
• Saitou Jyo

Classifications

• C01G51/82 Primary

  Compounds containing cobalt, with or without oxygen or hydrogen, and containing two or more other elements · CPC title

• H01M4/48

  of inorganic oxides or hydroxides · CPC title

• H01M4/38

  of elements or alloys · CPC title

• H01M4/36

  Selection of substances as active materials, active masses, active liquids · CPC title

• H01M10/0525

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