US 12,394,791 B2
Positive electrode active material for secondary battery, positive electrode for secondary battery, and secondary battery
Yuki Niwata, Kyoto (JP); Saurabh Ranjan, Kyoto (JP); Kensuke Sameshima, Kyoto (JP); and Yosuke Hosoya, Kyoto (JP)
Assigned to Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed by MURATA MANUFACTURING CO., LTD., Kyoto (JP)
Filed on Dec. 27, 2022, as Appl. No. 18/089,366.
Application 18/089,366 is a continuation of application No. PCT/JP2021/009522, filed on Mar. 10, 2021.
Claims priority of application No. 2020-126633 (JP), filed on Jul. 27, 2020.
Prior Publication US 2023/0139370 A1, May 4, 2023
Int. Cl. H01M 4/525 (2010.01); H01M 10/0525 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/525 (2013.01) [H01M 10/0525 (2013.01); H01M 2004/028 (2013.01)] 8 Claims
 
1. A positive electrode active material for a secondary battery, the positive electrode active material comprising a lithium composite oxide of a layered rock-salt type, wherein
the lithium composite oxide includes lithium, cobalt, aluminum, magnesium, an additional element, and oxygen as constituent elements, the additional element including at least one of fluorine, phosphorus, or sulfur,
according to an analysis of the positive electrode active material by inductively coupled plasma optical emission spectrometry, a content of aluminum is greater than a content of magnesium, and
according to an analysis of a surface of the positive electrode active material by X-ray photoelectron spectroscopy, a sum of an abundance of chemical bonds between magnesium and oxygen and an abundance of chemical bonds between magnesium and the additional element is greater than a sum of an abundance of chemical bonds between aluminum and oxygen and an abundance of chemical bonds between aluminum and the additional element.