US 12,230,794 B2
Secondary battery positive electrode active material, and secondary battery
Hiroshi Kawada, Hyogo (JP); Kosuke Kuroda, Osaka (JP); and Atsushi Fukui, Hyogo (JP)
Assigned to PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO., LTD., Osaka (JP)
Appl. No. 17/604,654
Filed by Panasonic Intellectual Property Management Co., Ltd., Osaka (JP)
PCT Filed Apr. 16, 2020, PCT No. PCT/JP2020/016666
§ 371(c)(1), (2) Date Oct. 18, 2021,
PCT Pub. No. WO2020/218136, PCT Pub. Date Oct. 29, 2020.
Claims priority of application No. 2019-085367 (JP), filed on Apr. 26, 2019.
Prior Publication US 2022/0216467 A1, Jul. 7, 2022
Int. Cl. H01M 4/505 (2010.01); H01M 4/02 (2006.01); H01M 4/525 (2010.01)
CPC H01M 4/505 (2013.01) [H01M 4/525 (2013.01); H01M 2004/028 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A positive electrode active material for secondary battery, containing a lithium transition metal composite oxide, wherein
the lithium transition metal composite oxide is represented by general formula Liα[LixMnyCozMe(1-x-y-z)]O2 (where Me is at least one selected from Ni, Fe, Ti, Bi, and Nb, and 0.5<α<1, 0.05<x<0.25, 0.4<y<0.7, and 0<z<0.25 hold true), and has at least one crystal structure selected from O2 structure, T2 structure, and O6 structure, and
a ratio (Co2/Co1) of a Co molar ratio (Co2) at a surface of the oxide to a Co molar ratio (Co1) in the entire lithium transition metal composite oxide satisfies 1.2<(Co2/Co1)<6.0,
wherein the O2 structure constitutes at least 50 vol. % of an entire crystal structure of the lithium transition metal composite oxide.