US 11,942,631 B2
Positive electrode active material and method of producing positive electrode active material
Ryuhei Hattori, Tokushima (JP); Yoshitomo Miyashita, Tokushima (JP); Tatsuya Yokoyama, Anan (JP); Chika Nishio, Anan (JP); and Takashi Sugimoto, Tokushima (JP)
Assigned to NICHIA CORPORATION, Anan (JP)
Filed by NICHIA CORPORATION, Anan (JP)
Filed on Feb. 16, 2023, as Appl. No. 18/170,373.
Application 18/170,373 is a continuation of application No. 16/926,613, filed on Jul. 10, 2020, granted, now 11,621,415.
Claims priority of application No. 2019-129204 (JP), filed on Jul. 11, 2019; and application No. 2020-097755 (JP), filed on Jun. 4, 2020.
Prior Publication US 2023/0197943 A1, Jun. 22, 2023
Int. Cl. H01M 4/485 (2010.01); C01G 53/00 (2006.01); H01M 4/02 (2006.01); H01M 4/131 (2010.01); H01M 4/1391 (2010.01)
CPC H01M 4/485 (2013.01) [C01G 53/40 (2013.01); C01G 53/42 (2013.01); H01M 4/131 (2013.01); H01M 4/1391 (2013.01); C01P 2002/52 (2013.01); H01M 2004/028 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A positive electrode active material, comprising:
secondary particles each composed of an aggregate of primary particles that contain a lithium transition metal composite oxide having a layered structure and a composition ratio of a number of moles of nickel to a total number of moles of metals other than lithium of from 0.7 to less than 1,
wherein a compound containing boron is attached on at least a part of surfaces of the primary particles,
a compound containing sodium is present in at least a part of particle boundaries of the secondary particles, and
a value obtained by dividing a standard deviation of detection amounts of boron element in any three regions in a cross-sectional surface of the secondary particles by an average of the detection amounts is less than 0.18.