US 12,087,946 B2
Positive electrode active material and lithium secondary battery comprising the same
Gwang Seok Choi, Cheongju-si (KR); Moon Ho Choi, Cheongju-si (KR); Jun Won Suh, Cheongju-si (KR); Jin Kyeong Yun, Cheongju-si (KR); Jung Han Lee, Cheongju-si (KR); Seung Woo Choi, Cheongju-si (KR); Joong Ho Bae, Cheongju-si (KR); and Du Yeol Kim, Cheongju-si (KR)
Assigned to ECOPRO BM CO., LTD., Cheongju-si (KR)
Filed by ECOPRO BM CO., LTD., Cheongju-si (KR)
Filed on Jul. 22, 2021, as Appl. No. 17/382,667.
Claims priority of application No. 10-2020-0140017 (KR), filed on Oct. 27, 2020.
Prior Publication US 2022/0131143 A1, Apr. 28, 2022
Int. Cl. H01M 4/525 (2010.01); H01M 4/505 (2010.01); H01M 10/0525 (2010.01); H01M 4/02 (2006.01)
CPC H01M 4/525 (2013.01) [H01M 4/505 (2013.01); H01M 10/0525 (2013.01); H01M 2004/028 (2013.01)] 13 Claims
OG exemplary drawing
 
1. A positive electrode active material, comprising:
a lithium composite oxide enabling lithium intercalation/deintercalation,
wherein at least one metal element of the lithium composite oxide exhibits a concentration gradient including a first concentration gradient section having a (+) slope and a second concentration gradient section having a (−) slope from the outermost surface toward the center of the lithium composite oxide,
the first concentration gradient section is present from the outermost surface of the lithium composite oxide to a predetermined depth, and the second concentration gradient section is present at an inner side of the first concentration gradient section,
in the first concentration gradient section, a nickel concentration of the lithium composite oxide is decreased, and a cobalt concentration of the lithium composite oxide is increased from the surface toward the center of the lithium composite oxide, and
in the second concentration gradient section, a nickel concentration of the lithium composite oxide is increased, and a cobalt concentration of the lithium composite oxide is decreased from the surface toward the center of the lithium composite oxide,
wherein:
in the first concentration gradient section, a concentration of at least one selected from manganese and aluminum thereof is increased from the surface toward the center of the lithium composite oxide;
in the second concentration gradient section, a concentration of at least one selected from manganese and aluminum thereof is decreased from the surface toward the center of the lithium composite oxide;
there is a concentration maintenance section which is located at an inner side of the second concentration gradient section, and in which the concentration of at least one metal element of the lithium composite oxide is maintained from the surface toward the center of the lithium composite oxide; and
a nickel concentration of the lithium composite oxide in the concentration maintenance section is higher than those in the first concentration gradient section and the second concentration gradient section.