	US 11,695,114 B2
	Positive electrode active material and lithium secondary battery comprising the same
Moon Ho Choi, Cheongju-si (KR); Hyun Jong Yu, Cheongju-si (KR); and Jung Bae Park, Cheongju-si (KR)
Assigned to ECOPRO BM CO., LTD., Cheongju-si (KR)
Filed by ECOPRO BM CO., LTD., Cheongju-si (KR)
Filed on Nov. 13, 2020, as Appl. No. 17/97,094.
Claims priority of application No. 10-2020-0037343 (KR), filed on Mar. 27, 2020.
Prior Publication US 2021/0305558 A1, Sep. 30, 2021
Int. Cl. H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 10/0525 (2010.01); H01M 4/02 (2006.01)

CPC H01M 4/505 (2013.01) [H01M 4/525 (2013.01); H01M 10/0525 (2013.01); H01M 2004/021 (2013.01); H01M 2004/028 (2013.01)]

11 Claims

1. A positive electrode active material, comprising:

a positive electrode active material comprising a lithium-based composite oxide having a single crystal structure,

wherein a cation-mixing layer is present on the surface of the lithium-based composite oxide, and

a ratio (d1/x1) of the thickness (d1) of the cation-mixing layer to the average particle size (x1) of primary particles ranges from more than 0.0008 and less than 0.0052, wherein the lithium-based composite oxide is represented by Formula 1 below:

Li_aNi_1-(b+c+d+e)CO_bM1_cM2_dM3_eO_f [Formula 1]

Here, M1 is Mn or Al,

M2 and M3 are each independently selected from Al, Ba, B, Ce, Cr, Mg, Mn, Mo, Na, K, P, Sr, Ti, W, Nb, and Zr, and

M1 to M3 are different metals

(0.90≤a≤1.05, 0≤b≤0.20, 0≤c≤0.20, 0≤d≤0.05, 0≤e≤0.05, and 1.0≤f≤2.0), wherein the cation-mixing layer comprises a composite oxide represented by Formula 2 below:

Li_gNi_1-(h+i+j+k)Co_hM4_iM5_jM6_kO_l [Formula 2]

Here, M4 is Mn or Al,

M5 and M6 are each independently selected from Al, Ba, B, Ce, Cr, Mg, Mn, Mo, Na, K, P, Sr, Ti, W, Nb, and Zr, and

M4 to M6 are different metals

(0.0≤g≤1.05, 0≤h≤0.20, 0≤i≤0.20, 0≤j≤0.05, 0≤k≤0.05, and 1.0≤l≤2.0), wherein the crystal structure of the composite oxide represented by Formula 2 is different from the lithium-based composite oxide.