US 12,322,797 B2
Positive electrode active material, and positive electrode and lithium secondary battery including same
Won Sig Jung, Daejeon (KR); Kang Hyeon Lee, Daejeon (KR); Tae Young Rhee, Daejeon (KR); and Hwan Young Choi, Daejeon (KR)
Assigned to LG Chem, Ltd., Seoul (KR)
Appl. No. 17/768,548
Filed by LG Chem, Ltd., Seoul (KR)
PCT Filed Oct. 23, 2020, PCT No. PCT/KR2020/014606
§ 371(c)(1), (2) Date Apr. 13, 2022,
PCT Pub. No. WO2021/080384, PCT Pub. Date Apr. 29, 2021.
Claims priority of application No. 10-2019-0132505 (KR), filed on Oct. 23, 2019.
Prior Publication US 2023/0142182 A1, May 11, 2023
Int. Cl. H01M 4/485 (2010.01); H01M 4/02 (2006.01); H01M 4/505 (2010.01); H01M 4/525 (2010.01); H01M 10/0525 (2010.01)
CPC H01M 4/485 (2013.01) [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)] 10 Claims
 
1. A positive electrode active material, comprising:
a lithium transition metal oxide,
wherein the lithium transition metal oxide contains nickel in an amount of 60 mol % or greater based on a total number of moles of transition metals on the lithium transition metal oxide,
wherein the lithium transition metal oxide is in the form of a secondary particle, wherein the secondary particle is an aggregate of primary particles, and
wherein the positive electrode active material satisfies Equation (1) below:
−0.021x+4.0≤y≤−0.021x+5.5,  Equation (1)
wherein in Equation (1), x is a crystal grain size (nm) of the positive electrode active material, and y is a crystal grain aspect ratio of the positive electrode active material,
wherein x is obtained by fitting a full width at half-maximum (FWHM) of all peaks, obtained by X-ray diffraction (XRD) analysis on the positive electrode active material, with the Caglioti equation, and
wherein y is a ratio of a long axis length (a) to a short axis length (c) obtained by a least square estimation method after applying a full width at half-maximum (FWHM) of each peak, obtained by performing X-ray diffraction (XRD) analysis on the positive electrode active material, to Equation (2) below:

OG Complex Work Unit Math
wherein d(hk1) is the full width at half-maximum (FWHM) of a corresponding peak,
wherein h, k, and I are the Miller indices in a crystal plane of the corresponding peak, K is a Scherrer constant, θ is a Bragg angle, A is an X-ray wavelength, a is the length of a long axis of a crystal grain, and c is the length of a short axis of the crystal grain.