Patent ID: 11024847

Abstract:
A positive electrode active material for a lithium secondary battery, including secondary particles formed by aggregation of primary particles capable of being doped and undoped with lithium ions, said positive electrode active material having: an α-NaFeO2 type crystal structure represented by formula: Li[Lix(NiaCobMncMd)1-x]O2 (I), wherein 0≤x≤0.1, 0.7<a<1, 0<b<0.2, 0≤c<0.2, 0<d<0.1, a+b+c+d=1, and M is at least one metal element selected from the group consisting of Fe, Cr, Ti, Mg, Al, Zr, Ca, Sc, V, Cr, Cu, Zn, Ga, Ge, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In and Sn; and a crystallite size α/crystallite size β ratio (α/β) of 1.60 to 2.40, wherein the crystallite size α is within a peak region of 2θ=18.7±1° and the crystallite size β is within a peak region of 2θ=44.4±1°, each determined by a powder X-ray diffraction measurement using Cu-Kα radiation.