CPC H01M 4/505 (2013.01) [H01M 4/0471 (2013.01); H01M 4/366 (2013.01); H01M 4/525 (2013.01); H01M 10/0525 (2013.01); H01M 2004/028 (2013.01)] | 20 Claims |
1. A positive electrode active material for a secondary battery, the positive electrode active material is a lithium composite transition metal oxide represented by the following formula:
LipNi1−(x1+y1+z1)Cox1Mny1Maz1O2+δ [Formula 1]
wherein, Ma is at least one selected from the group consisting of Al, Zr, Ti, Mg, Ta, Nb, Mo, Cr, Ba, Sr, and Ca, 1≤p≤1.3, 0<x1≤0.5, 0<y1<0.5, 0≤z1≤0.1, and −0.1≤δ≤1,
wherein a particle of the lithium composite transition metal oxide comprises a core portion and a resistance portion formed on a surface of the core portion, and is composed of a single particle, and
wherein the core portion has a layered crystal structure of space group R-3m, and the resistance portion has a cubic rock-salt structure of space group Fm-3m.
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