| 摘要 |
PROBLEM TO BE SOLVED: To provide a positive electrode active material for a lithium ion battery, suppressed in an increase of resistance during charge/discharge cycles, capable of prolonging battery life, and excellent in battery characteristics.SOLUTION: A positive electrode active material for a lithium ion battery is represented by compositional formula: LiNiCoZAO(in the formula, 1.00≤a≤1.08, b≥0.8, b+c+d=1, 0.02<d≤0.10 and 0.001≤e≤0.02 are satisfied, Z represents Mn or Al, A represents at least one element selected from Al, Mg, Ti, Zn, Zr, Nb, V and Ta when Z represents Mn, and represents at least one element selected from Mg, Ti, Zn, Zr, Nb, V and Ta when Z represents Al.), and comprises a primary particle and a secondary particle formed by aggregating a plurality of the primary particles. When a load is applied on the secondary particle by pressing an indenter at a loading speed of 0.532 mN/s, a first stage displacement in which both of a displacement amount of a secondary particle and a load are increased is caused, and subsequently, after an increase in a displacement amount of a secondary particle, a second stage displacement in which both of a displacement amount of a secondary particle and a load are increased is caused.SELECTED DRAWING: Figure 1 |
