| 摘要 |
The positive electrode of a lithium ion secondary battery contains active material particles containing a lithium complex oxide represented by the following formula: LivNi1-w-x-y-zCow CaxMgyMzO2 (wherein 0.85 <= v <= 1.25, 0 < w <= 0.75, 0 < x <= 0.1, 0 < y <= 0.1, 0 <= z <= 0.75, 0 < w + x + y + z <= 0.80, and the element M represents an element other than Co, Ca and Mg). (i) In the case where 0 < z, the element M includes at least one element Me selected from the group consisting of Mn, Al, B, W, Nb, Ta, In, Mo, Sn, Ti, Zr and Y, and at least one element Mc selected from the group consisting of Ca, Mg and the element Me is found more in the surface layers than the inner portions of the active material particles. (ii) In the case where 0 = z, at least one element Mc selected from the group consisting of Ca and Mg is found more in the surface layers than the inner portions of the active material particles. |
