| 摘要 |
Disclosed is a positive electrode active material for nonaqueous electrolyte secondary batteries which contains a complex oxide mainly containing sodium, nickel and a tetravalent metal while having a hexagonal structure. This positive electrode active material enables to obtain a nonaqueous electrolyte secondary battery with high operating voltage. The complex oxide is preferably expressed as Na [Na (1/3 - 2x/3) Ni (x-y) M (2/3-x/3-y) A 2y ]O 2 (wherein M represents one or more tetravalent metals, A represents one or more trivalent metals, O<x‰¦0.5, 0‰¦y<1/6, and x>y). |
