POSITIVE ELECTRODE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

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)A2y]O2 (wherein M represents one or more tetravalent metals, A represents one or more trivalent metals, 0y).