Positive electrode material for nonaqueous electrolyte secondary battery and battery using the same

A positive electrode active material for a nonaqueous electrolyte secondary battery includes at least a lithium-containing manganese layered composite oxide represented by the formula Li1-xAxMnO2, or the formula Li1-xAxMn1-yMyO2. The lithium-containing manganese composite oxide includes a lithium substitute metal A, such as Na, K, Ag, substituting for part of Li. The lithium substitution quantity x may be In the range of 0.03