POSITIVE ACTIVE MATERIAL FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, POSITIVE ELECTRODE FOR NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, METHOD FOR MANUFACTURING NONAQUEOUS ELECTROLYTE SECONDARY BATTERY, AND METHOD OF USING NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

A positive active material for a nonaqueous electrolyte secondary battery, containing a lithium-transition metal composite oxide, in which the lithium-transition metal composite oxide has an α-NaFeO2 structure, with the molar ratio Li/Me of Li to the transition metal (Me) being 1.05 ≤ Li/Me < 1.4, and contains Ni and Mn, or contains Ni, Co, and Mn as the transition metal (Me), with the molar ratio Mn/Me of Mn to Me being 0.4 ≤ Mn/Me < 0.6, and the molar ratio Ni/Me of Ni to Me being 0.2 ≤ Ni/Me ≤ 0.6.