| 摘要 |
A positive electrode active material for a non-aqueous electrolyte secondary battery, comprising a lithium-containing composite oxide, wherein the composite oxide is represented by the general formula: Li<SUB>z</SUB>Co<SUB>1-x-y</SUB>Mg<SUB>x</SUB>M<SUB>y</SUB>O<SUB>2</SUB>, the element M included in the general formula is at least one selected from the group consisting of Al, Ti, Sr, Mn, Ni and Ca, the values x, y and z included in the general formula satisfy: (i) 0<=z<=1.03; (ii) 0.005<=x<=0.1; and (iii) 0.001<=y<=0.03, the composite oxide has a crystal structure attributed to a hexagonal system in an overcharged state having a potential over 4.25 V relative to metallic Li, and a maximum value of an oxygen generation peak in a gas chromatograph mass spectrometry measurement of the composite oxide in the overcharged state is in the range of 330 to 370° C. |
