There is provided a positive electrode active material for a non-aqueous electrolyte
secondary battery, comprising a composite oxide represented by the general formula
(1): (Li1-xMx)a(Co1-yMy)bOc
where lithium and cobalt are partly replaced with element M in the crystal structure
of LiCoOc, wherein element M is at least one selected from the group
consisting of Al, Cu, Zn, Mg, Ca, Ba and Sr, and 0.02x+y0.15, 0.90a/b1.10,
and 1.8c2.2 are satisfied.
