A positive electrode active material is provided to contain: a solid solution lithium-containing transition metal oxide (A) represented by Li 1.5 [Ni a Co b Mn c [Li] d ]O 3 (where a, b, c and d satisfy the relations of a+b+c+d=1.5, 0.1

A lithium primary battery including: a positive electrode containing a mixed crystalline manganese oxide; a negative electrode containing at least one selected from the group consisting of lithium and a lithium alloy; and a lithium-ion conductive non-aqueo...