POSITIVE ELECTRODE ACTIVE SUBSTANCE FOR NON-AQUEOUS ELECTROLYTIC SECONDARY CELLS, POSITIVE ELECTROD

A purpose of the present invention is to provide a positive electrode active substance for non-aqueous electrolytic secondary cells that is capable of suppressing a reduction in capacitance restoration rate after storage at a high temperature. The non-aqueous electrolytic secondary cell according to the present invention includes : secondary particles formed by agglomerating primary particles of a lithium-containing transition metal oxide; secondary particles formed by agglomerating primary particles of a rare earth compound; and a magnesium compound. On surfaces of the secondary particles of the lithium-containing transition metal oxide, the secondary particles of the rare earth compound are attached to recesses formed between adjacent primary particles of the lithium-containing transition metal oxide, and are attached to each of the primary particles forming the recesses. The magnesium compound is attached to surfaces of the secondary particles of the lithium-containing transition metal compound.