NON-AQUEOUS ELECTROLYTE CELL AND POSITIVE ELECTRODE ACTIVE MATERIAL THEREFORE

A lithium ion cell less costly than a control lithium ion cell is provided. The lithium ion cell is improved appreciably in operational stability under special conditions, such as high temperatures, and exhibits superior characteristics against over-discharging, while guaranteeing compatibility to the operating voltage of a conventional lithium ion cell and an energy density equivalent to that of the conventional lithium ion cell. To this end, the lithium ion cell includes a positive electrode, a negative electrode and a non-aqueous electrolyte, and uses, as a positive electrode active material, a composite material of a first lithium compound represented by the general formula LiMPO, where 0