NONAQUEOUS ELECTROLYTE SECONDARY BATTERY POSITIVE ELECTRODE ACTIVE MATERIAL AND METHOD FOR MANUFACTURING SAME, AND NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

Provided are: a nonaqueous electrolyte secondary battery positive electrode active material that has high crystallinity, that causes less amount of Mn deposition on a negative electrode, and that can form a secondary battery having excellent cycle characteristics; and a nonaqueous electrolyte secondary battery using the nonaqueous electrolyte secondary battery positive electrode active material. The nonaqueous electrolyte secondary battery positive electrode active material according to the present invention is formed of a lithium-manganese-nickel complex oxide including a spinel-type crystal structure, wherein the lithium-manganese-nickel complex oxide has a crystallite diameter not smaller than 1000 Å and is formed of primary particles that have a polyhedron shape having more than eight surfaces. The proportion of ungrown particles not having the polyhedron shape of the primary particles in the lithium-manganese-nickel complex oxide is preferably not higher than 5%.