NONAQUEOUS ELECTROLYTE SECONDARY BATTERY

摘要

PROBLEM TO BE SOLVED: To suppress the reduction of the battery capacity after the charging/ discharging cycle elapses and improve the charging/discharging cycle characteristics by containing ruthenium in the lithium-manganese composite oxide of a positive electrode having a spinel structure. SOLUTION: A separator 3 is inserted between a (Ru-LiMn2 O4 ) positive electrode 1 containing ruthenium in a lithium-manganese composite oxide used as a main material and a negative electrode 2 using Li as the active material in this nonaqueous electrolyte secondary battery. Mn is substituted with Ru in the crystal of Ru-LiMn2 O4 . The atomic ratio between Ru and Mn in Ru-LiMn2 O4 is preferably set within the range of 0.02<=Ru/(Ru+Mn)<=0.4. The portion substituted with Ru causes no battery reaction, and the portion serves as a skeleton to stabilize the crystal structure. The crystal structure is not collapsed even when charge and discharges are repeated, and the charging/discharging cycle characteristics are improved.