METHOD FOR CHARGING/DISCHARGING LITHIUM SECONDARY BATTERY

PROBLEM TO BE SOLVED: To stabilize a positive electrode layer of a positive electrode while suppressing the growth of lithium like dendrite.SOLUTION: In a method for charging/discharging a lithium secondary battery including a positive electrode, a negative electrode, a separator and a nonaqueous electrolyte, the positive electrode has a positive electrode layer including a positive electrode active material including first and second active materials capable of occluding and releasing lithium. The first active material is a lithium titanium-based composite oxide; and the second active material is a lithium-containing compound (except the lithium titanium-based composite oxide). The first active material is included at a rate of 1-30 mass% to a total mass of the first and second active materials. The negative electrode includes metallic lithium as a negative electrode active material. As to charge and discharge operations after assembling the secondary battery, the discharge operation is performed first. A discharge cutoff voltage in the first discharge operation is made a reaction potential of the first active material. The discharge cutoff voltage in a discharge operation since the first discharge operation is made a potential which causes no reaction with the first active material.SELECTED DRAWING: Figure 2 【課題】リチウムのデンドライト状の成長を抑制しつつ、正極の正極層を安定化ができる。【解決手段】正極、負極、セパレータ及び非水電解質を備えたリチウム二次電池の充放電方法であって、正極は、それぞれリチウムを吸蔵及び放出することが可能な第１の活物質及び第２の活物質を含む正極活物質を含有する正極層を備え、第１の活物質は、リチウムチタン系複合酸化物であり、第２の活物質は、リチウム含有化合物（前記リチウムチタン系複合酸化物を除く）であり、第１の活物質は、第１の活物質及び第２の活物質の合量に対して、１質量％以上３０質量％以下の割合で含有され、負極は、金属リチウムを負極活物質として含み、二次電池の組立後の充放電を放電から初め、初回放電時の放電カットオフ電圧を第１の活物質の反応電位とし、初回放電以降の放電時の放電カットオフ電圧を第１の活物質と反応しない電位とすることを特徴とするリチウム二次電池の充放電方法。【選択図】図２