| 摘要 |
PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery having a positive electrode containing a positive electrode active material resolving the lithium ion trap problem of a negative electrode containing a carbon material at the time of an initial charge and having little deterioration due to repeated charges/ discharges, i.e., little cycle deterioration. SOLUTION: In this lithium ion secondary battery, lithium ions are stored or released between a positive electrode 2 containing a positive electrode active material and a negative electrode 4 containing a carbon material at the time of a charge/discharge. The positive electrode active material is constituted of a lithium manganese spinel compound expressed by the formula Li1+x Mn2-x O4 (where 0<=x<0.2) and a lithium manganese composite oxide containing the tetragonal system lithium manganese composite oxide expressed by the formula Li2 Mn2 O4 . |
