| abstract |
(57) [Summary] The composition during charge and discharge is represented by the formula: Li x Mn. 2-yz Ni y M z O 4 [where M is Fe, Co, T at least one element selected from the group consisting of i, V, Mg, Zn, Ga, Nb, Mo and Cu, 0.02 ≦ x ≤ 1.10 (where x fluctuates with insertion and extraction of lithium ions during charging and discharging), 0.25 ≤ y ≤ 0.6 0, 0 <z ≦ 0.10. And a lithium-containing manganese composite oxide having a spinel-type crystal structure represented by the following formula: [Effect] A high-voltage lithium secondary battery having good charge / discharge cycle characteristics is provided. |