| abstract |
A secondary battery both having a cathode and an anode with a separator in between. The cathode comprises a stable complex oxide Li x Ni 1-y-z Mn y MI z O 2 and a highly conductive complex oxide Li s MII l-t-u Mn t MIII u O 2 . Each of MI and MIII includes at least one kind selected from the group consisting of elements in Group 2 through Group 14, and MII includes at least one kind selected from the group consisting of Ni and Co, and the values of x, y, z, s, t and u are within a range of 0.9≦x≦1.1, 0.25≦y≦0.45, 0.01≦z≦0.30, 0.9≦s≦1.1, 0.05≦t≦0.20, and 0.01≦u≦0.10, respectively. |