To provide a non-aqueous secondary battery that has high voltage and high capacity as well as excellent cycle characteristics.
The non-aqueous secondary battery uses as its positive electrode active material a lithium-contained complex oxide as expressed in a general formula LixAyBzCo(1-y-x)O2 (wherein, A is at least one kind selected from a group of Ti, Ta and Nb, B is at least one kind selected from Al, Fe, Ni, Y, Zr, W, Mn, In, Sn and Si; x, y, z are respectively 0≤x≤1.2, 0.005≤y≤0.05, 0≤z≤0.05). It is desirable that the above non-aqueous secondary battery is charged so as to make the upper limit value of its positive electrode potential to be 4.4 V or more and 4.6 V or less at the lithium standard potential, and discharged so as to meke the lower limit value of its positive electrode potential to be 3.2 V or more at the lithium standard potential.
ITSU TETSUO
KITA FUSAJI
HONBO MICHIKO
GOTO AKIHIRO
HITACHI LTD