Lithium-containing composite oxide and nonaqueous secondary cell using the same, and method for manufacturing the same

A method for producing a lithium-containing complex oxide having a composition represented by General Formula:

• Li1+x+αNi(1−x−y+δ)/2Mn(1−x−y−δ)/2MyO2 (where 0≦x≦0.05, −0.05≦x+α≦0.05, 0≦y≦0.4;
• −0.1≦δ≦0.1 (when 0≦y≦0.2) or −0.24≦δ≦0.24 (when 0.2≦y≦0.4);
• and M is at least one element selected from the group consisting of Ti, Cr, Fe, Co, Cu, Zn, Al, Ge and Sn), the method comprising sintering a complex compound containing at least Ni and Mn as constituent elements and a Li compound.

A non-aqueous secondary battery comprising a positive electrode made of a positive active material, a negative electrode made of a negative active material, and a non-aqueous electrolyte, wherein the positive active material is a lithium-containing complex oxide having a composition represented by General Formula:

• Li1+x+αNi(1−x−y+δ)/2Mn(1−x−y−δ)/2MyO2 (where 0≦x≦0.05, −0.05≦x+α≦0.05, 0≦y≦0.4;
• −0.1≦δ≦0.1 (when 0≦y≦0.2) or −0.24≦δ≦0.24 (when 0.2≦y≦0.4);
• and M is at least one element selected from the group consisting of Ti, Cr, Fe, Co, Cu, Zn, Al, Ge and Sn).