Patent ID: 7255963

Claim:
A non-aqueous electrolyte rechargeable battery comprising: (a) a positive electrode capable of charging and discharging lithium; (b) a negative electrode capable of charging and discharging lithium; (c) a separator or a lithium ion conductive layer interposed between said positive electrode and said negative electrode; and (d) a lithium ion conductive non-aqueous electrolyte, wherein said positive electrode contains a mixture of a first positive electrode active material and a second positive electrode active material, said first positive electrode active material comprises lithium oxide containing manganese, said lithium oxide further contains aluminum and/or magnesium and said second positive electrode active material comprises Li x Co 1-y-z Mg y Al z O 2 where 1≦x≦1.03, 0.005≦y≦0.1 and 0.001≦z<0.02, wherein the content of the second positive electrode active material in the mixture of the first and second positive electrode active materials is 10 wt % or higher and 40 wt % or lower.