Patent ID: 7544443

Claim:
A nonaqueous electrolyte secondary battery comprising: a positive electrode including a positive electrode active material capable of intercalating and deintercalating lithium; a negative electrode including a negative electrode active material capable of intercalating and deintercalating lithium; and a nonaqueous electrolyte having lithium ion conductivity, the positive electrode active material being a layered lithium transition metal composite oxide represented by Li 1+x (Ni y Co z Mn 1−y−z ) 1−x O 2 , where 0≦x≦0.15, 0.1≦y≦0.6, and 0≦z≦0.5 to which Zr and Nb are added, wherein the amount of Zr to the layered lithium transition metal composite oxide is 0.05˜3 mole %, and that of said Nb is 0.05˜3 mole %.