| abstract |
A nonaqueous electrolyte secondary battery including a positive electrode, a negative electrode, and a nonaqueous electrolyte, in which the positive electrode includes, as an active material, a lithium-transition metal composite oxide that has an α-NaFeO<sub>2</sub>-type crystal structure, and is represented by the general formula Li<sub>1+α</sub>Me<sub>1-α</sub>O<sub>2</sub> (0 < a, Me is a transition metal element containing Ni and Mn, or containing Ni, Mn, and Co), and has a diffraction peak observed in the range of 20° or more and 22° or less in an X-ray diffraction pattern obtained with a CuKa line. |