abstract |
An active material for a battery contains a niobium composite oxide represented by the formula: Li x M (1-y) Nb y Nb 2 O (7+δ) , where M represents at least one kind selected from Ti and Zr. X, y, and δ are numbers respectively satisfying the following: 0≤x≤6, 0≤y≤1, and −1≤δ≤1. |