| abstract |
A positive electrode for a secondary battery having excellent charge / discharge cycle characteristics, maintaining a high battery capacity comparable to that of conventional LiNiO 2 even when the number of cycles is increased, and improved cycle characteristics (stability) at high temperatures Provide active material. The general formula (I): Li y Ni 1-x Co x1 M x2 O 2 (wherein M is at least one selected from the group consisting of Al and B, and y is 0.9 ≦ When y ≦ 1.3, x is 0 <x ≦ 0.5, x1 is 0 <x1 <0.5, x1 + x2 = x, and M is Al, x2 is 0 <x2 ≦ 0.3 and M is B In this case, x2 is 0 <x2 <0.1, and when M is B and Al, x2 is 0 <x2 <0.3, but the proportion of B is in the range of 0 to 0.1 ). [Selection] Figure 1 |