| abstract |
A secondary battery capable of reducing operating voltage while ensuring battery characteristics is provided. A secondary battery includes an electrolyte solution together with a positive electrode and a negative electrode. The negative electrode includes an active material capable of occluding and releasing lithium, and the active material is Li 2 + n1 Na 2-x1 K x1 Ti 6 O 14 (0 ≦ n1 ≦ 2, 0 <x1 ≦ 1.2), Li 2 + n2 Na 2-x2 -y2 K x2 Rb y2 Ti 6 O 14 (0 ≦ n2 ≦ 2,0 ≦ x2 ≦ 1.2,0 <y2 ≦ 0.5,0 <5x2 + 12y2 ≦ 6), and Li 2 + n3 Na 2-x3- y3-z3 K x3 Rb y3 Cs z3 Ti 6 O 14 (0 ≦ n3 ≦ 2,0 ≦ x3 ≦ 0.25,0 ≦ y3 ≦ 0.05,0 <z3 ≦ 0. 05, 0 <y3 + z3 ≦ 0.05) at least one of lithium titanium-containing oxides. [Selection] Figure 1 |