| 摘要 |
Disclosed is a lithium ion secondary battery which includes a positive electrode, a negative electrode and a nonaqueous electrolyte solution. The positive electrode contains, as the positive electrode active material, a lithium-transition metal composite oxide having a layered structure. The positive electrode active material includes at least one metal element M0 from among Ni, Co and Mn, and includes at least one metal element M′ from among Zr, Nb and Al, and further includes W. When 2 g of a powder of the positive electrode active material and 100 g of pure water are stirred together to prepare a suspension and the suspension is filtered to obtain a filtrate, the amount of W eluted into the filtrate, as measured by inductively coupled plasma mass spectrometry, is 0.025 mmol or less per gram of filtrate. |
