| 摘要 |
PROBLEM TO BE SOLVED: To provide a power storage device having a large discharge capacity and a high energy density.SOLUTION: A power storage device includes: a positive electrode in which a positive electrode active material is provided over a positive electrode current collector; and a negative electrode opposed to the positive electrode with an electrolyte therebetween. The positive electrode active material includes a first region made of a compound containing lithium and nickel and a second region which covers the first region and is made of a compound containing lithium and at least one of iron, manganese, and cobalt but not containing nickel. Because the entire surface layer of a positive electrode active material particle is formed by the region not containing nickel, nickel is not in contact with an electrolyte solution. Thus, the onset of catalyst effect of nickel is prevented and a high discharge potential of nickel can be utilized. |
