| abstract |
An electrical device having excellent cycle durability is provided. Lithium nickel composite oxide, and a spinel crystal-based lithium manganese composite oxide, and an electrolyte containing a compound having an S = O bond in the molecule, wherein the lithium nickel-based composite oxide of the positive electrode active material layer Wherein the content of the complex oxide is 50% by mass or more based on the total mass of the lithium nickel composite oxide and the spinel crystal-based lithium manganese composite oxide, and the concentration of the compound having an S = O bond in the molecule in the electrolyte is 0.4 To 2.0% by mass. |