Non-aqueous electrolyte secondary battery including phosphoric acid ester compound containing at least one metal element

Provided is a nonaqueous electrolyte secondary battery including a nonaqueous electrolyte and an electrode assembly including a positive electrode, a negative electrode, and a separator disposed between the positive electrode and the negative electrode. The electrode assembly further includes a layer containing a metal oxide powder between the positive electrode and the negative electrode. The positive electrode contains a phosphate ester compound represented by Formula (1); where X and Y each independently represent a metal atom, a hydrogen atom, or an organic group; at least one of X and Y represents a metal atom; X and Y are coincident when the metal atom is divalent; and n represents an integer of 2 or more and 10 or less.