A battery according to one aspect of the present disclosure includes: a positive electrode; a negative electrode; and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein the positive electrode includes a positive electrode active material and a first solid electrolyte material coating at least a portion of a surface of the positive electrode active material, the first solid electrolyte material includes Li, M1, and F, where M1 is at least one selected from the group consisting of Ti, Al, and Zr, and a ratio a of a capacity of the negative electrode to a capacity of the positive electrode satisfies 0.78≤a≤1.31.