BATTERY

A battery according to the present disclosure includes: a positive electrode; a negative electrode; and an electrolyte layer positioned between the positive electrode and the negative electrode. The positive electrode includes a positive electrode material. The positive electrode material includes a positive electrode active material and a first solid electrolyte material. The positive electrode active material includes an oxide consisting of Li, Ni, Mn, and O. The first solid electrolyte material includes: Li; at least one selected from the group consisting of metalloid elements and metal elements except Li; and at least one selected from the group consisting of F, Cl, and Br. The negative electrode includes an alloy as a negative electrode active material, and the alloy includes Ni and Bi.