ALL-SOLID-STATE BATTERY

An all-solid-state battery includes a positive electrode layer, a solid electrolyte layer, and a negative electrode layer. A negative electrode mixture layer of the negative electrode layer contains either one or both of a negative electrode active material and a carbon material, a first phase in contact with at least a part of the negative electrode active material and the carbon material, and a second phase in contact with at least a part of the first phase. The first and second phases contain a Li element and an X element which is at least one halogen element selected from the group consisting of F, Cl, Br, and I. An X element concentration in the first phase is higher than in the solid electrolyte layer. An X element concentration in the second phase is lower than the in the first phase and in the solid electrolyte layer.