SOLID-STATE BATTERY

A solid-state battery of the present disclosure includes: a negative electrode layer including a negative electrode active material; a positive electrode layer; a solid electrolyte layer positioned between the positive electrode layer and the negative electrode layer. The negative electrode active material includes: a graphite particle being an aggregate of a plurality of primary particles including graphite, the graphite particle having a void inside; and a solid electrolyte being present in the void. At least a portion of the void may be filled with the solid electrolyte. The void has a minimum diameter of, for example, 1 nm or more and 70 nm or less.