SOLID-STATE BATTERY

A solid-state battery comprising a positive electrode, a negative electrode, and a solid electrolyte membrane between the positive electrode and the negative electrode, the solid electrolyte membrane including a first solid electrolyte layer and a second solid electrolyte layer, is provided. The first solid electrolyte layer faces the positive electrode and includes a first sulfide-based solid electrolyte, and the second solid electrolyte layer includes a second sulfide-based solid electrolyte having an average particle diameter (D50) larger than an average particle diameter (D50) of the first sulfide-based solid electrolyte.