SOLID ELECTROLYTE, METHOD OF PREPARING THE SAME, AND SOLID-STATE SECONDARY BATTERY INCLUDING THE SAME

A solid electrolyte includes a sulfide solid electrolyte, a first binder, and a second binder, wherein the first binder and the second binder have a different energy of adhesion from each other with respect to the sulfide solid electrolyte, wherein the energy of adhesion of the first binder with respect to the sulfide solid electrolyte is less than −300,000 kcal/mol and the energy of adhesion of the second binder with respect to the sulfide solid electrolyte is −300,000 kcal/mol or more, wherein the energy of adhesion of the first binder with respect to the sulfide solid electrolyte has a greater absolute value than the energy of adhesion of the second binder. A solid-state secondary battery includes a cathode, an anode, and a solid electrolyte layer disposed therebetween, wherein at least one of the cathode, the anode, or the solid electrolyte layer includes the solid electrolyte.