SOLID ELECTROLYTE, PREPARATION METHOD THEREOF, LITHIUM AIR BATTERY INCLUDING THE SOLID ELECTROLYTE, AND ELECTROCHEMICAL DEVICE INCLUDING THE SOLID ELECTROLYTE

A solid electrolyte includes: a first electrolyte layer including an inorganic lithium ion conductor; and a second electrolyte layer disposed on at least one side of the first electrolyte layer and including a compound represented by Formula 1 Li(HfM)(POQ) Formula 1 wherein in Formula 1, M is at least one of a monovalent to a hexavalent element, wherein 0