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

The present invention relates to SOLID ELECTROLYTE, PREPARATION METHOD THEREOF, LITHIUM-AIR BATTERY INCLUDING THE SAME, AND ELECTROCHEMICAL DEVICE INCLUDING THE SAME. A solid electrolyte including: a compound represented by Formula 1, Formula 1 LixM12-yM2y(PO4-zXz)3wherein, in Formula 1, M1 is a tetravalent element,M2 is a monovalent element, a divalent element, a trivalent element, a tetravalent element, a pentavalent element, a hexavalent element, or a combination thereof,X is a halogen atom, a pseudohalogen, or a combination thereof,0