Solid electrolyte, preparation method thereof, lithium air battery including the same, and electrochemical device including the same

A method of preparing a solid electrolyte, the method comprising:

• mixing a lithium precursor, at least one of an M1 precursor, an M2 precursor, or an M3 precursor, and optionally at least one of an X precursor or a D precursor, to prepare a precursor mixture;
• and
• heat-treating the precursor mixture to prepare the solid electrolyte,
• wherein the solid electrolyte is an ion conductor represented by at least one of
• Formulae 1 to 3,
• Li1+3xM11−xO2 Formula 1
• wherein, in Formula 1,
• M1 is a trivalent element, and
• 0<x<1;
• Li1−yM2O2−yXy Formula 2
• wherein, in Formula 2,
• M2 is a trivalent element,
• X is at least one of a halogen atom or pseudohalogen, and
• 0<y<1;
• and
• L1−z(a−3)M31−zDzO2 Formula 3
• wherein, in Formula 3,
• M3 is a trivalent element,
• D is at least one of a monovalent element to a hexavalent element,
• a is an oxidation number of D, and
• 0<z<1.