SOLID ION CONDUCTOR COMPOUND, SOLID ELECTROLYTE COMPRISING THE SAME, ELECTROCHEMICAL CELL COMPRISING THE SOLID ION CONDUCTOR COMPOUND, AND PREPARATION METHOD THEREOF

A solid ion conductor compound includes a compound represented by Formula 1: LiHfMOZ Formula 1 where, in Formula 1, M is an element having an oxidation number of a and a is 5, 6, or a combination thereof, Z is an element having an oxidation number of −1, and 0