SOLID ELECTROLYTE FOR A LITHIUM SECONDARY BATTERY

A solid electrolyte includes a compound represented by LiA1A2A3(Y)(X). Li is lithium. A1, A2, and A3 are different from each other and A1, A2, and A3 each comprise antimony (Sb), tin (Sn), germanium (Ge), silicon (Si), or phosphorus (P). Y comprises oxygen (O), sulfur(S), selenium (Se), or tellurium (Te). X comprises chlorine (Cl), bromine (Br), iodine (I), or X1X2. X1 and X2 are different from each other and X1 and X2 each comprise Cl, Br, or I. Further, a satisfies 5≤a≤8, b1, b2, and b3 each satisfy 0≤b1≤1, 0≤b2≤1, 0≤b3≤1, b1+b2+b3=1, c satisfies 4≤c≤6, d satisfies 0≤d≤2, and e satisfies 0