Solid electrolyte, method for preparing solid electrolyte, and lithium battery including solid electrolyte

Provided are a solid-state electrolyte, a method for preparing the same, and a lithium battery including the same, in which the solid-state electrolyte is a garnet-type solid-state electrolyte containing a compound represented by Formula 1, and in which in an extended X-ray absorption fine structure (EXAFS) spectrum of Zr in the garnet-type solid-state electrolyte, the X-ray absorption fine structure (EXAFS) spectrum of Zr is represented by Formula 1. A ratio Ib/Ia of an intensity (Ia) of a first peak having an inter-atomic distance of # imgabs0 # imgabs1 # and an intensity (Ib) of a second peak having an inter-atomic distance of # imgabs2 # is from about 0.3 to about 0.75, and an ionic conductivity of the solid electrolyte is 7 * 10-6 S/cm or more, where in Formula 1, A is a monovalent cation, a divalent cation, a trivalent cation, or a combination thereof, and B is a monovalent cation, a divalent cation, a trivalent cation, or a combination thereof. B is a monovalent cation, a divalent cation, a trivalent c