HIGH ION CONDUCTIVE SOLID ELECTROLYTE FOR ALL-SOLID STATE BATTERY AND METHOD FOR PREPARING SAME

Disclosed is a method of preparing a solid electrolyte, the method including (a) preparing a solid electrolyte precursor by subjecting a mixed solution composed of a lanthanum precursor, a zirconium precursor, a gallium precursor, a complexing agent, and a pH adjuster to coprecipitation, (b) washing and drying the solid electrolyte precursor, (c) preparing a mixture by mixing the washed and dried solid electrolyte precursor with a lithium source, and (d) calcining the mixture to give a calcined solid electrolyte, which is a gallium (Ga)-doped lithium lanthanum zirconium oxide (LLZO), as represented by Chemical Formula 1. A solid electrolyte having increased ionic conductivity and an improved potential window can be provided using the method of preparing the solid electrolyte.