Both safety and high energy density are essential for the large size batteries propelling electric vehicle. All solid state batteries have received great attention as a next generation power source due to its safe characteristics with non-flammable solid electrolyte. A solid electrolyte with high ion conductivity is key to the development of all solid state battery. Solid electrolytes were mainly synthesized by conventional solid state method. Recently, liquid based new synthesis method was proposed to avoid mechanical milling process which takes long time to prepare. Moreover, new materials might be obtained via liquid based synthesis method which cannot be successfully achieved by solid state synthesis.
In this study, tetrahydrofuran (THF) and anhydrous ethanol were used as a solvent for liquid based synthesis. Li2S, P2S5 and LiBr with a stoichiometric ratio were added in solvent, and then dried at 150 C under vacuum to obtain solid electrolyte powder. Crystallinity was examined by X-ray diffraction method and ion conductivity was evaluated by AC impedance technique. All solid state batteries were fabricated using LiNi0.8Co0.1Mn0.1 (NCM811) active material and Li6PS5Br solid electrolyte obtained by liquid based synthesis process. Reaction mechanism was investigated and the detailed results will be discussed.