Novel Low Temperature Molten Salt Synthesis of a Li₅La₃Nb₂O₁₂ Solid State Electrolyte and Its Properties

Abstract

The solid state electrolyte (SSE) of Li₅La₃Nb₂O₁₂ (LLNO) was synthesized via a novel molten salt synthesis (MSS) method at the relatively low temperature of 900°C. The low sintering temperature prevented the loss of lithium that commonly occurs during synthesis of the SSE using conventional solid state or wet chemical reactions. Recent publications have demonstrated that preserving the Li content is critical in improving the ionic conductivity of SSEs. The LLNO in this experiment showed a high Li-ion conductivity which is comparable to other values reported for LLNO. X-ray diffraction (XRD) measurements confirmed the formation of the cubic garnet Ia-3d crystal structure. In addition, the morphology was examined by scanning electron microscopy (SEM), which showed a uniform grain size and crack-free microstructure. These results demonstrate that MSS is a powerful synthesis method to fabricate LLNO at a relatively low temperature while still achieving a high quality material.