LAUSR

Abstract Using low-melting-point electrolytes could overcome various key challenges of low-cost sodium-based liquid metal batteries (Na-LMBs), e.g. high rates of self-discharge and degradation of structural materials, by lowering their operating temperatures. Molten halide salts are considered promising electrolyte candidates for Na-LMBs due to their high stability and electrical conductivity. In this work, thermodynamic simulation via FactSageTM and thermal analysis via e.g. Differential Scanning Calorimeter (DSC) were carried out to explore the NaI-LiI-KI system, since it could be a promising electrolyte for Na-LMBs due to its low melting point and Na solubility. The results show that the eutectic NaI-LiI-KI performs as a pseudo-binary salt with a melting point of ~290 °C. In this pseudo-binary salt, the solubility of NaI in the eutectic LiI-KI is ~7 mol%. Using the eutectic NaI-LiI-KI electrolyte, Na-LMBs could be operated at