A Self-Binding, Melt-Castable, Crystalline Organic Electrolyte for Sodium Ion Conduction.

The preparation and characterization of the cocrystalline solid-organic sodium ion electrolyte NaClO (DMF) (DMF=dimethylformamide) is described. The crystal structure of NaClO (DMF) reveals parallel channels of Na and ClO ions. Pressed pellets of microcrystalline NaClO (DMF) exhibit a conductivity of 3×10  S cm at room temperature with a low activation barrier to conduction of 25 kJ mol . SEM revealed thin liquid interfacial contacts between crystalline grains, which promote conductivity. The material melts gradually between 55-65 °C, but does not decompose, and upon cooling, it resolidifies as solid NaClO (DMF) , permitting melt casting of the electrolyte into thin films and the fabrication of cells in the liquid state and ensuring penetration of the electrolyte between the electrode active particles.