Effects of Ion Fraction in an Inorganic Ionic Liquid Electrolyte on Performance of Intermediate-Temperature Operating Sodium-Sulfur Batteries

Sodium-sulfur (Na-S) batteries are promising energy storage systems for renewable energy sources which redeem an intermittent energy source. This study reports the effects of the Na[SO3CF3] fraction in an inorganic Na[SO3CF3]-Cs[N(SO2CF3)2] ionic liquid electrolyte (x(Na[SO3CF3]) = 0.2, 0.3, and 0.4) on the performance of Na-S batteries. Measurements of physicochemical and electrochemical properties demonstrated that decrease in the Na[SO3CF3] fraction decreases viscosity and increases ionic conductivity and the solubility of polysulfides into the ionic liquid, which contributes to the enhanced capacity in the low potential region during discharging.

Automated summary

This study investigates the influence of the Na[SO3CF3] fraction in an inorganic Na[SO3CF3]-Cs[N(SO2CF3)2] ionic liquid electrolyte on the performance of Na-S batteries. Results show that decreasing the Na[SO3CF3] fraction improves the battery's low potential capacity by reducing viscosity and enhancing ionic conductivity and polysulfide solubility.