Stable High-Temperature Cycling Of Na Metal Batteries On Na3v2(Po4)(3) And Na2fep2o7 Cathodes In Nafsi-Rich Organic Ionic Plastic Crystal Electrolytes

Sodium batteries have emerged as a promising alternative for large-scale energy storage applications due to the low cost and high abundance of sodium. Sodium batteries require safe, high-voltage, and cost-effective electrolytes and cathode materials for their practical applications to be realized. In the present study, Na metal cells with a mixed-phase electrolyte comprising a high concentration of Na salt in an organic ionic plastic crystal (OIPC), namely, triisobutylmethylphosphonium bis(fluorosulfonyl)imide, are investigated.coupled with either a sodium vanadium phosphate-carbon composite (NVP/C) or a sodium iron pyrophosphate (NFpP) cathode. The performance of the Na/NVP/C and Na/NFpP cells are evaluated using cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic cycling at 60 degrees C and room temperature. The results reported herein indicate the performance improvement in terms of cycling stability, with high Coulombic efficiency at 60 degrees C granted by the OIPC and ionic liquid mixtures, compared to a conventional organic solvent electrolyte.