A superior compatible non-flammable electrolyte to hard carbon anodes for robust sodium ion batteries

Abstract

A compatible non-flammable electrolyte to hard carbon anodes is developed for sodium ion batteries. In contrast to the adsorption-dominant behaviour in conventional carbonate electrolytes, the weak-solvating NaFSI/TFEP electrolyte with robust anion-derived SEI presents a dramatically decreased desodiation barrier. The Na/HC half-cell in NaFSI/TFEP displays high reversible capacity (246.6 mA h g⁻¹ at 0.2 C) and long-term cycling stability over 400 cycles without capacity decay.