Electrolyte Optimization for Enhancing Electrochemical Performance of Antimony Sulfide/Graphene Anodes for Sodium-Ion Batteries-Carbonate-Based and Ionic Liquid Electrolytes

The electrolyte is a key component in determining the performance of sodium-ion batteries. A systematic study is conducted to optimize the electrolyte formulation for a Sb₂S₃/graphene anode, which is synthesized via a facile solvothermal method. The effects of solvent composition and fluoroethylene carbonate (FEC) additive on the electrochemical properties of the anode are examined. The propylene carbonate (PC)-based electrolyte with FEC can ensure the formation of a reliable solid-electrolyte interphase layer, resulting in superior charge-discharge performance, compared to that found in the ethylene carbonate (EC)/diethyl carbonate (DEC)-based electrolyte. At 60 °C, the carbonate-based electrolyte cannot function properly. At such an elevated temperature, however, the use of an N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ionic liquid electrolyte is highly promising, enabling the Sb₂S₃/graphene electrode to deliver a high reversible capacity of 760 mAh g^-1 and retain 95% of its initial performance after 100 cycles. The present work demonstrates that the electrode sodiation/desodiation properties are dependent significantly on the electrolyte formulation, which should be optimized for various application demands and operating temperatures of batteries.