Sulfite-Based Electrolyte Chemistry with Ion–Dipole Interactions and Robust Interphase Achieves Wide-Temperature Sodium-Ion Batteries

Abstract

Currently, ether- and carbonate-based electrolytes have been extensively studied for applications in harsh conditions; however, it is difficult to develop a suitable electrolyte system that is compatible with both high and low temperatures. Herein, for the first time, a cyclic sulfite-based electrolyte is formulated to successfully achieve the wide-temperature operation of sodium-ion batteries (SIBs) from -60 to 60 °C. By precisely modulating ion-dipole interactions, the dominant ion coordination states are screened directionally to accelerate the desolvation process and simultaneously maintain sufficient electrostatic constraints, laying the foundation for high- and low-temperature compatibility. And the coordinated anions and additives synergistically decompose to enable inorganic-rich interphases with robustness and favorable ion diffusion, extending the voltage window and temperature range. As a result, Na₃V₂(PO₄)₂O₂F demonstrates 58 mA h g^-1 at -50 °C while stably cycling at 60 °C for 300 cycles with 80% capacity retention. Additionally, Na₃V₂(PO₄)₃ and NaFe_1/3Ni_1/3Mn_1/3O₂ cathodes also exhibit discharge specific capacities of 50 and 65 mA h g^-1 at -60 °C. Eventually, the Ah-class pouch cell displays 0.64 A h with 56% capacity retention at -40 °C. In short, the introduced electrolyte formulation enhances the wide temperature operation of SIBs, shedding light on the development of all-weather systems.