Ether-Based Electrolyte Chemistry Towards High-Voltage and Long-Life Na-Ion Full Batteries.

Although ether-based electrolytes have been extensively applied in anode evaluation of batteries, anodic instability arising from solvent oxidability is always a tremendous obstacle to matching with high-voltage cathodes. Herein, by rational design for solvation configuration, the fully coordinated ether-based electrolyte with strong resistance against oxidation is reported, which remains anodically stable with high-voltage Na3 V2 (PO4 )2 O2 F (NVPF) cathode under 4.5 V (versus Na+ /Na) protected by an effective interphase. The assembled graphite//NVPF full cells display superior rate performance and unprecedented cycling stability. Beyond that, the constructed full cells coupling the high-voltage NVPF cathode with hard carbon anode exhibit outstanding electrochemical performances in terms of high average output voltage up to 3.72 V, long-term cycle life (such as 95 % capacity retention after 700 cycles) and high energy density (247 Wh kg-1 ). In short, the optimized ether-based electrolyte enriches systematic options, the ability to maintain oxidative stability and compatibility with various anodes, exhibiting attractive prospects for application.