Inhibiting Grain Pulverization and Sulfur Dissolution of Bismuth Sulfide by Ionic Liquid Enhanced Poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) for High-Performance Zinc-Ion Batteries

Aqueous zinc-ion batteries (ZIBs) possess energy storages advantages, including low cost, high safety, and durable lifetimes. Materials are worth exploring to achieve high-performance batteries. Although Bi₂S₃ is predicted to be highly capable for energy storage, it has never been used in aqueous ZIBs due to the structure degradation. Herein, we apply Bi₂S₃ in aqueous ZIBs and develop an ionic liquid enhanced poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) coating to perfectly stabilize the Bi₂S₃ electrode, which plays three roles of providing high conductivity, inhibiting grain pulverization and sulfur dissolution, and acting as an artificial solid electrolyte interphase. The synergistic merits of the desirable capacity of Bi₂S₃ and a versatile polymer provide a capacity of 275 mAh g^-1 and excellent cycling stability up to 5300 cycles with 95.3% retention. A reversible conversion mechanism into hexagonal ZnS is revealed by investigation of a variety of spectra. The prepared quasi-solid battery based on a high concentration salt electrolyte/polyacrylamide hydrogel exhibits a high energy density (315 Wh kg^-1) and long-term cyclability over 5300 cycles. For demonstration, a single battery can power a digital hygrometer thermometer for more than 14 h 48 min. This work highlights a ground-breaking demonstration of incorporating structural integrity with stable interfacial chemistry.