Regulating the Electrolyte Solvation Structure Enables Ultralong Lifespan Vanadium-Based Cathodes with Excellent Low-Temperature Performance

Aqueous Zn||vanadium oxide batteries (ZVBs) have recently received considerable attention owing to their high capacity, safety, environmental friendliness, and cost effectiveness. However, the limited cycling stability caused by the irreversible dissolution in traditional aqueous electrolytes still restricts their further application. Herein, a novel 3 m Zn(CF3SO3)(2) electrolyte with a mixture solvent of propylene carbonate (PC) and H2O is adopted for aqueous vanadium-based zinc-ion batteries. With the manipulation of the electrolyte solvation structure, the optimized P20 (20% PC in volume ratio) electrolyte enables super-stable cycling performance with high-capacity retention of 99.5%/97% after 100/1000 cycles at 0.1/5 A g(-1) at ambient environment in the Zn||NaV3O8 center dot 1.5H(2)O batteries. Systematical electrochemical testing and characterizations illustrate the addition of PC effectively reduces the active water molecule in Zn2+-solvent cations and H+ in the electrolyte, thereby suppressing the cathode dissolution caused by the inserted H+ and co-inserted H2O during the discharge/charge process. Impressively, the PC addition also enabled the Zn||NaV3O8 center dot 1.5H(2)O batteries present high specific capacity of 183/168 mAh g(-1) and high-capacity retention of 100%/100% over 300/400 cycles at 0.1/0.2 A g(-1) at -40 degrees C, thus efficiently broadening the practical application for ZVB. This research may provide a promising strategy for designing high-performance electrolytes for aqueous vanadium-based batteries.

Automated summary

A novel 3 m Zn(CF3SO3)2 electrolyte was used to improve the cycling performance and specific capacity of aqueous vanadium-based zinc-ion batteries. By manipulating the solvation structure of the electrolyte, the batteries showed super-stable cycling performance and high specific capacity.