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

Abstract 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(CF 3 SO 3 ) 2 electrolyte with a mixture solvent of propylene carbonate (PC) and H 2 O 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||NaV 3 O 8 ·1.5H 2 O batteries. Systematical electrochemical testing and characterizations illustrate the addition of PC effectively reduces the active water molecule in Zn 2+ ‐solvent cations and H + in the electrolyte, thereby suppressing the cathode dissolution caused by the inserted H + and co‐inserted H 2 O during the discharge/charge process. Impressively, the PC addition also enabled the Zn||NaV 3 O 8 ·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 ° 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.