Interfacial Electrochemical Media-Engineered Tunable Vanadium Zinc Hydrate Oxygen Defect for Enhancing the Redox Reaction of Zinc-Ion Hybrid Supercapacitors

摘要

Zinc-ion hybrid supercapacitors (ZIHCs) are promising electrochemicalenergy storage system candidates owing to their eco-friendliness, low-cost,reliable safety, and high-power density. Of particular note, ZIHCs are desirablealternatives to lithium-ion batteries (LIBs) because they can overcome thedisadvantages of LIBs, such as the explosion hazard and the complexmanufacturing process. Nevertheless, the low specific capacity of ZIHCscaused by their limited active sites and poor cycling stability because of theirlow wettability and irreversible Zn dendrite formation at the electrode hashindered their commercial application. Herein, for the first time, thefabrication and interfacial engineering of ZIHCs using vanadium (Ⅳ) oxidesulfate (VOSO_4) as an additive chemistry agent is described, and the effect ofthe additive on the electrochemical performance is demonstrated. After theactivation process, the resultant supercapacitor exhibits a zinc vanadiumhydrate (ZVO) layer on both the anode and cathode. The electrochemical roleof the ZVO layer on the electrodes are as follows: ⅰ) improved active sites forZn-ion intercalation at the cathode, ⅱ) enhanced wettability betweenelectrolyte and electrodes, andⅲ) buffer layer for the suppression ofundesirable and irreversible Zn dendrites at the anode.