Abstract
Rechargeable aqueous Zn−ion batteries (RAZIBs) with the merits of cost effectiveness and high safety have been rejuvenated as tantalizing energy storage systems to meet the demand for grid−scale applications (ACS Energy Lett., 2021;6:404-412). Currently, the energy storage capability of the positive electrode (cathode) holds the key for the overall performance of RAZIBs (Mater. Today, 2021;42: 73-98). In this work, we reveal two strategies to improve the energy storage capability of VO2 cathode in RAZIBs, including heterostructure and carbon quantum dots (CQDs) engineering strategies. For heterostructure engineering, the presence of a heterojunction between VO2 and V10O24·12H2O (HVO) enables built−in electric field to boost electron transport kinetics. The VO2/HVO sample integrates the merits of high−capacity VO2 and high−stability HVO, showing promising electrochemical performance with high capacity (317 and 239 mAh g−1 at 1 and 4 A g−1, respectively) and good cycle stability (80% after 2000 cycles). For CQDs engineering, the VO2/CQDs sample can be constructed by strong interface interaction, and the CQDs decorated sample has higher specific surface area, better electrolyte wettability, reduced charge−transfer resistance, and facilitated ion diffusion coefficient. The attainable capacity of VO2/CQDs can even reach 427 mAh g−1 at 0.2 A g−1. The proposed strategies effectively improve the electrochemical performance of pure VO2 counterpart.
Published Version
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