Interface coupling engineering of nano flower-like porous carbon with V2O5 for enhancing rapid transport of zinc ions in aqueous zinc-vanadium batteries

Rechargeable aqueous zinc ion battery is a promising energy storage device owing to their appealing features with intrinsic safety, low cost, and scalability. However, since zinc ion is a divalent cation, it is difficult to find a cathode material that allows for the rapid and reversible insertion and extraction of zinc ions. Here, we proposed a coupling strategy to prepare capping V 2 O 5 /nano flower-like porous carbon-based zinc ion cathode materials for high electrochemical performance. Surprisingly, the interfacial coupling and transport effects between layered V 2 O 5 and nano flower-like porous carbon provided an interconnected three-dimensional network for highly efficient charge carriers thereby conferring efficient electron/ion transport. Among them, the nano flower-like porous carbon material increased the interfacial conductivity and layer spacing, and shortened the ion insertion and extraction channels due to the existence of pores. Meantime, the layered V 2 O 5 provided transport pathways and abundant active sites for zinc ions, enabling rapid and reversible insertion/extraction of hydrated Zn 2+ . The composite cathode material exhibited excellent energy storage performance compared to individually assembled zinc-vanadium battery, including high capacity (244.4 mAh g −1 at 50 mA g −1 ), high energy density (171 Wh kg −1 ), as well as cycling stability of up to 7000 cycles with capacity retention rate of 92 %. Moreover, the zinc-vanadium battery showed excellent low-temperature performance (specific capacity value of 171 mAh g −1 and specific capacity retention of 70 % at −20 °C). This work provided a new avenue for the design and development of high-performance aqueous rechargeable zinc-ion energy storage devices.