Interface engineering of V2O5 nanofiber/MBene heterojunctions for ultra-stable and high-rate aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) display great promise for large-scale energy storage due to their high safety and low cost, but they are still hampered by limited capacity and insufficient cycling stability due to the cathodic expansion, anodic hydrogen evolution and corrosion, and the inherently low ionic conductivity. This work designed a V 2 O 5 nanofiber/MBene heterojunction to suppress expansion of cathode. The V 2 O 5 nanofibers provide multidimensional ion transport channels and abundant electrochemically active sites, while the introduction of MBene helps establish a more efficient electron-transport network and lowers the interfacial charge-transfer resistance. This unique heterojunction enhances the structural stability and enables highly efficient reversible redox reactions through a synergistic effect. The optimized VM-73 delivered a reversible specific capacity of 210 mAh g −1 at 1 A g −1 , with 92% capacity retention after 1000 cycles and 62.9% capacity retention even after 30,000 cycles. The electrode exhibits pronounced surface-controlled kinetics at high scan rates, with the surface-controlled contribution reaching 89%, together with a Zn 2+ diffusion coefficient ranging from 10 −8 to 10 −10 cm 2 s −1 , demonstrating rapid charge transfer and interfacial reaction kinetics. DFT calculations suggest that interfacial electronic coupling in the heterojunction is favorable for Zn 2+ storage and interfacial charge transport, leading to superior amplification performance and cycling stability. The synergistic effect of V 2 O 5 and MBene effectively promotes multi-step reversible reactions and suppresses side reactions, significantly improving the long-term electrochemical stability of the electrode.