Achieving high-rate and long-life Zn metal anodes via constructing interfacial gradient heterostructure

The practical application of aqueous zinc-ion batteries (AZIBs) is hampered by dendrite growth and side reactions. Herein, we designed an interfacial gradient heterostructure protective layer (MXene/ZnSe), comprising a conductive MXene nanosheets and an semiconductors ZnSe nanoparticles, to reconstruct the Zn anode surface. Theoretical calculations and experiments show that the interfacial gradient can rearrange the energy bands to facilitate electron/ion transfer. The protective layer not only mitigates the corrosion of Zn anode, but also induces uniform Zn deposition. Therefore, the elaborate gradient heterostructure enables the MXene/ZnSe@Zn symmetric cell to have an excellent long lifespan over 7700 cycles at 20 mA cm−2, surpassing most of the MXene-based related materials reported in the literature. When paired with the commercial V2O5, the MXene/ZnSe@Zn//V2O5 cell achieves an exceptional capacity of 230 mAh/g at 5 A/g. This work paves a new yet powerful tactic for designing a multi-functional gradient heterostructure with strong interface effect toward high-rate and calendar-life AZIBs.