NaBi_x/NaV_yO_z Hybrid Interfacial Layer Enables Stable and Dendrite-Free Sodium Anodes

The challenges of sodium metal anodes, including formation of an unstable solid-electrolyte interphase (SEI) and uncontrolled growth of sodium dendrites during charge-discharge cycles, impact the stability and safety of sodium metal batteries. Motivated by the promising commercialization potential of sodium metal batteries, it becomes imperative to systematically explore innovative protective interlayers specifically tailored for sodium metal anodes. In this work, a NaBi_x/NaV_yO_z hybrid and porous interfacial layer on sodium anode is successfully fabricated via pretreating sodium with bismuth vanadate. The hybrid interlayer effectively combines the advantages of sodium vanadates and alloys, raising a synergistic effect in facilitating sodium deposition kinetics and inhibiting the growth of sodium dendrites. As a result, the modified sodium electrodes (BVO-Na) can stably cycle for 2000 h at 0.5 mA cm^-2 with a fixed capacity of 1 mAh cm^-2, and the BVO-Na||Na₃V₂(PO₄)₃ full cell sustains a high capacity of 94 mAh g^-1 after 600 cycles at 5 C. This work demonstrates that constructing an artificial hybrid interlayer is a practical solution to obtain high performance anodes in sodium metal batteries.