Spontaneous phase tansformation of V2O3/VN-CNFs to dynamically construct crystal/amorphous VOx heterointerface for high-efficiency and stable aqueous zinc-ion battery

A dynamic crystal-amorphous interface engineering strategy is proposed to address the intrinsic challenges of sluggish kinetics and structural degradation in vanadium-based cathodes for aqueous zinc-ion batteries (AZIBs). Through spontaneous electrochemical phase transformation, vanadium oxide/vanadium nitride anchored on carbon nanofibers (V 2 O 3 /VN-CNFs) is in situ converted into a vanadium oxide electrode featuring an intimately coupled crystalline/amorphous VO x (c-VO x /a-VO x ) heterointerface. This adaptive structure combines the merits of both phases: the crystalline domains ensure efficient electron conduction and framework stability, while the amorphous regions offer numerous defective sites for rapid Zn 2+ storage and diffusion. The strong coupling between the two phases generates built-in electric fields at the interface, which effectively promote charge transfer and reduce Zn 2+ diffusion barriers, as further elucidated by DFT calculations. Benefiting from this unique architecture, the c-VO x /a-VO x -CNFs cathode achieves a remarkable capacity of 715.3 mAh g −1 at 0.5 A g −1 , excellent rate performance (400.1 mAh g −1 at 100 A g −1 ), and outstanding cycling stability (95.5% retention after 20,000 cycles). This study highlights the promise of electrochemically self-optimized heterointerfaces in advancing high-performance AZIBs.