Carbon nanofiber embedded with amorphous VO_x as a functional framework for Zn anode modification

Aqueous Zn metal batteries (AZMBs) show significant potential for flexible energy storage devices. However, the Zn anodes face persistent challenges in practical applications (including dendrite growth, corrosion, and hydrogen evolution), which compromise cycling stabilities and Coulombic efficiencies, thereby hindering commercialization of AZMBs. Herein, a self-supporting framework is synthesized by electrostatic spinning and controllable pyrolysis using gelatin and ammonium metavanadate as precursors. The framework consists of N-doped carbon fibers integrated with amorphous VO_x (denoted as VO_x@GC), which serves to modify the Zn anode. It is revealed that the VO_x@GC host contains abundant metal and non-metal zincophilic sites, which not only facilitates Zn²⁺ desolvation and decreases diffusion resistance, but also provides plentiful nucleation sites. Consequently, the nucleation barrier of Zn²⁺ is substantially reduced, promoting dendrite-free Zn²⁺ deposition. In symmetric cells, the VO_x@GC modified Zn anode (VO_x@GC@Zn) realizes a long cycling life of 4000 and 1600 h with low polarization potentials under low and high capacities conditions, respectively. The VO_x@GC@Zn//NH₄V₄O₁₀ full cell provides a high capacity of 219.6 mAh·g⁻¹ over 2000 cycles at 2 A·g⁻¹ (N/P = 4.2). Furthermore, the pouch cell maintains good performance over 300 cycles at 0.2 A·g⁻¹, with a capacity retention of 88.3%, highlighting strong potential for practical applications.