Heterostructure Design of Amorphous Vanadium Oxides@Carbon/Graphene Nanoplates Boosts Improved Capacity, Cycling Stability and High Rate Performance for Zn²⁺ Storage

As a promising power supplier, flexible aqueous zinc ion batteries (AZIBs) have drawn great attention and been demonstrated potential applications in portable electronic devices, yet their capacity, stability, and rate performance are severely limited by cathode materials. Herein, a spontaneous encapsulation and in situ phase transformation strategy is proposed for the construction of heterostructured amorphous vanadium oxide@carbon/graphene (A-VO_x@C/G) nanoplates as highly stable and efficient cathode materials for Zn²⁺ storage. In this design, A-VO_x provides abundant active sites with rapid ion diffusion channels and robust tolerance against ion insertion/extraction, while N-doped carbon encapsulation and interlaced graphene network ensure efficient electron transfer. The mechanisms respectively for phase transformation during electrochemical amorphization and charge storage during cycling are investigated in detail. The as-prepared A-VO_x@C/G achieves an outstanding electrochemical performance with 429 mAh g⁻¹ at 0.5 A g⁻¹, 73% retained at 20 A g⁻¹ (315 mAh g⁻¹), and excellent stability over 2000 cycles at 20 A g⁻¹ (91% retention). Moreover, quasi-solid-state AZIBs assembled from A-VO_x@C/G cathode exhibit high flexibility and can sustain large mechanical deformation without performance degradation. It is believed that this study provides a guideline toward designing high-performance cathode materials for AZIBs through structure optimization.