Sodium Ion Intercalation in Metal-Organic-Framework-Derived Porous V₂O₅ Nanobelts Toward Durable and High-Capacity...

Vanadium (V)-based composites are promising cathodes for aqueous zinc (Zn)-ion batteries (AZIBs), but their low surface area, poor conductivity, and sluggish Zn²⁺ diffusion severely limit performance. Here, metal-organic-framework-derived porous Na_0.33V₂O₅ (NVO) nanobelts (NBs) are synthesized by a simple hydrothermal route, with controlled sodium (Na) contents of 1, 3, and 5 wt%. Strong Na─O bonding with lattice oxygen reinforces the layered framework and stabilizes the structure during cycling. Among them, the NVO-3wt% electrode delivers a high specific capacity of 650 mA h g^-1 at 0.5 A g^-1, excellent rate capability (298 mA h g^-1 at 32 A g^-1), and outstanding long-term durability with ∼85% capacity retention at 30 A g^-1 after 20 000 cycles. Ex situ structural and spectroscopic analyses reveal a reversible mixed Zn²⁺/H⁺ storage mechanism in NVO-3wt%. In addition, flexible full cells are assembled using NVO-3wt% cathodes, highlighting their strong potential for application in wearable AZIBs. Hence, this study holds significance for developing high-performance V-based electrodes for wearable AZIBs.