A Selenium-Modified Sandwich-like Stack of Vanadium-Carbon Nanobelts for High-Performance Aqueous Zinc-Ion Batteries...

Vanadium-based compounds are promising cathode materials for aqueous zinc-ion batteries (ZIBs), while the relatively poor high-rate performance, unstable long-term stability, and slow migration of Zn²⁺ ions have limited their practical applications. In this work, a sandwich-like stack of vanadium oxide-carbon nanobelts engineered with selenium defects (SL-V₂O₃/C-Se) was synthesized and used as a high-performance cathode for aqueous ZIBs. Taking advantage of the ordered and parallel arrangement of nanobelts with abundant selenium defects that facilitated the migration of the Zn²⁺ ion and electrolyte, SL-V₂O₃/C-Se exhibited rate performance and long-term stability much better than those of commercial V₂O₃ and V₂O₃/C without selenium doping. Even at a current density of 10 A g^-1, SL-V₂O₃/C-Se exhibited a reversible capacity of 300 mAh g^-1, which could retain 66% of its original capacity after 7000 cycles. This work provides an innovative approach to improve the capacity, long-term stability, and rate capability of electrode materials.