Sulfur-Driven Structural Reinforcement for Long-Life Zn-Ion Storage

Developing high-performance cathode materials with enhanced stability and fast charge transport kinetics is crucial for advancing aqueous zinc-ion batteries (ZIBs). Herein, we introduce S-doped VO₂ (S-VO₂) as a cathode material, leveraging sulfur incorporation to regulate the electronic structure, suppress vanadium dissolution, and improve electrochemical performance. The introduction of sulfur not only induces oxygen vacancies, which enhance electronic conductivity and facilitate rapid electron transfer, but also strengthens the V-O bond, effectively mitigating vanadium dissolution during cycling. As a result, the S-VO₂ cathode delivers a high specific capacity of 386.3 mA h g^-1 at 0.1 A g^-1, retains 79.6% of its capacity over 1600 cycles at 2.0 A g^-1, and exhibits outstanding long-term durability with 80.3% capacity retention after 6000 cycles at 10.0 A g^-1. Ex situ XRD, in situ Raman, and XPS analyses confirm the highly reversible Zn²⁺ storage mechanism, while XANES and EXAFS studies reveal that S doping stabilizes the local coordination environment of vanadium, reducing structural distortions and enhancing cycling stability. This work highlights the synergistic role of sulfur doping and oxygen defects in optimizing cathode materials, providing valuable insights for the design of next-generation AZIBs with superior performance and long-term reliability.