(Potassium Ions Pre-Intercalated Vanadium Oxide Cathodes for Aqueous Zn-Ion Batteries

Aqueous rechargeable zinc-ion batteries (ZIBs) have garnered considerable attention due to their safety, cost-effectiveness, and eco-friendliness. There is a growing interest in finding suitable cathode materials for ZIBs. Layered vanadium oxide has emerged as a promising candidate due to its high storage capacity for zinc ions. However, the development of high-performance zinc-ion batteries faces challenges such as irreversible phase transformation, sluggish diffusion of zinc ions caused by the high energy barrier between V₂O₅ layers, and hence low capacity than the theoretical value. In this study, we synthesized nanofibers of V₂O₅ intercalated with potassium ions (KVO) through a straightforward hydrothermal process. The introduction of potassium ions not only increased the interlayer distance (d₍₀₀₁₎ = 9.35 Å) but also reduced the V⁵⁺/V⁴⁺redox couple (from 7.18 to 1.01) thereby improving the electrochemical performance. The resulting KVO cathode exhibited a high specific discharge capacity (274.18 mAh g^-1 at 0.1A g^-1, second cycle), enhanced cycling stability, and significantly reduced charge transfer resistance (8.92 Ω) compared to pristine V₂O₅ (98.67 mAh g^-1at 0.1A g^-1 and 67.31 Ω charge transfer resistance). This study contributes to the understanding and advancement of KVO cathode materials, providing valuable insights for the design and optimization of cathode materials to enhance the electrochemical performance of ZIBs.<br/><br/>&lt;quillbot-extension-portal&gt;&lt;/quillbot-extension-portal&gt;