Enhanced electrochemical performance of iron-doped (NH4)2V12O27·xH2O as a cathode material for aqueous zinc-ion batteries

Abstract

Aqueous zinc ion batteries (ZIBs) have attracted significant attention due to their high energy density, non-toxicity, robust security, and low cost. The cathode material is a crucial factor affecting the cost and performance of ZIBs. However, vanadate-based materials suffer from low conductivity and sluggish reaction kinetics, which impede the transfer of Zn²⁺ and electrons, leading to rapid capacity loss. In this study, we report the solvothermal synthesis of Fe-doped (NH₄)₂V₁₂O₂₇·xH₂O, which greatly enhances the electrochemical performance of the material. The resulting product exhibits a remarkably high capacity of 165 mA h g⁻¹ at 50 mA g⁻¹, and an ultrahigh stability with 74.2% retention over 1000 cycles at 1 A g⁻¹. This improvement in performance is attributed to the increased intrinsic conductivity from Fe doping, which promotes the absorption and release kinetics of Zn²⁺ and prevents the gradual dissolution of the V–O layer.