Developing High-Rate Aqueous Zinc-Ion Batteries with Zn-Doped V10O24·12H2O Cathode.

Abstract

Aqueous zinc-ion batteries (AZIBs) have garnered attention as a cost-effective and safer alternative to lithium-ion batteries (LIBs). However, developing suitable cathode materials which can reversibly host Zn2 + ions remains a challenge. Herein we explore the effect of zinc doping into hydrothermally synthesized V₁₀O₂₄.12H₂O (ZVO) and demonstrate that such doping enhances electronic conductivity and structural stability, leading to improved rate capability and cycling performance of ZVO as a cathode material for AZIBs. The effect of zinc doping in the V₁₀O₂₄.12H₂O as a ZIB cathode has not been previously explored. The ZVO materials had a bundled rod-like morphology with a zinc content of 1.3% and an average oxidation state of 4.86 for the vanadium. DFT calculations further validate that Zn doping to the pristine V₁₀O₂₄ is thermodynamically favorable, which also improves the electronic conductivity of the ZVO. As a result, the Zn//ZVO cell exhibited superior specific capacity and improved rate performance over the pristine V₁₀O₂₄.12H₂O (VO) electrode, with a high specific capacity of 359 mAh/g at 0.1 A/g and sustained 121 mAh/g at 5 A/g. The Zn//ZVO cell also showed commendable cycle stability with 90 mAh/g capacity retention over 1110 cycles, which was equivalent to the starting capacity of the pristine VO cathode.