Oxygen Vacancies on NH4V4O10 Accelerate Ion and Charge Transfer in Aqueous Zinc–Ion Batteries

Abstract

AbstractVanadium‐based compounds are identified as promising cathode materials for aqueous zinc ion batteries due to their high specific capacity. However, the low intrinsic conductivity and sluggish Zn2+ diffusion kinetics seriously impede their further practical application. Here, oxygen vacancies on NH4V4O10 is reported as a high‐performing cathode material for aqueous zinc ion batteries via a facile hydrothermal strategy. The introduction of oxygen vacancy accelerates the ion and charge transfer kinetics, reduces the diffusion barrier of zinc ions, and establishes a stable crystal structure during zinc ion (de‐intercalation). As a result, the oxygen vacancy enriched NH4V4O10 exhibits a high specific capacity of ≈499 mA h g−1 at 0.2 A g−1, an excellent rate capability of 296 mA h g−1 at 10 A g−1 and the specific capacity cycling stability with 95.1% retention at 5 A g−1 for 4000 cycles, superior to the NVO sample (186.4 mAh g−1 at 5 A g−1, 66% capacity retention).