Zinc Storage Performance of Oxygen-Deficient NH₄V₃O₈: Theoretical and Experimental Study

Using density functional theory (DFT), the density of states of NH4V3O8 (NVO) was analyzed pre- and post-oxygen defect (Od) formation. The findings revealed a reduced bandgap in NVO after Od introduction, emphasizing the role of Od in enhancing conductivity of the material, thus improving its electrochemical attributes. Through the water bath method, both NVO and its oxygen-deficient counterpart, (NH4)2V10O25·8H2O (NVOd), were synthesized as potential cathode materials for aqueous zinc-ion batteries (AZIBs). Experimental outcomes resonated with DFT predictions, highlighting the beneficial role of oxygen defects in boosting electrical conductivity. Notably, the refined material displayed a remarkable capacity of 479.3 mAh g−1 at 0.1 A g−1, underscoring its promise for advanced energy storage solutions.