Synergistic effect of morphology evolution with oxygen vacancies on layered cathodes derived from polyoxovanadates for aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have attracted increasing attention owing to their low cost, high safety and sustainability, whereas the poor electronic conductivity and durability of the cathode materials severely limit their large-scale application. Herein, the layered vanadate Fe₅V₁₅O₃₉(OH)₉·9H₂O with nanobelt morphology (FeVO-B) was synthesized using polyoxovanadates as precursors, which gives rise to a nanorod-like FeVO material (FeVO-R) possessing larger surface area and abundant oxygen vacancies upon introducing graphene oxide as a surfactant. The collaborative effect of morphological tailoring with oxygen vacancies significantly accelerates the reaction kinetics, thus facilitating efficient zinc ion storage. As expected, the FeVO-R cathode displays a high specific capacity of 409.6 mAh g⁻¹ at 0.1 A g⁻¹ and significant cycle stability at 10 A g⁻¹ (87.5% capacity retention after 3000 cycles). This work utilizes multiple strategies to achieve high performance cathodes for AZIBs.