Cobalt–nickel bimetallic ion co-intercalation facilitates layered vanadium oxide cathodes for aqueous zinc-ion batteries
摘要
Aqueous zinc-ion batteries (AZIBs) have garnered increasing attention in large-scale energy storage systems due to the advantages of metallic zinc, including a high theoretical specific capacity, moderate redox potential, abundant and low-cost resources, and enhanced safety. Vanadium-based materials, with their variable valence states and tunable ion diffusion channels, are considered promising cathode materials for zinc-ion batteries. However, their practical applications are severely hampered by the narrow interlayer spacing, low conductivity, and high solubility in electrolytes. Herein, we design a cobalt–nickel co-intercalated vanadium oxide (CoNiVOH) cathode to enhance the performance of δ-MxV2O5 in AZIBs. The co-intercalated dual ions induce lattice distortion, expanding the interlayer spacing within the crystal. This enhances ion transport kinetics and reduces the internal resistance to electron transport. The CoNiVOH cathode delivers high specific capacities of 431.6 and 285.7 mAh g⁻1 at current densities of 0.1 and 0.6 A g⁻1, respectively. The influence of the transition-metal-ion intercalation upon Zn2+ insertion/deinsertion behavior is also studied through cyclic voltammetry, galvanostatic intermittent titration technique, and ex situ structural characterization. This study delves into the functional roles of Co/Ni cations, offering a new strategy to improve the electrochemical performance of AZIBs through the design of bimetallic ion co-intercalated cathodes.