Aqueous zinc-ion batteries (AZIBs) have been considered one of the promising large-scale energy storage devices in the future due to their high energy density, simple preparation process, efficient and safe discharge process, abundant zinc reserves, and low cost. In order to improve the performance of AZIBs, the development of high-performance cathode materials with a stable structure is essential. Among the AZIB cathode materials, vanadium-based compounds have received great attention for their diverse structures and high reversible capacities.
Vanadium sulfides, also known as vanadium disulfide (VS2), are conducting transition metal disulfides (TMDs) that exhibit metallic behavior and can be used as an electrode material in lithium-ion batteries. However, they have been limited by their poor stability, which leads to the pulverization of their crystals during charging and discharging. To overcome this problem, VS2-based electrodes are generally combined with mechanically resilient carbon materials.
VS2 is also an excellent anode material for aqueous zinc-ion batteries, as demonstrated by its high operating voltage and specific capacity of
The crystal structures of VS2 are quite complex, with a combination of layers, chains, and tunnels. In addition, the valence states of the sulfides are symmetrically distributed between the atomic layers and can be changed to form V2+, V3+, V4+, or V5+ oxidation states. These valence states are important for their chemical transformations and electrochemical activities, which provide an attractive design strategy for the further development of VS2-based cathode materials in AZIBs.
