2D-TiS₂/Zn-ion Capacitors for Advanced Energy Storage Applications

The unique properties of two-dimensional (2D) materials have garnered significant attention for their potential applications in energy storage systems. Among them, titanium disulfide (TiS₂) stands out due to its tunable layered structure, which provides a high surface area, metallic conductivity, and advantageous intercalation chemistry. In this study, TiS₂ nanosheets fabricated through a scalable exfoliation process were vacuum filtered and restacked into TiS₂ films, which were used as positive electrodes in zinc-ion capacitors. Electrochemical testing and structural characterizations showed successful zinc ion intercalation within 2D TiS₂ nanosheets resulting in increased interplanar spacing. Further characterizations confirmed well-dispersed network of TiS₂ nanosheets, facilitating efficient ion diffusion and electron transport. Devices fabricated with restacked TiS₂ films showed discharge capacities of 66.33, 75.00, and 96.67 mAh/g at rates of 1, 0.5, and 0.1 A/g with 2M of ZnSO₄ aqueous electrolyte. These values were significantly higher than those obtained from control devices fabricated with bulk TiS₂ powders. This work demonstrates the energy storage performance of 2D TiS₂ in zinc ion capacitors, paving the way for further exploration of 2D material-based energy storage systems.