Molybdenum sulfide with abundant crystalline water as an anode for zinc ion hybrid capacitors

Zinc-ion hybrid capacitors (ZIHCs) have gained significant interest because of their excellent safety and remarkable energy density. To a substantial extent, the properties of anode materials constrain the advancement of ZIHCs. Among numerous anode materials, two-dimensional (2D) molybdenum disulfide (MoS₂), with its unique layered structure, makes it an ideal host for zinc-ion intercalation. In this study, MoS₂ nanosheets with abundant crystalline water were synthesized on carbon cloth (H-MoS_2@CC) via a hydrothermal method. The crystalline water embedded in the structure acts as a structural pillar to expand interlayer spacing, improving the ion transport pathways and facilitating the intercalation of Zn^2+. As a result, H-MoS_2@CC demonstrates outstanding specific capacitance and cycling performance. It can achieve a specific capacitance of 1273.2 mF cm^-2 when tested at 1 mA cm^-2, coupled with excellent rate performance. Additionally, H-MoS_2@CC demonstrates an outstanding cycling property, after 1000 cycles at 5 mA cm^-2, it can retain 97.5% of its initial capacity. The study highlights the superior ion diffusion kinetics enabled by the incorporation of crystalline water, which effectively enhances the electrochemical performance of the material.