In Situ Generation of Ultrathin MoS2 Nanosheets in Carbon Matrix for High Energy Density Photo-Responsive Supercapacitors

Stimuli-responsive supercapacitors have attracted broad interest in constructing self-powered smart devices. However, due to the demand for high cyclic stability, supercapacitors usually utilize stable or inert electrode materials, which are difficult to exhibit dynamic or stimuli-responsive behavior. Herein, this issue is addressed by designing a MoS2@carbon core-shell structure with ultrathin MoS2 nanosheets incorporated in the carbon matrix. In the three-electrode system, MoS2@carbon delivers a specific capacitance of 1302 F g(-1) at a current density of 1.0 A g(-1) and shows a 90% capacitance retention after 10 000 charging-discharging cycles. The MoS2@carbon-based asymmetric supercapacitor displays an energy density of 75.1 Wh kg(-1) at the power density of 900 W kg(-1). Because the photo-generated electrons can efficiently migrate from MoS2 nanosheets to the carbon matrix, the assembled photo-responsive supercapacitor can answer the stimulation of ultraviolet-visible-near infrared illumination by increasing the capacitance. Particularly, under the stimulation of UV light (365 nm, 0.08 W cm(-2)), the device exhibits a approximate to 4.50% (approximate to 13.9 F g(-1)) increase in capacitance after each charging-discharging cycle. The study provides a guideline for designing multi-functional supercapacitors that serve as both the energy supplier and the photo-detector.

Automated summary

This study addresses the issue of low dynamic or stimuli-responsive behavior in supercapacitors by designing a MoS2@carbon core-shell structure. The structure exhibits high specific capacitance and cyclic stability, and can increase capacitance under the stimulation of light.