In Situ Generation of Ultrathin MoS 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 MoS @carbon core-shell structure with ultrathin MoS nanosheets incorporated in the carbon matrix. In the three-electrode system, MoS @carbon delivers a specific capacitance of 1302 F g at a current density of 1.0 A g and shows a 90% capacitance retention after 10 000 charging-discharging cycles. The MoS @carbon-based asymmetric supercapacitor displays an energy density of 75.1 Wh kg at the power density of 900 W kg . Because the photo-generated electrons can efficiently migrate from MoS 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 ), the device exhibits a ≈4.50% (≈13.9 F g ) 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.