WS2@PPy heterostructured high performance supercapacitor self-powered by PVDF piezoelectric separator

Self-charging supercapacitors have elicited immense concern for grid-scale power supply applications. Designing energy harvesting and storage systems as an integrated device has therefore become an imperative research interest. Herein, for the very first time, WS2 nanospheres adorned with polypyrrole (PPy) nanowires have been explored for supercapacitor application. The electroactive WS2@PPy heterostructure exhibited a specific capacitance of 245 F/g at a current density of 1 A/g and high cyclic stability of 99.2 % up to 10,000 cycles. Self-powered symmetric supercapacitor device (SPSSC) was assembled employing WS2@PPy heterostructure as electrode material and a PVDF film separator as a piezo-generator. The self-charging piezoelectric phenomenon of SPSSC device was tested by finger pressing, which offered a maximum output potential of 880 mV in 60 s and the device exhibited a specific capacitance of 337.7 F/g, energy density of 26.38 Wh/kg and power density of 1874 W/kg within a wide voltage window of 1.5 V. This work can open up avenues in employing WS2 based electrode materials for new era self-powered supercapacitor applications.