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.