High performance self-charging supercapacitors using a porous PVDF-ionic liquid electrolyte sandwiched between two-dimensional graphene electrodes

Research on the development of all-in-one self-charging supercapacitor power cells (SCSPCs) has received increasing attention during recent years. Herein, we reported a novel SCSPC device comprising twodimensional graphene sheets as electrodes for energy storage and a porous PVDF incorporated TEABF4 electrolyte as a solid-like piezo-polymer separator. Initially, the energy harvesting properties of porous PVDF films and the energy storage performance of the graphene based SCSPC device were evaluated separately. The porous PVDF film generated a voltage from 4 to 11 V when subjected to compressive forces of 5-20 N, respectively. The graphene SCSPC device delivered a highest specific device capacitance of 28.46 F g(-1) (31.63 mF cm(-2)) with a specific energy of 35.58 Wh kg(-1) and high-power density of 7500 W kg(-1), respectively. Further, evaluation of the self-charging properties of the graphene SCSPC was performed by subjecting the SCSPC device to various applied compressive forces. Strikingly, the graphene SCSPC device can be charged up to 112 mV under a compressive force of 20 N within 250 seconds and the mechanism of self-charging via the piezo-electrochemical energy conversion process is discussed in detail. The experimental findings on the graphene SCSPC device can provide new insights towards the development of next-generation all-in-one energy conversion and storage devices.