Proton conducting solid electrolyte-piezoelectric PVDF hybrids: Novel bifunctional separator for self-charging supercapacitor power cell

Self-charging supercapacitor power cell (SCSPC) attains tremendous research interest due to their ability to harvest-, convert-, and store- energy in a solitary integrated energy device. The use of liquid electrolytes in SCSPC limits the mechanical to electrical energy conversion efficiency, therefore, the development of alternative electrolyte system is highly required. Here, we have developed a piezo-electrolyte film comprising of solid proton conducting electrolyte (phosphotungstic acid (PTA)) embedded in the piezoelectric PVDF matrix and utilized the free-standing film as separator cum electrolyte in SCSPC devices. Physico-chemical characterizations of the prepared PTA-PVDF piezo-electrolyte films such as X-ray diffraction, morphological, elemental, Raman spectroscopy and mapping analyses suggested the homogeneous distribution of PTA electrolyte in the PVDF matrix. Interestingly, the inclusion of PTA in the PVDF results in improved mechanical to electrical energy conversion properties as well as supply of electrolyte ions. Further, a graphene based SCSPC device was fabricated using PTA-PVDF piezo-electrolyte film as separators which makes the graphene SCSPC to self-charge (for about 110 mV) when subjected to an external force of 2 N. The self-charging process involved in the graphene SCSPC with PTA-PVDF piezo-electrolyte was discussed via piezo-electrochemical energy conversion process. These experimental findings pave a new paradigm in the field of integrated SCSPC that will be useful in the development of next-generation integrated energy devices.

Automated summary

The research interest in self-charging supercapacitor power cells (SCSPC) is driven by their ability to harvest, convert, and store energy in an integrated device. The use of liquid electrolytes limits efficiency, prompting the development of alternative systems. A piezo-electrolyte film composed of phosphotungstic acid (PTA) embedded in a piezoelectric PVDF matrix was developed and used in SCSPC devices, showing improved mechanical to electrical energy conversion properties and electrolyte ion supply. The experimental findings suggest a new approach for integrated SCSPC devices, with potential for next-generation energy devices.