Development study of proton conductor: poly(vinyl alcohol)-based gel electrolyte for energy storage devices

Developing high-performance energy storage devices using sustainable materials is essential for their widespread application in electronic devices. The energy density of carbon-based electric double-layer capacitors (EDLCs) can be optimized through the integration of polymer-based electrolytes and ionic liquids. Poly(vinyl alcohol) (PVA)-based gel electrolytes, in particular, have attracted significant interest due to their solubility, biodegradability, and biocompatibility. In this study, we fabricated EDLC samples employing a PVA gel polymer electrolyte (GPE) enhanced with an ionic liquid and phosphoric acid. Our focus was on developing a proton-conducting PVA-based GPE and utilizing activated carbon as the electrode material. Optimal performance was achieved with an ionic liquid concentration of 25 wt% in a GPE film placed between the carbon-based EDLC electrodes. The device demonstrated a discharge specific capacitance of 45.8 F/g with stable performance over extensive cycling tests.