Investigation of the effect of lithium salt doping in gel polymer electrolytes for symmetrical solid‐state supercapacitors

Stable and high‐mechanical‐strength gel polymer electrolytes have been investigated by doping lithium salts (LiBr, LiClO4, and Li2SO4) as additive factors into PVA‐CH3COONa systems and highly activated carbon electrodes for symmetrical solid‐state supercapacitors (SSCs). The investigation of the supercapacitors with the presence of lithium salts in the electrolyte not only enhances the mechanical property of gel polymer electrolytes (GPEs) but also improves the energy capability of supercapacitor devices. The electrode‐specific capacitance of supercapacitor‐doped LiClO4 salt was at its maximum value at 100 F g−1 (current density: 1.5 A g−1). These symmetrical SSCs are considered to have potential for developing eco‐friendly energy storage devices.