Effect of electrode substrate and poly(acrylamide) hydrogel electrolytes on the electrochemical performance of supercapacitors

In this research, poly(acrylamide) hydrogels were produced by means of free radical mechanism. Lithium acetate with different weight percentages (wt.%) such as 10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.% as a source of mobile ions were incorporated into the hydrogel, and the samples were labeled as LAM1, LAM2, LAM3, and LAM4, respectively. The electrochemical impedance spectroscopy (EIS) revealed that LAM4 hydrogel electrolyte achieved the highest ionic conductivity of 9.45 × 10 −3 Scm −1 with lowest activation energy (0.038 eV) at ambient temperature. The electrochemical performance of the fabricated supercapacitors using optimized LAM4 hydrogel electrolyte and different conducting substrates namely graphite foil, nickel foam, and carbon cloth was analyzed. The cyclic voltammetry and galvanic charge–discharge analyses reported that EDLC with carbon cloth resulted in maximum specific capacitance of 198.64 F g −1 at 5 mV s −1 and 439.87 F g −1 at 500 mA g −1 , respectively.