Advanced structural and electrochemical insight into VHCF–PMMA hybrid electrodes for high-performance supercapacitors
摘要
The quest for high-performance energy storage materials has led to the exploration of a novel binary nanocomposite composed of vanadium hexacyanoferrate (VHCF) and polymethyl methacrylate (PMMA). The synthesized VHCF-PMMA nanocomposites were fabricated as working electrodes in various stoichiometric ratios (50:50, 70:30, and 80:20) for supercapacitors. The effective encapsulation of VHCF within the PMMA matrix was confirmed through FESEM, HRTEM, and XRD analyses. BET analysis reported an impressive surface area of 356.35 m2/g and an average pore size of 2.92 nm for the VHCF-PMMA nanocomposite. The electrochemical properties of the VHCF-PMMA electrodes were investigated in a three-electrode assembly (0–0.5 V working voltage window) using 1 M KOH electrolyte. From CV profile, VHCF-PMMA (80:20) electrode demonstrated the highest specific capacitance (575 F/g at 10 mV/s) in comparison to 70:30 (274 F/g) and 50:50 (188 F/g) electrode compositions. GCD analysis of the VHCF-PMMA (80:20) electrode also displayed the highest specific capacitance (455 F/g at 0.5 A/g) with minimal IR drop. Significant capacitive retention of 72.1% was exhibited by the optimized VHCF-PMMA electrode even after 5000 cycles. Further, the symmetric supercapacitor fabricated using the optimized electrodes yielded a specific capacitance of 119.06 F/g (0.5 A/g) with 66.5% capacitive retention and stable coulombic efficiency after the completion of 5000 cycles. The fabricated device delivered the maximum energy density of 23.56 Wh/Kg at a power density of 299.95 W/Kg (0.5 A/g) and exhibited a high power density of 3015 W/Kg at the energy density of 8.04 Wh/Kg (5 A/g). Hence, the current research is a demonstration of an increase in the structural and electrochemical properties of VHCF due to the mechanical integrity provided by PMMA in the novel VHCF-PMMA combination for its effective usage in supercapacitors.