Coalescing of lanthanum oxide and PPy @graphitic carbon nitride to achieve ultrahigh energy density electrode material for supercapacitors applications

Abstract

Faster charging and discharging rate and long cycle life make supercapacitors compatible for energy storage devices. However, supercapacitors' poor energy density prevents them from replacing batteries. This study reports a facile method of synthesizing PPy/g-C3N4/La2O3 (LGP) nanocomposite electrodes via in-situ polymerization by varying the lanthanum oxide concentration. The electrochemical application of synthesized nanocomposites was performed in 1 M H2SO4 by cyclic voltammetry (CV), Galvanostatic Charge Discharge (GCD) and electrochemical impedance spectroscopy (EIS). It was observed that the addition of lanthanum oxide has a synergistic effect on already reported PPy/g-C3N4 composite resulting in a specific capacitance of 1763.56 F g−1 at 10 mV s−1 with ultrahigh energy density of 198.18 W h kg−1 and power density of 450.01 W kg−1 at a current density of 1 A g−1 for 0.4 LGP. From EIS studies, the solution resistance was 1.53 ohm and the charge transfer resistance was 0.50 ohm for PPy, while for 0.4 LGP it was 1.00 ohm and 0.23 ohm respectively. Additionally, the capacitance of 0.4 LGP composite increased to 131% after 10,000 cycles showing the enhanced cyclic stability of electrode material in 1 M H2SO4 electrolyte demonstrating its capability as an electrode material for future supercapacitors.