Abstract

The electrochemical stability of carbon makes it ideal for energy storage applications. Graphitic carbon nitride (g-C3N4) is a highly nitrogen-containing carbonaceous material that has good cyclic stability for supercapacitor applications but low electrical conductivity. Recent research shows that incorporating transition metal oxides into g-C3N4 significantly boosts its specific capacitance. We synthesized Zinc oxide (ZnO)-modified g-C3N4 nanosheets through a sol–gel route. This hybrid electrode exhibited a high specific capacitance of 136.3 F/g at a current density of 1 A/g. Remarkably, it retained 71.1% of its rate capability even at a high current density of 4 A/g in 6 M KOH electrolyte. After 2000 GCD cycles at a high current density of 4 A/g, the hybrid electrode exhibited improved performance, maintaining an impressive 103.8% capacitance retention and a remarkable increase in coulomb efficiency, reaching close to 100%. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to The Materials Research Society 2024.