High-performance supercapacitor of ZnO-incorporated structurally modified g-C3N4 with circular mesoporous channels attained via a template-free approach

Abstract Here, the superior structural features of g-C3N4 in combination with integrated mesoporous channels have been explored for its use as a supercapacitor electrode material. A facile template-free strategy is adopted for the ZnO-incorporated modified g-C3N4 nanocomposite preparation, where the material characterization via XRD, FTIR spectroscopy, FESEM, TEM, and XPS analyses revealed the presence of structurally modified g-C3N4 having uniform circular mesoporous channels with well dispersed ZnO with strong Zn-C and Zn-N interactions. The electrical double-layer capacitance together with the pseudocapacitance of the ZnO/g-C3N4 electrode material resulted in improved performance leading to a specific capacitance of 146.3 F/g at a current density of 0.5 A/g; an increased capacitance is observed in 5000 repeated charge-discharge cycles. The symmetric coin cell supercapacitor fabricated from the material displayed an energy density of 38.8 mWh/kg at a power density of 4259 mW/kg. Additionally, the long life of 6000 cycles (retaining 100% specific capacitance) exhibited by the coin cell supercapacitor further indicates the promising energy storage nature of the ZnO-incorporated modified g-C3N4 mesoporous nanoarchitecture. The real sense application of the ZnO/g-C3N4-derived supercapacitor is narrated by lighting up a green LED with a series connection of four coin cells.