Facile fabrication of PANI/g-C3N4/MXene composites as electrode materials for supercapacitors

Abstract

Polyaniline (PANI) is a widely used conducting polymer for electrode materials because of its good conductivity and electrochemical properties, while its poor stability during charging/discharging cycles limits its development and applications. 2D MXene has recently attracted much attention because of its high conductivity and surface functional groups. But MXene still has some drawbacks when used for electrode materials, such as aggregation, low specific capacitance, and poor physiochemistry stability. To address these issues, a ternary PANI/graphitic carbon nitride (g-C₃N₄)/MXene (PCM) composite has been successfully prepared by introducing graphitic carbon nitride (g-C₃N₄) via in situ chemical polymerization and a vacuum-assisted filtration. The resulting ternary PCM composite exhibits excellent physicochemical properties and morphologies, leading to an enhanced electrochemical performance when compared with individual components. The PCM composite shows a high specific capacitance of 570 F g⁻¹ at a scan rate of 5 mV s⁻¹. More importantly, the PCM electrode exhibits a better electrochemical stability at high scan rates (i.e., 100 mV s⁻¹, 200 mV s⁻¹ and 500 mV s⁻¹) than PANI and PANI/g-C₃N₄. When the PCM composite electrode is assembled to form a symmetric supercapacitor, it displays an energy density of 18.8 W h kg⁻¹ at a power density of 1563 W kg⁻¹. These results demonstrate that the PCM composite is an excellent electrode material for supercapacitors, providing new insights into the rational design of composite electrodes.