A comparative study of polyaniline-based composites doped with two-dimensional and three-dimensional structured carbon: the potential of coal for supercapacitor electrodes

This work examined the properties of reduced graphene oxide (rGO) with a 2D structure and activated carbon (AC) with a 3D structure, both doped with polyaniline (Pani), and synthesized through the polymerization method. The crystal structure, morphology, and molecular structure were analyzed using XRD, SEM, and FTIR methods respectively. The electrochemical properties of the composites were evaluated using CV, GCD, and EIS. The energy storage device characteristics, such as energy density and power density, were calculated from an assembled electrochemical capacitor with a 1 cm² working electrode. From the GCD measurements, Pani/AC exhibited the highest specific capacitance of 181.9 F/g at a current density of 1 A/g, while Pani/rGO had a specific capacitance of 145.8 F/g. Additionally, Pani/AC demonstrated a high capacitance retention rate. An energy density of 3.6 Wh/kg at a power density of 500 W/kg was observed in the Pani/rGO//Pani/rGO symmetric supercapacitor at a voltage of 1 V and a current density of 1 A/g. An energy density of 6.5 Wh/kg at a power density of 600 W/kg was observed in the Pani/AC//Pani/AC symmetric supercapacitor at a voltage of 1.2 V and 1 A/g. The electrochemical performance results indicate that the Pani/rGO and Pani/AC composites are effective electrode materials for supercapacitors. Therefore, we suggest that activated Mongolian coal could be a suitable electrode material for supercapacitor applications.