Synthesis and performance evaluation of supercapacitor based on banana peel–derived biochar loaded manganese dioxide with polyaniline ternary composite

The properties of banana peel (BP)–derived biochar were altered by introducing MnO₂ using precipitation method. The resulting MnO₂–BP composite was modified by in situ polymerization of aniline monomer in the composite matrix, and obtained the MnO₂–BP@PAni electrode. After performing the physicochemical studies using XRD, XPS, FT-IR, TGA, UV–Vis, and BET analyses, the electrode materials were subjected to cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The MnO₂–BP@PAni electrode exhibited specific capacitance as high as 512.8 F g⁻¹, improved capacitance retention of 86.89% after 10,000 cycles at a current density of 1.0 A g⁻¹, and a lower resistance of 1.28 Ω resulting from the dense growth of PAni backbone on the surface of the MnO₂–BP owing to electrostatic interaction. Moreover, the electrode shows a specific energy of 23.4 Wh·kg⁻¹ at a specific power of 306.9 W·kg⁻¹. These results demonstrate that MnO₂–BP@PAni has admirable electrochemical properties and can be regarded as a promising electrode for SCs.