High-Performance Supercapacitor Electrodes from Optimized Single-Step Carbonized Michelia Champaca Biomass

Abstract

This study explores the potential of Michelia champaca wood as a sustainable and locally available precursor for the fabrication of high-performance supercapacitor electrodes. Activated carbons were synthesized through single-step carbonization at 400 °C and 500 °C (SSC-400 °C and SSC-500 °C) and double-step carbonization at 400 °C (DSC-400 °C), with all samples activated using H₃PO₄. The effects of carbonization stratergy on the structural, morphological, and electrochemical characteristics of the resulting carbon materials were systematically evaluated, using techniques such as BET, SEM, TEM, XRD, Raman scattering, FTIR, CV, GCD and EIS.  Among the samples, SSC-400 °C exhibited the best electrochemical performance, achieving a specific capacitance of 292.2 Fg⁻¹, an energy density of 6.4 Wh kg⁻¹, and a power density of 198.4 W kg⁻¹. This superior performance is attributed to its optimized pore structure, improved surface functionality and enhanced conductivity. SSC-500 °C showed marginally lower performance, whereas, DSC-400 °C displayed the least favorable results, indicating that double-step carbonization process may negatively affect material quality by disrupting the pore network. This work highlights a strong correlation between synthesis methodology and electrochemical efficiency, directly reinforcing the importance of process optimization in electrode material development. The findings contribute to the broader goal of developing cost-effective, renewable and environmentally friendly energy storage systems. By valorizing biomass waste, the study supports global movements toward green energy technologies and circular carbon economies, offering a viable pathway for sustainable supercapacitor development and practical applications in energy storage devices.