Phase-controlled α-MnO2/biomass-derived N-doped carbon hybrid electrodes for supercapacitors
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Date
2027
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Elsevier
Abstract
Systematic phase engineering followed by interfacial integration with biomass-derived conductive carbon offers a rational strategy for overcoming the intrinsically low electrical conductivity of MnO2-based supercapacitor electrodes. In this work, MnO2 was synthesized by a hydrothermal method followed by thermal treatment (200–600 °C) to investigate the relationship between phase evolution and electrochemical behavior. Structural characterization revealed a progressive transformation from layered δ-MnO2 to tunnel-structured tetragonal α-MnO2, with complete phase conversion at 500 °C. The optimized MO-500 sample exhibited a well-defined nanorod morphology, improved crystallinity, and a specific capacitance of 200 F g−1 in 1 M KOH. To further improve charge transport, MO-500 nanorods were integrated with intrinsically N-doped porous carbon derived from Gliricidia sepium biomass (GSC5K). The optimized 15% MO-500/GSC5K composite showed uniform oxide dispersion and effective interfacial coupling, delivering a specific capacitance of 591 F g−1 at 5 mV s−1 in 1 M H2SO4 with 88.3% capacitance retention after 5000 cycles. Interestingly, composite formation shifted the preferred electrolyte from alkaline medium for pristine α-MnO2 to acidic medium, indicating that oxide–carbon interfacial engineering influences the charge-storage process. This work demonstrates that systematic phase optimization of MnO2 followed by integration with biomass-derived N-doped porous carbon provides an effective strategy for developing sustainable, high-performance supercapacitor electrodes.
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NATURAL SCIENCES::Chemistry
Citation
Biomass and Bioenergy. 217; 2027; 110036pp.