Fabrication of hierarchically ordered porous carbons using sugarcane bagasse as the scaffold for supercapacitor applications

• The sugarcane bagasse-based hierarchically porous carbon material (HPCM) has been successfully synthesized.
• CO2-activated HPCM has an excellent electrochemical behavior for fast electrolyte and electron transport.
• The hierarchical structure of HPCMs improves the utilization of micropore surface area for high specific capacitance.
• The HPCM electrode exhibits high energy density and long-term cyclability.

A promising strategy for the fabrication of hierarchically porous carbon materials (HPCMs) using sugarcane bagasse as the scaffold was developed for the application of supercapacitors with enhanced electrochemical performance. HPCMs were fabricated by evaporation-induced self-assembly using resol polymer and triblock copolymer F127 as the carbon precursor and structural directing agent, respectively. The HPCMs show a 2-dimensional hexagonally ordered structure with pore size distribution centered at 3.4 nm. After activation with carbon dioxide at 850 °C for 12 h to remove residual carbons and/or impurities, the specific surface area increases to 1638 m2 g−1 with micropore surface area of 1058 m2 g−1, which can facilitate the fast electrolyte and electron transport. The CO2-activated HPCM electrodes exhibit excellent specific capacitances of 144–232 F g−1 at the scan rates of 10–50 mV s−1, and the specific capacitance can be up to 8.8–14.2 μF cm−2. In addition, the activated HPCMs show a good cycling stability, low IR drop, and the energy and power densities are in the range 12.3–26.1 Wh kg−1 and 1.05–4.91 kW kg−1, respectively. Results obtained in this study clearly demonstrate a cost-effective and environmentally benign method for synthesis of bagasse-based HPCMs, which can potentially apply to supercapacitor with enhanced electrochemical performance and improved energy density.

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