Facile synthesis of nitrogen-doped porous carbon materials using waste biomass for energy storage applications

A simple, low-cost, and green route for the preparation of lotus carbon (LC) materials using lotus parts including leaves, flowers, fruits (seed pods), and stems as a renewable precursor is reported. Different porous carbons, leaf-carbon (LF-carbon), flower-carbon (FL-carbon), fruit-carbon (FR-carbon), and stem-carbon (ST-carbon) were synthesized from different parts of the lotus plant by simple carbonization method. The as-synthesized LC materials were well-characterized by many techniques such as electron microscopy and spectroscopy techniques, X-ray diffraction, and BET-surface area analysis. These techniques confirmed the porous structure of LC materials and the existence of heteroatoms in the prepared LC materials. The mesoporous structure of LC materials suggested employing it for the supercapacitor applications. The obtained FR-Carbon exhibits a high specific capacitance of 160 F/g in a three-electrode system in an aqueous 1 M H₂SO₄ electrolyte with a high rate performance of 52% retention from 0.5 to 5.0 A/g with good cycling stability of 95%. These results indicate that the porous carbon derived from lotus fruits is a potential electrode material for high-performance supercapacitors.