Nanostructured Carbon\nMaterials Derived from Lignin\nvia Flame-Induced Oxidation for Supercapacitors

The development of high-performance, low-cost supercapacitors\nholds\nsignificant importance for the use of renewable energy. However, enhancing\ntheir energy density without compromising their inherent properties\nremains a formidable challenge. In this study, the method of flame-induced\noxidation is introduced to enhance the wettability and porosity of\nlignin-based carbon nanomaterial. The results of FTIR, XRD, XPS, and\nRaman spectroscopy confirmed the effectiveness of flame-induced oxidation.\nThe finally obtained carbon nanomaterial possesses a specific surface\narea of 497.84 m<sup>2</sup> g<sup>–1</sup> and abundant heteroatom\ncontent (O: 7.3%, N: 6.9%, and S: 1.5%). As a result, the assembled\nsupercapacitors demonstrated an energy density of 26.45 W h kg<sup>–1</sup> at a power density of 800 W kg<sup>–1</sup>. The Trasatti method and ion diffusion analysis reveal that the\noutstanding energy storage properties are attributed to the synergistic\neffect of enriched heteroatom content and developed nanopore structure.\nThis work introduces an approach for designing carbon material with\nappropriate pore size and heteroatom content to develop high-performance\nsupercapacitors.