Lignin, a type of abundant and low-cost biomass, is successfully utilized as a carbon precursor to prepare carbon nanosheets (CNSs) by freeze-casting of a lignin aqueous dispersion followed by direct carbonization without any activating treatment. The size and specific area of the obtained lignin-derived CNSs can be manipulated by controlling the concentrations of lignin aqueous dispersions, which in turn influences the graphitization degree of the CNSs as confirmed by wide angle X-ray scattering analysis and Raman spectroscopy. X-ray photoelectron spectroscopy study indicates that the CNSs contain ～11–16 at% oxygen heteroatoms, which contribute to additional pseudocapacitance. The three-electrode supercapacitors based on optimized CNSs show a high capacitance of 281 F g?1 at 0.5 A g?1current density and good cycling stability in H2SO4 aqueous electrolyte. The study provides a simple, inexpensive, and environmentally friendly method for preparation of CNSs from various water-soluble biomass carbon precursors.
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机译：木质素是一种丰富而低成本的生物质，通过木质素水分散体的冷冻浇铸，然后直接碳化而不进行任何活化处理，已成功地用作碳前体以制备碳纳米片（CNS）。可以通过控制木质素水分散体的浓度来控制所获得的木质素衍生的CNS的大小和比表面积，这又会影响CNS的石墨化程度，如广角X射线散射分析和拉曼光谱法所证实的那样。 X射线光电子能谱研究表明，中枢神经系统含有约11-16 at％的氧杂原子，这有助于增加伪电容。基于优化的CNS的三电极超级电容器在0.5 A g ？1 <时显示出281 F g ？1 的高电容H 2 SO 4 水溶液中的/ small>电流密度和良好的循环稳定性。该研究为从各种水溶性生物质碳前体制备CNS提供了一种简单，廉价且环保的方法。
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