High-performance carbon materials for supercapacitors were prepared by a one-step molten salt carbonization of tobacco stem in molten carbonate. Physicochemical properties of the as-prepared carbon materials were studied by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, Fourier-transform infrared spectroscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption/desorption isotherms, as well as electrochemical properties were measured by tests of cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. All of the carbon materials possess hierarchically porous structure with rich self-doping of oxygen for introducing pseudocapacitance and high specific surface area for providing sufficient active sites, and exhibit ideal capacitive behavior with high performance which is comparable to that of commercial activated carbon material. Carbon material obtained by molten salt carbonization for 2 h delivers specific capacitance of 225.3 F/g at 0.2 A/g, energy density of 31.2 Wh/kg at 0.2 A/g and power density of 989.5 W/kg at 2 A/g besides acceptable rate capacity and long-term cyclic stability using a three-electrode configuration in 1 mol/L H₂SO₄ aqueous solution. Moreover, it possesses specific capacitance of 143.5 F/g at 0.2 A/g, energy density of 5.0 Wh/kg at 0.2 A/g and power density of 491.3 W/kg at 2 A/g besides excellent rate capacity using a symmetrical two-electrode configuration in 6 mol/L KOH aqueous solution. The dependence of the capacitive performance on hierarchically porous structure is also discussed.

通过烟梗在熔融碳酸盐中一步熔融盐碳化制备了用于超级电容器的高性能碳材料。通过扫描电子显微镜、X射线衍射、拉曼光谱、傅里叶变换红外光谱、X射线光电子能谱和氮吸附/解吸等温线研究了制备的碳材料的物理化学性质，并测量了电化学性质通过循环伏安法、恒电流充放电和电化学阻抗谱测试。所有的碳材料都具有分级多孔结构，具有丰富的氧自掺杂以引入赝电容和高比表面积以提供足够的活性位点，并表现出理想的电容行为，具有可与商业活性炭材料相媲美的高性能。通过熔盐碳化 2 小时获得的碳材料在 0.2 A/g 时的比电容为 225.3 F/g，在 0.2 A/g 时的能量密度为 31.2 Wh/kg，2 A/g 时的功率密度为 989.5 W/kg。可接受的倍率容量和长期循环稳定性在 1 mol/LH 中使用三电极配置₂ SO ₄水溶液。此外，它在 0.2 A/g 时的比电容为 143.5 F/g，在 0.2 A/g 时的能量密度为 5.0 Wh/kg，在 2 A/g 时的功率密度为 491.3 W/kg，此外还使用对称的两个- 6 mol/L KOH 水溶液中的电极配置。还讨论了电容性能对分级多孔结构的依赖性。