Oxygen and nitrogen co‐enriched hierarchical porous carbon hollow microspheres are synthesized by using biomass‐derivative sodium lignosulfonate as a feedstock through a facile and scalable process. This four‐step synthesis process involves spray drying, thermal stabilization, carbonization, and post nitric acid modification. The as‐obtained carbon exhibits a moderate but efficient porosity (specific surface area of 991 m² g⁻¹, total pore volume of 0.75 cm³ g⁻¹), small particle size of 0.2–5 μm, high electrode density of 0.45 g cm⁻³, and abundant surface oxygen/nitrogen species (13.12 at.%/0.97 at.%). Its electrochemical performance is evaluated by assembling into supercapacitors in 7 M KOH electrolyte. The three‐electrode cell presents a high gravimetric capacitance of 284 F g⁻¹ at 0.1 A g⁻¹ and good rate capability of 43.6 % at 20 A g⁻¹. While the two‐electrode cell gives an impressive volumetric capacitance of 21.2 F cm⁻³ at 0.1 A g⁻¹, marvelous volumetric energy density of 2.9 Wh L⁻¹ at 11.3 W L⁻¹, and remarkable cycling stability of 93.4 % capacitance retention after 10000 cycles, which is superior or comparable to that of commercial activated carbon.

中文翻译：

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木质素磺酸钠中富氧和富氮的可持续多孔碳空心微球，用于高体积能量密度的超级电容器

氧和氮共同富集的分级多孔碳中空微球是通过生物质衍生的木质素磺酸钠作为原料，通过简便且可扩展的过程合成的。此四步合成过程涉及喷雾干燥，热稳定，碳化和硝酸后改性。如此获得的碳具有适度但有效的孔隙率（比表面积991 m ²  g ^-1，总孔体积为0.75 cm ³  g ^-1），小粒径为0.2-5μm，高电极密度为0.45 g厘米^-3，以及丰富的表面氧/氮物质（13.12 at。％/ 0.97 at。％）。通过在7 M KOH电解质中装配超级电容器来评估其电化学性能。三电极电池在0.1 A g ^-1时具有284 F g ^-1的重电容，在20 A g ^-1时具有43.6％的良好倍率能力。尽管两电极电池在0.1 A g ^-1时可提供令人印象深刻的21.2 F cm ^-3的体积电容，在11.3 W L ^-1时可提供2.9 Wh L ^-1的出色体积能量密度，以及93.4％的显着循环稳定性10000次循环，优于或可与商用活性炭相媲美。