Abstract The rational design of electrodes mimicking the cellular structure of natural bio-resources has been a matter of increasing interest for applications in energy storage. Due to their anisotropic and hierarchical porosity, monolithic carbon materials from natural wood precursors are appealing as electrodes for supercapacitor applications due to their interconnected channels, relatively low cost and environmentally friendly synthesis process. In this work, a liquid-phase oxidative treatment with refluxing nitric acid at 100 °C for 8 h was performed to enhance the surface properties of beech-derived graphitized carbons treated with an iron catalyst. Microstructural, textural and surface investigations revealed that this strategy was successful in removing amorphous carbon and in functionalizing their surfaces. The crystallinity, accessible surface area, micropore volume and surface functionality of beech-derived carbons were increased upon the reflux treatment. The resulting porous carbon materials were evaluated as binderless monolithic electrodes for supercapacitors applications in aqueous KOH electrolyte. A maximum specific capacitance of 179 F·g−1 and a volumetric capacitance of 89 F·cm−3 in galvanostatic charge/discharge experiments were reached. Monolithic electrodes exhibited good cycling stability, with a capacitance retention over 95% after 10,000 cycles.

中文翻译：

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无粘合剂超级电容器电极：通过回流酸处理优化单片石墨化碳

摘要 模拟天然生物资源细胞结构的电极的合理设计已成为能量存储应用越来越感兴趣的问题。由于其各向异性和分级孔隙率，来自天然木材前驱体的单片碳材料由于其互连通道、相对较低的成本和环境友好的合成过程，作为超级电容器应用的电极很有吸引力。在这项工作中，用回流硝酸在 100°C 下进行液相氧化处理 8 小时，以提高用铁催化剂处理的山毛榉衍生石墨化碳的表面性能。微观结构、纹理和表面研究表明，该策略成功地去除了无定形碳并使其表面功能化。结晶度，回流处理增加了山毛榉衍生碳的可及表面积、微孔体积和表面功能。所得多孔碳材料被评估为无粘合剂单片电极，用于 KOH 水溶液中的超级电容器应用。在恒电流充电/放电实验中达到了 179 F·g-1 的最大比电容和 89 F·cm-3 的体积电容。单片电极表现出良好的循环稳定性，10,000 次循环后电容保持率超过 95%。在恒电流充电/放电实验中达到了 179 F·g-1 的最大比电容和 89 F·cm-3 的体积电容。单片电极表现出良好的循环稳定性，10,000 次循环后电容保持率超过 95%。在恒电流充电/放电实验中达到了 179 F·g-1 的最大比电容和 89 F·cm-3 的体积电容。单片电极表现出良好的循环稳定性，10,000 次循环后电容保持率超过 95%。