High-performance biochar-based supercapacitors extremely depend on the reasonable microstructure of electrode materials, so optimizing pore structure and surface properties is an important research topic. In this paper, HNO3 and H2O2 were used to modify wood chip biochar, which enhanced the oxygen-containing functional groups of biochar and optimized the pore size distribution. NPCBC-45 and HPCBC-20 micropore sizes were concentrated at 0.92 nm and 0.90 nm, respectively, and the mesoporosity was 33 % and 65 %, respectively. The supercapacitors using NPCBC-45 and HPCBC-20 as electrodes exhibited excellent specific capacitance, reaching 338.88 F∙g−1 and 165 F∙g−1, respectively, which were increased by 137.39 % and 15.59 %, respectively. The prepared double-layer capacitor showed good cycle stability, and the cycle efficiency was 94 % after 2000 cycles. Therefore, the results of this study show that HNO3 and H2O2 have application value in optimizing the microstructure of carbon material electrodes.

中文翻译：

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改性生物炭的制备及电化学性能


高性能生物炭基超级电容器极度依赖于电极材料的合理微观结构，因此优化孔隙结构和表面性能是一个重要的研究课题。本文采用 HNO3 和 H2O2 对木屑生物炭进行改性，增强了生物炭的含氧官能团，优化了孔径分布。NPCBC-45 和 HPCBC-20 微孔大小分别集中在 0.92 nm 和 0.90 nm 处，中间孔度分别为 33 % 和 65 %。使用 NPCBC-45 和 HPCBC-20 作为电极的超级电容器表现出优异的比电容，分别达到 338.88 F∙g−1 和 165 F∙g−1，分别提高了 137.39 % 和 15.59 %。所制备的双层电容器表现出良好的循环稳定性，2000 次循环后循环效率为 94 %。因此，本研究结果表明，HNO3 和 H2O2 在优化碳材料电极的微观结构方面具有应用价值。