Porous carbon is a common electrode material used in electrochemical double-layer capacitors, in which energy is stored by physical adsorption of electrolyte ions on the carbon’s surface, forming an electrical double layer (EDL). However, due to the complex nanoporous network of carbon materials, it is difficult to characterize the EDL structure. This work demonstrates that the understanding of the EDL structure in nanoporous carbon materials can be improved by defining the pore shapes using ultrahigh resolution scanning electron microscopy (SEM). The SEM images reveal a continuous network of curved pores. This characterization, along with the experimentally determined surface areas and pore sizes, enabled the investigation of the applicability of various models describing the EDL configuration. This study found that, by using the microscopic information to characterize the 3-D nanostructure and select the appropriate models for the pore shape, it is possible to predict a porous carbon material’s experimental capacitance within ±8%. This updated approach may be used to identify ideal pore structures and top-performing carbon materials. It is clear that using ultrahigh resolution SEM images to understand the relationship between pore shape, EDL structure, and capacitance provides valuable insight into the complexity of energy storage in nanoporous carbon materials.

中文翻译：

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阐明孔结构在确定纳米多孔碳材料的双层电容中的重要性

多孔碳是电化学双层电容器中常用的电极材料，其中能量通过电解质离子在碳表面上的物理吸附而存储能量，从而形成双电层（EDL）。然而，由于碳材料的复杂的纳米孔网络，难以表征EDL结构。这项工作表明，通过使用超高分辨率扫描电子显微镜（SEM）定义孔的形状，可以改善对纳米多孔碳材料中EDL结构的理解。SEM图像揭示了弯曲孔的连续网络。这种表征以及通过实验确定的表面积和孔径可以研究描述EDL配置的各种模型的适用性。这项研究发现，通过使用微观信息表征3-D纳米结构并为孔形状选择合适的模型，可以预测多孔碳材料的实验电容在±8％以内。这种更新的方法可用于确定理想的孔结构和性能最佳的碳材料。显然，使用超高分辨率SEM图像来了解孔形状，EDL结构和电容之间的关系，可为纳米多孔碳材料中能量存储的复杂性提供有价值的见解。