Impedance Analyses on Porous Electrodes Considering the Distribution of Time Constants

本研究为应用电化学阻抗谱（EIS）对能量器件的电极结构进行分析做出了贡献。本研究包括对多孔电极的EIS分析和对电池结构的有限元分析。在EIS的应用中，将多孔电极的阻抗谱根据频率范围进行分离，发现多孔结构在中频范围内出现特征轨迹。基于阻抗谱研究了孔隙的大小和电解质性质。采用有限元法计算了阻抗测量过程中的电流分布。结果发现，电流分布随施加的频率而变化。讨论了多孔结构与特征阻抗轨迹的关系，并将阻抗结果与计算得到的电流分布进行了比较。本文所建立的分析方法可用于各种能源装置的材料研制和运行监测。

This study has been carried out to contribute to analyses on electrode structures of energy devices by applying an electrochemical impedance spectroscopy (EIS) to them. This study consists of EIS analyses on porous electrodes and cell structure analyses by finite element method (FEM). In the application of EIS, impedance spectra of porous electrode was separated depending on the frequency ranges, and itwas found that characteristic locus appeared for the porous structure in the middle frequency range. Pore size and electrolyte nature in the pore were investigated on the basis of impedance spectra. The current distribution during impedance measurement was calculated by FEM. It was found that the current distribution was changed depending on the imposed frequency. The relation between the porous structure and the characteristic impedance locus was discussed comparing the impedance results with the calculated current distribution. The analytical method developed by this study can be contributed to the material developments and operation monitoring’s of various energy devices.