High-Precision Symmetric-Cell Impedance Analysis for Visualizing Resistance Components in Porous Electrodes

抄録

The elucidation and quantification of individual resistance contributions in porous electrodes remain critical challenges in electrochemical energy-storage devices, particularly Li-ion batteries. To address this challenge, we propose an integrated analytical framework combining high-precision symmetric-cell electrochemical impedance spectroscopy (EIS) with equivalent circuit modeling based on a transmission-line model (TLM), enabling the systematic visualization and separation of these contributions. In conventional cell configurations with a counter electrode, the interfacial impedance responses of the working electrode are inherently affected by the opposing electrode, complicating the accurate interpretation of single-electrode behavior. In contrast, symmetric-cell EIS using thermodynamically identical electrodes enables the precise characterization of the intrinsic interfacial response of a single electrode. The integration of high-resolution measurements with TLM offers enhanced resolution and reproducibility, allowing the quantitative evaluation of resistance components that are otherwise difficult to resolve and providing deeper insight into electrochemical processes in porous electrodes. We comprehensively validated this unified measurement–modeling methodology across diverse porous electrode systems, demonstrating its applicability under various electrochemical conditions and electrode architectures and establishing it as a systematic and quantitative approach for resistance analysis in porous electrodes.