Hierarchical framework for slurry impedance analysis of lithium-ion battery cathodes using a coin cell platform

Abstract

Understanding the internal microstructure of lithium-ion battery slurries is essential for achieving highperformance electrodes. However, conventional rheological metrics such as viscosity and modulus offer only indirect insight into the electrically active network formed by conductive agents. Here, we present a standardized coin cell-based impedance spectroscopy framework that directly quantifies the internal structure of lithium-ion battery slurries. By applying the distribution of relaxation times analysis, we resolve distinct dielectric responses attributed to interfacial polarization and electrical conduction, and propose a unified equivalent circuit model. The extracted resistance and capacitance exhibit strong correlations with electrode-level electrical conductivity, microstructural tortuosity, and cell-level electrochemical performance metrics including initial capacity and rate capability. This scalable and reproducible approach enables predictive evaluation of slurry quality using only a coin cell and potentiostat, offering a practical tool for process monitoring and optimization in both lithium-ion and emerging battery systems.