Opportunities and Limitations of Partial Transport Quantification in All-Solid-State Composite Electrodes

Titelangaben

Puls, Sebastian ; Ketter, Lukas ; Zeier, Wolfgang G. ; Vargas-Barbosa, Nella M.:
Opportunities and Limitations of Partial Transport Quantification in All-Solid-State Composite Electrodes.
In: ACS Electrochemistry. Bd. 1 (2025) Heft 11 . - S. 2432-2447.
ISSN 2997-0571
DOI: https://doi.org/10.1021/acselectrochem.5c00258

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Abstract

Microstructure and partial transport are key features that must be optimized in all-solid-state battery (ASSB) composite electrodes. While from the measurement perspective impedance spectroscopy is a preferred method to determine partial transport because of its speed and simplicity, interpretation of the impedance spectra can be challenging. This is especially true for ASSB composite electrodes, where two conductive species with similar conductivity are present, and transmission line models (TLMs) are often used to fit the spectra. In this study, we present three different TLMs and their impedance responses in Nyquist plots, giving basic insights into how different combinations of circuit elements result in specific spectra from which partial ionic and electronic conductivities can be calculated. The effects of the applied stack pressure and temperature during the measurements on the resulting spectra and their corresponding partial conductivities are evaluated. Combined computational and experimental results show that the partial conductivities and tortuosity depend on the thickness of the composite electrode. Moreover, our results demonstrate that well-matched partial transport of ions and electrons in composite electrodes at 0% state-of-charge does not directly correlate with a superior cycling performance. As such, we report on the limitations of TLMs and advocate for additional techniques to evaluate other microstructural factors, such as the contact areas between components that cannot be quantified with transport measurements alone.