Correlative Potential and Impedance Microscopy Reveals Particle-Level Degradation and Transport Heterogeneity in Solid-State Composite Cathodes
Year: 2026
Type: preprint
Abstract: The electrochemical performance of composite cathodes in all-solid-state batteries is governed by local reaction and transport processes; however, directly linking cell-level electrochemical responses to individual activematerial particles and local microstructural features remains challenging. Here, we investigate a composite cathode in sulfide-based all-solid-state cells using correlative microscopy combining Kelvin probe force microscopy (KPFM) and scanning impedance microscopy (SIM). Following high-voltage degradation, KPFM revealed that some cathode active-material particles exhibited smaller changes in contact potential difference (CPD) between the charged and discharged states or deviations from the overall trend. Furthermore, a particle-by-particle correlation was observed between the charge–discharge CPD response and the corresponding low-frequency local AC voltage response measured by SIM. Analysis of the SIM spatial distributions using a transmission line model further provided a framework for interpreting changes in the relative contributions of electronic transport, ionic transport, and cathode active material/solid electrolyte interfacial impedance between the charged and discharged states and following high-voltage degradation. This approach provides a basis for linking particle-level reaction heterogeneity to local transport networks in composite cathodes.
Source: ChemRxiv
Language: English
Subfield: Electrical and Electronic Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7220721574