Performance assessment of all-solid-state lithium-ion cells with a novel solid polymer electrolyte: A multiscale modeling approach

Solid electrolytes are critical components in all-solid-state batteries. However, achieving high transport properties, compatibility with electrode materials, low cost, sustainability, and manufacturing compatibility remains a challenge. This work investigates the performance of a novel solid polymer electrolyte through an integrated approach combining experiments and numerical modeling. The electrolyte was tested for mechanical, electrochemical, and transport properties at different pressures, demonstrating good elasticity, high ionic conductivity, and adequate lithium diffusivity. Coin cells containing NMC622 and metallic Li were also fabricated and tested to evaluate its potential use with standard materials. To further investigate the cell behavior, a 3D-resolved model of the composite cathode was developed using a stochastic approach. The modeled microstructures were characterized in terms of connectivity, electrical conductivity, ionic tortuosity, and Young’s modulus. A coupled electrochemical–mechanical model was then used to predict the cell performance operating with currents from C/20 to 1C. Compared to experimental voltammetry tests, the model showed good alignment. Furthermore, the parameters for an equivalent circuit model were derived from the microscale model and validated against dedicated experimental results, confirming its accuracy. The proposed multiscale modeling framework proved to bridge the gap between detailed microscale simulations and practical cell design, providing valuable insights into the optimization of solid-state cell architectures.