Mitigating stress and delamination via porous current collectors: A chemo-mechanical model for layered electrodes

Porous current collectors (PCCs) exhibit enhanced electrochemical performance in terms of cyclic capacity, rate performance, and cycle life. However, the underlying chemo-mechanical coupled mechanisms are not yet fully understood. Here, lithium diffusion kinetics and the associated stress evolution in PCC-configured electrodes are systematically investigated through a one-way coupled theoretical framework. The symmetric PCC configuration induces a symmetric stress distribution relative to the midplane of active coatings along the thickness direction. This stress distribution is significantly influenced by the biaxial modulus and the thickness ratios of the PCC to the active coating. Compared to the traditional current collector at the equivalent average lithium concentration, the PCC electrode configuration can significantly lower stress levels, minimize the stress difference at the interface between the current collector and the active coating, and decrease the energy release rate associated with interface delamination. These findings suggest that PCC-based electrode architectures can effectively mitigate mechanical failure and enhance structural integrity in symmetric electrode systems, highlighting the potential and critical importance of chemo-mechanical considerations in advanced battery engineering.