Capturing multiscale-multiphase dynamics to predict onset of lithium plating on porous graphite electrodes under fast charging

Lithium plating on porous graphite electrodes during the fast charging of lithium-ion batteries ac- celerates degradation and raises safety concerns. The onset of lithium plating is obscured by the reaction and transport resistance within the porous graphite electrodes. We extend the classic porous electrode theory by incorporating a Cahn-Hilliard phase-field appraoch to account for the phase-separation of LixC6, and we consider hierarchical pore structures at both electrode and par- ticle scales using the method of volume averaging. Our hierarchical multiphase porous electrode theory is rigorously examined in Li/graphite half-cells with identical graphite materials but different capacities and fast charging condition. By obtaining all parameters through experiments, or ab initio calculations, our model quantitatively agrees with measured cell voltages profiles, and, more impor- tantly, experimentally determined onset of lithium plating across multiple fast charging conditions.