Modeling Onset of Lithium Plating on Porous Graphite Anode in Fast Charging

Abstract

Lithium plating is one major degradation mechanism of the anode in lithium-ion batteries. The redox potential of graphite, the most widely used anode material, is 0.1V vs. Li+/Li, thus making parasitic Li plating inevitable during operation without precise control. Capturing the onset of lithium plating on graphite on the fly usually relies on both experimental and modeling techniques. We combine the phase-field approach and a hierarchical porous electrode theory to capture the dynamics of reaction and transport in the porous graphite electrode. The model is validated against the lithiation dynamics of porous graphite anode measured in-operando, capturing both the spatial and temporal non-uniformity. We then parameterize the model to a Li/Graphite half-cell setup and find a good agreement of materials-related parameters obtained across multiple datasets. The model respects the reaction kinetics and transport in a phase-separating material, thus transferable, and can guide the experimental design of battery and characterization methods for early detection of lithium plating.