Phase-Field Model of Lithium Dendrite Growth in Confined SEI Channels: Geometric Effects on Dendrite Suppression

Lithium batteries have garnered significant research interest owing to its exceptionally high theoretical specific energy. During the electrochemical cycle, the reduction and non-uniform deposition of lithium ions on electrode surfaces induce lithium dendrites formation and growth. However, the continuous growth of lithium dendrite results in substantial safety risks caused by separator penetration, potentially triggering internal short circuit and catastrophic thermal runaway events. In this paper, a phase field is proposed to investigate the growth process of lithium dendrites in the different width/height channels of solid electrolyte interphase. The results reveal that geometric confinement effects in narrow transport channels significantly suppress the growth of lithium dendrites, manifesting as reduced growth velocities and morphological refined lithium deposition patterns. Upon channel expansion approaching critical dimensional thresholds, the growth rate of lithium dendrites exhibits stabilization behavior. Note that, extending channel length intensifies concentration polarization along lithium deposition pathways. It demonstrates that under fixed cross-sectional confinement conditions, axial elongation of transport channels significantly enhances the growth rate of lithium dendrites. Through systematic parametric analysis, this work establishes that transport channel dimensions of width-to-length ratio regulate dendrite proliferation mechanisms. These findings provide critical insights into the solid electrolyte interphase design strategies for next-generation high-safety lithium metal batteries.