Mechanistic Insight into Lithium Electrodeposition in Porous Host Architectures

Large volumetric changes and dendrite growth are major challenges to achieving enhanced cycling efficiency and safety in lithium (Li) metal batteries. Porous hosts for Li storage can potentially accommodate large volumetric changes and enable stable deposition morphologies. In this study, we mechanistically explore the Li electrodeposition process in porous host architectures that contain well-aligned channels. It is identified that the channel architecture helps regulate Li-ion flux and stabilize Li electrodeposition when the channel size is comparable to the characteristic size of the dendrites. Dendrite growth due to local inhomogeneity in ion flux/reaction kinetics can be alleviated through the confinement effect of vertically aligned channel walls. The critical effect of host architectural features, such as channel patterns, pore size, and connectivity, on the local morphological stability have been quantified. For high-rate applications, vertically aligned channel design with minimal interchannel connectivity is found to be an effective strategy for dendrite suppression when compared to horizontally aligned channels. This study provides fundamental insight into Li morphological growth within porous host architectures, identifying design guidelines to address the interfacial instability challenges in Li metal batteries.