Wetting and Infiltration of Molten Lithium on Graphene Oxide Membranes: Implications for Anode Fabrication

Molten lithium (Li) infiltrating into graphene oxide (GO) membranes to fabricate composite Li anodes has been an effective approach to inhibit volumetric expansion, dendrite formation, and other issues in the application of Li-based batteries. However, the potential wetting behavior of Li atoms and their spreading mechanisms on GO membranes are not fully understood. Density functional theory (DFT) and molecular dynamics (MD) simulations combined with experiments are carried out to investigate the wetting behavior of molten Li droplets on the GO surface and the infiltration performance of Li atoms within the GO interlayers. First, the interaction between Li atoms and GO membranes is analyzed by DFT and fitted to obtain the van der Waals (vdW) parameters, which are further used in MD simulations. Then, the wetting performance of molten Li droplets on the GO surface is evaluated by MD simulations and compared with experimental measurements. At last, the infiltration of Li atoms into GO nanochannels is investigated and discussed in detail. The variations in the infiltrating depth and diffusion velocity of molten Li with the oxidation concentration and interlayer distance of the GO membranes are analyzed. This study may provide a deep understanding of the diffusion mechanisms of molten Li in nanoconfined conditions, which is of great importance for improving the electrical and mechanical behaviors of composite Li anodes.