Elucidating the Role of Rational Separator Microstructures in Guiding Dendrite Growth and Reviving Dead Li

Li metal has attracted considerable attention as the preferred anode material for high-energy batteries. However, Li dendrites have limited the development of Li-metal batteries. Herein, the effects of tuning the porous separator microstructure (SM) for guiding Li dendrite growth and reviving dead Li are revealed using a mechano-electrochemical phase-field model. A strategy of guiding, instead of suppression, was applied to avoid disordered Li dendrite growth. By analyzing the effects of the number of layers, thickness, degree of staggered overlap in the separator, interlayer spacing, and porosity of SM on Li dendrite behavior, we discovered that applying a rationally designed SM can finely guide the Li nucleation and growth direction toward dense deposition. The revival of dead Li was also observed via an in situ experiment on Li dendrites. The reactivation of dead Li after it recontacts Li metal was verified. These findings not only provide fundamental information for the tuning of the SM but can also help better understand the dendrite growth of other alkali metal-ion batteries.

Automated summary

In this study, the effects of tuning the microstructure of a porous separator on the growth of lithium dendrites and the revival of dead lithium were investigated using a mechano-electrochemical phase-field model. By rationally designing the porous separator, the growth of lithium dendrites can be guided towards dense deposition. In addition, the revival of dead lithium was observed after it made contact with lithium metal.