Dendrite Suppression by Detouring Li Transport within a Mechanically Anisotropic Solid Electrolyte

Li metal solid-state batteries (LMSSBs) offer higher safety and energy density but are limited by nonuniform Li⁺ flux leading to dendrite issues. This work investigates the correlations between dendrite growth and microstructural anisotropies of Li₆PS₅Cl (LPSCl) solid electrolyte (SE) separators. Modeling and experiments reveal that LPSCl separators are mechanically weakest along θ = 0° and strongest along θ = 45° of the densification direction. We propose an innovative dendrite suppression strategy that detours growth away from the mechanically weakest direction using ring-shaped anode electrodes. The critical current density (CCD) obtained relative to the SE densification direction was ∼1 mA/cm² at θ = 0° and increased to ∼5 mA/cm² at θ = 45°, indicating directional dependence of Li⁺ transport. This work presents a novel strategy to redirect dendrite growth away from microstructurally weak regions of the separator, emphasizing the need for advanced SE processing and battery designs.