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.