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

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• Li metal solid-state batteries (LMSSBs) promise enhanced safety and energy density.
• Nonuniform Li+ flux in LMSSBs leads to lithium dendrite formation, a major safety concern.
• Microstructural anisotropies in solid electrolyte (SE) separators can influence dendrite growth patterns.

Purpose of the Study:

• Investigate the relationship between microstructural anisotropies in Li6PS5Cl (LPSCl) SE separators and Li dendrite growth.
• Develop and evaluate an innovative strategy to suppress lithium dendrite formation in LMSSBs.

Main Methods:

• Combined experimental and computational modeling approaches.
• Analysis of LPSCl SE separator microstructures and mechanical properties.
• Evaluation of dendrite growth under varying current densities and separator orientations.
• Implementation of ring-shaped anode electrodes for dendrite growth redirection.

Main Results:

• LPSCl separators exhibit mechanical weakness at θ = 0° and strength at θ = 45° relative to the densification direction.
• Critical current density (CCD) for dendrite initiation is directionally dependent, lower at θ = 0° (∼1 mA/cm²) and higher at θ = 45° (∼5 mA/cm²).
• The proposed ring-shaped anode electrode strategy effectively detours dendrite growth away from mechanically weakest regions.

Conclusions:

• Microstructural anisotropies significantly impact Li+ transport and dendrite propagation in LPSCl SEs.
• A novel strategy using tailored anode geometry can mitigate dendrite issues by guiding growth away from weak SE zones.
• Advanced SE processing and rational battery design are crucial for realizing the full potential of LMSSBs.