Suppressing Dendrite-Induced Cracking in Solid-State Electrolytes: Pressure Constraints and Mechanical Properties.

Area of Science:

• Materials Science
• Electrochemistry
• Mechanical Engineering

Background:

• Solid-state batteries (SSBs) face challenges with solid-state electrolyte (SSE) cracking due to lithium dendrite penetration.
• This cracking leads to battery failure and safety concerns.

Purpose of the Study:

• To develop a model predicting and mitigating SSE cracking in Li-metal SSBs.
• To investigate the synergistic effects of mechanical pressure and material properties on battery failure.

Main Methods:

• A coupled electrochemical-mechanical-phase-field cracking (EMPC) model was developed.
• Systematic analysis of biaxial pressure (stack and lateral) and intrinsic mechanical properties (Young's modulus, fracture toughness).

Main Results:

• Under zero pressure, lithium dendrites cause cracks to propagate, leading to penetration failure.
• Stack pressure delays but requires high MPa for suppression; excessive pressure causes short circuits.
• Lateral pressure effectively suppresses cracks at lower MPa by reducing tensile strain.
• Enhanced fracture toughness disrupts dendrite-crack feedback; Young's modulus shows nonlinear effects.

Conclusions:

• Lateral pressure is a more efficient strategy than stack pressure for crack suppression.
• Optimizing mechanical properties and applying tailored pressure strategies are crucial for stable SSBs.
• The study provides fundamental insights for designing robust solid-state batteries.