Correlating the Microstructure and Current Density of the Li/Garnet Interface

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state lithium batteries offer advanced energy storage potential.
• Lithium filament formation in solid electrolytes is a major obstacle to their widespread adoption.

Purpose of the Study:

• To investigate how the morphology of garnet-type solid electrolytes affects their resistance to lithium filament penetration.
• To develop and validate a novel method for assessing electrolyte resistance to lithium filaments.

Main Methods:

• Cyclic linear sweep voltammetry was employed to evaluate electrolyte resistance against lithium filaments.
• Kelvin probe force microscopy and finite element method simulations were used to analyze the influence of microstructure on ion transport.

Main Results:

• A strong correlation was observed between solid electrolyte morphology and resistance to lithium filament formation.
• Electrolytes with minimized pores and numerous grain boundaries exhibited superior performance, reaching a critical current density of 3.2 mA cm^-2.
• Enhanced long-term cycling stability was achieved with optimized morphology.

Conclusions:

• Minimizing pores and creating a uniform morphology with small grains and abundant grain boundaries are crucial for inhibiting lithium penetration.
• Controlling microstructure is essential for developing robust and safe solid-state lithium batteries.