Tailoring Composite Microstructure Through Milling for Dry-Processed Sulfide-Based Solid-State Battery Cathodes

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Solid-state batteries (SSBs) are crucial for next-generation energy storage.
• Composite cathodes, combining solid electrolytes and active materials, are key components of SSBs.
• The influence of mechanical processing on SSB composite properties remains underexplored.

Purpose of the Study:

• To investigate the impact of mechanical process parameters during planetary ball milling on Li6PS5Cl and LiNi0.83Co0.11Mn0.06O2 composite cathodes.
• To understand how milling affects microstructure, particle size, and aggregate formation.
• To correlate milling energy input with electrochemical performance.

Main Methods:

• Planetary ball milling of Li6PS5Cl and LiNi0.83Co0.11Mn0.06O2.
• Microstructural analysis (particle size, aggregate formation).
• Discrete element simulations to model microstructure evolution.
• Electrochemical performance testing.
• Dry film production and analysis.

Main Results:

• Milling significantly alters composite microstructure, affecting solid electrolyte particle size and electrolyte-active material aggregation.
• Increased milling energy initially improves electrochemical performance by increasing heterocontact density.
• Excessive milling energy negatively impacts performance due to decreased Li6PS5Cl crystallite size and increased LiNi0.83Co0.11Mn0.06O2 strain.
• Dry film production can partially compensate for non-optimized milling, but precise control is paramount.

Conclusions:

• Mechanical processing, specifically planetary ball milling, is a critical factor in determining the properties and performance of composite cathodes for SSBs.
• Optimizing milling parameters is essential for maximizing electrochemical performance.
• Understanding and controlling the interplay between milling energy, microstructure, and material properties is vital for advancing SSB technology.