Tailoring Sulfide Particle Size for All-Solid-State Lithium Metal Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Precise control of sulfide solid electrolyte (SSE) particle size is critical for efficient ion-conducting networks in composite cathodes.
• All-solid-state lithium metal batteries (ASSLBs) require optimized SSE for improved performance.

Purpose of the Study:

• To systematically investigate the impact of SSE particle size distribution (D10, D50, D90) on ASSLB performance.
• To establish quantitative guiding principles for SSE particle engineering in composite cathodes.

Main Methods:

• Controlled mechanical grinding of Li6PS5Cl SSE to achieve specific particle size distributions.
• Electrochemical testing (capacity, rate capability, cyclability) of ASSLBs with varying SSE particle sizes.
• Microstructural analysis to correlate particle configuration with ion-conducting network formation.

Main Results:

• Optimal SSE particle size composition resulted in a reversible capacity of 202.2 mAh/g at 0.25C.
• Superior rate capability (76% capacity retention at 5C/0.25C) and cyclability (80% at 5C after 4000 cycles) were achieved.
• A hierarchical ion-conducting network formed under specific cathode-to-SSE particle size ratios (7.3 ≤ D50Cathode/D50SSE and 2.0 ≤ D90Cathode/D90SSE ≤ 3.5).

Conclusions:

• Optimized SSE particle size engineering is crucial for high-performance ASSLBs.
• Fine SSE particles fill cathode gaps, while medium particles facilitate ion transport.
• Deviations in particle size ratios negatively impact interfacial contact and ion transport pathways.