High Cathode Loading and Low-Temperature Operating Garnet-Based All-Solid-State Lithium Batteries -...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Batteries

Background:

• All-solid-state lithium batteries (ASSLBs) offer enhanced safety over conventional lithium-ion batteries.
• Garnet-type solid electrolytes are promising due to their high ionic conductivity.
• Current fabrication methods for ASSLBs often involve high pressure and long sintering times, limiting scalability.

Purpose of the Study:

• To develop a high-pressure-free, scalable fabrication method for garnet-based ASSLBs.
• To enhance the electrochemical performance and stability of ASSLBs.
• To investigate the mechanical integrity and failure mechanisms within ASSLBs during operation.

Main Methods:

• Utilized quick liquid phase sintering (Q-LPS) for garnet-type solid electrolytes and cathode layers.
• Optimized sintering parameters including heating rate (50-100 K min⁻¹) and dwell time (10 min).
• Performed multiphysics analyses to understand internal stress and mechanical failures.

Main Results:

• Achieved an initial discharge capacity of 1 mAh cm⁻² and 130 mAh g⁻¹ at 25 °C with LiCoO₂ loading of 8.1 mg.
• Demonstrated improved capacity retention at reduced temperatures (10 °C) and higher rates (0.1 C).
• Identified significant internal stress (up to 1 GPa) leading to mechanical failures like interface delamination and network breakdown.

Conclusions:

• Q-LPS is a viable and scalable method for manufacturing high-performance ASSLBs.
• Simultaneous optimization of materials, processes, and architecture is crucial for battery performance.
• Internal mechanical stress is a critical factor limiting the long-term stability and cycle life of ASSLBs.