Mitigating the Interfacial Degradation in Cathodes for High-Performance Oxide-Based Solid-State Lithium Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Solid-state lithium batteries (SSLBs) offer enhanced safety and energy density over conventional lithium-ion batteries.
• Interfacial engineering and mechanical stability remain critical challenges, particularly with stiff oxide electrolytes.

Purpose of the Study:

• To investigate the impact of cathode particle size on interfacial properties and electrochemical performance in SSLBs.
• To develop strategies for improving mechanical retention and reducing interfacial resistance in oxide-based SSLBs.

Main Methods:

• Fabrication of SSLBs using a cosintering method with Li3BO3 as a sintering agent, binding NMC cathode and LLTO solid electrolyte.
• Comparison of SSLBs utilizing small NMC primary particles versus large NMC secondary particles.
• Analysis of interfacial adhesion, mechanical retention, internal resistance, and electrochemical performance.

Main Results:

• Interfacial resistance fluctuates during cycling due to microcracks induced by NMC volumetric changes, leading to overall increase.
• Mechanical degradation at interfaces upon cycling causes capacity decay and reduced Coulombic efficiency.
• SSLBs with small NMC particles exhibit improved particle distribution, mitigated volumetric changes, and reduced mechanical degradation, resulting in better performance.

Conclusions:

• Optimizing cathode particle size is crucial for enhancing mechanical stability and electrochemical performance in SSLBs.
• Small NMC primary particles offer a viable strategy to improve interfacial integrity and long-term cyclability in oxide-based SSLBs.
• Findings provide insights for designing robust and high-performance next-generation solid-state batteries.