Probing Domain-Boundary-Induced Structural Degradation in Single-Crystalline LiCoO₂ by Nanoscale Imaging

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• High-capacity cathode materials are crucial for advanced lithium-ion batteries.
• Single-crystalline cathodes are preferred but may contain defects.
• Understanding degradation mechanisms in single crystals is vital.

Purpose of the Study:

• To investigate the presence and impact of nanoscale defects in single-crystalline LiCoO2 cathodes.
• To elucidate the role of these defects in battery degradation.
• To identify strategies for enhancing cathode stability.

Main Methods:

• Super-resolved nanoscale X-ray computed tomography (Nano-CT).
• Scanning probe nanodiffraction imaging (SPNDI).
• Advanced data-driven statistical analysis.
• Electrochemical performance testing.

Main Results:

• Ubiquitous nanoscale domain boundaries were identified within LiCoO2 single crystals.
• These boundaries act as hotspots for strain accumulation and microcrack formation.
• Residual strain at boundaries accelerates irreversible phase transitions.

Conclusions:

• Intragranular domain boundaries significantly impact mechanical and electrochemical degradation.
• Targeted doping can stabilize these critical interfaces.
• Intragranular domain regulation is essential for next-generation high-energy-density batteries.