Diffraction-Enabled Operando Nanoscale Tracking of Li-ion Dynamics of Solid Electrolyte and Inhomogeneous Diffusion...

Area of Science:

• Materials Science
• Electrochemistry
• Solid-State Chemistry

Background:

• Lithium-ion (Li+) diffusion is crucial for battery performance, but primarily studied in liquid electrolytes, not solid-state electrolytes (SSEs) or all-solid-state batteries (ASSLBs).
• Understanding Li+ dynamics in SSEs is essential for advancing ASSLB technology.

Purpose of the Study:

• To establish diffraction as a viable method for studying Li+ diffusion in SSEs within ASSLBs.
• To investigate Li+ migration pathways and kinetics in Li3InCl6, a component of composite cathodes.

Main Methods:

• Operando synchrotron X-ray diffraction to observe lattice changes and Li+ insertion/extraction.
• X-ray nanodiffraction (XND) to map nanoscale Li+ distribution and diffusion within individual SSE particles.
• Integration with electrochemical techniques to correlate diffusion behavior with charging rates.

Main Results:

• Diffraction angle shifts in Li3InCl6 indicated preferred Li+ migration pathways and diffusion kinetics.
• XND revealed inhomogeneous Li+ distribution, highlighting the role of high-crystallinity regions and SSE/cathode active material (CAM) interfaces.
• High transient charging rates, not overall depth, were identified as the cause of irreversible Li+ diffusion.

Conclusions:

• Diffraction is a powerful tool for probing complex Li+ dynamics in ASSLBs.
• Microscopic insights into Li+ diffusion mechanisms can guide the design of more efficient and robust ASSLBs.