In-Situ Internal Observation of Silicon Composite Anode in All-Solid-State Battery Using X-ray CT

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Silicon anodes offer high theoretical capacity for next-generation batteries.
• Volume expansion/contraction during cycling causes particle cracking and loss of contact with solid electrolytes.
• Mechanical restraint is crucial for stable operation of silicon anodes in all-solid-state batteries.

Purpose of the Study:

• To investigate the nanostructure evolution of silicon/solid electrolyte composite anodes under mechanical constraint during battery operation.
• To understand the failure mechanisms of silicon anodes in all-solid-state batteries.
• To provide insights for enhancing the performance and stability of silicon-based all-solid-state batteries.

Main Methods:

• Fabrication of an all-solid-state battery with a silicon and Li6PS5Cl composite anode.
• In situ computed tomography (CT) measurements under constrained charge-discharge conditions.
• Analysis of internal structural changes at the nanometer scale during battery cycling.

Main Results:

• Observed distinct cracking modes during charging and discharging processes.
• Identified cracking and reattachment phenomena during charging.
• Revealed anisotropic void formation during discharging.
• Demonstrated the importance of mechanical restraint in influencing failure mechanisms.

Conclusions:

• Understanding in situ structural changes under mechanical constraint is vital for silicon anode development in all-solid-state batteries.
• Different failure modes during charging (cracking/reattachment) and discharging (void formation) necessitate tailored strategies.
• This research provides a foundation for designing more robust silicon anodes for advanced energy storage applications.