Variable-Energy Hard X-ray Photoemission Spectroscopy: A Nondestructive Tool to Analyze the Cathode-Solid-State...

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• All-solid-state batteries offer higher energy density than Li-ion batteries.
• Interfacial resistance between electrodes and solid electrolytes limits performance.
• Elemental interdiffusion and low ionic conductivity interlayers are key issues.

Purpose of the Study:

• To investigate interfacial phenomena in all-solid-state batteries.
• To compare variable-energy hard X-ray photoemission spectroscopy (XPS) with traditional methods.
• To demonstrate methods for suppressing interdiffusion.

Main Methods:

• Nondestructive variable-energy hard X-ray photoemission spectroscopy (XPS).
• Comparison with angle-resolved XPS and X-ray absorption spectroscopy.
• Verification using focused ion beam (FIB) and high-resolution transmission electron microscopy (HRTEM).
• Atomic layer deposition (ALD) for creating artificial interfacial layers.

Main Results:

• Variable-energy hard XPS accurately detected elemental chemical states at the cathode-electrolyte interface.
• Elemental interdiffusion was identified as a performance-limiting factor.
• ALD-created artificial layers significantly suppressed interdiffusion.

Conclusions:

• Variable-energy hard XPS is a valuable tool for analyzing solid-state battery interfaces.
• Suppression of interdiffusion is crucial for enhancing all-solid-state battery performance.
• ALD offers a viable strategy for mitigating interfacial issues.