External Voltage-Induced Restructuring of the Solid-State Electrode/Electrolyte Interface Revealed by X-ray...

Area of Science:

• Materials Science
• Electrochemistry
• Surface Science

Background:

• Solid/solid interfaces are crucial for all-solid-state energy devices.
• Microscopic investigation of buried interfaces presents significant challenges.

Purpose of the Study:

• To investigate the restructuring of buried interfaces between metal cathodes and yttria-stabilized zirconia (YSZ).
• To understand the fundamental interfacial reactions impacting device performance.

Main Methods:

• Construction of metal|yttria-stabilized zirconia (YSZ)|Au model cells.
• Quasi in situ X-ray photoelectron spectroscopy depth profiling analysis.

Main Results:

• Interfacial Zr4+ ions in YSZ are reduced and interdiffuse with metal cathodes (Au, Ni, Ag) forming a ZrM alloy interlayer.
• Interface restructuring degree follows Au > Ni > Ag.
• Zr surface segregation on the cathode follows Ag > Ni > Au, suppressed by ZrM alloy formation.

Conclusions:

• ZrM alloy formation enhances interface restructuring but suppresses Zr surface segregation.
• Fundamental understanding of interfacial reactions at buried electrode/electrolyte interfaces is provided.