Suppressing Cation Interdiffusion at CeO₂/ZrO₂ Heterointerfaces via Dopant Segregation

Area of Science:

• Materials Science
• Chemical Engineering
• Solid State Chemistry

Background:

• Cation interdiffusion at heterointerfaces is a detrimental side reaction in advanced materials.
• Diffusion barrier layers are commonly employed to mitigate this issue.
• Controlling interdiffusion is crucial for optimizing material performance and device longevity.

Purpose of the Study:

• To propose and demonstrate a novel method for suppressing cation interdiffusion using dopant segregation.
• To investigate the mechanism of interdiffusion suppression at the CeO2/ZrO2 heterointerface.
• To evaluate the impact of the proposed method on solid oxide fuel cell performance.

Main Methods:

• Fabrication of nanometer-thick diffusion barrier layers via dopant segregation.
• Utilizing Sc acceptor dopant segregation at the CeO2/ZrO2 heterointerface.
• Employing density functional theory (DFT) for defect formation energy calculations.

Main Results:

• Sc acceptor dopant segregation effectively suppressed Ce-Zr interdiffusion at the CeO2/ZrO2 heterointerface.
• DFT calculations revealed that the Sc layer impedes vacancy formation in the CeO2 layer, reducing VCe4- concentration.
• Implementation of the Sc segregation layer resulted in lower ohmic and polarization resistance and enhanced long-term fuel cell durability.

Conclusions:

• Dopant segregation is a viable and effective strategy for suppressing cation interdiffusion.
• The Sc segregation layer significantly improves the performance and durability of composite oxide-based fuel cells.
• Careful selection of dopants is critical for impeding interdiffusion and achieving superior fuel cell performance.