Ultrathin Atomic Layer-Deposited CeO₂ Overlayer for High-Performance Fuel Cell Electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Catalysis

Background:

• High activity and thermal stability are crucial for catalysts in high-temperature energy conversion devices.
• Platinum (Pt) is a known effective catalyst for low-temperature solid oxide fuel cells (LT-SOFCs) but can face stability challenges at elevated temperatures.

Purpose of the Study:

• To design and fabricate a heterogeneous catalyst with an ultrathin cerium dioxide (CeO2) overlayer on Pt electrodes.
• To enhance the activity and thermal stability of cathodes for LT-SOFCs.
• To achieve high performance in thin-film SOFCs.

Main Methods:

• Atomic layer deposition (ALD) was used to create an ultrathin CeO2 overlayer on Pt electrodes.
• Fabrication of thin-film SOFCs utilizing an anodized aluminum oxide (AAO) substrate.
• Electrochemical testing to evaluate catalyst performance and stability.

Main Results:

• The CeO2-overcoated Pt cathode (five ALD cycles) exhibited a 50% reduction in activation resistance after 10 hours of operation.
• The catalyst demonstrated a twofold increase in thermal stability compared to a Pt-only cathode.
• A thin-film SOFC with the CeO2-overcoated cathode achieved a peak power density of 800 mW cm⁻² at 500 °C.

Conclusions:

• The ultrathin CeO2 overlayer significantly enhances the performance and stability of Pt-based cathodes for LT-SOFCs.
• ALD is an effective technique for fabricating advanced catalytic materials for energy applications.
• The developed catalyst represents a breakthrough in AAO-based SOFC technology, offering record performance at 500 °C.