Enhancing Electrode Performance by Exsolved Nanoparticles: A Superior Cobalt-Free Perovskite Electrocatalyst for...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Solid oxide fuel cells (SOFCs) require efficient, durable, and cost-effective electrocatalysts for the oxygen reduction reaction (ORR) at intermediate temperatures.
• Cobalt-based perovskites, while effective, face challenges due to cost and potential health concerns, driving research into cobalt-free alternatives.

Purpose of the Study:

• To design, fabricate, and characterize a novel cobalt-free cathode material for SOFCs.
• To investigate the impact of exsolved NiO nanoparticles on the ORR performance of a SrFeTiNiO3-δ cathode.
• To develop a regeneration strategy for maintaining cathode performance over time.

Main Methods:

• Synthesis and fabrication of SrFe0.85Ti0.1Ni0.05O3-δ perovskite cathode.
• Controlled exsolution of NiO nanoparticles onto the cathode surface.
• Electrochemical characterization including ORR activity measurements.
• Development and testing of a NiO nanoparticle regeneration process.

Main Results:

• The developed SrFe0.85Ti0.1Ni0.05O3-δ cathode decorated with uniformly distributed NiO nanoparticles exhibited enhanced ORR activity.
• The performance surpassed that of a benchmark cobalt-based cathode (Ba0.5Sr0.5Co0.8Fe0.2O3-δ).
• A regeneration process was successfully developed to address performance degradation caused by NiO particle coarsening.

Conclusions:

• Exsolution of NiO nanoparticles is an effective strategy to enhance the performance of cobalt-free SOFC cathodes.
• The developed cathode demonstrates potential for commercialization of intermediate-temperature SOFCs.
• The exsolution-dissolution approach offers a general pathway for designing advanced electrocatalysts for fuel cells and other electrochemical systems.