Ni-Doped SFM Double-Perovskite Electrocatalyst for High-Performance Symmetrical Direct-Ammonia-Fed Solid Oxide Fuel...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Conversion

Background:

• Ammonia is a promising carbon-free fuel for solid oxide fuel cells (SOFCs) due to its high energy density and hydrogen content.
• Developing efficient and stable anode materials is crucial for direct-ammonia SOFCs.
• Nickel-doped SFM double-perovskite (Sr1.9Fe0.4Ni0.1Mo0.5O6-δ) is investigated as a novel anode material.

Purpose of the Study:

• To evaluate the electrocatalytic potential of a novel Ni-doped SFM double-perovskite as an anode material for symmetrical direct-ammonia SOFCs.
• To investigate the material's performance, stability, and ammonia consumption mechanism.

Main Methods:

• Synthesis and characterization of Ni-doped SFM double-perovskite (Sr1.9Fe0.4Ni0.1Mo0.5O6-δ).
• Utilized scanning and transmission electron microscopy (SEM/TEM) and X-ray diffraction (XRD) for material analysis.
• Tested 3D-printed symmetrical cells with SFNM-GDC electrodes using H2 and NH3 fuels under various operating conditions.

Main Results:

• Exsolution of Ni-Fe nanoparticles (NPs) and formation of FeNi3 phase observed under anode conditions.
• Achieved a maximal ammonia conversion rate of 97.9% at operating temperatures (550-800 °C).
• Demonstrated comparable polarization resistances and peak power densities (430 mW cm⁻² for H2, 416 mW cm⁻² for NH3) with long-term stability (0.48% voltage loss per 100 h).

Conclusions:

• The Ni-doped SFM double-perovskite exhibits excellent electrocatalytic activity and stability for direct-ammonia SOFCs.
• The study elucidates the ammonia consumption mechanism as a multistep process involving ammonia decomposition and hydrogen oxidation.
• This material presents a promising pathway for advancing clean energy conversion technologies using ammonia-based SOFCs.