Dual-functional La₂NiO₄ impregnation for enhancement of catalytic activity and microstructure in SOEC fuel electrodes

Achieving high efficiency and long-term durability in solid oxide electrolysis cells (SOECs) requires innovative electrode engineering. In this study, we report a simple and scalable impregnation strategy to enhance the performance and stability of SOECs by modifying the conventional Ni-YSZ fuel electrode with La₂NiO₄. Under operating conditions, La₂NiO₄ undergoes in-situ decomposition, forming a nanocomposite of Ni nanoparticles embedded within La(OH)₃ substrate. This unique structure provides abundant catalytic sites for H₂O dissociation and suppresses Ni coarsening, thereby ensuring stable electrochemical performance. The impregnated electrode delivered a high current density of −1.36 A cm⁻² at 1.3 V and 750 °C, while exhibiting significantly enhanced stability with a low degradation rate of only 0.25 mV h⁻¹ over 200 h, significantly outperforming the unmodified electrode counterpart. Electrochemical and microstructural analyses further confirmed reduced polarization resistance and excellent microstructural robustness. These findings highlight the promise of this impregnation approach for developing high-performance, durable SOEC electrodes, advancing sustainable hydrogen production technologies.