Distribution of Relaxation Times of Fuel Electrodes for Reversible Solid Oxide Cells Fabricated Under Various Conditions

Reversible solid oxide cells (r-SOCs) are electrochemical energy devices that can reversibly switch between power generation by solid oxide fuel cells (SOFCs), and hydrogen production by solid oxide electrolysis cells (SOECs) the reverse operation of SOFCs. For the development of high-performance and durable r-SOCs, it is essential to understand not only the I-V characteristics but also the electrode reaction processes systematically. Here in this study, Ni-GDC cermet fuel electrodes, a composite of Ni and mixed-conducting Gd-doped ceria (GDC), were prepared at different sintering temperatures and electrode thicknesses. Electrochemical impedance measurements and distribution of relaxation times (DRT) analysis were performed in both SOFC and SOEC modes to investigate the influence of fabrication conditions on the fuel electrode reaction processes.