Nanoengineered fuel electrode for large-scale flat-tube solid oxide electrolysis cell enhanced with Gd0.2Ce0.8O2 nanoparticles for durable seawater hydrogen production

Solid oxide electrolysis cells (SOECs) are recognized for their efficient and versatile conversion of renewable energy into hydrogen's chemical energy. However, the long-term stability of large-scale seawater electrolysis remains an area that requires further exploration. In this work, Gd0.2Ce0.8O2-δ (GDC) is impregnated into the fuel electrode channels of a large-scale flat-tube SOEC using an infiltration technique. This approach is designed to mitigate the degradation associated with charge transfer at the fuel electrode, thereby enhancing the cell's long-term operational stability. The GDC-decorated electrolysis cell exhibits stable operation over a 500 h period with seawater, with a degradation rate of approximately 0.015 %/h, which is less than half of the non-impregnated cell, which registers a degradation rate of 0.031 %/h. Utilizing the distribution of relaxation time technology, it is determined that the degradation of the electrolysis cell predominantly correlated with the oxygen ion transport and charge transfer processes at the fuel electrode, with no significant relation to the processes at the air electrode or to gas adsorption/desorption. This work demonstrates that the infiltration strategy for decorating the fuel electrode can effectively prolong the service life of SOECs.