Towards understanding of oxygen electrode processes during solid oxide electrolysis operation to improve simultaneous fuel and oxygen generation

Solid oxide electrolysis cells (SOEC) present a very promising technology to utilize excessive renewables among other available technologies. In comparison to other electrolyzers, SOECs enable simultaneous generation of valuable fuels, e.g. hydrogen and syngas, and pure oxygen. Pure oxygen can be used to increase efficiency of industrial combustion processes or for medical purposes. Nevertheless, increasing oxygen partial pressure on the oxygen electrode seems to be critical point for numerous conventional materials used. In this study, we showed that increasing oxygen partial pressure has a positive effect on the oxygen electrode durability. Supply with pure oxygen significantly reduced performance degradation, thus presenting the cells developed as very promising candidates for pure oxygen generation. Moreover, the cells were tested under operating conditions designed to accelerate degradation. This resulted in LSCF decomposition and formation of Sr-layer. Undesired morphology changes of the oxygen electrode were successfully identified with online-monitoring tools, thus providing a great contribution in preventing irreversible electrode degradation by suggesting more appropriate operating conditions.