Towards strategies to mitigate degradation and regenerate performance of a solid oxide electrolyzer during co-electrolysis operation

One of the main objectives towards the broad commercialization of solid oxide electrolysis cells (SOEC) is to reduce the effects of degradation and extend the lifetime of the technology. Special industrially relevant operating conditions can, however, amplify and accelerate the degradation of SOECs, thus significantly reducing the lifetime of the technology. Nevertheless, not all degradation processes are completely irreversible, especially if they are detected at an early stage. In order to develop strategies to mitigate degradation and to regenerate performance, several experiments were performed on a five-layer SOEC stack operating in steam and co-electrolysis mode. The experiments were performed at different industrially relevant gas mixtures, reactant conversion rates and operating temperatures. The experimental results revealed different types and degrees of effects of the degradation, mitigation and regeneration strategies on the performance of the stack, which were analyzed in detail and linked to the underlying mechanisms and processes. As a result, promising strategies for mitigating degradation and regenerating the performance of SOECs could be derived and optimized. In addition, this study provides a set of recommendations for safe and stable operation of SOECs under various operating conditions. •Extensive experimental investigations of a SOEC stack in co-electrolysis mode.•Development of degradation mitigation and regeneration strategies for SOEC.•Detailed insight into electrode processes and mechanisms via DRT analysis.