Transient High-Temperature Oxygen Evolution Reaction

水（或蒸汽）电解产生氢气作为化学能载体，是间歇性可再生发电长期储存的基石。氢气的产生总是伴随着在电解池的反电极或空气电极处的氧气析出。 由于不利的过电位，这种电催化析氧反应（OER）对制氢效率起着决定性作用，造成严重的整体损失。在已知的电解工艺中，高温固体氧化物电解池（SOEC）构成了在间歇供电的情况下操作的最有前途的技术，因为升高的温度在电解质中产生更高的离子电导率、更快的电极反应动力学和最低的OER过电位。在过去，该方法已经被优化用于在恒定负载下的最佳性能，将被扩展到动态操作条件。空气电极的加速降解问题，如分层和电催化剂材料的化学不稳定性将得到解决。改进的氧传导固体电解质和OER电催化剂涂层的开发以及瞬态操作条件的优化将导致生产精制的SOEC电池和电池组。为了实现这些目标，电化学和相关的原子尺度的过程中的体相和最先进的材料LSM和LSCF，支持YSZ的接口的基本理解将被开发。为此，我们采取了整体的方法，连接从头算理论和操作表征技术，在微观尺度上的实时调查。

Water (or steam) electrolysis, producing hydrogen gas as a chemical energy carrier, is a corner stone for the long-term storage of intermittent, renewably generated electricity. Hydrogen production is always accompanied by oxygen evolution at the counter- or air-electrode of the electrolysis cell. This electro-catalytic oxygen evolution reaction (OER) plays a decisive role for the efficiency of the hydrogen production due unfavorable overpotentials, causing severe overall losses. Among the known electrolysis processes, high-temperature solid oxide electrolysis cells (SOECs) constitute the most promising technology for the operation in a scenario with intermittent power supply, as elevated temperatures yield higher ionic conductivity in the electrolyte, faster electrode reaction kinetics, and the lowest OER overpotentials.In this project, the scope of applicability of high-temperature SOECs, which have been optimized for optimum performance under constant load in the past, will be extended to dynamic operating conditions. Problems of accelerated degradation of the air-electrode like delamination and chemical instability of the electro-catalyst materials will be addressed. The development of improved oxygen-conducting solid electrolytes and OER electro-catalyst coatings, as well as the optimization of transient operating conditions will result in the production of refined SOEC cells and stack setups. To meet these objectives, a fundamental understanding of the electrochemical and relevant atomic-scale processes in the bulk phases and at interfaces of the state-of-the-art materials LSM and LSCF, supported on YSZ will be developed. For this we take a holistic approach, linking ab initio theoretical and operando characterization techniques for real-time investigations at the microscopic scale.