Transient High-Temperature Oxygen Evolution Reaction

水（或蒸汽）电解产生氢气作为化学能量载体，是长期储存间歇性可再生发电的基石。在电解池的反电极或空气电极上，氢气的产生总是伴随着氧气的析出。这种电催化析氧反应（OER）由于不利的过电位对制氢效率起决定性作用，造成严重的总体损失。在已知的电解工艺中，高温固体氧化物电解电池（soec）是最有前途的技术，用于间歇性供电的情况下，因为高温会产生更高的电解质离子电导率，更快的电极反应动力学，以及最低的OER过电位。在本项目中，高温soec的适用范围将从过去针对恒负荷下的最佳性能进行优化扩展到动态运行条件。解决了空气电极的加速降解问题，如脱层和电催化剂材料的化学不稳定性。改进的导氧固体电解质和OER电催化剂涂层的发展，以及瞬态操作条件的优化，将导致生产精细化的SOEC电池和堆装置。为了实现这些目标，将开发YSZ支持的最先进材料LSM和LSCF的体相和界面的电化学和相关原子尺度过程的基本理解。为此，我们采取整体方法，将从头算理论和操作表征技术联系起来，以便在微观尺度上进行实时调查。

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.