Structural Evolution of a High-Temperature Oxygen Evolution Catalyst under Transient Working Conditions

固体氧化物电解电池（SOECs）作为一种高效的电能到x （P2X）转换技术，用于间歇性可再生能源的化学储存，在稳定和动态运行条件下，其降解过程尚不清楚。在第一个项目阶段，获得了阳极/电解质界面的定性新描述，被确定为纳米级的外观。这一发现构成了以下资助期的基础，我们建议在此期间研究动态操作条件下SOEC的空气电极/电解质界面。我们将在第一个项目阶段开发的紧密交织的多模态微观、光谱和第一性原理理论方法的基础上，将其扩展到近环境operando和准原位条件。这项多模式研究的结果将使影响催化活性和相关降解过程的结构因素合理化。我们将重点关注基于LSM的电解电池，它将在恒定和动态的反应条件下进行电化学表征。该项目的目的是评价反应条件下的肤色，以便为其在电化学过程中的作用提供证据。表面和空气电极/电解质界面的非原位分析将通过电子显微镜和光电子能谱进行。为了用相关环境扫描电镜（ESEM）和operando x射线光电子能谱研究阳离子的结构和氧化态，将制备专用电池。该电池将通过在YSZ衬底上沉积LSM （< 10 nm）来生产。这个非常薄的电极层将允许光电子从肤色发出离开电化学活性域。在恒定载荷和动态载荷作用下，将研究薄细胞中肤色的形成和稳定性。同位透射电镜成像（ILI）将补充非原位分析，并作为后续操作实验的结构基础。实验研究将得到DFT计算的补充。从基于力场采样技术产生的YSZ/LSM界面的大型肤色模型开始，我们将生成DFT可处理模型单元的集合，其中每个集合代表与YSZ/LSM界面平行的肤色内的薄截面。为了确定混合电导率（MIEC）催化活性界面结构的性质，将在生成的小DFT单元群中使用NEB DFT模拟计算沿氧化物离子传导途径的跳跃过程的激活势垒。最佳的MIEC切片将用于构建代表催化活性位点可能的表面结构的板模型。

Solid oxide electrolysis cells (SOECs) as an efficient power-to-X (P2X) conversion technology for chemical storage of intermittent renewable energy suffer from poorly understood degradation processes under steady and dynamic operating conditions. In the first project phase a qualitatively new description of the anode/electrolyte interface was gained which was identified as a nano-scale complexion. This finding forms the basis of the following funding period in which we propose to investigate, the air electrode/electrolyte interface of the SOEC under dynamic operating conditions. We will build upon our tightly interwoven multi-modal microscopic, spectroscopic, and first-principle theoretical approach developed during the first project phase and extend it to near-ambient operando and quasi in situ conditions. The outcome of this multi-modal study will rationalize structural factors that influence the catalytic activity and related degradation processes. We will focus on LSM based electrolysis cells, which will be characterized electrochemically under constant and dynamic reaction conditions. The aim of this project is the evaluation of the complexion under reaction conditions in order to deliver evidence for its role in the electrochemical process. Ex situ analysis of the surface and the air electrode/electrolyte interface will be performed by electron microscopy and photoelectron spectroscopy. For the study of the structure and the oxidation states of the cations with correlative environmental scanning electron microscopy (ESEM) and operando X-ray photoelectron spectroscopy special cells will be prepared. The cells will be produced by the deposition of LSM (< 10 nm) on an YSZ substrate. This very thin electrode layer will allow the photoelectrons emanating from the complexion to leave the electrochemically active domain. The formation and stability of the complexion in the thin cells will be studied under constant and dynamic loads. Identical location TEM imaging (ILI) will complement the ex situ analysis and act as a structural basis to subsequent operando experiments. The experimental investigations will be complemented by DFT calculations. Starting from large complexion models of the YSZ/LSM interface, produced by force-field based sampling techniques, we will generate ensembles of DFT tractable model cells where each ensemble is representative of a thin section within the complexion that is parallel to the YSZ/LSM interface. To establish the properties of the complexion as a mixed conductivity (MIEC) of catalytically active interface structure, activation barriers for the hopping processes along the oxide ion conduction pathways will be computed using NEB DFT simulations within the small DFT cell ensembles generated. The optimal MIEC slice will be used to construct slab models representing possible surface configurations at the catalytically active site.