Ceria-based Cathodes for High Performance Electrolysis Cells

更广泛的研究背景/理论框架：高温固体氧化物电解槽(SOECs)分解H2O和CO2是生产绿色H2和CO的一种高效和有前途的方法。新型CeO2基阴极具有高的电催化活性、低的降解率和在CO2电解下的低结焦敏感性，有可能使SOEC技术向前迈进一大步。因此，对CeO2基阴极的电化学性能、三维微结构和力学行为之间复杂的相互关系的详细了解是必不可少的。假设/研究问题/目标：我们提出了两种策略来获得制造这种最高性能和长期稳定的CeO2基SOEC阴极所需的基本知识。首先，我们将阐述一种新的工艺概念，通过氧化还原诱导自修饰来制备Ni/Gd掺杂CeO2(GDC)电极，在此过程中，CeO2相部分地生长在Ni颗粒上。这提供了高结焦容限、机械强度和大的GDC表面积，从而实现了高的电催化活性。其次，我们将利用GDC在还原条件下的离子/电子混合导电性来开发具有单相GDC有源层的新型SOEC阴极。我们将通过掺杂变化、原位膨胀测量和数值模拟来解决化学膨胀问题，以深入了解力学行为。途径/方法：为了实现我们的目标，我们将实施跨学科的工作计划，并与专业研究小组密切合作，这些小组已经在联合项目中拥有值得注意的合作经验。成功的关键是了解基于CeO2的SOEC阴极的原子级，并将这些知识用于新工艺路线的有针对性的设计。我们将使用模型系统对基本材料进行表征，并将结果直接传输到3D多孔CeO2阴极的加工以及操作电极的相场模拟中。三维微结构分析和原位电子显微镜将对相关过程及其相互作用提供详细的见解。原创性/创新性：这项提议的高度新颖性源于贡献组的方法广度异常广泛，这将使我们能够在所用材料的基本性质和原子过程的水平上了解基于CeO2的3D多孔SOEC阴极的行为。从而为获得新型、高成形率、长期稳定、抗结焦的CeO2基燃料电极提供基础认识，这将推动SOEC技术向前迈进一大步。

Wider research context/theoretical framework: H2O and CO2 splitting in high temperature solid oxide electrolysis cells (SOECs) is a highly efficient and promising approach for producing green H2 and CO. Novel ceria-based cathodes have the potential to take SOEC technology a giant step further due to their high electro-catalytic activity, low degradation rates, and low coking susceptibility under CO2 electrolysis. Hence, detailed knowledge on the complex interrelations between electrochemical performance, 3D microstructure, and me-chanical behaviour of ceria-based cathodes is essential. Hypotheses/research questions/objectives: We propose two strategies to achieve the basic knowledge required for fabricating such highest per-forming and long-term stable ceria-based SOEC cathodes. First, we will elaborate a novel processing concept for Ni/Gd-doped CeO2 (GDC) electrodes by redox-induced self-modification, during which the ceria phase partly overgrows the Ni particles. This provides high coking tolerance, mechanical strength and large GDC surface area for high electro-catalytic activity. Second, we will use the mixed ionic/electronic conductivity of GDC in reducing conditions to develop novel SOEC cathodes with single-phase GDC active layer. We will tackle the issue of chemical expansion by doping variations, in-situ expansion measurements, and numerical simulations to gain in-depth understanding of the mechanical behaviour. Approach/methods: To reach our goals we will implement an interdisciplinary working plan with tight cooperation of specialised research groups, who already have noteworthy experience working together in joint pro-jects. The key to success is to understand ceria-based SOEC cathodes down to the atomistic level and to use this knowledge for a targeted design of novel processing routes. We will use model systems for basic material characterization and directly transfer the results to processing of 3D porous ceria cathodes as well as phase field simulations of operating electrodes. 3D microstructure analysis and in-situ electron microscopy will deliver detailed insights into the relevant processes and their interplay. Level of originality/innovation: The high degree of novelty of this proposal arises from the uncommonly large methodological breadth of the contributing groups, which will allow us to understand the behaviour of ceria-based 3D porous SOEC cathodes on the level of elementary properties and atomistic processes of the used materials. We will thus be able to provide the basic understanding for obtaining novel, highest per-forming, long-term stable, and coking resistant ceria-based fuel electrodes, which will push SOEC technology a large step forward.