Ceria-based Cathodes for High Performance Electrolysis Cells

更广泛的研究背景/理论框架：在高温固体氧化物电解电池（SOEC）中分解H2O和CO2是一种高效且有前途的生产绿色H2和CO的方法。新型铈基阴极具有高电催化活性，低降解率和低焦化敏感性，因此有可能使SOEC技术向前迈出一大步。因此，详细了解电化学性能、三维微观结构和铈基阴极力学行为之间复杂的相互关系是必不可少的。假设/研究问题/目标：我们提出了两种策略来获得制造这种高性能和长期稳定的基于二氧化铈的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，通过氧化还原诱导的自修饰来制备Ni/ gd掺杂的CeO2 （GDC）电极，在此过程中，铈相部分超过Ni颗粒。这提供了高的焦化耐受性，机械强度和大GDC表面积高电催化活性。其次，我们将利用GDC在还原条件下的混合离子/电子电导率来开发具有单相GDC活性层的新型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，以深入了解机械行为。途径/方法：为了实现我们的目标，我们将实施一个跨学科的工作计划，与专业研究小组紧密合作，他们已经在联合项目中有了显著的合作经验。成功的关键是了解基于二氧化铈的SOEC阴极的原子水平，并利用这些知识有针对性地设计新的加工路线。我们将使用模型系统进行基本的材料表征，并直接将结果转移到3D多孔铈阴极的加工以及操作电极的相场模拟中。3D微观结构分析和原位电子显微镜将提供有关过程及其相互作用的详细见解。原创性/创新水平：该提案的高度新颖性源于贡献小组的不同寻常的大方法广度，这将使我们能够理解基于二氧化铈的3D多孔SOEC阴极在基本性质和所用材料原子过程水平上的行为。因此，我们将能够为获得新型的、高性能的、长期稳定的、抗结焦的铈基燃料电极提供基本的理解，这将推动SOEC技术向前迈出一大步。

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.