Multiscale in-situ characterisation of degradation and reactivity in solid oxide fuel cells

随着替代能源和低碳能源技术在国际上的重要性日益增加，关于最适当的发电技术解决方案存在着相当大的辩论。对于功率输出在kW至MW范围内的分布式发电方案，固体氧化物燃料电池（SOFC）是领先的竞争者，许多国际公司进行了开发。与新技术相关的一个领域是器件的寿命，并且由于SOFC在高温下运行，任何组件的退化都可能加速。由于这些设备的复杂性，已经有有限的范围来分析现场的SOFC的操作，并从这个确定降解过程的机械信息。固体氧化物燃料电池的降解和反应性可以通过发生在各种长度尺度上的过程来表征，从原子尺度上的化学反应和扩散过程到表面化学，功能层中的应力和超过mm和cm的热管理。每个过程都有助于整体电池降解，但可能会根据相关的功能组件而不同地演变-因此阳极和阴极过程将显着不同。由于这些是表征这些过程的复杂装置，并且它们的起源具有挑战性，并且目前来自尸检分析。虽然这是了解设备故障的一种途径，但在操作条件下的现场表征将提供详细的直接理解。我们的方法是开发一个互补的技术组合，将允许使用衍射，光谱，离子散射，建模和发射率测量设备操作的详细研究。我们将解决燃料电池中已知的退化问题，包括阴极的碳酸盐和铬中毒，阳极上的碳形成和电极分层，并将与英国超级燃料电池计划密切互动。通过该计划，我们将能够向工业合作伙伴提供缓解策略，以最大限度地减少设备退化，并将这些信息用于开发新材料。

As alternative and low carbon energy technologies are of increasing international importance there is considerable debate as to the most appropriate technology solutions for power generation. For a distrubted generation scenario with power output in the range of kW to MW the solid oxide fuel cell (SOFC) is a leading contender, with development undertaken by many international companies. One of the areas of concern with new technologies is the lifetime of the device and as SOFCs operate at elevated temperatures any degradation of components may be accelerated. Due to the complexity of these devices there has been limited scope to analyse the operation of the SOFC in-situ, and from this determine mechanistic information on degradation processes. It is the aim of this proposal to tackle this challenge.Degradation and reactivity of solid oxide fuel cells may be characterised by processes occuring on a variety of length scales, from chemical reactivity and diffusion processes on the atomic scale through surface chemsitry, stress in functional layers and thermal management over mm and cm. Each of the processes contributes to the overall cell degradation, but may evolve differently depending on the functional component concerned - hence anode and cathode processes will be significantly different. As these are complex devices characterising these processes and the origin of them is challenging and currently results from post-mortem analysis. Whilst this is one route to understanding the failure of devices, an in-situ characterisation under operating conditions will provide detailed direct understanding. Our approach is to develop a combination of complimentary techniques that will allow detailed study of device operation using diffraction, spectroscopy, ion scattering, modelling and emissivity measurements. We will tackle known degradation issues in fuel cells including carbonate and Cr poisoning of cathodes, carbon formation on anodes and electrode delamination and will interact strongly with the UK Supergen Fuel Cells programme. As a result of this programme we will be able to inform industrial partners of mitigation strategies to minimise device degradation and use this information in development of new materials.