Investigating carbon formation in solid oxide fuel cell range extenders operating on sustainable alcohol fuels for electric vehicles

能源成本正在上升，英国必须同时解决能源安全和气候变化问题。运输是一个值得关注的问题，因为减少对化石衍生液体燃料的依赖尤其具有挑战性。在交通运输领域，有三种最常被考虑的替代能源载体，生物燃料，氢和燃料电池，以及电池电动汽车。然而，汽车是复杂的消费产品，在理想世界中，替代技术必须具有以下特点：生命周期效率好、成本低、可用性好、二氧化碳净排放量为零、能量密度高、能量转换装置成本低、易于操作、运输和加油。这三种技术都不能单独满足所有这些要求。然而，很明显，在现有基础设施中使用生物燃料和通过插电式混合动力车实现公路车辆电气化，可以在短期内最快地减少公路运输的二氧化碳排放。然而，从长远来看，将需要替代技术。通常考虑完全电气化和氢燃料电池。然而，第四种替代品，可持续液体酒精燃料和固体氧化物燃料电池（sofc）往往被忽视。由于sofc可以用作电动汽车的增程器，并且酒精燃料具有高能量密度，可以克服电动汽车的一些缺点，因此该方法具有协同作用。还可以利用封闭的碳循环，通过大气封存（或短期内从烟道气中捕集二氧化碳）和减少二氧化碳，利用可再生能源生产酒精燃料。利用SOFCs作为固体氧化物电解器（SOEC）产生合成气（一氧化碳和氢气），可以实现二氧化碳的电化学还原，这是通过费托合成（Fischer-Tropsch synthesis）制造燃料的第一步。因此，成功将为氢经济提供一个潜在的替代方案，使用可持续液体燃料和sofc，其优势是能量密度更高，能够与现有的燃料基础设施和发动机技术一起运输和使用，大大降低了转移到新能源载体的风险和成本。实现这一目标需要克服的主要挑战是了解低成本中温sofc中的碳沉积，其中碳形成是一个问题。因此，为了开发能够在酒精燃料上运行的sofc和能够电化学减少CO2的soec，详细了解涉及碳的反应动力学是必要的。现有的电极材料也不足以用于这种应用，对碳形成的科学理解将使新的材料和电极结构得以开发，以减轻碳沉积。研究将涉及新兴技术，如原位拉曼光谱和新的原位技术的发展，以及反应机制的分子模拟和具有可控微纳米形态的新电极材料和结构的发展。为此，固体氧化物技术的发展将是突破性的，并且研究SOEC中电化学还原CO2的机制将是全新的。此外，电化学在soec中减少二氧化碳的成功示范将被转移到其他领域，例如未来的火星机器人甚至载人任务，那里的大气中二氧化碳含量超过95%，并且任务或返程的燃料很可能必须从太阳能和当地资源中就地产生。

Energy costs are rising and the UK must address both energy security and climate change. Transport is a concern as it is particularly challenging to reduce its dependence upon fossil derived liquid fuels. In the transport sector there are three alternative energy carriers that are most often considered, biofuels, hydrogen and fuel cells, and battery electric vehicles. However, vehicles are complex consumer products and the replacement technology must in an ideal world have the following characteristics: good lifecycle efficiency, low cost, good availability, zero net CO2 emissions, high energy density, low cost of energy conversion device, and be easy to handle, transport and refuel. None of the three technologies fulfil all these requirements on their own. However, it is clear that the utilisation of biofuels in existing infrastructure and the electrification of road vehicles via plug in hybrids can deliver the quickest reductions in CO2 emissions from road transport in the near term. However, in the long run alternative technologies will be required. Full electrification and hydrogen fuel cells are often considered. However a fourth alternative, sustainable liquid alcohol fuels and solid oxide fuel cells (SOFCs) are often overlooked. The approach is synergistic as SOFCs can be used as range extenders for electric vehicles and the alcohol fuel with its high energy density can overcome some of the disadvantages of electric vehicles. It is also possible to make the alcohol fuels from renewable energy using a closed carbon cycle via atmospheric sequestration (or in the short term CO2 capture from flue gas) and reduction of CO2. Electrochemical reduction of CO2 is possible using SOFCs as solid oxide electrolysers (SOEC) to produce syngas (carbon monoxide and hydrogen) which is the first step in making a fuel via Fischer-Tropsch synthesis. Success will therefore offer a potential alternative to a hydrogen economy using sustainable liquid fuels and SOFCs with the advantage of higher energy densities and the ability to be transported in and used with existing fuel infrastructure and engine technologies, significantly reducing the risk and cost of transferring to a new energy carrier.Major challenges that need to be overcome to realise this are understanding carbon deposition in low cost intermediate temperature SOFCs, where carbon formation is a problem. A detailed understanding of the reaction kinetics involving carbon is therefore necessary in order to develop both SOFCs capable of operating on alcohol fuels and SOECs that can electrochemically reduce CO2. Existing electrode materials are also insufficient for this application, and developing a scientific understanding of carbon formation will enable new materials and electrode structures to be developed to mitigate carbon deposition. Investigations will involve emerging techniques such as in-situ Raman spectroscopy and the development of new in-situ techniques, alongside molecular modelling of reaction mechanisms and the development of new electrode materials and structures with controlled micro and nano morphologies.The development of solid oxide technology for this purpose will be groundbreaking, and investigating the mechanism for electrochemical reduction of CO2 in an SOEC entirely novel. In addition, the successful demonstration of electrochemical reduction of CO2 in SOECs will be transferrable to other areas, such as future robotic and even manned missions to Mars, where the atmosphere is over 95% CO2, and where fuel to power missions or a return trip will most likely have to generated in-situ from solar energy and local resources.