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。运输是一个令人关切的问题，因为减少对化石衍生液体燃料的依赖特别具有挑战性。在运输部门，最常考虑的替代能源载体有三种：生物燃料、氢和燃料电池以及电池电动汽车。然而，车辆是复杂的消费品，理想情况下，替代技术必须具有以下特征：良好的生命周期效率，低成本，良好的可用性，零净CO2排放，高能量密度，低成本的能量转换设备，以及易于处理，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以及通过插电式混合动力汽车实现道路车辆的电气化，可以在短期内最快地减少道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，可持续液体醇燃料和固体氧化物燃料电池（SOFC）往往被忽视。该方法是协同的，因为SOFC可以用作电动汽车的增程剂，并且具有高能量密度的醇燃料可以克服电动汽车的一些缺点。也可以通过大气封存（或短期内从烟道气中捕获CO2）和减少CO2，使用封闭的碳循环从可再生能源中制造醇燃料。使用SOFC作为固体氧化物电解器（SOEC）以产生合成气（一氧化碳和氢气）可以电化学还原CO2，这是通过费托合成制备燃料的第一步。因此，成功将为使用可持续液体燃料和固体氧化物燃料电池的氢经济提供一种潜在的替代方案，其优点是能量密度更高，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，显著降低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间体中的碳沉积。高温SOFC，其中碳的形成是一个问题。因此，为了开发能够在醇燃料上操作的SOFC和能够电化学还原CO2的SOEC，需要详细了解涉及碳的反应动力学。现有的电极材料也不足以用于该应用，并且发展对碳形成的科学理解将使得能够开发新的材料和电极结构以减轻碳沉积。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建模和新的电极材料和结构的发展与控制的微米和纳米形态。为此目的的固体氧化物技术的发展将是开创性的，并研究在SOEC中电化学还原CO2的机制是全新的。此外，SOEC中电化学还原CO2的成功示范将可转移到其他领域，例如未来的机器人甚至载人火星任务，那里的大气层超过95% CO2，并且为任务或回程提供动力的燃料很可能必须从太阳能和当地资源就地产生。

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.