Microwave processing for fast, green preparation of insertion electrodes

应对气候变化的任务，加上化石燃料供应的减少，将电化学存储推向了材料研究的前沿。随着便携式电子产品数量的不断增加和混合动力汽车的发展，锂离子电池对于我们日益增长的能源需求具有巨大的重要性和持续的兴趣。在这一关键的研究领域仍然存在挑战，本提案将解决这一问题。在这里，我将结合储能和纳米技术领域，提供高度结晶的纳米颗粒，可以用作锂离子电池的正极。要制备的电极是插入式化合物；它们包含锂离子，在随后的放电和充电循环中，锂离子可以在阴极(正极)和阳极(负极)之间穿梭。因为这些过程重复了许多次，我们必须考虑这些电极结构退化的可能性，这会导致随着时间的推移而失去电力。在解决这些问题的同时，我们还希望使用既环保又具有成本效益的材料和方法。我在EPSRC First Grant中提出的研究将解决这些重要问题，方法是使用创新的合成方法来制备结晶度高的纳米颗粒，这将优化性能，同时铁(而不是常用的钴)作为氧化还原活性金属，既无毒又廉价。传统的固相合成方法需要在非常高的温度(~1000摄氏度)下进行长时间的反应，通常会产生大而大的颗粒。在这里，我将使用微波来驱动我的反应。与更传统的方法相比，这种方法提供的优势包括快速反应的高升温速率，对反应条件的自动控制，以及允许形成小的、均匀的、高度结晶的颗粒的增强的反应动力学。这项提议的新颖性在于使用新的醇铁前驱体作为我的反应的起始材料。这是这种起始材料首次与微波结合使用来制备电池电极，由于它们的反应性，我预计这些化合物的反应速度会更快。这可能会开辟一个新的研究领域，因为这种化学的一个令人兴奋的前景是有可能设计出包含未来所有所需最终材料成分的量身定制的前体。通过使用这些合成路线(微波与醇盐相结合)，我将开发出清洁的路线，以获得几乎没有缺陷的高度结晶的材料，从而优化电池性能。这些颗粒的超小尺寸将缩短锂离子必须传播的扩散路径，并增加电极和电解液之间的相互作用，所有这些都将促进有效的电化学。通过这种方式，我的团队将为英国在能源研究方面的强大研究努力增添一个新的维度，并确立我们作为纳米颗粒开发和应用领域的领导者的地位。

The task of tackling climate change, coupled with the diminishing supplies of fossil fuels, has propelled electrochemical storage to the forefront of materials research. With the ever-increasing number of portable electronics and developments of hybrid electric vehicles, Li ion batteries are of immense importance and continued interest for our growing energy needs. Challenges remain in this critical research area, which this proposal will address. Here, I will combine the fields of energy storage and nanotechnology to provide highly crystalline nanoparticles which can be employed as positive electrodes in Li ion batteries. The electrodes to be prepared are insertion compounds; they house lithium ions which may be shuttled between the cathode (positive electrode) and anode (negative electrode) during subsequent discharge and charge cycles. Because these processes are repeated many times over, we must consider the possibility of structural degradation of these electrodes which leads to a loss of power over time. While tackling these concerns, we also want to use materials and methods which are both environmentally benign and cost effective. The research I propose in this EPSRC First Grant will tackle these important issues by using innovative synthetic methods to prepare nanoparticles of high crystallinity, which will optimise performance, together with iron (instead of the commonly used cobalt) as the redox active metal, which is both non-toxic and cheap. Traditional approaches to solid-state synthesis involve long reaction times at very high temperatures (~1000 C), often yielding large, bulk particles. Here, I will use microwaves to drive my reactions. The advantages this method provides over more traditional routes include high heating rates for faster reactions, automated control over reaction conditions, and enhanced reaction kinetics allowing for the formation of small, uniform, highly crystalline particles. Adding to the novelty of this proposal is the use of new iron alkoxide precursors as starting materials for my reactions. This is the first time such starting materials will be used in combination with microwaves to prepare battery electrodes and due to their reactivity, I expect faster reaction rates for these compounds. This could open up a new area of research since an exciting prospect of this chemistry is the possibility of designing tailored precursors which contain all desired end-material components in the future. By using these synthetic routes (microwaves in combination with alkoxides), I will develop clean routes to highly crystalline materials with little defects and therefore optimised battery behaviour. The ultrasmall sizes of these particles will decrease the diffusion pathlengths the lithium ions must travel and also increase interactions between the electrode and the electrolyte, all of which will promote efficient electrochemistry. In this manner, my group will add a new dimension to the strong research effort on energy research in the UK and establish ourselves as leaders in the field of nanoparticle development and application.