AMorphous Silicon Alloy Anodes for Multiple Battery Systems - "AMorpheuS"

锂离子电池（lib）的碳阳极被认为是阻碍锂离子电池成为运输应用（需要更高容量以延长行驶里程）或电网存储应用（需要长循环寿命）的可行选择的一个限制因素。与碳相比，硅的能量密度要高得多，近年来一直是研究的重点，刺激了Amprius和Nexeon等备受瞩目、高投资的大学衍生公司的形成。硅是地壳中第二丰富的元素，因此从成本和可用性的角度来看，它是一种可持续的电池材料。然而，尽管它对锂离子电池具有理想的性能，但它也以其缺点而闻名，即大体积膨胀，粉碎和通过与电解质（锂离子扩散）的化学反应持续的锂损失。这种现象阻碍了这种材料在商用锂离子电池中的广泛应用，尽管全球无数的研究小组正在努力寻找使其可行的方法，例如通过纳米结构。AMorpheuS计划提出了一种制造硅阳极的替代方法，不依赖于复杂、昂贵的纳米结构或试图控制电极结构。该方法简单地使用电沉积方法从溶液中沉积，并使用聚合物化学钝化非晶薄膜，这种聚合物化学物质已经被证明是有效的硅电极粘合剂。在实际的电池运行过程中，对这些电极的结构和表面特性有一个基本的了解，从而确定最佳的硅合金和聚合物化学，并合理地优化性能。该项目将开发不仅用于锂离子系统的硅电极，还可以在钠离子和锂硫电池中进行可逆循环。各种硅合金化学将被探索，包括硅-锡合金，因为这些显示出相当大的希望作为钠离子电池的阳极。目标是开发第一个硅基钠阳极。这种灵活性为各种新兴电池系统（分别为锂离子、钠离子和锂离子）的高能量、可持续和更安全技术提供了许多技术转移机会。新电池将在英国第一个非商业环境的全电池原型生产线上进行测试。完全理解电池在充电/放电时发生了什么是很复杂的。电池是一个具有不断变化的域的封闭系统。该项目成功的核心是原位表征技术的应用，用于分析锂离子在阳极和阴极之间来回传递（或为什么它们没有）时发生的实时、动态结构和表面变化。这些知识随后将指导电极设计的持续改进。为了全面了解电池充电/放电时发生的化学反应，提出的主要技术是多核核磁共振和x射线计算机断层扫描。这些技术为电池研究人员提供了大量重要的实时洞察，特别是关于硅材料的失效机制。AMorpheuS项目的方法将减少对电极材料的额外加工需求，例如：(1)高表面积碳（需要高能量混合工艺）和(2)工业标准粘合剂（需要有毒溶剂才能将其加工成涂层）。这一策略将减少生产时间并消除有毒化学品。这些改进将显著降低制造成本，提高英国的能源安全。

Carbon anodes for Li-ion batteries (LIBs) are regarded as one limiting factor preventing Li-ion batteries from being a viable option for transport applications (which require higher capacity for extended driving ranges) or grid storage applications (which require long cycle life). Compared to carbon, silicon has a much higher energy density and has been the focus of considerable research effort in recent years, stimulating the formation of high-profile, high-investment university spin-out companies such as Amprius and Nexeon. Silicon is the second most abundant element in the earth's crust and is thus a sustainable battery material candidate from a cost and availability perspective. However, despite its desirable properties for Li-ion batteries, it is also renowned for its drawbacks, namely large volume expansion, pulverisation and continued lithium loss through chemical reactions with the electrolyte (which the lithium ions diffuse in). Such phenomena have hindered the successful widespread uptake of this material in commercial Li-ion batteries, despite the myriad of global research groups working on finding ways to make it viable, e.g. by nano-structuring. Project AMorpheuS presents an alternative way to fabricate Si anodes that does not rely on complex, costly nanostructuring or attempting to control electrode architectures. The approach is simply to deposit from solution using electrodeposition methods and to passivate the amorphous thin films with polymer chemistries that have already been shown to be effective as binders for Si electrodes. A fundamental understanding of the structural and surface properties of these electrodes will be obtained during realistic battery operation so as to identify the optimum Si alloy and polymer chemistry and optimise performance rationally. This project will develop Si electrodes that are not exclusively destined for use in Li-ion systems but can also be reversibly cycled in Na-ion and Li-S batteries. A variety of Si-alloy chemistries will be explored, including Si-Sn alloys, since these show considerable promise as anodes for Na-ion batteries. A goal is to develop the first Si-based Na anode. This flexibility opens up numerous technology transfer opportunities in a variety of emerging battery systems focused on higher energy, sustainable, and safer technologies (e.g. Li-ion, Na-ion and LiS, respectively). The new batteries will be tested in the UK's first full battery prototyping line in a non-commercial environment. Fully understanding what occurs in a battery as it is charged / discharged is complex. The battery is a closed system with constantly changing domains. Central to the success of this project is the application of in-situ characterisation techniques for analysing real-time, dynamic structural and surface changes that occur as Li ions pass back and forth between the anode and cathode (or why they do not). This knowledge will subsequently guide continued improvements in electrode designs. The major techniques proposed to gain a comprehensive understanding of the chemistry occurring in the battery as it is charged/discharged are multinuclear NMR and X-ray computed tomography. These techniques have provided battery researchers with a wealth of vital, real-time insight - especially regarding failure mechanisms in silicon materials. Project AMorpheuS's approach will reduce the need for additional processing of materials in the electrodes, e.g., (i) high surface area carbons (which need energy-intense mixing processes) and (ii) industry-standard binders (which require toxic solvents to enable them to be processed into coatings). This strategy will reduce production time and eliminate toxic chemicals. These improvements will significantly reduce manufacturing cost and increase the UK's energy security.