New Multifunctional Thermoplastic Polymer Nanocomposites for Structural Power Materials, Towards Green Aviation

运输部门是温室气体的重要贡献者，这些系统的电气化无疑将有助于大气的脱碳。这就是我们进入‘结构动力复合材料’这一令人兴奋的领域的地方，它既可以作为结构材料，也可以作为储能装置。伦敦帝国理工学院结构电力复合材料小组已经在结构超级电容器的开发方面取得了重大进展。它们通常使用一种由环氧树脂和离子液体(IL)混合而成的电解液，然而，微观结构层面的问题仍然存在，即碳纤维被电解液的结构相覆盖。改进结构电解液仍然是该领域面临的最大挑战之一。这是因为具有高离子导电性的材料通常机械性能较差，反之亦然，因此很难在两者之间获得良好的平衡。本研究的主要目的是通过在电解液中加入热塑性塑料(TPS)来扩展在结构超级电容器方面所做的工作，最终目标是提高这些器件的机械和电化学性能。使用TPS的其他好处包括：更高的韧性、更好的可回收性和更高的化学稳定性。该项目打算回答的一些问题是：哪些TPS适合用于结构电解液？使用TPS是否可以提供诸如更轻的储能设备等好处？在电解液中使用TPS能否以更低的成本和更大的规模制造结构性超级电容器？我们可以回收基于TP的结构电解液吗？将采用的主要策略是：i)将TPS与离子液体混合或ii)将多孔TPS与液体电解质(如水溶液、离子液体、锂盐溶液)回填。该项目的第一阶段将根据一些标准选择合适的高性能热塑性塑料(HPTP)，如“玻璃化转变温度”、“熔融温度”和“单位质量价格”。目标是进行这些TPS在离子液体中的溶解度测试，首先定性地观察两者混合时的行为，然后进行定量。Kat极性标度本质上是一个用极性、酸度和碱度来描述溶剂性质的体系，可以用来定量TP在离子液体中的溶解度。这些用于HPTP的KAT参数在文献中并不广泛可用，因此本研究项目旨在为更广泛的科学界找到并发布它们。在获得一些常见HPTP的Kat参数后，将首次系统地建立不同HPTP/IL体系的两相相图。这些基本上显示了HPTP和IL的不同组合是如何相互作用的。HPTP通常在高温下加工，当HPTP与IL混合时，由于后者可能被降解，这可能会导致并发症。因此，对入围的HPTP的加工窗口进行实验研究，以缩小寻找最佳结构电解液的范围，将是非常重要的。在敲定可能的高压热泵和离子液体的候选方案后，下一个目标将是优化高压热泵和离子液体混合物的结构，使它们完全混合和相互连接。将用扫描电子显微镜研究所获得的形貌，并将研究结构电解液的全部机械和电化学性质。总而言之，将结构电解液的研究开放给TPS可能会给该领域带来潜在的革命性变化，使我们离更环保、更可持续的航空更近一步。

The transport sector is a significant contributor to greenhouse gases, and electrification of these systems would undoubtedly help to decarbonize the atmosphere. This is where we enter the exciting field of 'Structural Power Composites' which act as both structural materials and energy storage devices. The Imperial College London Structural Power Composites group has already made significant progress in the development of structural supercapacitors. These typically utilize an electrolyte that is made by mixing an epoxy with an Ionic Liquid (IL), however, issues at the microstructural level persist whereby carbon fibers are being sheathed by the structural phase of the electrolyte. Improving the structural electrolyte is still one of the biggest challenges associated with the field. This is because materials with high ionic conductivity typically have poor mechanical performance and vice-versa, so it is difficult to obtain a good balance between the two.The primary aim of this research is to extend the work done on structural supercapacitors by incorporating thermoplastics (TPs) into the electrolyte with the ultimate goal being to improve both the mechanical and electrochemical performance of these devices. Other benefits of using TPs include: higher toughness, improved recyclability and higher chemical stability. Some of the questions that the project intends to answer are: What TPs are suitable to be used in structural electrolytes? Can the use of TPs offer benefits such as lighter-weight energy storage devices? Can structural supercapacitors be manufactured at a lower cost and at a larger scale using TPs in the electrolyte? Can we recycle TP-based structural electrolytes? The main strategies that will be employed are: i) blending TPs with ionic liquids or ii) backfilling porous TPs with liquid electrolytes like aqueous electrolytes, ionic liquids, lithium salts solutions. The first stage of the project will be to select suitable high-performance thermoplastics (HPTPs) based on a few criteria such as the 'glass transition temperature', 'melting temperature', and 'price per unit mass'. The objective will be to conduct solubility tests of these TPs in the ionic liquids, initially qualitatively by observing the behavior when mixing the two together and then quantitatively. The KAT polarity scale is essentially a system that depicts solvent properties using polarity, acidity, and basicity and can be used to quantify the solubility of a TP in an ionic liquid. These KAT parameters for HPTPs are not widely available in the literature and so this research project aims to find and publish them for the wider scientific community. After obtaining the KAT parameters for some common HPTPs, systematic work will be done to build, for the first time, bi-phasic phase diagrams for different HPTP/IL systems. These essentially show how different combinations of HPTPs and IL interact with each other. HPTPs are typically processed at high temperatures which could cause complications when blending the HPTP with the IL, due to possible degradation of the latter. It will therefore be important to study the processing window of the shortlisted HPTPs experimentally, to narrow down the search for the optimal structural electrolyte. After finalizing the possible candidates of HPTPs and ILs, the next objective will be to optimize the structure of the HPTP and IL blends such that they are thoroughly mixed and interconnected. The morphologies obtained will be studied by 'Scanning Electron Microscopy' and the full mechanical and electrochemical properties of the structural electrolyte will be investigated. In conclusion, opening the research on structural electrolytes to TPs could potentially revolutionize the field, bringing us one step closer to greener, more sustainable aviation.