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

交通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脱碳。这就是我们进入令人兴奋的“结构动力复合材料”领域的地方，它既可以作为结构材料，也可以作为储能设备。帝国理工学院伦敦结构功率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。这些通常利用通过将环氧树脂与离子液体（IL）混合而制成的电解质，然而，微观结构水平的问题仍然存在，由此碳纤维被电解质的结构相包覆。改进结构电解质仍然是与该领域相关的最大挑战之一。这是因为具有高离子电导率的材料通常具有较差的机械性能，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将热塑性塑料（TP）引入电解质中来扩展结构超级电容器的工作，最终目标是改善这些设备的机械和电化学性能。使用TP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：什么TP适合用于结构电解质？TP的使用能否带来诸如重量更轻的储能设备等好处？在电解质中使用TP可以以更低的成本和更大的规模制造结构超级电容器吗？我们可以回收TP基结构电解质吗？将采用的主要策略是：i）将TP与离子液体共混或ii）多孔TP与液体电解质如水性电解质、离子液体、锂盐溶液共混。该项目的第一阶段将是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”。目的是进行这些TP在离子液体中的溶解度测试，首先通过观察将两者混合在一起时的行为进行定性，然后进行定量。KAT极性标度本质上是一个使用极性、酸度和碱度描述溶剂性质的系统，可用于量化TP在离子液体中的溶解度。这些HPTP的KAT参数在文献中并不广泛，因此本研究项目旨在为更广泛的科学界找到并发布它们。在获得了一些常见的HPTP的KAT参数后，将进行系统的工作，以首次构建不同HPTP/IL体系的两相相图。这些基本上显示了HPTP和IL的不同组合如何相互作用。HPTP通常在高温下加工，这在将HPTP与IL共混时可能由于后者的可能降解而引起并发症。因此，重要的是通过实验研究入围的HPTP的加工窗口，以缩小对最佳结构电解质的搜索。在最终确定HPTP和IL的可能候选物之后，下一个目标将是优化HPTP和IL共混物的结构，使得它们充分混合和互连。将通过“扫描电子显微镜”研究获得的形态，并研究结构电解质的全部机械和电化学性能。总之，向TP开放结构电解质的研究可能会彻底改变该领域，使我们更接近绿色，更可持续的航空。

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.