Novel monomers from sugars: synthesis, catalysis, polymerisation and applications in degradable electronics

本博士的研究主题将是从糖中合成新型可降解聚合物及其在能源应用中的应用，即电池技术。目前，主流的锂离子电池（lib）以及新一代电池都依赖于水电解质在电极之间传输阳离子。由于一些原因，这些类型的电池引起了严重的安全问题。另一方面，固体聚合物电解质（spe）是一种很有前途的替代电解质材料，它可以提供高的机械强度、柔韧性和比其他固体电解质（如陶瓷）更低的成本。聚乙烯氧化物（PEO）作为一种SPE材料得到了大量的研究，PEO的离子电导率模型也得到了很好的理解。然而，虽然PEO是锂离子的良导体，但它确实有一些局限性，这意味着它在任何现实的未来电池应用中都不是一种合适的材料。为了开发未来的聚乙烯基电池，需要新的材料来改善聚合物（如PEO）的性能。聚碳酸酯具有高离子电导率的潜力，是一种很有前途的SPE材料聚合物。它们也可以从天然原料中获得，并且在使用寿命结束时具有生物降解性的优势。然而，聚碳酸酯难以功能化，因此难以调整到所需的性能。布查德小组已经有了一个可持续聚碳酸酯的平台，该平台是由二氧化碳与来自糖的可再生二醇反应制成的。这些聚合物在碳主链上也具有烯烃功能化，具有从可再生原料中开发新型可生物降解的SPE材料的潜在理想。这项研究将着眼于评估这些聚合物在不同结晶度、分子量、烯烃顺反比等方面的锂离子导电能力。烯烃键也将被功能化（聚合后），加入锂配位基和/或任何其他官能团，这将为聚合物提供理想的spe性能。此外，在碳酸盐部分用硫取代氧，得到单硫代碳酸盐和黄药单体，也将作为获得更好聚合物性能的SPE材料的一种方式进行探索。随着新型聚合物的成功合成，将进行严格的机械和物理化学表征，其中多核核磁共振，质谱（MALDI），尺寸排除色谱（SEC），差示扫描量热法（DSC）， x射线散射和应力/应变测试将是重要的技术。然后将与F. Marken教授（巴斯大学的第二导师）合作，通过离子电导率和循环伏安法测量，研究锂盐聚合物的电化学特性。与D. Mercerreyes教授（西班牙巴斯克大分子设计与工程中心）合作，将在构建真正的硬币电池装置中提出有前途的材料。我们的新聚合物作为SPE材料的应用将在lib中进行测试，也将在其他有前途的电池类型中进行测试，如Li-S和na离子电池。其他能源应用也将被考虑，例如烯烃键的功能化与导电有机基序，用于合成用于有机光伏器件的新型聚合物。这项工作将有可能与剑桥大学的H. Bronstein博士合作。

The topic of research for this PhD will be the synthesis of novel degradable polymers sourced from sugars and their applications in energy applications, namely battery technology. Currently, mainstream lithium-ion batteries (LIBs) as well as new generation batteries rely on aqueous electrolytes to transport cations between the electrodes. These types of batteries pose serious safety concerns for a number of reasons. On the other hand, solid polymer electrolytes (SPEs) are a promising class of alternative electrolyte materials which can offer high mechanical strength, flexibility and a lower cost than other solid electrolytes such as ceramics.Polyethylene oxide (PEO) has been heavily studied as a SPE material and the model for the ionic conductivity of PEO is well understood. However, whilst PEO is a good conductor of lithium ions, it does have some limitations that means it will not be a suitable material in any realistic future battery applications. In order to develop future SPE-based batteries, novel materials are needed which can improve upon the properties of polymers such as PEO.Polycarbonates have been shown to be a promising class of polymers for SPE materials with the potential for high ionic conductivity. They can also be sourced from natural feedstocks and have the advantage of biodegradability for their end of life. However, polycarbonates can be difficult to functionalise and therefore difficult to tune for desired properties.The Buchard group already has a platform of sustainable polycarbonates made from the reaction of CO2 with renewable diols from sugars. These polymers also have alkene functionalisation in the carbon backbone with the potential ideal for developing novel biodegradable SPE materials from renewable feedstocks. This research will look to assess the lithium-ion conducting capabilities of these polymers with varying degrees of crystallinity, molecular weight, cis/trans ratios of the alkene, etc. The alkene bond will also be functionalised (post-polymerisation) to incorporate lithium-coordinating groups and/or any other functional groups which will provide the polymer with properties ideal for SPEs. Moreover, the replacement of oxygen with sulfur in the carbonate moiety, giving monothiocarbonate and xanthate monomers, will also be explored as a way to access better polymer properties for SPE materials.Following the successful synthesis of novel polymers, rigorous mechanical and physicochemical characterisation will be performed, for which multinuclear NMR, mass spectrometry (MALDI), Size-Exclusion Chromatography (SEC), Differential Scanning Calorimetry (DSC), X-ray scattering and stress/strain tests will be important techniques. Electrochemical characterisation of the polymers with lithium salts will then be investigated, in collaboration with Prof F. Marken (second supervisor at Bath), via ionic conductivity and cyclic voltammetry measurements. Promising materials will be put forward in the construction of real coin cell devices in collaboration with Prof D. Mercerreyes (Basque Center for Macromolecular Design and Engineering, Spain). The application of our new polymers as SPE materials will be tested in LIBs but also in other promising battery types, such as Li-S and Na-ion batteries. Other energy applications will also be considered, such as the functionalisation of the alkene bond with conducting organic motifs for the synthesis of novel polymers for uses in organic photovoltaic devices. This work will have the potential for collaboration with Dr H. Bronstein in Cambridge.