Evaluating organic mixed-conductor materials for sustainable electrochemical energy storage

实现可再生电力资源的全部潜力将需要新的、可持续的和高性能的材料，用于电池和超级电容器的电化学储能。有机电子和离子传输材料因其丰富、低成本、低毒性、机械性能以及易于制造和回收而成为电极和电解液的候选材料[1]。共轭聚合物特别适合用作电池或超级电容器设备的电极。它们快速充电和放电，在许多循环中都是稳定的，并且使用无毒的盐水电解液[2]，尽管它们的比容量仍然有限[3]。一旦正确理解了它们的作用机制，就可以通过化学设计来调整它们的性质。因此，基于聚合物的电极材料将使一种全新的低环境影响的电化学存储技术成为可能。在这个项目中，我们的目标是通过在微观水平上更深入地了解离子、电子和分子之间的相互作用以及充电过程，并利用这些想法来开发新的材料设计，来提高共轭聚合物电极的电化学存储性能。我们将利用电化学和光谱方法研究基于不同材料的聚合物电极的离子传输和充电特性、比容量、氧化还原稳定性和微观结构，并寻求将观察结果与化学结构和能量学联系起来。这些结果将有助于确定合适的电极材料，并在简单的电池设备中进行测试。学生将有机会使用计算方法(可能包括器件模型、电子结构和分子动力学)来解释实验测量。关键问题是：-最终限制共轭聚合物电极容量的是什么？-化学结构和影响操作稳定性的是什么？-更高性能的材料和器件结构的化学设计规则是什么？这项研究的最终目标是通过探索储存和使用可再生能源的选择，为全球气候稳定努力做出贡献。

Realising the full potential of renewable electricity resources will require new, sustainable and high-performance materials for electrochemical energy storage in batteries and supercapacitors. Organic electron- and ion-transporting materials are interesting candidates for both electrodes and electrolytes because of their abundance, low cost, low toxicity, mechanical properties and the potential ease of both manufacture and recycling [1]. Conjugated polymers are particularly attractive for use as electrodes in battery or supercapacitor devices. They charge and discharge rapidly, are stable over many cycles and work with non-toxic salt-water electrolytes [2], although their specific capacity is still limited [3]. Their properties can be tuned via chemical design, once their operational mechanisms are properly understood. Polymer-based electrode materials would thus enable a completely new electrochemical storage technology of low environmental impact. In this project we aim to improve the electrochemical storage properties of conjugated polymer-based electrodes by developing a deeper understanding of the interactions between ions, electrons and molecules and of the charging process at a microscopic level and using these ideas to develop new material designs. We will study the ion transport and charging characteristics, specific capacity, redox stability and microstructure of polymer electrodes based on different materials using electrochemical and spectroscopic methods; and seek to relate the observations to chemical structure and energetics. These results will help to identify suitable electrode materials and test them within simple battery devices. The student will have the opportunity to use computational methods (possibly including device models, electronic structure and molecular dynamics) to interpret experimental measurements.The key questions are:- What ultimately limits the capacity of a conjugated polymer electrode?- How does chemical structure and influence operational stability?- What are the chemical design rules for higher performing materials and device architectures? The ultimate goal of this research is to contribute to global climate stabilisation efforts, by exploring the options for storage and use of renewable energy.