Cathode-solid electrolyte interface in solid-state batteries

传统的锂离子电池化学正在接近其物理化学极限。需要采用高能活性材料来开发高能量密度、低成本和安全的电池，以满足不断扩大的电动汽车市场的需求，并为电动飞行等新应用提供动力。这可以通过用固体电解质代替有机液体电解质来实现，并且能够在全固态电池（SSB）配置中安全地实现Li金属阳极。SSB中的主要挑战是设计具有足够顺应性的阴极，使得当活性颗粒膨胀或收缩时避免高应力，以便在充电和放电时保持接触。商业阴极是强氧化性的，因此通常在界面处降解固体电解质，特别是硫化物基固体电解质。已经研究了陶瓷涂层以抑制反应性，但是机械问题仍然存在。作为阴极颗粒涂层的聚合物，具有机械性能、粘附性、离子电导率和低界面阻抗的必要组合，可以帮助在循环时保持固体电解质和阴极颗粒之间的接触，同时最小化其对倍率性能的影响。在该项目中，将研究阴极/固体电解质界面作为充电状态、循环、电流密度、温度和压力学生将接受电化学表征（3电极电池）和阻抗谱，等离子体FIB SEM，样品细化和TEM，操作X射线断层扫描和XPS的形态学研究的培训。等静压将与电化学相结合，以建立复合材料的机械响应。该项目属于EPSRC能源研究领域的福尔斯。这一主题的目的是让英国实现其环境和能源目标。

The conventional Li-ion battery chemistry is approaching its physicochemical limit. High energy active materials need to be implemented to develop the high energy density, low-cost and safe batteries that can meet the requirements of the expanding electric vehicle market and empower novel applications such as electric flight. This could be achieved by replacing the organic liquid electrolyte with a solid electrolyte and enabling the safe implementation of Li-metal anodes in an all-solid-state battery (SSBs) configuration. A major challenge in SSBs is to design cathodes with sufficient compliance so that high stresses are avoided when active particles swell or contract, in order to maintain contact upon charge and discharge. Commercial cathodes are strongly oxidising, and thus generally degrade solid electrolytes at interfaces, especially sulphide-based solid electrolytes. Ceramic coatings have been investigated to suppress reactivity, but the mechanical problems remain. A polymer, as a cathode particle coating, with the necessary combination of mechanical properties, adhesion, ionic conductivity and low interfacial impedance, could help maintain contact between the solid electrolyte and the cathode particles upon cycling while minimising its impact on rate capability.In this project, the cathode/solid electrolyte interface will be studied as a function of charge state, cycling, current density, temperature, and pressure. The student will be trained on electrochemical characterisation (3-electrodes cells) and impedance spectroscopy, morphology studies by plasma-FIB SEM, sample thinning and TEM, operando X-ray tomography and XPS. Isostatic pressing will be combined with electrochemistry to establish the mechanical responses of composites. This project falls within the EPSRC Energy research area. The aim of this theme is for the UK to meet its environmental and energy targets.