Cathode-solid electrolyte interfaces

阴极-固体电解质界面

• 批准号: 2285723
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2285723
• 关键词: Cathode; solid; electrolyte; interfaces

A major challange in all-solid-state batteries is to design cathodes with sufficient compliance that high stresses are avoided when active particles swell or contract, so that contact is maintained upon charge and discharge. Practical cathodes like NMC are strongly oxidising, and so generally degrade solid electrolytes at interfaces. LiTaO3 and LiNbO3 coatings have been investigated to suppress reactivity, but the mechanical problems remain. Ceramic coatings are not compliant, and tend to detach as active particles charge or discharge. To understand the impact of volume changes within composite electrodes the student will compare directly zero-strain active materials, such as Li4Ti5O12, with volume-change materials, e.g. LixNb16W5O55 and LixTiS2. This will decouple volume effects from surface phenomena. The project will focus on sulphide solid electrolytes because of the higher ionic conductivities required for the longer path lengths in cathodes (80-100 mu m) compared with the separator (10 mu m). Comparing LixNb16W5O55 and LixTiS2 will show how electrode hardness affects interfacial integrity. 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, in-operando X-ray tomography, XPS, and EDX. Isostatic pressing will be combined with electrochemistry to establish the mechanical responses of composites.EPSRC Research Area Theme: Energy

全固态电池面临的一个主要挑战是设计具有足够顺应性的阴极，以避免活性颗粒膨胀或收缩时产生的高应力，从而在充电和放电时保持接触。像NMC这样的实用阴极具有很强的氧化性，因此通常会降解界面上的固体电解质。研究了LiTaO3和LiNbO3涂层抑制反应性的方法，但力学问题仍然存在。陶瓷涂层是不兼容的，并倾向于分离的活性粒子充电或放电。为了了解复合电极内体积变化的影响，学生将直接比较零应变活性材料，如Li4Ti5O12，与体积变化材料，如LixNb16W5O55和LixTiS2。这将使体积效应与表面现象分离。该项目将专注于硫化物固体电解质，因为与分离器（10 μ m）相比，阴极（80-100 μ m）中更长的路径长度需要更高的离子电导率。比较LixNb16W5O55和LixTiS2将显示电极硬度如何影响界面完整性。阴极/固体电解质界面将作为电荷状态、循环、电流密度、温度和压力的函数来研究。学生将接受电化学表征（三电极电池）和阻抗谱的培训，等离子体fib扫描电镜的形态学研究，样品稀释和透射电镜，手术中x射线断层扫描，XPS和EDX。等静压将与电化学相结合来建立复合材料的力学响应。EPSRC研究领域主题：能源