Probing the chemical degradation of cathode material interfaces in Li-ion Batteries

探究锂离子电池正极材料界面的化学降解

• 批准号: 2594431
• 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: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2594431
• 关键词: Probing; chemical; degradation; cathode; material

For future generations of lithium ion batteries to be implemented in electric vehicles, significant improvements in their lifetime and power densities are required. One of the most important aspects in achieving a long battery lifetime is the stability of the cathode materials (positive electrode). Over many charge-discharge cycles or when operated under extreme temperatures, undesirable side reactions occur at the surface of these materials such as electrolyte decomposition, transition metal dissolution and gas evolution. Current techniques to look at these electrode-electrolyte interfaces must be performed after the battery has been disassembled, due to the major challenge of accessing such buried interfaces. However, such approaches are unreliable as battery interfaces are usually highly reactive and liable to change during disassembly and transfer to the measurement system. This project aims to investigate the changes occurring at interfaces between the cathode (positive electrode) and electrolyte in Li-ion batteries during operation. This will make use of novel electrochemical cells that incorporate thin membranes through which hard X-ray photoelectron spectroscopy (HaXPES) and X-ray Absorption Spectroscopy (XAS) can be performed. It will also use a specially designed chamber for assembling and disassembling batteries in a vacuum environment that can be directly connected to surface-sensitive characterisation tools. These approaches will be used to reveal the reversible and irreversible reactions occurring, such as the formation of surface layers, transition metal dissolution and the subsequent plating of these species onto the anode (negative electrode). Application-relevant battery materials will be studied to obtain novel insights about their interfacial stability, and this understanding will inform the design of cathode materials and cycling protocols to help extend the life of Li-ion batteries. The use of new characterisation tools will also help demonstrate the capabilities these can provide to the battery research community. This project is linked with Johnson Matthey and will involve work with both the Battery Materials and Advanced Surface Characterisation Groups at Johnson Matthey's Technology Centre. In situ and operando X-ray measurements will be performed at Diamond Light Source and other international synchrotron facilities. This project falls within the EPSRC research areas of Energy Storage and Physical Sciences, where advanced characterisation techniques will be used to study chemical changes occuring in battery materials.

对于电动汽车中使用的下一代锂离子电池，需要显着提高其使用寿命和功率密度。实现长电池寿命的最重要方面之一是正极材料（正极）的稳定性。在许多充放电循环中或在极端温度下操作时，这些材料的表面会发生不良副反应，例如电解质分解、过渡金属溶解和气体逸出。由于接近这些埋藏界面的主要挑战，目前观察这些电极-电解质界面的技术必须在电池被拆卸后进行。然而，这种方法并不可靠，因为电池接口通常具有高反应性，并且在拆卸和传输到测量系统期间容易发生变化。该项目旨在研究锂离子电池在工作过程中阴极（正极）和电解质之间界面发生的变化。这将利用包含薄膜的新型电化学电池，通过该薄膜可以进行硬 X 射线光电子能谱 (HaXPES) 和 X 射线吸收光谱 (XAS)。它还将使用专门设计的室在真空环境中组装和拆卸电池，该室可以直接连接到表面敏感的表征工具。这些方法将用于揭示发生的可逆和不可逆反应，例如表面层的形成、过渡金属溶解以及随后将这些物质电镀到阳极（负极）上。将研究与应用相关的电池材料，以获得有关其界面稳定性的新见解，这种理解将为阴极材料和循环方案的设计提供信息，以帮助延长锂离子电池的寿命。新表征工具的使用也将有助于展示这些工具可以为电池研究界提供的功能。该项目与庄信万丰相关，并将涉及与庄信万丰技术中心的电池材料和高级表面表征小组的合作。原位和操作 X 射线测量将在钻石光源和其他国际同步加速器设施中进行。该项目属于 EPSRC 能源存储和物理科学研究领域，其中先进的表征技术将用于研究电池材料中发生的化学变化。