Mapping Chemical, Ionic and Electronic Properties of High Capacity Cathode Materials

开发具有更高能量密度和更低成本的锂离子电池（lib）是全球交通运输部门采用电动汽车和减少碳排放的关键要求。目前的技术很大程度上受到阴极活性材料的限制，这意味着在这方面的改进将对性能有显著的好处。富镍阴极材料具有更高的容量，同时由于其较低的钴含量也降低了成本。然而，这些材料受到加速容量衰退的影响，这限制了电池的使用寿命，从而限制了它们的商业可行性。为了克服这一挑战并开发改进的材料，需要了解这种能力衰退的起源，包括这些材料在反复充电和放电时的结构和化学变化。该项目旨在应用多模态成像能力来揭示高容量阴极材料的局部化学和结构特性及其电子和离子电导率之间的相互作用。关键在于从空间上解决这些特性在不同循环阶段和不同循环次数后在单个阴极颗粒内的变化，从而深入了解导致这些材料容量衰减的关键降解机制。这将涉及x射线光谱显微镜和电化学扫描探针技术，可以实现从纳米到微米的空间分辨率，并检测锂含量，过渡金属氧化态以及电子和离子电导率的变化。重点将放在研究实际的电极材料上，这些材料已经被用作法拉第研究所（Faraday Institution）一个更大的电池降解项目的一部分，这些材料将按照既定的协议进行电化学循环。将开发在惰性环境下对这些样品进行切片的方法，以产生所需的平面横截面，从而从所提出的空间化学成像技术中获得最多信息。利用这些样品开发的理解将为阴极材料的设计和循环方案提供信息，以帮助延长锂离子电池的寿命。该项目属于EPSRC能源存储和分析科学研究领域，其中先进的光谱显微镜技术将用于研究电池材料中化学、电子和离子性质之间的相关性。这将包括使用钻石光源和其他国际设施提供的x射线方法。法拉第资助学生

The development of Li-ion batteries (LIBs) with increased energy density and lower cost is a key requirement for the adoption of electric vehicles and reduction in carbon emissions in the global transport sector. Current technology is largely limited by the cathode active material, meaning improvements here will have significant benefits to performance. Nickel-rich cathode materials promise higher capacities, whilst also reducing cost due to their lower cobalt content. However, these materials suffer from accelerated capacity fading, that limits battery lifetime and consequently their commercial viability. To overcome this challenge and develop improved materials requires an understanding of the origins of this capacity fade, including how the structure and chemistry of these materials change as they are repeatedly charged and discharged. This project aims to apply multimodal imaging capabilities to reveal the interplay between local chemical and structural properties of high capacity cathode materials, and their electronic and ionic conductivities. Key to this will be spatially resolving how these properties vary within individual cathode particles at different stages of cycling and after different number of cycles, providing insights into the key degradation mechanisms responsible for capacity fade in these materials. This will involve X-ray spectromicroscopy and electrochemical scanning probe techniques that can achieve spatial resolutions from nanometres up to microns and detect variations in Lithium content, transition metal oxidation state, and electronic and ionic conductivities. The focus will be on studying realistic electrode materials already used as part of a larger Faraday Institution project on battery degradation and these will be electrochemically cycled following established protocols. Methods will be developed for sectioning these samples under inert environments to produce the flat cross-sections needed to get the most information from the proposed spatio-chemical imaging techniques. The understanding developed using these samples will inform the design of cathode materials and cycling protocols to help extend the life of Li-ion batteries.This project falls within the EPSRC research areas of Energy Storage and Analytical Science, where advanced spectromicroscopy techniques will be used to study the correlation between chemical, electronic and ionic properties in battery materials. This will include the use of X-rays methods available at Diamond light source and other international facilities.Faraday funded student