Investigation into Surface-Modified Electrode Materials for Li-Ion Batteries

非技术描述：电池现在比以往任何时候都无处不在，为我们的笔记本电脑、智能手机和其他便携式电子设备供电。其他应用包括医疗设备（例如便携式除颤器）以及电动汽车。电池电极表面的性质对电池的性能和容量有很大的影响；表面修饰被广泛用于缓解电极问题，从而提高电池性能。尽管对电极表面的研究已经付出了巨大的努力，但对这些表面上的电化学和表面修饰提高性能的机制的详细了解仍然缺乏。这个项目的动机是利用独特的光谱工具在操作条件下直接探测电极表面（更好地复制真实的电池操作条件）。该项目的成果将通过同行评审的出版物广泛传播，新的科学知识有望对电极表面和界面的合理设计产生重大影响，从而提高电池性能。这些新知识也被纳入佐治亚理工学院的课程，并最终被纳入其他大学的课程。技术细节：利用拉曼光谱直接探测与电极反应相关的许多重要表面物质和新相的可行性已经得到证明。在这个项目中，表面增强拉曼光谱（SERS）被应用于精心设计的模型系统（例如基于limn2o4的电极），以便更深入地了解电极表面。电池电极的表面结构和组成直接关系到其对电池容量、倍率能力、循环寿命和容量保持能力的影响，揭示通过表面改性提高电池性能的机理，为合理设计优质电极材料和结构提供科学指导。随着各种应用（便携式个人电子产品、医疗设备、电动汽车等）对更好的电池寿命和性能的需求不断增长，该项目旨在更好地了解支撑电池性能的电极表面。一名研究生和一至两名本科生在项目中担任研究助理；学生们在歌剧人物刻画技术方面获得了宝贵的经验。

NON-TECHNICAL DESCRIPTION: Batteries are now more ubiquitous than ever, powering our laptops, smartphones, and other portable electronic devices. Other applications include medical devices (e.g. portable defibrillators) as well as electric cars. The performance and capacity of batteries are greatly influenced by the properties of their electrode surfaces; surface modifications are widely used to mitigate electrode problems and thus enhance battery performance. Although enormous effort has been devoted to the study of electrode surfaces, a detailed understanding of the electrochemistry on these surfaces and the mechanisms by which surface modifications enhance performance is still lacking. The motivation for this project is to utilize unique spectroscopic tools to directly probe electrode surfaces under in operando conditions (that better replicate real-world battery operating conditions). The results of the project will be widely disseminated through peer-reviewed publications, and the new scientific knowledge is expected to have a significant impact on the rational design of electrode surfaces and interfaces for improved battery performance. The new knowledge is also being incorporated into courses offered at Georgia Tech, and eventually at other universities as well.TECHNICAL DETAILS: The feasibility of using Raman spectroscopy to directly probe many important surface species and new phases relevant to electrode reactions has been demonstrated. In this project, in operando surface enhanced Raman spectroscopy (SERS) is applied to well-designed model systems (e.g. LiMn2O4-based electrodes) in order to gain deeper insights into electrode surfaces. The surface structure and composition of battery electrodes are directly correlated to their effects on battery capacity, rate capability, cycling life, and capacity retention in order to unravel the mechanisms of performance enhancement through surface modification and to provide scientific guidelines for rational design of superior electrode materials and structures. With rising demand for better battery life and performance for a variety of applications (portable personal electronics, medical devices, electric cars, etc.), this project seeks to better understand the electrode surfaces that underpin battery performance. One graduate student and one to two undergraduate students are working as research assistants on the project; the students are gaining valuable experience with cutting-edge in operando characterization techniques.