CAREER: Elucidating the Correlative Interfacial Solvation, Nucleation, and Growth Processes in Battery Electrolytes

主要以电池形式存在的电化学能量储存对于促进从化石燃料向可再生能源的过渡至关重要。锂离子电池的发明已经改变了范式，在移动的手机、笔记本电脑、电动汽车等领域得到了广泛的应用。然而，电池技术的持续发展和改进目前面临着重大挑战，因为现有的电池化学物质在能量密度和安全性方面受到限制。决定这种限制的基本因素仍然没有得到很好的理解。该项目将通过使用一套工具来探测阳极-电解质界面处发生的内部过程来弥合这一知识差距。该项目将专注于电池循环过程的早期阶段，并确定界面电解质和钝化层结构。从该项目中获得的见解将作为设计新型电解质的指导原则，以实现更安全，更强大，更耐用的电池。该项目的教育活动与研究工作相配合，侧重于通过实际操作仪器培训、科学演示、辅导和教学，向科学界和公众，特别是代表性不足的少数群体传播表面/界面科学和可再生能源方面的知识。这些努力将加强研究界的材料表征能力，提高K-12学生以及公众对清洁能源和STEM的认识和兴趣，并提高本科生对电化学和可再生能源的知识。从长远来看，研究和教育活动的结合将培养多元化的合格人才在STEM和能源领域工作。在锂离子电池中，一个关键组成部分是固体电解质界面（SEI），它是在早期电池循环期间在阳极-电解质界面形成的。虽然研究界已经投入了大量的努力来表征完全生长的SEI的结构和组成，但它们的动态成核和生长过程以及潜在的机制在很大程度上仍然难以捉摸，这是阻碍针对目标电池应用的电解质和SEI的预测性设计的主要瓶颈。该项目将研究阳极-电解质界面的溶剂化层（也称为双电层）结构如何在SEI成核和生长过程中起主导作用。该项目将通过结合原位表面增强拉曼光谱和电化学3D原子力显微镜（PI实验室最近开发的）、非原位方法和原子模拟来确定双电层（EDL）和SEI的结构和动态演化过程。该项目的一个成果将是量化的电解质-EDL-SEI相关性。具体目标包括：（I）确定原始石墨（阳极）表面的EDL结构，（II）解开初始SEI成核和与EDL的相关性，以及（III）破译成熟的SEI结构及其形成机制。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Electrochemical energy storage, mainly in the form of batteries, is crucial to foster the transition from fossil fuel to renewable energy. The invention of lithium-ion batteries has been paradigm-shifting, finding widespread applications in mobile phones, laptops, electric vehicles, and more. However, the continuous development and improvement of battery technologies is currently facing major challenges, as existing battery chemistries are limited in energy density and safety. The fundamental factors determining such limits are still not well understood. The project will bridge this knowledge gap by using a set of tools to probe the internal processes occurring at anode-electrolyte interfaces. The project will focus on the early stages of the battery cycling process and determine the interfacial electrolyte and passivation layer structure. The insights gained from this project will serve as guiding principles to design novel electrolytes for safer, more powerful, and more durable batteries. Education activities of this project, in synergy with the research efforts, are focused on disseminating knowledge on surface/interface science and renewable energy to the scientific community and the general public, especially underrepresented minorities, through hands-on instrument training, scientific demonstration, mentoring, and teaching. These efforts will strengthen the materials characterization capabilities in the research community, raise the awareness and stimulate interest in clean energy and STEM among K-12 students as well as the general public, and enhance the knowledge of electrochemistry and renewable energy among undergraduate students. In the long term, the research and education activities combined will foster a diverse population of qualified individuals to work in STEM and the energy sector.In lithium-ion batteries, a critical component is the solid-electrolyte interphase (SEI), which is formed at the anode-electrolyte interface during early battery cycles. While significant efforts in the research community have been devoted to characterizing the structure and composition of fully-grown SEIs, their dynamic nucleation and growth process and the underlying mechanism remain largely elusive, which is a major bottleneck preventing the predictive design of electrolytes and SEIs for targeted battery applications. The project will study how the structure of solvation layers (also called electrical double layers) at the anode-electrolyte interface plays a dominant role in the SEI nucleation and growth processes. The project will determine the structure and dynamic evolution processes of the electric double layer (EDL) and SEI by combining in situ surface-enhanced Raman spectroscopy and electrochemical 3D atomic force microscopy (recently developed in the PI’s lab), ex situ methods, and atomistic simulations. One outcome of the project will be a quantified electrolyte-EDL-SEI correlation. Specific objectives include: (I) determining the EDL structure at pristine graphite (anode) surface, (II) unraveling initial SEI nucleation and correlation with EDL, and (III) deciphering the mature SEI structure and its formation mechanism.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.