Collaborative Research: Understanding and Tailoring the Anode-Electrolyte Interfacial Layers on the Stabilization of Lithium Metal Electrode

金属锂(Li)具有较高的理论比能量和较低的还原电位，被认为是最有希望取代传统石墨的锂离子电池负极材料之一。然而，电极上的枝晶生长和不稳定的固体-电解液界面相(SEI)的形成已经引起了人们对锂电池安全的担忧，并阻碍了实际应用。在锂金属电极上引入人工保护层是稳定锂电极的有效策略，但这种保护层如何与锂金属阳极的电化学过程相互作用还不是很清楚。本项目将结合实验和模拟，了解保护层的物理和化学性质如何影响锂金属电极的电化学性能。所获得的基础知识将指导开发用于电动汽车和其他高能量密度电子存储设备的高性能和更高安全性的新型锂金属电极。该项目还将通过课程开发、夏令营和当地博物馆的外展活动，对研究生、本科生和K-12学生进行教育。该项目的总体目标是对导致锂金属电极稳定充放电过程的保护层的关键物理和化学性质有一个新的认识。该模型仅考虑了保护层的有限力学性能对锂金属电极稳定性的影响，存在不足。在这个项目中，通过实验合成、表征和相场模拟的有效结合，将对电化学和抑制枝晶的变形/破坏机制产生新的理解，包括质量传输、电势、应力和变形。(1)保护层的力学性能对抑制锂枝晶生长的影响；(2)保护层的离子传质行为对锂金属电极稳定性的影响；(3)用于高性能组装电池的新型锂金属保护层。保护层的物理和化学性质与电极的电化学过程之间的关系的阐明有望为锂金属电极的新设计和制造开辟道路，导致稳定和高性能的下一代储能设备。该项目由CBET电化学系统计划和既定的刺激竞争研究计划(EPSCoR)联合资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Metallic lithium (Li) is considered as one of the promising next-generation anode materials to replace conventional graphite in Li-ion batteries because of its high theoretical specific energy capacity and low reduction potential. However, dendrite growth on the electrode and unstable solid-electrolyte interphase (SEI) formation have created safety concerns in Li batteries and hindered practical applications. Introducing an artificial protective layer on the Li metal electrode is an effective strategy to stabilize the Li electrode, yet how this protective layer interacts with the electrochemical process of Li metal anode is not well understood. This project will integrate experiments and simulations to understand how the physical and chemical properties of the protective layer affect the electrochemical performance of the Li metal electrode. The fundamental knowledge gained will guide development of novel Li metal electrodes with high performance and improved safety for electric vehicles and other high-energy-density electrical storage devices. The project will also involve the education of graduate, undergraduate students, and K-12 students by course development, summer camp, and outreach activities in local museums. The overarching goal of this project is to develop a new understanding of the key physical and chemical properties of the protective layer that leads to stable charge/discharge processes of the Li metal electrode. The state-of-the-art guideline is insufficient, and the model only considers the influences of the limited mechanical properties of the protective layer on the stabilization of the Li metal electrode. In this project, by an effective integration of experimental synthesis, characterization and phase-field simulations, a new understanding will be generated on electrochemistry and deformation/failure mechanism of suppressing dendrites, including mass transport, electric potential, stress, and deformation. The research goal will be reached by working on several objectives: (1) Effect of mechanical properties of the protective layer on the suppression of Li dendrite growth; (2) Effect of ionic mass transfer behaviors of the protective layer on the stabilization of the Li metal electrode; (3) Novel protective layer on Li metal for the high-performance assembled cells. The elucidated correlation between physical and chemical properties of the protective layer, and the electrochemical processes of the electrode is expected to open pathways for the novel design and fabrication of Li metal electrodes, leading to stable and high-performance next-generation energy storage devices.This project is jointly funded by the CBET Electrochemical Systems program and the Established Program to Stimulate Competitive Research (EPSCoR).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.