Collaborative Research: A New Rational Design of Functionally Graded Materials for Durable Lithium-Ion Batteries

对于高性能和可靠的储能技术，特别是锂离子电池（LIB）的需求越来越大，用于许多尖端应用，如远程电动汽车和大规模智能电网。可靠性和可循环性是目前这些市场的LIB技术中最关键的瓶颈。通常，电极材料的组成和结构不稳定性是导致可靠性问题的最常见问题。提高电极稳定性的现有技术方法是使用不均匀的涂层来保护电极表面。然而，在电极/涂层界面处产生的内部电阻对性能具有负面影响。 该项目将研究下一代储能技术中LIB中FGM的可控合成和电化学稳定性。该项目还包括相关课程的开发，本科生的研究经验和推广计划，以当地高中。本项目旨在通过可控的表面重构来理解锂电池（LIB）电极的界面稳定机制，并建立用于构建耐用LIB的功能梯度材料（FGM）的实验方法。该项目将使用原位同步加速器X射线表征技术，以确定电池的化学，配位几何形状，并在FGM涂层电极的相变行为。该项目将通过将先进的表征与电化学分析相结合，全面研究LIB的FGM加工-结构-性能关系。本研究将通过以下几个方面来实现：（1）结合多种原位和非原位电化学和光谱表征手段，了解功能梯度材料中结构/成分梯度的形成机理;（2）研究功能梯度材料的结构/成分梯度对提高LIBs耐久性的作用，了解结构/成分梯度对电极材料的电学和电化学性能的影响;（3）了解功能梯度材料的电极保护机理，建立方法，以探索结构和成分重建的FGM持久LIB。这个奖项反映了NSF的法定使命，并已被认为是值得支持，通过评估使用基金会的学术价值和更广泛的影响审查标准。

There is an increasing demand for high-performance and reliable energy storage technologies, especially lithium-ion batteries (LIBs), for many cutting-edge applications such as long-range electric vehicles and large-scale smart grids. Reliability and cyclability are among the most critical bottlenecks in the current LIBs technologies for these markets. In general, the compositional and structural instabilities of electrode materials are the most encountered problems responsible for the reliability issues. The state-of-the-art approach to improve the electrode stability is to protect the electrode surfaces using inhomogeneous coating layers. However, the internal resistance generated at the electrode/coating-layer interface has negative effects on performance. This project will investigate the controllable synthesis and electrochemical stability of FGM in LIBs for next-generation energy storage technologies. The project also includes related course development, undergraduate research experience and outreach plans to local high schools. This project aims to understand the interfacial stabilization mechanism of lithium battery (LIB) electrodes through a controllable surface reconstruction and to establish experimental approaches for constructing functional graded materials (FGM) for durable LIBs. The project will use in-situ synchrotron X-ray characterization techniques to identify battery chemistry, coordination geometry, and phase transition behaviors in FGM coated electrodes. The project will comprehensively access the processing-structure-property relationship of FGM for LIBs by integrating advanced characterizations with electrochemical analyses. The research goals will be accomplished through the following objectives: (1) understanding the formation mechanism of structure/composition gradients in FGM by combining multiple in-situ and ex-situ electrochemical and spectroscopic characterization tools; (2) studying the roles of structure/composition gradient of FGM in improving the LIBs durability, understanding the effects of structure/composition gradients on the electrical and electrochemical properties of electrode materials; and (3) understanding the electrode protection mechanism of FGM, establishing approaches to probe the structural and compositional reconstruction of FGM for durable LIBs.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.