Probing the Electrochemical Interface with Operando Surface-Enhanced Raman Spectroscopy

新一代锂离子电池具有更高的能量密度、更好的安全特性、更低的成本和更长的循环寿命，在电力运输、可再生能源存储和物联网(IoT)等新兴技术方面拥有巨大的潜力。电池性能持续提高的一个技术障碍是对电解液在电极表面的分解和沉积了解不足。这是因为缺乏化学分析工具来监测反应过程中电解液/电极界面的分子相互作用。在这个项目中，研究人员将开发一个高性能的平台，实时探测电解液/电极界面上化学特征的演变。这项新技术将用于研究更安全、更轻、更高容量的锂离子电池新电极材料的界面反应机理。它还将使其他化学和电化学系统受益，在这些系统中，实时化学分析对于阐明反应机理和提高性能至关重要。此外，项目团队将让历史上代表性不足的内陆帝国社区参与教育和外联活动，旨在增加科学和工程高等教育的多样性，这伴随着NSF 2018-2022年战略计划，通过准备和聘用多样化的美国STEM工作人员。该项目的技术目标是开发一种稳定和高性能的电化学操作界面表面增强拉曼光谱(SERS)技术，以研究下一代锂离子(Li-ion)充电电池的电化学界面。所提出的技术将解决对操作面光谱工具的关键需求，以了解电解液/电极界面上的界面反应和界面物种的形成机理。PIS将采用大面积紧密堆积的(电化学)化学坚固的Ag@Au外延核壳纳米立方体(NC)作为SERS衬底的独特设计，为电化学界面的Operando化学分析提供高、均匀和稳定的信号增强。计划进行两项主要工作：(1)合成和组装用于大面积高增强SERS衬底的Ag@Au外延核壳纳米立方体，并通过研究碳/电解液与已知界面化合物的界面来验证/优化OPANDO SERS平台；(2)应用优化的OPANDO SERS平台研究包括硫和硅在内的两种新型电极材料的电极/电解液界面。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。

Next generation Li-ion batteries with higher energy densities, better safety characteristics, lower cost and longer cycle life holds enormous potential for electric transportation, renewable energy storage and emerging techniques such as the Internet of Things (IoT). One technical barrier to the continued improvement of battery performance is the insufficient understanding of the electrolyte decomposition and deposition on the electrode surface. This stems from a lack of chemical analysis tools to monitor the molecular interactions at the electrolyte/electrode interface during the reaction. In this project, the investigators will develop a high-performance platform to probe in real-time the evolution of chemical signatures at electrolyte/electrode interface. The new technology will be used to investigate the interface reaction mechanism of promising new electrode materials for safer, lighter and higher capacity Li-ion batteries. It will also benefit other chemical and electrochemical systems where real-time chemical analysis is crucial in elucidating reaction mechanisms and improving performance. Furthermore, the project team will engage the historically underrepresented Inland Empire community in educational and outreach activities aiming at increasing diversity in science and engineering higher education, which accompanies NSF Strategic Plan for 2018-2022 by preparing and engaging a diverse U.S. STEM workforce.The technical goal of this project is to develop a stable and high-performance electrochemical operando surface-enhanced Raman spectroscopy (SERS) technique to study the electrochemical interfaces in next-generation lithium-ion (Li-ion) rechargeable batteries. The proposed technique will address the critical needs for operando spectroscopic tools to understand the interfacial reactions at the electrolyte/electrode interface and the formation mechanism of interfacial species. The PIs will employ a unique design of large-area close-packed films of (electro)chemically-robust Ag@Au epitaxial core-shell nanocubes (NC) as the SERS substrate, that offers for high, homogeneous and stable signal enhancement for operando chemical analysis of electrochemical interfaces. Two major task are planned: (1) synthesize and assemble the Ag@Au epitaxial core-shell nanocubes for large-area high-enhancement SERS substrates, and validate/optimize the operando SERS platform by investigating the carbon/electrolyte interface with known interfacial compounds; and (2) apply the optimized operando SERS platform to study the electrode/electrolyte interfaces of two novel electrode materials including sulfur and silicon.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.