IN-SITU RAMAN SPECTROSCOPY STUDY OF LITHIUM-AIR BATTERY WITH BI-CONTINUOUS SERS-ACTIVE ELECTRODE AND MEMBRANE

1706681 PI：Zhu，Yu机构：阿克伦大学锂空气电池是有前途的高密度储能系统。锂空气电池的理论能量密度与汽油相当。然而，目前的锂-空气电池系统遭受阴极上和电解质溶液中的缓慢且不可逆的电化学反应。对这些系统中发生的反应的基本理解对于设计更好的电极和电解质至关重要，这些电极和电解质可以提高电池更换前的储能容量和循环次数。实验研究旨在通过真实的时间监测锂空气电池阴极上的化学物种，以更好地理解可以改进电池设计的化学反应机制。该提案旨在使用原位拉曼光谱来探索锂空气电池阴极上发生的反应。提出了使用聚合物模板来制造由原始化学气相沉积的石墨烯、金或过渡金属间隙化合物制成的组织良好的双连续电极。为了增强拉曼信号，双连续电极将通过使用受控蒸发或模板掩蔽吸附均匀且规则组装的金纳米颗粒来改性。改性电极可以允许通过表面增强拉曼光谱（Sers）检测痕量中间化合物。为了检测电解质溶液中形成的中间体和产物，将具有与电极类似结构的SERS活性绝缘膜应用于组装的锂空气电池。 一套表征工具（包括拉曼、FTIR、TEM、XPS和XRD）将能够对空气阴极和电解质溶液上的材料进行研究。特别令人感兴趣的是在充电和放电过程中形成的中间化合物，这将能够解决与电解质/电极稳定性相关的基本材料挑战。这些研究可以提供对锂空气电池阴极反应机制的更好理解，并可能导致高性能可逆锂空气电池的工程解决方案。除了研究生和本科生的培训，外展工作提出，将包括一个科学奥林匹克周末的学生在4-6年级和活动，通过ACS种子计划针对经济困难的高中学生在阿克伦，OH，地区。

1706681 PI: Zhu, Yu Institution: University of AkronLithium-air batteries are promising high-density energy storage systems. The theoretical energy density of lithium-air batteries is comparable with that of gasoline. However, the current lithium-air battery systems suffer from slow and irreversible electrochemical reactions on the cathode and in the electrolyte solution. A fundamental understanding of the reactions taking place in these systems is essential for designing better electrodes and electrolytes that improve energy storage capacity and the number of cycles before battery replacement. The experimental investigations seek to monitor in real time chemical species on the cathode of lithium-air batteries to provide a better understanding of the chemical reaction mechanisms that can lead to improved battery designs.The proposal aims at exploring the reactions taking place on the cathode of lithium-air batteries using in-situ Raman spectroscopy. The use of polymer templates to fabricate well- organized bi-continuous electrodes made of pristine chemical vapor deposited graphene, gold, or transition metal interstitial compounds is proposed. To enhance the Raman signal, the bi-continuous electrodes will be modified by the adsorption of uniform and regularly assembled gold nanoparticles using either controlled evaporation or template masking. The modified electrodes may allow the detection of trace intermediate compounds by surface-enhanced Raman spectroscopy (SERS). In order to detect the intermediates and products formed in the electrolyte solution, a SERS-active insulating membrane with similar structure as the electrode will be applied to the assembled lithium-air battery. A suite of characterization tools (including Raman, FTIR, TEM, XPS, and XRD) will enable investigation of the materials on the air-cathode and electrolyte solution. Of particular interest are intermediate compounds formed during the charging and discharging processes that will enable addressing fundamental material challenges associated with electrolyte/electrode stability. The studies may provide an improved understanding of lithium-air battery cathode reaction mechanisms and may lead to engineering solutions for high performance, reversible lithium-air batteries. In addition to the training of graduate and undergraduate students, outreach efforts are proposed that will include a Science Olympiad weekend for students in grades 4-6 and activities through the ACS SEED program targeting economically disadvantaged high school students in the Akron, OH, area.