CAS: Controlling Solid Electrolyte Interphases using Organometallic Electrolyte Additives

在化学系化学结构、动力学和机理B项目的支持下，伊利诺斯-芝加哥大学化学系的尼尔·曼卡德教授正在开发新的有机金属复合物，作为电池电解质的添加剂。这项研究的目标是利用这些化合物的小负荷来影响阳极表面的化学性质，最终目标是提高高密度电池（如锂金属阳极电池）的长期循环稳定性和操作安全性。该项目处于有机金属化学、电化学和电池设计的交叉点，因此非常适合各级科学家的教育。这个团队也有能力为在科学领域代表性不足的学生提供教育和培训。对芝加哥地区高中生进行科学辅导的外展活动也将是该项目的一部分。该项目基于团队获得的初步数据，该数据表明，由2-（2-甲氧基乙氧基）乙酸配体支持的四键二钼（II）配合物在第二个配位球中可逆地结合锂离子，诱导带阳离子的配位低聚物聚集，这些配位低聚物自组装在电化学电池的阳极表面。沉积后，发现修饰电极在固-电解质界面具有显著的修饰成分，并且与缺乏二钼添加剂的控制系统相比，显示出可测量的不同的锂电镀和剥离行为。本项目旨在解决三个问题：(i)在锂金属电池循环条件下观察到的行为机制是什么？（ii）当改变有机金属添加剂的结构以调节锂离子结合常数和/或还原电位时，其行为是如何变化的？（iii）这种行为是否延伸到钠和镁金属电池等“锂以外”技术？如果成功，这些研究可能会对电化学电池/电池的设计、性能和可持续性产生广泛的科学影响。该奖项反映了美国国家科学基金会的法定使命，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。

With support from the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professor Neal Mankad of the Department of Chemistry at the University of Illinois-Chicago is developing new organometallic complexes to serve as additives in battery electrolytes. The goal of this research is to exploit the ability of small loadings of these compounds to influence the chemistry at anode surfaces, with the ultimate goal of improving long-term cycling stability and operational safety of high-density batteries such as those with lithium metal anodes. The project lies at the interface of organometallic chemistry, electrochemistry, and battery design and is, therefore, well suited to the education of scientists at all levels. This team is also well positioned to provide education and training for students underrepresented in science. Outreach activities involving science coaching of Chicago-area high school students will also be part of the project.The project is based on preliminary data obtained by the team showing that quadruply-bonded dimolybdenum(II) complexes supported by 2-(2-methoxyethoxy)acetate ligands reversibly bind lithium ions in the second coordination sphere, inducing aggregation of cationically charged coordination oligomers that self-assemble onto the anode surface in electrochemical cells. Upon deposition, the modified electrodes are found to have significantly modified compositions at the solid-electrolyte interphases and display measurably different lithium plating and stripping behaviors compared to control systems lacking the dimolybdenum additive. This project aims to address three questions: (i) What is the mechanism of the observed behavior under lithium metal battery cycling conditions? (ii) How does the behavior change when the organometallic additive structure is varied to modulate the lithium ion binding constant and/or reduction potential? (iii) Does this behavior extend to “beyond lithium” technologies such as sodium and magnesium metal batteries? If successful, these research studies will likely have broad scientific impact on electrochemical cell/battery design, performance and sustainability.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.