CAREER: Understanding Ion Transport in Solvated Layered Oxides for Electrochemical Energy Storage

通过电池和电化学电容器进行的电化学能量存储在现代生活中无处不在，从手机和电动汽车到可再生能源电网。层状金属氧化物是一类重要的储能材料。它们可逆地将电解质中的离子储存在层间区域的空隙中。本研究将探索如何通过溶剂化调整这些材料的中间层来提高它们的储能性能。这项研究将有助于提高对储能基本机制的理解，以及设计出具有更好储能性能的新型层状材料。这项研究的教育部分的动机是，未来几十年全球能源使用的增加将主要来自发展中国家的电气化。该教育计划将培养学生在不同文化背景下合作应对全球挑战，强调工程的社会影响，以招募和留住材料科学和工程领域代表性不足的学生群体，并增加科学家和工程师的全球多样性。该教育计划包括与乌干达的大学合作，并将使用动手实验套件和虚拟团队合作来训练学生在不同的团队中工作，以应对全球挑战。第2部分：技术摘要由于它们对电化学储能的重要性，已致力于改善层状氧化物中阳离子的电化学传输。本研究将确定是否可以通过溶剂化修饰层间来改善层状氧化物中单价和二价阳离子的电化学传输。这种结构保留了大块氧化物的体积能量密度、寿命和安全性，同时提供了一个原子级的环境，可能有利于界面电荷转移和固态扩散。研究方法是利用层状钨和钼氧化物，因为它们在水和非水电解质中都具有多电子和多价氧化还原、水合多晶型和稳定性。溶剂交换将用于从水合层状氧化物合成溶剂化氧化物。界面电荷转移和固态扩散的动力学将通过电化学、微观和光谱技术（包括原位方法）来确定。对纳米尺度、溶剂化层状氧化物的阳离子传输的基本理解将在材料科学、电化学、表面科学和纳米流体学等领域产生广泛的影响。该教育计划利用并扩展了由该项目开发的“科学桥”项目，使美国和非洲的大学生参与可再生能源领域的教育推广。

Part I: Non-Technical SummaryElectrochemical energy storage via batteries and electrochemical capacitors is ubiquitous in modern life, from cell phones and electric vehicles to renewable power grids. Layered metal oxides are an important class of materials for energy storage devices. They reversibly store ions from the electrolyte within the empty spaces found in the interlayer region. This research will explore how tuning the interlayer of these materials by solvation could improve their energy storage properties. The research will lead to improved understanding of fundamental mechanisms of energy storage as well as the design of new layered materials with better energy storage properties. The educational component of this research is motivated by the fact that the rise in global energy use in coming decades will largely come from the electrification of developing countries. The educational plan will train students to collaborate on global challenges across diverse cultures, highlight the societal impact of engineering to recruit and retain under-represented student groups in materials science and engineering, and increase the global diversity of scientists and engineers. The education plan involves collaborations with universities in Uganda, and will use hands-on experiment kits and virtual teamwork to train students to work on diverse teams to tackle global challengesPart 2: Technical SummaryDue to their importance for electrochemical energy storage, significant research efforts have been dedicated to improving the electrochemical transport of cations in layered oxides. This proposed research will determine whether the electrochemical transport of monovalent and divalent cations in layered oxides can be improved by modifying the interlayer via solvation. Such structures preserve the volumetric energy density, lifetime, and safety of bulk oxides, while at the same time providing an atomic-level environment that may be beneficial for interfacial charge transfer and solid-state diffusion. The research approach is to utilize layered tungsten and molybdenum oxides because they offer multi-electron and multivalent redox, hydrated polymorphs, and stability in both aqueous and non-aqueous electrolytes. Solvent exchange will be used to synthesize solvated oxides from hydrated layered oxides. The dynamics of interfacial charge transfer and solid-state diffusion will be determined via electrochemical, microscopic, and spectroscopic techniques including in situ methods. Fundamental understanding of the transport of cations in nanoscale, solvated layers of layered oxides will have a broad impact in fields such as materials science, electrochemistry, surface science, and nanofluidics. The education plan leverages and extends the SciBridge project, developed by the PI, to engage U.S. and African university students in educational outreach in the area of renewable energy.