Comparative Evaluation of Ionic Transport Mechanisms in Solid-State Electrolytes

非技术描述：实现具有与化石燃料竞争的能量和功率密度的电池的一个关键方面是开发用作分隔阳极和阴极的膜的固态电解质。这种膜的最重要的特性是表现出高的离子电导率，它促进了与能量转换相关的电化学过程。这个问题就是为什么目前的电池技术依赖于液体电解质。固态电解质允许更紧凑的形状因子，更安全的操作和更长的电池寿命，但它们的离子导电性必须得到改善。为了实现这一目标，正在追求各种思想流派和材料类型，包括无机玻璃，细晶粒陶瓷和含有有机增塑剂的复合材料。到目前为止，这项工作大部分是通过试验和错误来完成的。在本项目中，固态电解质的最佳材料设计标准是通过比较研究确定的，涉及一系列精心构思的实验和原子计算机模拟。这项研究揭示了材料结构，机械性能和离子电导率之间的基本关系，包括改进的理论模型的发展，用于解释实验结果，能够预测所需性能特性的最佳材料设计。技术优势：固态电池电解质是绿色可再生能源存储技术进步的关键。在这项研究中，材料的设计标准正在开发的固态电解质，表现出所需的高传输速率和迁移数的小电荷载体阳离子。此外，这些电解质必须保持足以抑制锂枝晶生长和安全地分离自支撑装置结构中的电极的机械刚度，并且具有足够宽的电化学稳定性范围以适应大的电极电位差。目前材料设计概念的范围包括从结晶到无定形，从无机到有机的材料，通过这项研究，正在确定最有效的方法。为此，通过制定一系列原型材料系统，系统地隔离了决定性的离子传输机制，每个原型材料系统选择性地暴露了主要材料类型中特定结构特征对阳离子迁移率的影响，包括多晶陶瓷中的界面结构，混合有机-无机复合材料中的增塑剂相，以及离子交换氧化物玻璃中的工程缺陷。这些实验与广泛的原子模拟相结合，以解释实验结果，并开发理论模型，促进固态电解质的可靠和可转移的设计策略。本科生和研究生，以及博士后研究员从事研究，提供调查的计算和实验方法的培训，并通过预测材料设计的计算工具的开发推进国家材料基因组计划的任务。 PI正在建立一个桥梁计划，以吸引从少数民族服务机构（MSIs）毕业的硕士学位学生进入密歇根大学的博士课程。自2002年以来，他还帮助组织了由ASM国际赞助并由他的部门主办的高中教师教材营。

NON-TECHNICAL DESCRPTION: A key aspect towards achieving batteries with energy and power densities that are competitive with fossil fuel is to develop solid-state electrolytes for use as the membrane that separates the anode and cathode. The most important property of this membrane, which facilitates the electrochemical process associated with energy conversion, is to exhibit high ionic conductivity. This issue is why current battery technologies rely on liquid electrolytes. Solid-state electrolytes allow for a more compact form factor, safer operation, and better longevity of batteries, but their ionic conductivity must be improved. To accomplish this goal, various schools of thought and types of materials, including inorganic glasses, fine-grained ceramics, and composites containing an organic plasticizer are being pursued. To date, much of this work has been done by trial and error. In the present project, the optimal materials design criteria for solid-state electrolytes are identified through a comparative study that involves a series of carefully conceived experiments and atomistic computer simulations. This research reveals the underlying fundamental relationships between materials structure, their mechanical properties, and ionic conductivities, including the development of improved theoretical models for the interpretation of experimental findings, which are capable of predicting the optimal materials design for desired performance characteristics. TECHNICAL DETAILS: Solid-state battery electrolytes are key to the advancement of green renewable energy storage technologies. In this research, the materials design criteria are being developed for solid-state electrolytes that exhibit the required high transport rates and transference numbers for small charge carrier cations. Additionally, these electrolytes must maintain a mechanical rigidity sufficient to suppress lithium dendrite growth and safely separate electrodes in self-supporting device structures, and possess an electrochemical stability range wide enough to accommodate large electrode potential differences. The current scope of materials design concepts encompasses materials from crystalline to amorphous, and from inorganic to organic, and with this research the most effective approach is being identified. To this end, the decisive ionic transport mechanisms are systematically isolated by formulating a series of prototype materials systems, each one selectively exposing the influence on the cation mobility that specific structural features within the major materials types have, including interfacial structures in polycrystalline ceramics, plasticizer phases in hybrid organic-inorganic composites, and engineered defects in ion-exchanged oxide glasses. These experiments are coupled with extensive atomistic simulations to interpret experimental findings and to develop theoretical models that facilitate a reliable and transferrable design strategy for solid-state electrolytes. Undergraduate and graduate students, as well as postdoctoral fellows are engaged in research that provides training in both computational and experimental methods of investigation, and that advances the National Materials Genome Initiative mandate through the development of computational tools for predictive materials design. The PI is establishing a bridge program to attract students graduating with a Masters degree from Minority-Serving Institutions (MSIs) with terminal programs, into Doctoral programs at the University of Michigan. He also helps organize the High School Teachers Materials Camp sponsored by ASM International and hosted by his department since 2002.