CAREER: Understanding Interfaces in Solid State Energy Storage Systems and Cross-Disciplinary Education

用于车辆运输和可再生电网存储的先进锂离子电池可以提高国内能源安全，但在成本和电池寿命方面的性能差距限制了使用。电池失效的主要原因是设备内部难以量化和理解的不良化学副反应。由于缺乏基本的理解，工程师们不太能够设计出能够持续预期寿命的材料和设备。该CAREER项目将对先进的固态混合电解质进行基础研究，这些电解质具有更高能量密度的潜力，同时保持安全的操作环境。这些混合电解质可以取代目前使用的有长循环寿命问题的液体有机电解质。活性物质（锂离子）在电解质内和到电极的传输在这些杂化物中还不完全清楚。该项目将解决潜在的物理和化学转化的基础知识，以支持对混合电解质中离子传输的理解。这些知识也将在化学传感器、燃料电池和其他电池化学方面有深远的应用。该教育计划旨在通过范德比尔特纳米科学工程研究所、范德比尔特工程大使开展的外展项目，以及与Harpeth Hall女子学校的研究实习项目，将研究成果直接融入纳什维尔社区。所有外展活动都旨在扩大STEM中代表性不足的社区的科学和工程机会。本项目将研究一系列固体离子混合导体中的离子传输途径。这些电解质由两种不同类型的离子导体组成：(1)聚合物和(2)陶瓷。目前尚不清楚电解质中这两种材料之间的离子传递是如何发生的。为了实现电池能够快速充电和长时间使用，有必要控制这两种材料之间的离子传输。本CAREER项目的研究目标是通过关注电解质界面上离子传输的表征来理解离子传输。固体电解质中可以形成两种类型的界面：内在的和外在的。本征界面存在于无机和有机组分之间的杂化电解质中，也存在于陶瓷离子导体的晶界处。这些是离子在离子导体之间移动的界面的例子。外部接口是指在器件集成过程中出现的接口（电极、电解质），并且会影响器件的性能。这些界面涉及离子导体和离子与电子混合导体之间的传输。建立界面在离子传输中的作用将为实现具有竞争力的性能和功能提供途径。该项目将采用多模态方法，将基于物理的建模与电化学、光谱、x射线和中子实验相结合，来描述混合固体电解质的输运机制。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。

Advanced lithium-ion batteries for vehicle transport and renewable electricity grid storage applications could improve domestic energy security but performance gaps in cost and battery lifetime limit use. The main cause of battery failure is undesirable chemical side reactions within the device that are difficult to quantify and to understand. Because of the lack of fundamental understanding, engineers are less able to design materials and devices that can last the expected lifetimes. This CAREER project will conduct fundamental research on advanced solid-state hybrid electrolytes that have the potential for greater energy density while retaining a safe operating environment. These hybrid electrolytes could replace currently used liquid organic electrolytes that have had issues with long cycle life. The active material's (lithium ion) transport within the electrolyte and to the electrode is not fully understood in these hybrids. This project will address fundamental knowledge of the underlying physics and chemical transformations that support understanding of ionic transport in the hybrid electrolytes. This knowledge will also have far-reaching applications of chemical sensors, fuel cells, and other battery chemistries. The educational plan intends to integrate the research findings directly into the Nashville community through outreach programs run through the Vanderbilt Institute for Nanoscience Engineering, Vanderbilt Engineering Ambassadors, and a research internship program with Harpeth Hall School for Girls. All outreach activities seek to expand scientific and engineering opportunities to underrepresented communities in STEM. This project will examine ionic transport pathways in a family of solid ion hybrid conductors. These electrolytes are composed of two different types of ion conductors: (1) polymers and (2) ceramics. Currently, it is unknown how ionic transport occurs between these two materials within the electrolyte. In order to achieve batteries that can be charged quickly and last a long time, it is necessary to control ion transport between these two materials. The research objective of this CAREER project is to understand ionic transport by focusing on the characterization of ion transport at the interfaces within the electrolyte. There are two types of interfaces that can form in a solid electrolyte: intrinsic and extrinsic. Intrinsic interfaces occur in hybrid electrolytes between inorganic and organic constituents, and also occur in ceramic ion conductors at grain boundaries. These are examples of interfaces where an ion moves between ion conductors. Extrinsic interfaces are interfaces that emerge during device integration (electrode|electrolyte) and can affect performance. These interfaces involve transport between an ion conductor and a mixed ion and electron conductor. Establishing the role interfaces have on ionic transport will enable pathways toward achieving the competitive performance and functionality. This project will use a multi-modal approach which couples physics-based modeling with electrochemical, spectroscopy, x-ray, and neutron experiments to describe transport mechanisms in hybrid solid electrolytes.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.