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应用的先进锂离子电池可以改善国内能源安全，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难以理解的不良化学副反应。由于缺乏基本的理解，工程师们更难设计出能够持续预期寿命的材料和设备。这个职业项目将对先进的固态混合电解质进行基础研究，这些电解质具有在保持安全操作环境的同时具有更大能量密度的潜力。这些混合电解液可以取代目前使用的液体有机电解液，这些液态有机电解液的循环寿命较长。在这些杂化材料中，活性物质(锂离子)在电解液中的传输和到电极的传输还没有完全被理解。这个项目将涉及支持理解混合电解质中离子传输的基本物理和化学转换的基础知识。这些知识还将对化学传感器、燃料电池和其他电池化学产生深远的影响。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和哈佩斯·霍尔女子学校的研究实习计划，将研究成果直接整合到纳什维尔社区。所有外联活动都力求将科学和工程机会扩大到STEM中代表性不足的社区。该项目将研究固体离子杂化导体家族中的离子传输路径。这些电解液由两种不同类型的离子导体组成：(1)聚合物和(2)陶瓷。目前，还不清楚电解质中这两种材料之间的离子传输是如何发生的。为了实现快速充电和长时间充电的电池，有必要对这两种材料之间的离子传输进行控制。这一职业项目的研究目标是通过重点研究电解液内界面上的离子传输特性来了解离子传输。在固体电解质中可以形成两种类型的界面：本征界面和外在界面。本征界面出现在无机和有机成分之间的混合电解液中，也出现在晶界处的陶瓷离子导体中。这些是离子在离子导体之间移动的界面的例子。外部界面是在设备集成过程中出现的界面(电极|电解液)，可能会影响性能。这些界面涉及离子导体和混合离子和电子导体之间的传输。确定界面对离子传输的作用将使实现具有竞争力的性能和功能的途径成为可能。该项目将使用一种多模式方法，将基于物理的建模与电化学、光谱学、X射线和中子实验相结合来描述混合固体电解质中的传输机制。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.