SusChEM: Design and Manufacture of Electrodes for High Energy Density Rechargeable Sodium Batteries

可存储大量能量的可再充电电池是当今社会在诸如移动的电子设备和电动车辆等应用中的关键技术。在未来，这种电池也将是在商业和家庭电力中使用可再生能源的关键技术。如今，这种可充电电池的最广泛使用的形式是锂离子电池。用低得多的成本和更丰富的元素钠（即，食盐中常见的元素）。改用钠可以降低电池的成本，并允许相同大小的电池存储更多的电力。然而，这种从锂到钠的转换是具有挑战性的，因为电池的其他组件目前与钠的使用不兼容。特别是，当电池中使用钠时，收集这种电池产生的电流的电流材料会迅速损坏。该项目的目标是通过开发可成功用于钠离子电池的新型电极材料来解决这一重大挑战。除了直接的科学影响和更广泛的影响，交通和可再生能源，可以通过这项技术，该项目将支持跨学科的研究与教育的学生在研究生，本科和高中水平的能源存储。这项研究是一个很好的平台，让公众和K-12学生了解科学和工程对社会的价值，并将通过休斯顿地区的高中外展计划来吸引女性和第一代大学生到科学，技术，工程和数学（STEM）领域。这项工作的中心假设是，空间效应可以通过增加电池电极中使用的嵌入框架的晶格间距来减轻或消除。本研究的目标是开发通过化学分层-重新堆叠方法来调节层状材料的层间距的方法，该方法可以改善插层框架中的离子传输和离子容纳。这项工作结合了电化学，计算和微观表征实验，以了解这种方法的设计和行为，工作的重点是开发和理解钼金属氧化物MoO 3-聚合物纳米复合材料，其特征是MoO 3片和聚合物层的交替层状结构，用于高性能可充电钠电池。该计划的主要特点包括精确控制具有所需层间距的MoO 3-聚合物纳米复合材料的合成，通过电化学比较这些复合材料中锂、钠和钾的嵌入动力学来表征离子尺寸对这种复合材料中嵌入行为的影响，并通过密度泛函理论模拟和原位透射电子显微镜观察，对钠在膨胀MoO 3结构中的嵌入过程进行了原子理解。这项工作的结果将导致一个通用的策略，以操纵二维无机层状化合物在原子水平上作为有利的主机材料用于插入大阳离子用于电池电极材料。

Rechargeable batteries that can store a large amount of energy are a critical technology for society today in applications such as mobile electronics and electric vehicles. In the future, such batteries will also be a critical technology for use of renewable energy sources in commercial and home electric power. The most widely used form of such rechargeable batteries today is the lithium ion battery. There would be benefits to replacing lithium which is a somewhat expensive and scarce element in these batteries with the much lower cost and more abundant element sodium (i.e., the common element found in table salt). The change to sodium could lower the cost of the battery and could allow for the same size battery to store more power. However, this switch from lithium to sodium is challenging since the other components of the battery are not currently compatible with use of sodium. In particular, the current materials that collect the electric current produced by such batteries are damaged quickly when sodium is used in the battery. The goal of this project is to solve this major challenge by developing new electrode materials that can successfully be used in sodium ion batteries. In addition to the direct scientific impact and the broader impacts in transportation and renewable energy that could be enabled by this technology, this project will support interdisciplinary research on energy storage with education of students at the graduate, undergraduate, and high-school levels. This research makes an excellent platform in which to engage both the public and K-12 students on the value of science and engineering to society and will be used through a Houston-area high school outreach program to attract female and first generation college students to Science, Technology, Engineering, and Mathematics (STEM) fields. The central hypothesis of this work is that steric effects can be alleviated or eliminated by increasing the lattice spacing of the intercalation frameworks used in battery electrodes. The goal of this research is develop methods to tune the interlayer distances of layered materials through a chemical delamination-restacking approach that can allow for improved ion transport and ion accommodation in the intercalation framework. This work combines electrochemical, computational, and microscopic characterization experiments to understand the design and behavior of such an approach, with the focus of the work on development and understanding of a molybdenum metal oxide MoO3-polymer nanocomposite featuring an alternating layered structure of MoO3 sheets and polymer layers for high performance rechargeable sodium batteries. Key features of the plan include the precise control of the synthesis of MoO3-polymer nanocomposites with desired interlayer distances, characterization of the influence of ion size on intercalation behavior in such composites by electrochemically comparing the intercalation kinetics of lithium, sodium, and potassium in these composite materials, and the formulation of an atomistic understanding of the intercalation process of sodium in the expanded MoO3 structures by density functional theory modeling and in-situ transmission electron microscopic observation. The results of this work will lead to a general strategy to manipulate two-dimensional inorganic layered compounds at the atomic level as favorable host materials for intercalation of large cations for use in battery electrode materials.