EAGER: Ion Transport Properties and Engineering of Interfaces of Layered Kevlar Assemblies for High Performance Lithium Battery Membranes

1036672科托夫寻找一种高容量和快速放电的安全储能技术解决方案，对于美国向碳中性经济和石油独立过渡至关重要。锂金属聚合物电池和一些锂离子电池都有可能达到储电所需的参数，但必须解决所有锂电池技术的中心瓶颈，即界面质量/电荷传输的根本问题，即树枝晶的生长。它们是自行车性能迅速下降和严重的消防安全问题的根源。这导致迫切需要防止树枝晶生长的离子传导膜(ICM)的新概念。在对ICM-电极界面传输过程进行理论分析的基础上，从理论上证明了剪切模数G≥7 Gpa的ICM可以完全抑制枝晶生长。目前，还没有满足这一要求和其他关键要求的材料，如离子电导率大于10-4 S/m。为了解决这一瓶颈，并赋予表面上相互矛盾的材料特性，需要新的制造方法来设计界面工艺/性能，并实现电池材料的技术目标。智力优势：本项目将利用(1)逐层组装和(2)超强芳纶纳米纤维来获得能够完全抑制枝晶生长的新一代ICM。LbL是一种非常简单、廉价的技术，可获得具有出众的均匀性和高杨氏S模数的薄膜。使用芳纶纤维将进一步增强它们的机械性能。这种聚合物将以非传统的形式作为纳米纤维分散体使用，直径为50-70 nm，长度为1-3微米。基于令人鼓舞的初步结果，PI计划实现概念验证。目标是：(1)利用离子导电聚合物的离子模板，达到10~(-4)-10~(-3)S/米范围内的离子电导率；(2)通过使用固有的强Lbl组分和它们之间受控的界面交联，达到G>7 Gpa。这两个目标本质上都与材料的界面和质量传输过程有关，该集团在这方面拥有广泛的专业知识和技术能力。这是一种从根本上创新的制造ICM的方法，并且没有一批在树枝晶形成方面具有专业知识的研究人员。除了LBL技术作为一种制造ICM的新方法的引入外，离子在固体材料中的传输便利化为电池和其他能量转换技术的发展提供了独特的机会。这类技术还包括燃料电池和渗透能量发生器。凯夫拉纳米纤维的使用代表了对这种成熟的柔性装甲材料潜在用途的传统看法的巨大变化。锂离子模板工艺的发展也有望带来额外的智力影响，如果没有对ICM接口的纳米级控制，以前很难实现这一点。广泛影响：拟议的工作朝着缓解二氧化碳中性(能源)经济道路上的技术瓶颈迈出了重要的一步。新型ICM的开发可以为电动汽车提供具有竞争力的全电动选择，并为太阳能和风力发电场提供高容量的电力存储系统，从而大大减少二氧化碳排放。中间电存储块的安全是大型电池的另一个基本挑战，这里也在解决这一问题。在研究工作的同时，还将积极传播有关新材料对能源研究的重要性的信息。项目的这一部分将在密歇根州安娜堡社区高中的高中生和密歇根大学电气和计算机工程系的本科生的大力参与下完成，我们从2007年就与他们建立了关系。调查人员将与他们一起开发一个网站，解释现在和未来发电和用电量链的关键组成部分的原理。本科生和高中生的联合工作预计将对高年级学生的载体选择产生强大的积极影响，并将有助于将更多高素质、代表性不足的少数族裔和女性学生带入工程学。

1036672KotovFinding a technological solution for safe energy storage with high capacity and fast discharge rates is vital for the transition to the carbon neutral economy and oil independence in the USA. The required parameters for electricity storage can potentially be achieved for Li metal polymer batteries and some Li+ ion batteries, but one must resolve the central bottleneck of all lithium battery technologies related to the fundamental problems of interfacial mass/charge transport, i.e. the growth of dendrites. They are the source of rapid decrease the performance upon cycling and serious fire safety concerns. This leads to the acute need of new concepts in ion-conducting membranes (ICMs) preventing dendrite growth. Based on theoretical analysis of transport processes at the ICM-electrode boundary, it was theoretically established that dendrite growth can be inhibited entirely by an ICM with a shear modulus of G ¡Ý7 GPa. Presently, there are no materials available satisfying this and other key requirements, such as ionic conductivity ¡Ý 10- 4 S/m. To resolve this bottleneck and to impart seemingly contradictive material characteristics, new manufacturing methods are needed to engineer interfacial processes/properties and achieve the technological targets for battery materials.Intellectual Merit: This project will utilize (1) layer-by-layer assembly (LBL) and (2) ultrastrong Kevlar nanofibers to obtain a new generation of ICMs that can completely suppress dendrite growth. LBL is very simple inexpensive technique leading to films with exceptional uniformity and high Young¡¯s modulus. Their mechanical properties will be further enhanced with Kevlar. This polymer will be used in an unconventional form as nanofibers dispersion with a diameter of 50-70 nm and a length of 1-3 microns.Based on encouraging preliminary results, the PIs plan to achieve proof-of-concept. The Objectives are: (1) to reach ion-conductivity in 10-4-10-3 S/m range using ion templating of ion-conducting polymers; and (2) to attainG¡Ý 7 GPa by using inherently strong LBL components and controlled interfacial cross-linking between them. Both of these objectives are intrinsically related to the interfacial and mass transport processes of the materials, where the group has extensive expertise and technical capabilities. This is a fundamentally innovative method for manufacturing of ICMs and does not have an established pool of researchers with expertise in dendrite formation. Besides the introduction of LBL technique as a novel method for manufacturing the ICMs, facilitation of ion transport in solid materials provides unique opportunities for the development of batteries as well as other energy conversion technologies. Such technologies also include fuel cells and osmotic energy generators. The utilization of nanoscale fibers of Kevlar represents a great change from the traditional view of potential uses of this well-established flexible armor material. Additional intellectual impact is also expected from the development of lithium ion-templating process which would be difficult to realize before without nanoscale control of interfaces in ICMs.Broader Impact: The proposed work makes a significant step toward alleviating the technological bottlenecks on the way to CO2¨Cneutral (energy) economy. The development of new ICMs can greatly reduce CO2 emissions by making possible competitive full electric options for electrical vehicles and high capacity electrical storage systems for solar energy and wind farms. Safety of intermediate electrical storage blocks is another fundamental challenges for large scale batteries which is being addressed here as well. The research work will be accompanied by aggressive dissemination of information about importance of new materials for energy research. This part of the project will be done with strong involvement of the high school students from Community High School in Ann Arbor, MI with whom we have established relationships from 2007, and undergraduates from the UM Department of Electrical and Computer Engineering. Together with them, the investigators will develop a web-site explaining the principles of key components of the chain of electricity generation and consumption now and in the future. The joint work of undergraduates and high school students is expected to have a strong positive impact on the carrier choices of upper classmen and will help bringing greater number of highly qualified underrepresented minority and female students to engineering.