Free Standing Flexible Lithium-Ion Polymer Electrolyte Membranes formed by Photopolymerization

技术概述：该项目的主要目标是(1)证明对三相图的基本理解如何为独立柔性聚合物电池的简易制造提供指导；(2)阐明通过光刻技术产生各向同性排列的离子通道周期性阵列的控制原则，并具有良好的定义域大小和周期性。这些由光聚合诱导相分离产生的排列通道不仅可以作为离子导线（或微通道），而且可以在不牺牲独立电池膜的机械强度和完整性的情况下提高离子浓度。这种垂直方向的周期性通道阵列在太阳能电池应用有机材料的开发中被高度追求，以增强电子/激子的传输，以及在可充电聚合物电池中高效的Li+离子传输。该项目侧重于确定共晶相图，作为抑制和/或消除聚乙二醇二丙烯酸酯(PEGDA)/琥珀腈(SCN)/双（三氟甲基磺酰基）亚胺锂（LiTFSI）二元和三元混合物中不良成分晶体的手段。该体系的独特之处在于，PEGDA光刻交联不仅提高了网络的机械强度和完整性，而且增加了离子通过无扰动通道的输运。此外，定向排列的通道结构由于增加了界面面积和与SCN的腈基络合作用，也增加了离子存储容量。SCN的另一个优点是可以有效地电离离子盐，也可以完全消除不需要的LiTFSI晶体。更重要的是，制备的聚合物电解质膜是一种不需要有机溶剂的独立膜，在环境温度下具有高电导率（7.1x10-3 S/cm）。制造的聚合物电解质膜可以在40-80摄氏度的宽温度范围内工作。非技术摘要：该项目的目标是研究和开发用于“绿色”电动汽车的轻质可充电独立式聚合物锂离子电池。与传统的电解质电池不同，聚合物电解质膜不含有毒或易燃的有机溶剂，因此可以避免溶剂泄漏或电池燃烧等安全问题。目前的聚合物电解质是可塑成任何形状或形式的，因此它应该有更广泛的用途。柱状形貌沿膜厚方向垂直排列的策略将进一步改善离子通过通道的传输，并由于表面/界面面积的增加而增强离子储存能力。由此获得的知识可以转移到当前项目范围之外，特别是用于开发太阳能电池和信息技术中的光电开关的有机材料。该项目将培养研究生和本科生，他们将接触到高分子材料科学、工程数学和电化学的多学科研究。研究成果将通过PI的网站或阿克伦全球聚合物学院的远程学习项目向公众传播，该学院为高中科学教师及其学生举办讲习班。

TECHNICAL SUMMARY: The principal objectives of this project are (1) to demonstrate how the fundamental understanding of ternary phase diagrams may provide guidance to facile fabrication of free-standing flexible polymer batteries and (2) to elucidate governing principles for creation of periodic arrays of ionic channels aligned homeotropically via photolithography and having well defined domain size and periodicity. These aligned channels produced by photopolymerization-induced phase separation will not only serve as ion conducting wires (or micro-channels), but also increase the ion concentration without sacrificing the mechanical strength and integrity of the free-standing battery membranes. Such periodic arrays of channels with perpendicular orientation have been highly sought for enhanced electron/exciton transport in the development of organic materials for solar cell applications as well as for efficient Li+ ion transport in rechargeable polymer batteries. This project focuses on determination of the eutectic phase diagram as a means of suppressing and/or eliminating undesirable constituent crystals in the binary and ternary mixture of polyethylene glycol diacrylate (PEGDA)/succinonitrile (SCN)/lithium bis-(trifluoromethylsufonyl)imide (LiTFSI). The uniqueness of the present system is that photolithographic crosslinking of PEGDA not only affords improved mechanical strength and integrity of the networks, but also increases the ion transport through the unperturbed channels. Moreover, the aligned oriented channel structure will also increase the ion storage capacity due to increase in interface areas and complexation with nitrile groups of SCN. Another advantage is that SCN can effectively ionize the ionic salts and also completely eliminate the undesirable LiTFSI crystals. More importantly, the fabricated polymer electrolyte membrane is a free-standing film that requires no organic solvent and has a high conductivity (7.1x10-3 S/cm) at ambient temperature. The fabricated polymer electrolyte membrane may be operated over a wide temperature range, from 40-80 deg C.NON-TECHNICAL SUMMARY: The goal of this project is to study and develop lightweight and rechargeable free-standing polymer lithium ion batteries for "green" electric vehicles. Unlike conventional electrolyte batteries, the present polymer electrolyte membrane contains no toxic or flammable organic solvent and thus the safety issue such as solvent leakage or battery combustion may be avoided. The present polymer electrolyte is moldable in any shape or form, and thus it should find broader utility. The strategy of the perpendicular alignment of cylindrical columnar morphology along the film thickness direction will further improve ion transport through the channels and enhance ion storage capacity due to increase in surface/interface areas. The knowledge thus acquired can be transferred beyond the scope of the current project, specifically to development of organic materials for solar cells and photo-optical switching in information technology. This project will educate graduate and undergraduate students who will be exposed to multi-disciplinary research in polymer materials science, engineering mathematics, and electrochemistry. The research outcomes will be disseminated to the public through the PI's website or distance-learning programs of the Akron Global Polymer Academy, which conducts workshops for high-school science teachers and their students.