Safe, High-Performance, Polymer Electrolyte for Lithium Batteries

用于锂电池的安全、高性能聚合物电解质

• 批准号: 1157590
• 负责人: Peter Kofinas
• 金额: $ 26.87万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-15 至 2016-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1157590&HistoricalAwards=false
• 关键词: Safe; Performance; Polymer; Electrolyte; Lithium

Abstract1157590Kofinas, PeterIntellectual Merit:One of the key barriers to the widespread use of lithium-ion batteries is their potential for catastrophic failure. When cells are thermally or electrically abused, their temperature can rise and exothermic reactions between the combustible, liquid electrolyte and the charged electrodes can cause the battery to combust, giving rise to safety concerns. While improvements in the electrode would ultimately make the future battery more energy efficient, requiring less active material, safety and shape are still largely controlled by the electrolyte. By combining a polymer electrolyte with ionic liquids, the resultant solid system will possess all the desired properties and be conductive enough to be useful as a battery, which will be inherently safe because there is no longer a flammable liquid component. Battery power would also benefit greatly from the conformal and safe nature of solid polymer electrolytes. The goal of this research is to better understand the electrochemical properties and microstructure of novel thin film solid polymer electrolytes with enhanced performance. Experiments have been designed to explore new ionic liquid chemistries, and at the same time fully characterize the electrochemistry and microstructure of the polymer IL blend, while developing a better understanding the nature of the solid electrolyte interphase (SEI). The following objectives will be pursued:1. Never synthesized before IL chemistries will be developed consisting of sulfonium and tetrahyrdothiophenium architectures. The chemical structure of the novel ILs will be characterized using nuclear magnetic resonance and mass spectrometry.2. Solid electrolytes consisting of polyethylene oxide (PEO)-based homopolymers and block copolymers of PEO blended with the synthesized ILs will be prepared via solution casting, and optimized for high power and energy delivery. 3. Upon optimization, a full electrochemical characterization will be completed to allow better understanding of the movement of lithium ions in the bulk and at the SEI. The SEI will be investigated by differential scanning calorimetry (DSC) and accelerated rate calorimetry (ARC), to determine the reaction rates and mechanisms of the constituent materials within the cell. AC impedance experiments will allow the determination of the bulk and interfacial resistance. Overvoltage studies will determine the stability of this interphase. SEM imaging and mass spectroscopy will identify the extent of the SEI and breakdown products. With the development of novel sulfur based ionic liquid compounds proposed in this research, improved performance characteristics are expected of the solid polymer electrolyte. Such shape-conforming materials could be easily wound up into coils or processed as coatings or sheets, thus providing large area devices with integrated electronics. Effectively understanding the mechanism behind the enhanced electrochemical performance of the proposed solid electrolyte systems will greatly benefit the design of the next generation of batteries.Broader Impacts:The broader impact of this research is that it will ultimately help push forward an attractive alternative technology to combustible and corrosive liquid electrolytes. The proposed polymer electrolyte system offers flexibility in both mechanical properties and product design. Ionic liquids offer an attractive option and the electrochemical understanding of novel architectures based upon sulfur will lead to further potential uses for these novel compounds. The solid-electrolyte interphase (SEI) is among the most important yet least understood elements of a battery. Further insight into the polymer electrolyte SEI, would enable the design of tailored interfaces for a future generation of safer batteries with longer lifetimes.This project bridges fundamental concepts of electrochemistry, polymer science, and chemical engineering. In addition to the impacts on science, the proposed project will also broadly impact engineering education, training students of different educational levels and from diverse backgrounds. This training will poise them for successful careers in a wide range of industries or academia. Findings from this work will be published in peer-reviewed journals and presented at professional meetings. Several initiatives are planned including specific programs that assist in undergraduate and graduate education, graduate student mentoring, and training of high school students from schools in minority-rich communities. The PI also plans to mentor a diverse undergraduate "Gemstone" team project on energy storage at the University of Maryland. Gemstone students are members of a living-learning community comprised of fellow students, faculty and staff who work together to enrich the undergraduate experience. This community challenges and supports the students in the development of their research, teamwork, communication and leadership skills. The mentored team of students will presents its energy storage project in the form of a thesis to leaders in the field, and the students complete the program with a citation and a tangible sense of accomplishment.

Kofinas，Peter知识分子的优点：锂离子电池广泛使用的关键障碍之一是它们潜在的灾难性故障。当电池被热或电滥用时，它们的温度会上升，并且可燃的液体电解质和充电电极之间的放热反应会导致电池燃烧，从而引起安全问题。虽然电极的改进最终会使未来的电池更节能，需要更少的活性材料，但安全性和形状仍然在很大程度上由电解质控制。通过将聚合物电解质与离子液体组合，所得固体系统将具有所有所需的性质，并且具有足够的导电性以用作电池，这将是固有安全的，因为不再存在易燃液体组分。电池功率也将极大地受益于固体聚合物电解质的保形和安全性质。本研究的目的是更好地了解具有增强性能的新型薄膜固体聚合物电解质的电化学性能和微观结构。实验已被设计为探索新的离子液体化学，并在同一时间充分表征聚合物IL共混物的电化学和微观结构，同时开发更好地理解固体电解质界面（SEI）的性质。将实现以下目标：1.以前从未合成过的IL化学品将被开发，包括锍和四氢噻吩结构。新型离子液体的化学结构将使用核磁共振和质谱进行表征。将通过溶液浇铸制备由基于聚环氧乙烷（PEO）的均聚物和PEO与合成的离子液体共混的嵌段共聚物组成的固体电解质，并优化用于高功率和能量输送。3.在优化后，将完成完整的电化学表征，以更好地了解锂离子在本体和SEI中的运动。SEI将通过差示扫描量热法（DSC）和加速速率量热法（ARC）进行研究，以确定电池内组成材料的反应速率和机制。交流阻抗实验将允许确定体电阻和界面电阻。过电压研究将确定该相间的稳定性。SEM成像和质谱将识别SEI和分解产物的程度。随着本研究中提出的新型硫基离子液体化合物的开发，预期固体聚合物电解质的性能特性将得到改善。这种形状一致的材料可以容易地缠绕成线圈或加工成涂层或片材，从而提供具有集成电子器件的大面积设备。有效地理解所提出的固体电解质系统增强电化学性能背后的机制将极大地有利于下一代电池的设计。更广泛的影响：这项研究的更广泛的影响是，它最终将有助于推动一种有吸引力的替代技术，以取代易燃和腐蚀性的液体电解质。所提出的聚合物电解质系统在机械性能和产品设计方面都提供了灵活性。离子液体提供了一个有吸引力的选择和基于硫的新架构的电化学理解将导致这些新化合物的进一步潜在用途。固体电解质界面（SEI）是电池中最重要但最不了解的元素之一。 对聚合物电解质SEI的进一步深入了解，将为未来一代更安全、寿命更长的电池设计定制接口。该项目将电化学、聚合物科学和化学工程的基本概念联系起来。除了对科学的影响外，拟议的项目还将广泛影响工程教育，培训不同教育水平和不同背景的学生。这种培训将使他们在广泛的行业或学术界取得成功。这项工作的结果将发表在同行评审的期刊上，并在专业会议上发表。计划采取几项举措，包括协助本科和研究生教育、研究生辅导和培训少数民族丰富社区学校的高中生的具体方案。PI还计划在马里兰州大学指导一个关于储能的多元化本科生“宝石”团队项目。宝石学生是一个生活学习社区的成员，由同学，教师和工作人员谁共同努力，以丰富本科生的经验。这个社区的挑战和支持学生在他们的研究，团队合作，沟通和领导能力的发展。受指导的学生团队将以论文的形式向该领域的领导者展示其储能项目，学生们将以引用和切实的成就感完成该项目。