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.

Abstract1157590Kofinas，peterinlectual Feerit：广泛使用锂离子电池的关键障碍之一是它们造成灾难性故障的潜力。当细胞被热或电滥用时，它们的温度会升高，可燃，液体电解质和带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。尽管电极的改进最终将使未来的电池更效率更高，需要较少的活性材料，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相结合，所得的固体系统将具有所有所需的特性，并具有足够的导电性，可以用作电池，因为不再有易燃液体成分，这将是固有的。电池电量也将从固体聚合物电解质的共形性和安全性中受益匪浅。这项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特性和微结构。已经设计了实验来探索新的离子液体化学化学，同时完全表征了聚合物IL混合物的电化学和微结构，同时更好地理解了固体电解质中相（SEI）的性质。将实现以下目标：1。在将IL化学植物开发出由磺硫酸盐和四刺菌体构造组成之前，切勿合成。新型IL的化学结构将使用核磁共振和质谱法进行表征。2。由聚乙烯氧化物（PEO）组成的固体电解质将通过溶液铸造来制备，并将PEO与合成的IL融合在一起的PEO的嵌段共聚物，并针对高功率和能量递送进行了优化。 3。优化后，将完成完整的电化学表征，以更好地理解锂离子在散装和SEI中的运动。 SEI将通过差分扫描量热法（DSC）和加速速率量热法（ARC）进行研究，以确定细胞内组成材料的反应速率和机制。交流阻抗实验将允许确定散装和界面电阻。过压研究将确定该相间的稳定性。 SEM成像和质谱将确定SEI和分解产物的程度。随着这项研究中提出的新型基于硫的离子液体化合物的发展，固体聚合物电解质的性能特征得到了改善。这种结合形状的材料可以很容易地被缠绕到线圈中或作为涂层或板的加工，从而为大面积设备提供了集成的电子设备。有效地了解提出的固体电解质系统增强电化学性能的机制将极大地受益于下一代电池的设计。Broader的影响：这项研究的更广泛影响是，它最终将有助于推动有吸引力的替代技术来推动可燃的替代技术和腐蚀性液体电解质。提出的聚合物电解质系统具有机械性能和产品设计的灵活性。离子液体提供了一个有吸引力的选择，并且基于硫的新结构的电化学理解将导致这些新型化合物的进一步潜在用途。固素电解质相间（SEI）是电池中最不了解的元素之一。 对聚合物电解质SEI的进一步了解，可以设计量身定制的界面，以使未来一代更安全的电池具有更长的寿命。该项目Bridges Bridges的基本概念是电化学，聚合物科学和化学工程的基本概念。除了对科学的影响外，拟议的项目还将广泛影响工程教育，培训不同教育水平的学生以及不同背景。这项培训将使他们在各种行业或学术界的成功职业中为他们提供平衡。这项工作的发现将在同行评审期刊上发表，并在专业会议上提出。计划了几项举措，包括有助于本科和研究生教育的特定计划，研究生指导以及对少数富裕社区学校的高中生培训。 PI还计划指导马里兰州大学能源存储的多样化的本科“宝石”团队。宝石学生是一个生活学习社区的成员，由同学，教职员工组成，他们共同努力，以丰富本科生的体验。这个社区挑战并支持学生的研究，团队合作，沟通和领导能力。受过指导的学生团队将以论文的形式向该领域的领导者提出其能源存储项目，并以引文和有形的成就感来完成该计划。