Collaborative Research: Thermodynamics and Ion Transport in Block Copolymer/Lithium Salt Mixtures

技术综述：对嵌段共聚物和锂盐混合物中有序形态、颗粒结构和离子导电性之间的相互作用进行了基础性研究。这项工作的结果可能会对固体电解液高比能量电池的发展产生影响。这项工作将集中在通过阴离子聚合合成的聚苯乙烯-聚环氧乙烷嵌段共聚物和双三氟甲基磺酰亚胺(LiTFSI)的混合物上，LiTFSI是一种经常用于含有聚合物电解液的电池的盐。小角X射线散射和去偏振光散射将被用来确定这些材料中有序-无序和有序-有序相变的性质。电导率测量将使用交流阻抗谱在X射线和光散射研究中使用的相同样品上进行。测量范围广泛，包括嵌段共聚物组成、盐浓度、温度和热处理条件。非技术概述：本项目提出的基础工作的动机是需要为电动汽车和固定储能等与清洁能源相关的应用设计安全的可充电电池。提出的纳米结构离子导电固体将用作锂电池的电解液。通过用固体取代目前锂电池中使用的易燃液体电解液，人们可以使用更高能量的电极，这反过来又增加了电池的能量密度。没有易燃成分，电池就安全了。联合PIS将使用固态电池在其涉及高中生的外展活动中进行示范。Garetz与纽约市的David Packard技术和教育联盟中心合作，在与技术和研究相关的领域指导当地高中生。巴尔萨拉在伯克利的数学和科学暑期学院项目和丰富项目工作，该项目将奥克兰学区的学生带到加州大学。PIS将继续与波兰A.Mickiewicz大学的M.Banaszak教授就由NSF在波兰举办的一个研讨会产生的含离子聚合物的主题进行合作。

TECHNICAL SUMMARY:A fundamental study of the interplay between ordered morphology, grain structure, and ionic conductivity in mixtures of block copolymers and lithium salts is proposed. The results of the work have the potential to impact the development of high specific energy batteries with solid electrolytes. The work will focus on mixtures of polystyrene-polyethyleneoxide block copolymers, synthesized by anionic polymerization, and bis-trifluoromethylsulfonimide (LiTFSI), a salt that is often used in batteries containing polymer electrolytes. Small-angle X-ray scattering and depolarized light scattering will be used to determine the nature of the order-disorder and order-order phase transitions in these materials. Conductivity measurements will be made on the same samples as those used in the X-ray and light scattering studies using AC impedance spectroscopy. Measurements will be made over a wide range of block copolymer compositions, salt concentration, temperature, and annealing conditions. NON-TECHNICAL SUMMARY:The fundamental work proposed in this project is motivated by the need to design safe rechargeable batteries for clean energy-related applications such as electric vehicles and stationary energy storage. The proposed nanostructured ion-conducting solid will be used as the electrolyte in a lithium battery. By replacing the flammable liquid electrolyte that is used in current lithium batteries by a solid, one can use higher energy electrodes that, in turn increase the energy density of the battery. The absence of a flammable component makes the battery safe. The co-PIs will use solid-state batteries for demonstrations in their outreach activities involving high school students. Garetz works with the David Packard Center for Technology and Educational Alliances in New York City to mentor local high school students in fields related to technology and research. Balsara works with Math and Science Summer Academy program at Berkeley, and enrichment program which brings students from the Oakland School District to the University of California. The PIs will continue an ongoing collaboration with Professor M. Banaszak at A. Mickiewicz University, Poland on the subject of ion-containing polymers that arose from an NSF-sponsored workshop in Poland.