Scalable and Durable Lithium-sulfur Batteries Utilizing Self-healing Solid-state Hybrid Electrolyte Materials

可充电锂离子电池通过存储风能和太阳能等间歇性可再生资源产生的电力，或通过可再生资源充电为零排放电动汽车提供动力，帮助实现可持续能源系统。提高锂电池性能和降低成本的一个关键挑战是增加充电容量。使用硫元素作为阴极的固态锂电池的理论存储容量几乎是传统锂离子电池的三倍，但稳定电池所需的固体电解液的导电性较低。为了提高电解液的导电性，本项目将开发由陶瓷导体材料和聚亚胺材料混合而成的新型固体电解质材料。关键的创新是陶瓷材料将被设计成具有高锂离子导电性，聚亚胺将提高陶瓷导体材料在重复充放电循环中的机械稳定性。此外，为了促进技术转让给私营部门，固体电解质的制造步骤将被设计为在未来实现可扩展的制造。与该项目相关的教育活动包括本科生积极参与研究，特别是来自工程专业的代表不足的群体，通过科罗拉多大学博尔德分校的各种项目协调招聘。研究的总体目标是开发用于锂硫电池的固态混合电解液，由二元无机硫化锂和硫化磷基陶瓷导体以及作为粘结剂的可延展性自修复聚亚胺组成。所提出的固态混合电解质有望显著改善机械性能、锂离子导电性和循环稳定性。高导电性、无针孔和缺陷的薄膜电解液将被制造并集成到电化学电池中。将研究聚亚胺聚合物/陶瓷导体界面的聚合物结构和表面化学对电池性能的影响。该研究计划有四个目标。第一个目标是开发离子导电性、延展性、自愈性的聚亚胺聚合物作为固态混合电解质的基质。第二个目标是确定与基质聚合物具有良好表面附着力的导电陶瓷材料。第三个目标是开发一种可靠的离子导电薄层连续杂化膜的制备工艺，第四个目标是研究含有新型杂化电解液的固态锂硫电池的结构-性能关系。

Rechargeable lithium ion batteries help to enable sustainable energy systems by storing electricity generated by intermittent renewable resources such as wind and solar energy, or by powering zero-emission electric vehicles charged by electricity from renewable resources. A key challenge to improve performance and to reduce cost of lithium batteries is to increase charge capacity. Solid-state lithium batteries that use the element sulfur as the cathode have a theoretical storage capacity that is nearly three times higher than conventional lithium ion batteries, but suffer from low conductivity of the solid electrolyte needed stabilize the battery. To improve the conductivity of the electrolyte, this project will develop new solid electrolyte materials composed of ceramic conductor materials mixed with polyimine materials. The key innovations are that the ceramic materials will be engineered for high lithium ion conduction, and the polyimines will improve the mechanical stability of ceramic conductor material during repeated charging and discharging cycles. Furthermore, to facilitate technology transfer to the private sector, the solid electrolyte fabrication steps will be designed to enable scalable manufacture in the future. The educational activities associated with this project include active participation of undergraduates in research, particularly from under-represented groups in engineering, with recruitment coordinated through a variety of programs at the University of Colorado, Boulder.The overall goal of the research is to develop solid-state hybrid electrolytes for lithium-sulfur batteries composed of binary inorganic lithium sulfide and phosphorous sulfide based ceramic conductors, and malleable self-healing polyimines that serve as the binder material. The proposed solid-state hybrid electrolytes are anticipated to have significantly improved mechanical properties, lithium ionic conductivity, and cycling stability. Highly-conductive, thin film electrolytes free of pinholes and defects will be fabricated and integrated into the electrochemical cell. The effects of polymer structure and surface chemistry at the polyimine polymer/ceramic conductor interface on battery performance will be studied. The research plan has four objectives. The first objective is to develop ion-conducting, malleable, self-healing polyimine polymers to serve as the matrix of solid-state hybrid electrolyte. The second objective is to identify conductive ceramic materials with good surface adhesion to the matrix polymers. The third objective is to develop a reliable process for fabrication of ion-conducting thin continuous hybrid membranes, and the fourth objective is to study the structure-property relationships of the solid-state lithium-sulfur batteries containing the new hybrid electrolytes.