Rational Design of Barrier Films to Enable Rechargeable Mg-S Batteries

镁硫（Mg-S）可充电电池是一种潜在的具有成本效益和高能量密度的解决方案，可用于电动运输。该技术的一个技术障碍是，当与硫阴极一起使用时，可再充电Mg金属电池的电解质要求迄今为止限制了循环寿命。在该项目中，PI将对用于电解质-阴极界面的紫外光固化聚合物阻隔膜进行基础研究，以保持电池的容量。功能聚合物膜将防止某些反应性物质的交叉，从而减轻有害反应并保持电池的阳极、电解质和阴极的化学完整性。这项工作产生的基础科学知识可以使新材料的其他应用中的性能特性受到离子传输和离子排斥的影响。此外，将通过进一步开发高中外联模块以及扩大妇女和代表性不足的少数民族本科生和研究生对研究的参与，加强化学科学和工程学下一代研究人员的数量、多样性和培训。 该项目解决了Mg-S电池开发中的两个基本限制：活性阴极材料与电解质物质反应的分解和阴极中间体对阳极的钝化。这两个问题可以通过防止不期望的物质穿过电解质-阴极界面的传输来减轻。聚合物阻隔膜，使Mg-S电池循环的结构-性能关系将被询问。在该项目的第一个主题中，自支撑膜将通过高度可解离的镁滴定离子单体与各种不同化学和长度的双官能低聚单体交联而形成。 非原位研究将评估膜在传导镁阳离子和排除阴离子多硫化物和/或亲核络合物方面的功效。空间，介电和静电排斥的机制将独立探测。在第二个主题中，紫外线固化阻隔膜将直接刮涂到硫阴极片上。将研究膜的厚度、一致性和化学性质对全电池Mg-S电池性能的影响。电池的性能将与薄膜的基本特性相关联。

Magnesium-sulfur (Mg-S) rechargeable batteries are a potentially cost-effective and high energy density solution for use in electric transportation. One technical barrier to this technology is that the electrolyte requirements for rechargeable Mg metal batteries have thus far limited cycle life when used with sulfur cathodes. In this project, the PI will conduct fundamental research on UV light-curable polymeric barrier films for the electrolyte-cathode interface to enable capacity retention of the battery. The functional polymeric films will prevent cross-over of certain reactive species, thus mitigating deleterious reactions and maintaining chemical integrity of the anode, electrolyte, and cathode of the battery. The fundamental scientific knowledge generated by this work could enable advances in new materials for other applications where performance characteristics are influenced by ion transport and ion rejection. Additionally, the number, diversity, and training of the next generation of researchers in the chemical sciences and engineering will be enhanced by the further development of an outreach module for high schools and by the broadening participation of women and underrepresented minority undergraduate and graduate students in research. This project addresses two fundamental limitations in Mg-S battery development: breakdown of active cathode material by reaction with electrolyte species and passivation of the anode by cathode intermediates. Both issues may be mitigated by preventing the transport of undesirable species across the electrolyte-cathode interface. Structure-property relationships of polymeric barrier films to enable Mg-S battery cycling will be interrogated. In the first theme of the project, self-supporting films will be created by crosslinking of a highly dissociable magnesium-titrated ionic monomer with a variety of difunctional oligomeric monomers of varying chemistry and length. Ex-situ studies will evaluate the efficacy of the films in conducting magnesium cations and excluding anionic polysulfides and/or nucleophilic complexes. The mechanisms of steric, dielectric, and electrostatic exclusion will be independently probed. In the second theme, the UV-curable barrier films will be blade coated directly onto sulfur cathode sheets. Effects of thickness, conformity, and chemistry of the films on full cell Mg-S battery performance will be investigated. The performance of the cells will be linked with the fundamental characteristics of the films.