Moldable, self-healing, highly conductive organic co-crystalline solid electrolytes for safer lithium ion batteries

本项目由材料研究部固态与材料化学项目资助，由两位教授课题组组成。天普大学的Zdilla和Wunder正在开发一种用于锂离子电池的新型固体电解质分离器。目前的锂离子电池技术依赖于使用易燃且具有潜在爆炸性的液体电解质，这种电解质会导致移动设备、电动汽车和其他应用中的电池起火和爆炸。开发固体的、可燃性最低的替代品将提高这些设备的安全性。然而，许多目前研究的固体电解质表现出较差的性能或与现有电池化学不相容。凭借该奖项，主要研究人员将合成和研究软固体共晶电解质（即结合两种或多种分子成分但形成均匀晶体结构的电解质），以了解基础材料化学，从而实现更高的功率性能，并保证与现有和下一代电池组件的兼容性。研究人员还使用计算工具来更好地了解这些由有机框架分子和锂离子源的新组合组成的材料，并表征它们的电化学特性。该项目通过开发一种基本的理解，使技术能够提高电池的安全性和性能，从而符合国家利益。电池是移动设备、运输和清洁能源技术中日益重要的组成部分。实现安全、高功率、高能量的电池技术为太阳能储存和减少运输中化石燃料的使用提供了一条途径，这两者都为美国提供了更大的能源独立性，并为气候健康减少了碳足迹。此外，这项研究有助于在该国最多样化的学校之一培养下一代科学家，并为代表性不足的群体提供了巨大的影响。技术总结。本项目由材料研究部固态与材料化学项目资助，由两位教授组成的课题组。天普大学的Zdilla和Wunder开发了一种用于锂离子电池的新型固体电解质分离器。电池电解质研究的进展一直是渐进式的，基本上都是对液体有机体系、固体聚合物和固体陶瓷的改性。在这项工作下研究的新型固体电解质有可能比其他固体有机电解质具有更好的导电性，同时表现出比目前市场标准的液体更好的电压稳定性和电极稳定性窗口。研究人员从基础研究的角度研究了这种材料的新型机械物理特性，包括开发一种促进自我修复的表面液体层。虽然表面液固平衡的概念是已知的（如水冰的经典例子），但这种特性从未应用于电解质材料，因此代表了一个基本见解的机会。研究目标：1、电导率和锂离子转移数（tLi+）优化的离子基共晶的制备与表征。这是通过最大化阳离子的迁移率而最小化阴离子的迁移率来实现的，这是通过设计与阴离子而不是与阳离子强烈相互作用的矩阵来实现的。2：电化学性能和机械/热性能的评价。这是通过使用x射线衍射、电化学分析（电化学阻抗谱、循环伏安法、线性扫描伏安法和循环研究）、热分析（DSC、TGA）和电子显微镜进行尸检分析来实现的。3：利用分子动力学和量子分子计算模拟离子传导的物理性质和机制。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Non-Technical SummaryFor this project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, the research groups of Profs. Zdilla and Wunder at Temple University are developing a new class of solid electrolyte separators for lithium-ion batteries. Current lithium-ion battery technology relies on the use of a flammable and potentially explosive liquid electrolyte which has led to battery fires and explosions in mobile devices, electric vehicles, and other applications. The development of solid, minimally flammable replacements would enhance the safety of these devices. However, many currently investigated solid electrolytes exhibit poor performance or incompatibility with existing battery chemistry. With this award, the principal investigators synthesize and study soft-solid co-crystalline electrolytes (i.e. electrolytes that combine two or more molecular components but form a uniform crystalline structure) to understand the fundamental materials chemistry that could enable higher-power performance and promise compatibility with existing and next-generation battery components. The researchers also use computational tools to better understand these materials that consist of new combinations of organic framework molecules and lithium-ion sources and characterize their electrochemical properties. The project serves the national interest by developing a fundamental understanding that enables technologies to improve the safety and performance of batteries, an ever-more central component of technology in mobile devices, transportation, and clean energy. Realization of safe, high-power, high-energy battery technology provides a path toward solar energy storage and decreased use of fossil fuels for transportation, both of which provide greater energy independence for the United States, and a means to decrease carbon footprint for the health of the climate. Further, this research serves to train the next generation of scientists at one of the most diverse schools in the country and serves underrepresented groups with great effect.Technical Summary.For this project, supported by the Solid State and Materials Chemistry program in the Division of Materials Research, the research groups of Profs. Zdilla and Wunder at Temple University develop a new class of solid electrolyte separators for lithium-ion batteries. Progress in battery electrolyte research has been incremental and essentially relegated to modifications of liquid organic systems, solid polymers, and solid ceramics. The new class of solid electrolytes investigated under this effort has the potential to enable better conductivity than other solid organic electrolytes, while at the same time exhibiting better voltage stability and electrode stability windows than liquids, the current market standard. The researchers investigate the materials’ novel mechanophysical properties from a fundamental research perspective, including a developing a surface liquid layer that facilitates self-healing. While the concept of a surface liquid-solid equilibrium is known (as in the classic example of water-ice), this property has never been applied to electrolyte materials, and thus represents an opportunity for fundamental insights. The objectives of the research are: 1: Preparation and characterization of ion-matrix cocrystals with optimized conductivity and lithium-ion transference numbers (tLi+). This is achieved by maximizing the mobility of the cation while minimizing the mobility of the anion, which is achieved by designing matrices that interact strongly with the anion, but not with the cation. 2: Evaluation of electrochemical performance and mechanical/thermal properties. This is achieved using characterization using X-ray diffraction, electrochemical analysis (electrochemical impedance spectroscopy, cyclic voltammetry, linear sweep voltammetry, and cycling studies), thermal analysis (DSC, TGA), and post-mortem analysis by electron microscopy. 3: Modelling the physical properties and mechanism of ion conduction using molecular dynamics and quantum molecular computation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.