Optimizing Ion Mobility, Chemical Stability, and Mechanical Rigidity in Composite Electrolytes

非技术描述：能源存储是可持续和可再生能源技术以及移动信息系统的关键方面。阳极和阴极的化学性质决定了在给定尺寸的电池中可以储存的能量，而隔膜材料（或电解质）控制着电池的充电循环速率、寿命和结构完整性。负责电化学转换的离子（如锂）的高电导率有助于高功率释放和短充电时间。电解质和电极材料之间的化学相容性阻止了阻塞层的形成，从而抑制了电化学过程。电解液的机械刚性可以抑制枝晶的生长，从而使器件短路并导致灾难性故障（如自燃）。不幸的是，这些性能标准依赖于相互冲突的材料属性，而挑战在于设计一种能够最大化所有这些属性的复合结构。在这项研究中，基于模拟的预测设计、先进的材料合成方法、微观结构表征和性能监测相结合，开发了具有无与伦比性能的新型复合电解质。该项目以创新的方式培养博士生结合实验和计算工具进行研究的能力，为本科生提供研究经验，有助于人力资源的开发。通过ASM高中教师营与中学教育工作者建立联系。此外，他们还在为少数族裔服务机构的学生推行一项新的硕士指导计划。预计这将有双重好处——一方面，学生们对科学研究有了更深入的了解，另一方面，教师们在积极招募代表性不足的少数民族和女性进入科学和工程博士课程方面处于更有利的地位。技术细节：本研究的目标是开发具有高Li+导电性的复合电池电解质，其机械刚性足以抑制锂枝晶的生长，并在自支撑装置结构中安全地分离电极，并且具有足够宽的电化学稳定范围以适应大的电极电位差。虽然高离子电导率和转移数对电池的充放电率很重要，但刚度和电化学稳定性对于利用锂金属的完全氧化还原电位至关重要，从而增加这些设备的能量存储的重量容量。基于分子模拟的预测设计、有机-无机混合溶胶-凝胶合成、利用非弹性光散射对微观结构发展的原位监测以及介质阻抗测量相结合，用于系统地探索材料化学和构建块功能，以创建纳米多孔非均质电解质。通过增强的刚度、几何优化的Li+迁移路径、最小的阳离子和供体之间的耗散耦合以及可调的氧化还原电位，这些混合网络结构被设计成具有无与伦比的可充电电池电解质性能。

NON-TECHNICAL DESCRIPTION: Energy storage is a critical aspect of sustainable and renewable energy technologies, and mobile information systems. While the chemical nature of anode and cathode determines the amount of energy that can be stored in a battery of a given size, the separator material (or electrolyte) controls its charge cycling rates, lifetime, and structural integrity. High conductance of the ion responsible for the electrochemical conversion (e.g., lithium) facilitates high power release and short recharge times. Chemical compatibility between electrolyte and electrode materials prevents the formation of blocking layers that would suppress the electrochemical process. Mechanical rigidity of the electrolyte inhibits dendrite growth that can short circuit the device and lead to catastrophic failure (e.g., spontaneous combustion). Unfortunately, these performance criteria rely on conflicting materials properties, and the challenge lies in devising a composite structure that maximizes all these attributes. In this research, a combination of simulation-based predictive design, advanced materials synthesis approaches, microstructural characterization, and performance monitoring is employed to develop new composite electrolytes with unsurpassed performance. This project contributes to the development of human resources in an innovative way by training a doctoral student in combining experimental and computational tools of investigation, and providing research experiences for undergraduate students. Connections with secondary school educators are reached through an ASM High School Teachers Camp. As well, they are pursuing a new masters mentoring program for students from minority serving institutions. It is expected to have a dual benefit - on one hand, students are gaining insight into scientific research, and on the other hand, faculty are better-positioned to proactively recruit underrepresented minorities and women into doctoral programs in science and engineering.TECHNICAL DETAILS: The objective of this research is to develop composite battery electrolytes that exhibit high Li+ conductivity, that are mechanically rigid enough to suppress lithium dendrite growth and safely separate electrodes in self-supporting device structures, and that possess an electrochemical stability range wide enough to accommodate large electrode potential differences. While high ionic conductivity and transference numbers are important for the charge-discharge rates of batteries, stiffness and electrochemical stability are essential for taking advantage of the full redox potential of Li metal, and thus increase the gravimetric capacity of energy storage for these devices. A combination of molecular simulation-based predictive design, hybrid organic-inorganic sol-gel synthesis, in situ monitoring of microstructural developments using inelastic light scattering, and dielectric impedance measurements is used to systematically explore materials chemistries and building block functionalities for the creation of nano-porous heterogeneous electrolytes. By targeting enhanced stiffness, geometrically optimized Li+ migration paths, minimal dissipative coupling between cation and donor, and tunable redox potentials, these hybrid network structures are designed to exhibit unsurpassed performance as rechargeable battery electrolytes.