Dynamics and Structure in Complex Disordered FIC Electolytes: Is There a Maximum Ionic Conductivity in the Solid State?

[9972466]马丁这个项目将对无序电解质中的电荷输运有新的认识。对电池和燃料电池等基于电化学的便携式能源日益增长的依赖和性能要求，将迅速超过这些设备的核心技术所设定的当前技术基准。例如，电池和燃料电池电解质必须将其离子电导率提高几个数量级以上，以跟上这些设备所要求的不断增加的损耗率。几年前，电池和燃料电池中固体电解质离子电导率的这种提高是可能的，这一点没有受到质疑。PI的新研究表明，情况可能并非如此。他在化学优化的快速离子导电（FIC）玻璃上的工作表明，离子电导率的非阿伦尼乌斯温度依赖性很强，将离子电导率限制在比预期低100到1000倍的范围内。这一现象将对当今市场上众多基于电化学能量的设备产生巨大的设计影响，这些设备的数量正以指数速度增长。在这个项目中，新的银离子导体的电导率将被测量到更高的温度和更宽的频率范围，以确定电导率是否达到饱和或最大值。然后，新的锂离子导体将被测量，看看非阿伦尼乌斯电导率是否普遍存在。宽频率范围核自旋晶格弛豫率（NSLR）和电导率测量相结合，以确定活化能的温度无关分布是否可以用来拟合NSLR和电导率的温度和频率依赖关系。这种拟合将有力地检验简单活化过程理论是否描述了离子动力学，或者是否必须包括额外的动力学效应。此外，将建立包括强多体相互作用在内的电导率的温度和频率依赖的理论模型，将进行从强相互作用区到短时间弱相互作用区全时域响应的非弹性中子散射和高频电导率研究，将开发原子级传导拓扑的分子动力学模拟。弹性中子散射研究将在中间范围水平上进行探测玻璃结构，其中场地连通性很重要。该项目将涉及研究生研究团队与本科生和高中生合作，与美国和国际研究人员以及国内电池制造商密切合作。越来越多的依赖和性能要求的电化学便携式能源，如电池和燃料电池，用于如此多的消费产品，需要更好的和更好的能源。该项目将提供对电解质化学性质与其性能之间关系的理解，从而使离子电导率增加数量级的纳米级新电解质的设计成为可能。PI建立的强大研究团队，以及国际合作，有望在这一领域取得进展

9972466MartinThis project will develop fundamental new understandings of charge transport in disordered electrolytes. The ever increasing dependence upon and the performance requirements of electrochemically-based portable energy sources, such as batteries and fuel cells, will rapidly outpace the current technological benchmarks being set by the core technologies of these devices. Battery and fuel cell electrolytes, for example, will have to increase their ionic conductivity by more than a couple of orders of magnitude to keep pace with the ever increasing drain rates required of these devices. That such increases in the ionic conductivities of the solid electrolytes in batteries and fuel cells are possible was not questioned a few years ago. New research by the PI has shown that such may not the be the case. His work on chemically optimized fast ion conducting (FIC) glasses has shown that a strong non-Arrhenius temperature dependence of the ionic conductivity limits the ionic conductivity to values 100 to 1000 times below that expected. This phenomenon will have tremendous design implications for the multitude of electrochemical-energy based devices that are on the marketplace today and whose numbers are growing at an exponential rate. In this project, the conductivity of new silver-ion conductors will be measured to higher temperatures and wider frequency ranges to determine if the conductivity reaches a saturating or maximum value. Then, new lithium-ion conductors will be measured to see if the non-Arrhenius conductivity is universal. Wide frequency range nuclear spin lattice relaxation rate (NSLR) and conductivity measurements will be combined to determine if a temperature independent distribution of activation energies can be used to fit the temperature and frequency dependence of both the NSLR and the conductivity. Such fitting will be a powerful test of whether simple activated process theory describes the ion dynamics or whether additional dynamical effects must be included. In addition, theoretical models of the temperature and frequency dependence of the conductivity that include strong many-body interactions will be developed, inelastic neutron scattering and high frequency conductivity studies of the full time-domain response from the strongly interacting regime into the short time weakly interacting regime will be performed, molecular dynamics simulations of the atomic-level conduction topologies will be developed, and elastic neutron scattering studies will be performed to probe glass structure at the intermediate range level where site connectivity is important. The project will involve graduate student research teams working with undergraduate and high school students in a strong collaboration with both US and international researchers as well as a domestic battery manufacturer. %%%The ever increasing dependence upon and the performance requirements of electrochemically-based portable energy sources, such as batteries and fuel cells, used in so many consumer products, demand better and better energy sources. This project will provide understanding of the relationships between the chemistry of the electrolyte and its performance and thus will enable design at the nano-scale of new electrolytes with order of magnitude increases in ionic conductivities. The strong research team the PI has built, along with the international collaborations, promise advances in this area.***