CAREER: SusChEM: Structure-property relationships in bi-functional battery materials

非技术描述：虽然锂离子电池一直是便携式电子产品的主要电源，但其在运输和固定市场的大规模应用可能会受到锂丰度有限的阻碍。另一方面，钠元素的储量是锂的1000多倍，国内外都认为钠资源充足。钠基电池化学的发展对于确保人类的可持续能源未来至关重要。这个职业项目研究了一类独特的双功能(无论是作为阴极还是作为阳极)钠电极材料的结构-性能关系，以阐明可能导致材料性能增强和新材料的合理设计和发现的基本机制。该项目还将举办一个名为“电池：为过去、现在和未来提供动力”的博物馆展览，以提高公众对日常生活中无处不在的电池设备的科学和工程原理的认识和兴趣。技术细节：钛酸镍钠是一种独特的材料家族，由于高和低氧化还原电势过渡金属的共存，它既可以用作阳极，也可以用作阴极。然而，这些材料的结构-性能关系仍然难以捉摸。本项目旨在对钛镍钠系模型材料的原子和电子结构及其对离子和电子导电性的影响有一个基本的了解。通过结合中子/X射线散射探针、原子模拟和电学性质测量的综合实验和计算方法，该项目研究了钠原子的局域分布、迁移路径和离子电导率，以及局域电子分布及其对电子电导的影响。从这项工作中获得的知识对这一具有重要技术意义和科学吸引力的材料家族产生了直接影响，并有助于揭示一般混合离子-电子导体的结构-性能关系，从而导致合理设计和发现具有优异性能的新材料。

NON-TECHNICAL DESCRIPTION: While lithium-ion batteries have been the dominant power sources for portable electronics, their large-scale applications in the transportation and stationary markets are likely to be hindered by the limited lithium abundance. On the other hand, the element sodium is more than 1000 times more abundant than lithium and sodium resources are considered adequate nationally and internationally. Development of sodium-based battery chemistry is essential in ensuring a sustainable energy future for human kind. This CAREER project studies the structure-property relationships of a unique family of bi-functional (as either cathode or anode) sodium electrode materials, in order to shed light on the fundamental mechanisms that could lead to enhanced materials performance and rational design and discovery of new materials. This project also enables a museum exhibition named "Batteries: Powering the Past, Present, and Future" to raise awareness and inspire interests of the public in the science and engineering principles of ubiquitous battery devices in our daily lives.TECHNICAL DETAILS: Sodium nickel titanates are a unique family of materials that can function either as anode or cathode due to coexistence of both high and low redox-potential transition metals. However, the structure-property relationship of these materials remains elusive. This project seeks to develop a fundamental understanding of the atomic and electronic structures and their effects on the ionic and electronic conductivity of model materials in the sodium nickel titanate family. Through an integrated experimental and computational approach combining neutron/X-ray scattering probes, atomistic simulation, and electrical property measurement, the project studies the local distribution, migration pathways, and ionic conductivity of sodium atoms, as well as the local electron distribution and its effect on the electronic conductivity. Knowledge garnered from this work has an immediate impact on this family of technologically important and scientifically intriguing materials, and also helps to shed light on the structure-property relationships in general mixed ionic-electronic conductors, thus leading to rational design and discovery of new materials with superior performance.