CAREER: Identifying and Controlling Interfacial and Structural Instabilities in Transition Metal Oxide Cathodes for Na-ion Batteries

该项目由CBET电化学系统计划和既定的激励竞争研究计划(EPSCoR)共同资助。与人口增长、环境问题和技术进步相关的日益增长的能源需求给现代社会带来了利用可再生能源的压力。钠离子电池在原料来源的可获得性、成本的降低和对环境友好的性质方面，是大规模/电网规模储能的有前途的候选者。然而，由于正极材料的严重不稳定性，钠离子电池的电化学性能受到循环寿命短和容量衰减快的影响。由于缺乏对不稳定性机理的了解，限制了新型钠离子电池正极材料的设计。该研究计划将产生关于钠离子阴极不稳定和变形背后潜在控制力的基础知识。这一知识对其他“超越锂离子电池”的技术来说是一个潜在的变革性概念，如K离子、镁离子和钙离子电池。这份职业建议书的主要教育目标是促进K-12、本科生和研究生水平的电池基础知识的学习，以及增加公众对电池操作基础知识的了解。教育和外联活动包括为K-12学生编写关于电池操作机制的图形小说，为STEM领域未来的K-12教师提供教育平台，在科学博物馆准备电池展览，以及将研究成果整合到大学教育中。这份职业建议解决了与钠离子电池中过渡金属氧化物阴极界面和结构稳定性差相关的科学问题。该提案将重点放在由锰和铁等富含地球的矿物组成的过渡金属氧化物上。研究活动的目的是确定过渡金属、操作电压和电解液化学对过渡金属氧化物阴极化学机械不稳定性的影响。一般认为，Na+离子在过渡金属氧化物结构中的插层不可避免地改变了耦合的输运-反应过程，导致电极表面和结构中的化学机械不稳定性，从而导致容量的快速衰减。该项目将研究在有机液体电解液中循环的单一和二元过渡金属氧化物阴极的反应-传输行为和机械变形之间的耦合。在手术中，应力/应变测量将与化学和结构表征技术相结合，以确定对界面和结构变形的控制力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project is jointly funded by the CBET Electrochemical Systems program and the Established Program to Stimulate Competitive Research (EPSCoR) Program. Increasing energy demand associated with the growing population, environmental concerns, and technological advancements imposes pressure on modern society to utilize renewable energy sources. Sodium (Na)-ion batteries are promising candidates for large-scale/grid-scale energy storage in terms of availability of raw sources, cost reduction and its environmentally benign nature. However, the electrochemical performance of Na-ion batteries suffers from short cycle life and rapid capacity fade due to severe instabilities in the cathode materials. Lack of understanding of instability mechanisms limits the design of novel cathode materials for Na-ion batteries. The research program will generate fundamental knowledge of the underlying governing forces behind the instabilities and deformations in Na-ion cathodes. This knowledge is a potentially transformative concept for other “beyond Li-ion battery” technologies such as K-ion, Mg-ion, and Ca-ion batteries. The overarching educational objective in this CAREER proposal is to facilitate learning the fundamentals of batteries at K-12, undergraduate and graduate student levels as well as increase public knowledge of the fundamentals of battery operations. The educational and outreach activities include developing graphic novels about battery operation mechanisms for K-12 students, providing an educational platform for future K-12 teachers in STEM fields, preparing battery exhibits at a Science Museum, and integrating research outputs into college education. This CAREER proposal addresses the scientific problem related to poor interfacial and structural stabilities of transition metal oxide cathodes in Na-ion batteries. The proposal will focus on transition metal oxides made of earth abundant minerals such as manganese and iron. The goal of the research activities is to identify the impact of transition metals, operation voltage and electrolyte chemistry on chemo-mechanical instabilities in transition metal oxides cathodes. The guiding hypothesis is that intercalation of Na+ ions in transition metal oxide structure inevitably alters the coupled transport-reaction processes, leading to chemo-mechanical instabilities in the surface and structure of the electrode, resulting in rapid capacity fade. The project will examine the coupling between reaction-transport behavior and mechanical deformations in single and binary transition metal oxide cathodes cycled in organic liquid electrolytes. In operando stress / strain measurements will be coupled with chemical and structural characterization techniques to identify the governing force on interfacial and structural deformations.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.