金属氧化物纳米结构嵌/脱钠机理的原位研究

近年来，以储量丰富、价格低廉、环境友好的钠为基础原料的钠离子电池受到了人们的广泛关注。金属氧化物纳米结构以理论容量高、循环性能好、安全性高等优点被认为是理想的电极材料。然而，由于缺乏成熟知识结构的支撑以及常规分析技术的局限性，其电化学反应过程特别是钠脱/嵌机理尚不完全明确，这是其实用化的主要瓶颈。本课题提出运用原位透射电子显微技术，在微观尺度上对金属氧化物纳米结构的电化学反应过程进行表征并探索尺寸、微观结构对金属氧化物钠脱/嵌机理的影响。通过分析电极材料的原子尺度的结构、成分以及元素价态变化，结合第一性原理计算从更深层次认识电极反应机理并试图建立电极材料原子尺度结构与性能相关联的研究方向。

Recently, the sodium-ion batteries have attracted great attention due to the abundant, cheap and environmentally-friendly sodium resources on the earth. Metal oxide nanostructures are considered as the ideal electrode materials because of the high theoretical capacity, excellent cycle capability as well as the high safety. However, the electrochemical processes, especially the sodiation and desodiation mechanisms in the metal oxides remain largely unexplored due to the lacking of a well-established knowledge system and limitation of conventional techniques, which pose a huge challenge to their applications. In this context, this project aims to explore the sodiation and desodiation mechanisms as a function of specimen size, micro-structure in low-dimensional metal oxides nanostructures by employing the advanced in-situ transmission electron microscopy. Through the detailed analysis of the microstructures, compositions and elemental valences in electrode materials and the assistance of the first-principle calculations, we are trying to obtain a deep understanding of the reaction mechanisms and provide a possible pathway for investigating the relationship between atomic structures and electro-chemical properties in electrode materials.