金属基储能材料相界面的原子分辨率表征

Electrical energy storage device, such as supercapacitors and lithium-ion batteries are promising candidate to replace fossil energy, thus has arouse intense research interest. However, design of high performance electrode materials requires an urgent and better understanding of the structure-property relationship. Interfacial is one of the most important energy storage mechanism. Since the interfacial region is local and fine in nature, it is very difficult to characterize the interfacial energy storage mechanism. In this study, we will choose the metallic based energy storage materials and study their interfacial energy storage and electrochemical failure mechanism by means of aberration-corrected transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS). The ion conduction, electron structure and structure evolution at the metallic/compound interface will be focused at atomic spatial resolution and sub electron voltage energy resolution..Since metals contain free electrons at the surface, the influence of surface plasmon resonance on electrochemical properties and energy storage mechanism will be studied. As for the supercapacitor metal/oxide hybrid electrode, the charge transfer at the interface will be clarified to understand the synergistic effect of metal and oxide for high capacity performance. For lithium-ion batteries, the energy storage and electrochemical failure mechanism at the interface of metal and cathode compound will be studied in terms of ion and electron conduction. The interfacial film scale will be varied to study the size effect of ion conductivity. The ultimate goal is to build up the structure-property relationship for interfacial energy storage.

作为化石能源的替代者，电储能装置如超级电容器和锂离子电池引发了人们的研究热潮，高性能电极材料的设计迫切需要建立结构与性能间的关系。两相界面是一种重要的储能机制，由于其局域的特点，在过去很难观察相界面的储能机制。本项目选择具有代表性的金属基储能材料作为对象，以球差矫正透射电子显微与能量损失谱技术研究金属/无机物界面的离子传导、电子结构、结构演化，将揭示相界面的储能和失效机制。.金属表面富含自由电子，本项目将研究金属/电介质表面等离子体共振对电化学性能与界面储能的影响；研究超级电容器中金属/氧化物混合电极相界面的电荷转移机制，理解混合电极两相材料界面产生协同化效应的原因；研究锂离子电池中金属/正极材料相界面的储能和电化学失效机制，理解离子传导率的尺寸效应，建立界面结构与电化学性能的关系。

作为化石能源的替代者，电储能装置如超级电容器, 锂离子电池和燃料电池引发了人们的研究热潮，高性能电极材料的设计迫切需要建立结构与性能间的关系。两相界面是一种重要的能量储存和转换机制，由于其局域的特点，在过去很难观察相界面的能量储存和转换机制。本项目选择具有代表性的金属/氧化物储能材料作为对象，以球差矫正透射电子显微与能量损失谱技术研究了钛酸锂材料在充电过程中界面的离子传导、电子结构、结构演化，揭示了相界面的储能机制和动力学过程。.本项目研究了钛酸锂负极材料反应机制和动力学，发现界面电荷造成的电势差是钛酸锂快速嵌锂的主要原因，解释了钛酸锂零应变材料具有高倍率充放电性能的原因。此外，研究了金属/氧化物复合材料的氧还原催化性能，发现两相间的晶格匹配和电荷耦合是其具有优异循环稳定性的原因，为深入理解金属/氧化物的结合界面和金属/(氢)氧化物的协同催化效应奠定了基础。这些研究成果将深入理解电池反应和催化过程中材料的界面耦合、电子结构和失效过程。