MOx(M=Fe,Co,Ni)纳米结构的缺陷调控及其电化学储能性质研究

Defects play vital roles in physical and chemical properties for functional and structural materials. Design and tuning the defect structures in electrode materials on the nanoscale are of importance in the realization of next generation electrochemical energy storage systems, such as lithium-ion battery and sodium-ion battery, with performance better than those of the existing ones. In this project, typical metal oxides, MOx (M=Fe , Co, Ni), are chosen as negative materials to study their electrochemical energy storage performance. Firstly, MOx nanostructures are synthesized through wet chemical reaction and electrochemical deposition routes. MOx nanocrystallines with distinct morphologies can be obtained by controlling the nucleation and growth processes from thermodynamic and/or kinetic pathway. Then the defect structures (such as surface structures and oxygen vacancies) in MOx nanocrystallines can be well controlled by employing solution phase and/or gas phase reduction methods. Combining various microstructure characterization techniques (scanning electron microscope, image aberration-corrected transmission electron microscopy, and x-ray photoelectron spectroscopy) with electrochemical properties testings, the relations between the defects structures of MOx and the electrochemical energy storage performance are quantitative analyzed on the atomic-scale. We believe that the results are helpful to further reveal the atomic mechanism of lithium/sodium ion transportation in MOx electrode materials, and will shed light on optimizing performance in other MOx related electrochemical processes. Project from this proposed research will be of importance for the research and development of novel electrode materials with high energy storage performance.

缺陷对于材料的物理、化学性能具有重要影响，在纳米尺度设计和调控电极材料的缺陷结构是研发下一代电化学储能系统(锂离子电池、钠离子电池等)的关键之一。本申请项目将以典型的金属氧化物MOx(M=Fe , Co, Ni)电极材料作为研究对象，采用液相化学反应、电化学沉积等方法制备MOx纳米结构；从热力学和动力学控制的角度来调节MOx纳米结构的成核及长大过程，从而获得具有不同形貌的MOx纳米晶体。在此基础上结合液相还原、气相还原等方法，实现对MOx纳米晶体中缺陷结构(如表面结构、氧空位等)的调控。我们将结合多种微观结构表征手段(包括扫描电子显微镜、球差校正透射电子显微镜、x射线光电子能谱等)，以及电化学方法对MOx纳米结构进行表征，定量研究MOx的缺陷结构对于电化学储能性能的影响规律。本项目的完成对于促进新型电化学储能电极材料的研究和发展具有指导意义。

过渡金属氧化物引入缺陷结构如氧空位，界面结构等是一种有效的改性策略，可以改善材料固有电导率，提供更多的活性位点，促进锂离子的扩散和运输。本项目以典型的金属氧化物MOx(M=Co, Ni, Nb, Ti)电极材料作为研究对象，从热力学和动力学控制的角度来调节MOx纳米结构的成核及长大过程，从而获得了立方体，片状等不同形貌的MOx纳米晶体。并在此基础上结合激光辐照，液相还原、气相还原等方法，实现了对MOx纳米晶体中缺陷结构(如界面结构、氧空位等)的调控。采用多种微观结构表征方法（包括扫描电子显微镜、透射电子显微镜、x射线光电子能谱等）系统地研究了界面结构以及氧空位对其电化学性能的影响规律。本项目的完成对于促进新型电化学储能电极材料的研究和发展具有指导意义。