3D investigation by X-ray Nano Holo-Tomography of transition metal precursors used for the synthesis of Li-rich positive electrode materials

We would like to perform X-ray nano-Hollography Tomography to characterize the microstructure of the oxide precursors used to synthesize Li-rich layered oxide positive electrode materials. The oxides show secondary particles being about 10 µm in average with primary particles smaller than 40 nm (spatial resolution) for primary particles. The lithiated layered oxides are also characterized by secondary particles being about 10 µm in diameter, with primary particles up to 200 nm in diameter. The goal is to visualize the overall porosity of the spherical aggregates. They will be put in a resin that will be cut with a laser to get cylinders of approximately 100 µm high and 30-40 µm in diameter. Those will be put on a carbon pin. This preparation will allow to have enough particles cut to make a statistical analysis of the different oxide samples.

本研究拟采用X射线纳米全息层析成像（X-ray nano-Hollography Tomography）对用于合成富锂层状氧化物正极材料（Li-rich layered oxide positive electrode materials）的氧化物前驱体的微观结构进行表征。该氧化物前驱体的二次颗粒平均粒径约为10 μm，一次颗粒粒径小于40 nm，表征所需空间分辨率适配一次颗粒尺度。经嵌锂后的层状氧化物同样以二次颗粒为主要结构形态，其直径约为10 μm，一次颗粒直径最高可达200 nm。本研究的目标是可视化球形团聚体的整体孔隙率。将待测样品置于树脂中，通过激光切割制备得到高度约100 μm、直径30~40 μm的圆柱状试样，随后将此类圆柱试样放置于碳针之上。该制样方法可保证获得足够多的切割颗粒，以开展不同氧化物样品的统计分析。