Transmission X-ray microscope based three-dimensional XANES imaging

Abstract

The combination of full-field transmission X-ray microscopy (TXM) with X-ray absorption near edge structure (XANES) spectroscopy enables the acquisition of two-dimensional (2D) or three-dimensional (3D) morphological and chemical-specific information within samples at the tens of nanometer scale. This technique has a broad range of applications in material sciences and battery research. Despite its extensive applicability, 2D XANES imaging is subject to the disadvantage of information overlap when the sample thickness is uneven. 3D XANES imaging is a technique that combines 3D TXM with XANES, thereby enabling the acquisition of 3D distribution information pertaining to chemical states. A 3D XANES imaging method has been developed at the Shanghai Synchrotron Radiation Facility (SSRF) and has been employed to characterize the structure and chemical state of commercial LiNixCoyMnzO2 (NCM, x + y + z = 1) battery powder materials. The imaging results provide a visual representation of the 3D chemical state information of the particles with depth resolution, thus allowing for the direct observation of 3D nickel oxidation. This paper will provide a detailed account of the data acquisition, data processing, quantification and visualization analysis of 3D XANES imaging.