Development of XANES nanoscopy on BL7C at PLS-II

Abstract

X‐ray absorption near‐edge structure (XANES) imaging is a powerful tool to visualize the chemical state distribution of transition‐metal‐based materials at synchrotron radiation facilities. In recent years, the electrochemical working rechargeable battery has been the most studied material in XANES imaging owing to the large increase of portable electronics and electric vehicles. This work acknowledges the importance of battery analysis and has developed the XANES imaging system on BL7C at Pohang Light Source‐II (PLS‐II). BL7C employs an undulator taper configuration to obtain an energy band >130 eV near the K‐absorption edge of the target element with a minimum energy interval >0.2 eV. While measuring energy‐dependent images, the zone plate translation maintains the best focus, and then various data processes such as background correction, image registration and clustering allow single XANES spectrum extraction and chemical distribution mapping. Here, the XANES imaging process is described, the XANES spectrum quality is identified and the chemical states of the partially charged cathode material used in lithium‐ion batteries as an application example are examined.

Carbon nanotube-reduced graphene oxide fiber with high torsional strength from rheological hierarchy control

“…Due to the small total weight of fiber produced, classic BET measurements were not possible to probe pore quantity and structure; however, the reduced porosity in D-HF and D-GF compared to HF and GO was confirmed using x-ray nano-cryotomography data (Supplementary Fig. 5) 34 and cryotomographic TEM micrographs of the fibers (Supplementary Fig. 6).…”

Exploring spectroscopic X-ray nano-imaging with Zernike phase contrast enhancement

“…The ZPC-XANES experiment was conducted using the spectroscopic X-ray Nano Imaging Beamline (BL7C) of the Pohang Light Source II (PLS-II, South Korea). This beamline was operated in two modes: zone plate-based full-field transmission X-ray microscopy with Zernike phase 26 , 27 and TXM-XANES 28 . Unlike conventional on-axis TXM, BL7C utilizes off-axis illumination, which has the advantages of minimal phase contrast artifacts and easy alignment with the phase plate 25 .…”

“…The TXM-XANES setup at BL7C is briefly described below, and more details can be found elsewhere 26 – 28 . X-rays emitted from the undulator source were monochromatized by a double-crystal Si (111) monochromator in the range of 5–15 keV.…”

Soft X-ray Absorption Spectroscopic Investigation of Li(Ni0.8Co0.1Mn0.1)O2 Cathode Materials

“…The X-ray absorption images based on TXM were captured at various energies within a 1 eV interval in the range −20 to 80 eV from the main edge energies of each respective element. The XANES spectrum was extracted from these X-ray absorption images [22].…”

“…The X-ray absorption images based on TXM were captured at various energies within a 1 eV interval in the range −20 to 80 eV from the main edge energies of each respective element. The XANES spectrum was extracted from these X-ray absorption images [22].Soft XAS measurements of this cathode material at various charging and discharging states were performed with the 10D XAS-KIST beamline of the same laboratory in total electron yield (TEY) mode. The grating with 1100 grooves/mm was used to measure spectra at the Mn L-, Co L-, Ni L-, and O K-edges.…”