X-ray Absorption Fine Structure (XAFS) Studies of Oxide Glasses—A 45-Year Overview

Abstract

X-ray Absorption Fine Structure (XAFS) spectroscopy has been widely used to characterize the short-range order of glassy materials since the theoretical basis was established 45 years ago. Soon after the technique became accessible, mainly due to the existence of Synchrotron laboratories, a wide range of glassy materials was characterized. Silicate glasses have been the most studied because they are easy to prepare, they have commercial value and are similar to natural glasses, but borate, germanate, phosphate, tellurite and other less frequent oxide glasses have also been studied. In this manuscript, we review reported advances in the structural characterization of oxide-based glasses using this technique. A focus is on structural characterization of transition metal ions, especially Ti, Fe, and Ni, and their role in different properties of synthetic oxide-based glasses, as well as their important function in the formation of natural glasses and magmas, and in nucleation and crystallization. We also give some examples of XAFS applications for structural characterization of glasses submitted to high pressure, glasses used to store radioactive waste and medieval glasses. This updated, comprehensive review will likely serve as a useful guide to clarify the details of the short-range structure of oxide glasses.

High Performance Lithium‐Ion Batteries Using Layered 2H‐MoTe2 as Anode

“…The presence of oscillations in the region after the absorption edge is associated with the structural order within short distances. [ 25,51,52,54 ] From 0.5 V discharge voltage onward, the features are similar to the standard Mo foil. During the discharge process, due to a decrease of interaction between Mo and Te atoms, the oscillation gradually diminishes with the increase in the concentration of Li + and, finally, the feature matches with that of the Mo foil (Figure 5d).…”

“…These features are pre‐edge (transition from 1s to 3d bound state), [ 25,47,48,50 ] the main edge due to the transition of photoelectrons resonance from 1s to the continuum multiple scattering, [ 25,47,48,51–53 ] and the post‐edge above the main edge with the typical wiggles/oscillatory features, which provide information about the nearest neighbors and the local chemistry. [ 52 ] The CV curve (shown in Figure 3a) where, during the first discharge, the CV showed two broad peaks in between 1.5 and 0.9 V, which correspond to the intercalation of lithium into the MoTe 2 host lattice to form the Li x MoTe 2 structure. There is a sharp peak at 0.72 V, which is followed by a small peak at 0.4 V during Li + insertion; additionally, a sharp oxidation peak at 1.82 V during the removal of Li + is observed.…”

Local Structure and Magnetism of Fe2O3 Maghemite Nanocrystals: The Role of Crystal Dimension

“…The peak energy (7.114 keV) corresponds to transitions involving Fe 3+ . Indeed, a shoulder at lower energy (~7.111 keV) should appear in case of non-negligible Fe 2+ ions concentration [69,70]. Its progressive intensity-decrease on reducing the particles dimension could be due to either a reduction of local structural distortion around Fe ions or to an increased concentration of Fe vacancies in tetrahedral sites.…”

Effect of Germanium Incorporation on the Electrochemical Performance of Electrospun Fe2O3 Nanofibers-Based Anodes in Sodium-Ion Batteries

“…The WL of the spectrum of Fe 2 O 3 :Ge NFs, as well as for quartz-like GeO 2 , was unique and intense, as expected in case of tetrahedral coordination. Indeed, when Ge is in an octahedral environment (e.g., in rutile-like GeO 2 ), the WL is broadened and split into three distinct features [88,89].…”