X-Ray Absorption Fine Structure Spectroscopy as a Probe of Local Structure in Lithium Manganese Oxides

Investigation of Pseudocapacitive Charge-Storage Reaction of MnO[sub 2]⋅nH[sub 2]O Supercapacitors in Aqueous Electrolytes

“…The edge energy is known to increase with increasing Mn valence for Mn oxides. [26][27][28] As shown in Fig. 10b, the main absorption edge ͑B͒ progressively shifted to lower energies when the potential was reduced from 1.0 to 0.0 V, giving direct evidence to the reduction of Mn ions.…”

“…The spectrum of crystalline ␤-MnO 2 is also plotted for comparison. The line profiles of the XANES spectra taken at different potentials are similar, and they are characterized by features which can be divided among a pre-edge range A showing two weak broad peaks at 6538-6545 eV, a main edge range B having one inflection point, and resonance peak ranges C and D. [26][27][28] The pre-edge range A is ascribed 26 to 1 s → 3d transitions, which has been observed with weak intensity for octahedral coordination and strong intensity for tetrahedral coordination. Hence, the experimental spectra ͑Fig.…”

Analysis of the atomic structure of CdS magic-size clusters by X-ray absorption spectroscopy

“…The combination of X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) analyses, in particular, has proved to be a robust methodology for the characterisation of complex systems. [34][35][36][37][38] This approach can provide both local symmetry information (through XANES) as well as structural and stoichiometry information (through EXAFS) that can be used as an input for subsequent analysis of scattering data and computer modelling. Here we utilised X-ray absorption spectroscopy (XAS) to establish a rational basis for understanding the local atomic arrangement and Cd : S ratio in MSC samples that undergo isomerisation transition.…”

Electrochemical Capacitor of MnFe[sub 2]O[sub 4] with Organic Li-Ion Electrolyte

“…The edge energy is conventionally taken as the energy at the first inflection point, and it is known to increase with increasing valence of the transition-metal ion within the oxides. [16][17][18] It was found that the Mn ions in the as-synthesized state have a valence close to three, as the edge energy matches closely with that of Mn 2 O 3 . It has previously been shown 10 by the extended X-ray absorption fine structure ͑EXAFS͒ analysis that the Mn ions are randomly distributed over the tetrahedral and octahedral metal-ion sites within the spinel structure.…”

“…Each XANES spectrum can be divided into a pre-edge region A ͑ϳ6537-6545 eV͒ containing weak peaks, a main edge region B ͑6545-6555 eV͒, and resonance peak regions C ͑6555-6566 eV͒ and D ͑6566-6580 eV͒. [16][17][18] The peaks within preedge region A are ascribed to 1s → 3d transitions. 16 The main absorption region B can be assigned 16,18 to the transition from 1s to p-like states of t 1u symmetry.…”