%0 Journal Article
%T A Review on the Structural Studies of Batteries and Host Materials by X-Ray Absorption Spectroscopy
%A Marco Giorgetti
%J ISRN Materials Science
%D 2013
%R 10.1155/2013/938625
%X This review highlights the use of the X-ray absorption spectroscopy (XAS) as a local structural tool for selected atoms in several host materials. The main characteristics of XAS to be element-sensitive and its applicability to all states of matter, including crystalline solids and amorphous and liquid states, permit an in-depth study of the structural properties of a large variety of materials. This includes intercalation materials where a host structure can accommodate guest species. Host guest equilibria are at the basis of a large variety of technological applications; in particular they have been used for energy storage, ion-exchange membranes, electrochromism, and analytical sensing. A selection of XAS experiments conducted in the field of batteries, mainly on cathodes, and applications in the field of metal hexacyanoferrates and double layered hydroxides are outlined. 1. Introduction Since the discovery of X-rays by Rontgen [1] over 100 years ago in his laboratory in Wurzburg, X-rays have provided a nondestructive testing of a wide variety of materials. X-ray methods cover many techniques based on scattering, emission, and absorption properties of the X-ray radiation. X-ray diffraction probes the order of matter at the atomic level and X-ray crystallography is essential in relating the atomic structure of solids to their functions and physical properties. A review on high energy X-ray diffraction from glasses and liquids has been published in this journal [2] recently. X-ray emission spectroscopy makes possible the determination of the chemical composition of samples by simply looking at the emitted X-ray fluorescent lines and nowadays is one of the most useful analytical techniques [3]. The absorption property of X-rays has been used in analytical techniques based on contrast, like imaging and tomography. Owing to today¡¯s X-ray sources by which X-rays are generated by relativistic electrons or positrons in international laboratories, in storage rings machines, the beam intensity is trillions of times more brilliant with respect to traditional X-ray sources, offering unprecedented advantages. It is therefore possible to verify the existence of fine structures in X-ray absorption spectra and, once a theory has been formulated [4, 5], the X-ray absorption fine structure (XAFS) (XAFS is another term used nowadays. The general preference is to use either XAS or XAFS to refer to the entire spectrum, which comprises the XANES (near the edge spectrum, within 30£¿eV or so), and EXAFS to refer to the extended part. Therefore XAS = XAFS = XANES + EXAFS)
%U http://www.hindawi.com/journals/isrn.materials.science/2013/938625/