Multi-edge and Multiple Scattering EXAFS Analysis of Metal Hexacyanoferrates: Application in Battery Materials

The occurrence of multiple scattering (MS) phenomena in the extended portion of the X-ray absorption spectrum permits to disclose details of the local atomic structure of the target atom. The high order MS paths become relevant only in peculiar structures, regardless the crystallinity of the investigated sample, such as in metal hexacyanoferrates. General guidelines and prescriptions are presented in order to give the authors a useful guide for a correct interpretation of the EXAFS spectra of this class of compounds, which is characterized by close, but sufficiently separated, discontinuities of the absorption coefficient due to the probed contiguous transition metal K-edges. The large number of experimental points, the occurrence of large four-body MS terms, and the presence of multiple probes are discussed in the frame of the renewed attention of these compounds for their use in the battery community.