Structural modifications and electrochemical behavior of lithium-inserted In16Fe8S32

摘要

We have studied the structural modifications that occur during electrochemical insertion of lithium into the spinel compound In16Fe8S32. Studies by X-ray diffraction (Rietveld analysis) and Mossbauer spectroscopy of the lithiated products indicate that some cation migration takes place during the insertion process. The Mossbauer spectra show that no reduction of Fe2+ takes place during the insertion. The variation of the isomer shift indicates an increase in the covalency of the network. The results of the X-ray absorption experiments show the absence of a clear reduction of In3+ and the incorporation of incoming electrons into the delocalized band structure. Analysis of the discharge curve shows the presence of two different domains. For the first one there is a small interaction between inserted ions. The second one shows a repulsive interaction and a decrease in the diffusion coefficient. (C) 1998 Academic Press. [References: 16]