EXAFS characterization of TiVCrMn hydrogen storage alloy upon hydrogen absorption–desorption cycles

Extended X-ray absorption fine structure (EXAFS) measurements at room temperature at the Ti, V, and Cr K absorption edges were applied to a TiVCrMn alloy subjected to 300 cycles of hydrogen absorption-desorption. The model of the cubic symmetry and atom random distribution is used to fit the EXAFS spectra. The FEFF calculations show relatively good agreement using this model. The EXAFS analysis reveals the variation of local structure of the TiVCrMn alloy with cycling. Aside from the Ti–Cr and Cr–Cr distances, noticeable changes in the other bond lengths were observed during cycling, which can be due to the entrance of hydrogen and lattice contraction in the alloy cells.