TiCrV hydrogen storage alloy studied by positron annihilation spectroscopy

Origin of Degradation in the Reversible Hydrogen Storage Capacity of V1–xTix Alloys from the Atomic Pair Distribution Function Analysis

“…For instance, stacking faults, twin boundaries, and dislocations were observed in the high-resolution transmission electron microscopy (TEM) images of V−Ti−Mn alloys, 20 and the formation of vacancies and dislocations was identified in V 0.4 Ti 0.24 Cr 0.36 by positron annihilation lifetime measurements. 21 If present, all these structural defects could readily disturb and/or possibly reduce the hydrogen occupation sites in the fcc dihydride phase (Figure 1). Hence, we need to examine the effect of each of these structural defects on the PDF.…”

“…Dislocation is another type of defect found in V-based bcc alloys. , Our main interest is how strain fields around a dislocation core emerge in the PDF. This means it is necessary to have a realistic atomic arrangement of the dislocation core and its vicinity through theoretical calculation.…”

“…Various structural defects were reported to form in V-based ternary alloys during the hydrogenation and dehydrogenation process. For instance, stacking faults, twin boundaries, and dislocations were observed in the high-resolution transmission electron microscopy (TEM) images of V–Ti–Mn alloys, and the formation of vacancies and dislocations was identified in V 0.4 Ti 0.24 Cr 0.36 by positron annihilation lifetime measurements . If present, all these structural defects could readily disturb and/or possibly reduce the hydrogen occupation sites in the fcc dihydride phase (Figure ).…”

In operando study of TiVCr additive in MgH2 composites

“…Sync-XRD characterization has shown that the starting hydrogenated TiVCr additive is composed of two predominant phases which can be indexed in the face centered cubic (fcc) system, space group Fm-3m, and body centered cubic (bcc) system, space group Im-3m, respectively. Some authors have reported that the hydrogen poor solid solution formed in TiVCr alloys can be distorted in a body centered tetragonal phase (bct) as it has been observed in FeTiV alloys and in pure vanadium [36][37][38][39][40]. The angular resolution of the diffractograms and low diffraction intensity did not allow us to identify the bct structure.…”

Study of highly porous polymers for H2 fuel storage using positron annihilation lifetime spectroscopy

“…PALS has been successful in detecting holes at atomic scales in polymers, metals and semiconductors, as well as correlating free volume with many physical and chemical processes including gas/liquid separation [23,24], electromagnetic properties of porous semiconductor materials [25,26], and H 2 trapping in metal alloys [27,28]. However, thus far, no research group has reported using this technique to characterize highly porous polymeric materials for H 2 storage.…”