Improvement of the hydrogen storage properties of Ti–Cr–V–Fe BCC alloy by Ce addition

The hydrogen storage properties of (Ti0.267Cr0.333V0.40)93Fe7Cex (x = 0, 0.4, 1.1 and 2.0 at%) alloys have been investigated by XRD, EPMA and P-C-Isotherms. All samples consist of a major BCC phase with a lattice parameter of 0.302(1) nm. Ce-free alloy exhibits sloping plateau and lower hydrogen storage capacity due to chemical heterogeneity in the BCC phase. This heterogeneity is related to the precipitation of a secondary Ti2FeOx-type phase. In the case of the Ce-added alloys, the plateau is much flatter and wider, and the maximum and reversible hydrogen capacities increase up to 3.40 wt% and 2.16 wt% compared with 2.90 wt% and 1.70 wt% for the Ce-free alloy, respectively. Ce addition favors the chemical homogeneity of the BCC phase and, therefore, improves the hydrogen storage properties of the alloys.