Hydrogen storage properties of V–Ti–Cr–Fe alloys

A V–Ti–Cr–Fe alloys system was developed in this paper. For Vx–(Ti–Cr–Fe)100−x (Ti/(Cr+Fe) = 1.0, Cr/Fe = 2.5, x = 20–55) alloys, with the increase of V content, the hydrogen absorption capacity and desorption capacity both increase, and plateau pressure decreases. Two phases, BCC and Laves phase, appear when x < 30, and a single BCC phase appears when x ≥ 30. For the Vx–(Ti–Cr–Fe)100−x (Ti/(Cr+Fe) = 1.0, Cr/Fe = 2.5) alloys with V ≥ 30 at.%, three alloys, V30Ti33Cr27Fe10, V42Ti28Cr21.7Fe8.3 and V55Ti21.5Cr17.1Fe6.4 alloy, were developed through the further adjustment of Ti and Cr content, which have the higher desorption capacities of 2.06, 2.12 and 2.23 wt.% H at 298 K, respectively. Unit lattice dimension is a very important role deciding the absorption–desorption properties. The maximum desorption capacity in this alloys system is obtained at unit lattice dimension of 3.042 Å by the help of the statistical method and experiments, where V40Ti28.4Cr23.6Fe8 alloy absorbs 3.82 wt.% H and desorbs 2.30 wt.% H at 298 K. Additionally, this alloy with V/Fe ratio of 5:1 can be prepared by low-cost FeV80 master alloy.