Some factors influencing the hydrogen storage properties of 30V-Ti-Cr-Fe alloys

In this paper, the effects of Ti/(Cr + Fe) ratio, Cr/Fe ratio, Ti/Cr ratio, lattice parameter and e/a value on hydrogen storage properties of 30V-Ti-Cr-Fe alloys have been researched. Ti/(Cr + Fe) ratio, Cr/Fe ratio and Ti/Cr ratio have great influences on the hydrogen absorption and desorption capacities and plateau pressures in the desorption process, and the influences can be attributed to the effects of lattice parameter and e/a value in a great part. Lattice parameter (a) is the main factor which decides the hydrogen absorption and desorption capacities. When a < 3.03 Å, hydrogen absorption capacity increases with the increase of a, and it trends stably when a grows further. Hydrogen desorption capacity increases first and then decreases with the increase of a, and it reaches its maximum when a = 3.035 Å. A critical e/a value of 5.25 was found in 30V-Ti-Cr-Fe system. When e/a < 5.25, the alloys have high absorption capacities which decrease rapidly when e/a > 5.25. V30Ti32Cr31.91Fe6.09 alloy with high capacity was developed, which absorbs 3.78 wt.%H and desorbs 2.26 wt.%H at 298 K.