Improvement on the hydrogen storage properties of ZrFe2 Laves phase alloy by vanadium substitution

• Synthesis, structural and hydrogen storage behavior of ZrFe2 type compounds.
• With V substitution for Fe lattice get transforms from C15 to C14 structure.
• The hydrogen storage capacity increases with V substitution.
• V substitution leads to the increase in the stability of the hydrides.

In this paper, ZrFe2−xVx (x = 0.2, 0.4, 0.6, 0.8) alloys have been studied to see the effects of V substitution for Fe. The structure and hydrogen absorption desorption properties of V doped ZrFe2 system has been considered during the study. Though the stable structure of ZrFe2 is C15 cubic phase, certain amount of V substitution leads to the stabilization of C14 hexagonal phase. The hydrogen absorption desorption measurements have been done at different temperatures for all the alloys using Sievert's type set up. From the results the enthalpies of formation of the hydrides have been calculated. The study reveals that by V substitution for Fe, there is a great increase in the hydrogen storage capacity, with significant increase in the stability of the hydrides. The results are correlated well with the temperature programmed desorption data. The alloy ZrFe1.2V0.8 is found to absorb 3.78 H/formula unit with an enthalpy of formation value of −41.8 KJ/mol.