Hydrogen absorption-desorption characteristic of (Ti0.85Zr0.15)1.1Cr1-xMoxMn based alloys with C14 Laves phase

The microstructure and hydrogen absorption-desorption characteristic of (Ti0.85Zr0.15)1.1Cr1-xMoxMn (x ​= ​0.05, 0.1, 0.15, 0.2 ​at.%) alloys were investigated. The results showed that the corresponding alloys were determined as a single phase of C14-type Laves structure. With the increase of Mo content, the maximum and reversible hydrogen absorption capacity decreased, the slope factor Hf increased. Among the studied alloys, (Ti0.85Zr0.15)1.1Cr0.95Mo0.05Mn had the best overall properties for practical application of hydrogen storage materials. The maximum and reversible hydrogen storage capacity were 1.76 ​wt% and 1.09 ​wt%, the slope factor Hf was 0.51, and its dissociation enthalpy (ΔHd) and entropy change (ΔSd) were 23.1 ​kJ ​mol−1H2, 93.8J ​K−1mol−1H2 at 303K, respectively. By studying the dissociation pressures of the synthesized metal hydrides, it was found that Mo had a special effect on the dissociation pressure of Ti–Zr–Cr–Mo–Mn alloys. Among the four alloys, (Ti0.85Zr0.15)1.1Cr0.95Mo0.05Mn alloy had the largest hydrogen absorption capacity and the fastest hydrogen desorption rate, which can meet the commercialization demand of hydrogen fuel cell hydrogen supply system.