Optimized hydrogen storage properties of Ti–Zr–Mn–VFe-based alloys by orthogonal experiment for upscaled production

Abstract

Ti–Mn-based hydrogen storage alloys have been widely developed for hydrogen compressors and storage because of their excellent hydrogen storage properties. However, there is still a need to develop a high-capacity hydrogen storage based on low-cost and large-scale preparation. Herein, cheap VFe80 intermetallic alloy is employed to replace the expensive V, and Ti–Zr–Mn–VFe-based alloys ((Ti1-yZry)1+xMn1.88-z(VFe)z, x = 0, 0.05, 0.1, y = 0.05, 0.1, 0.15, z = 0.34, 0.44, 0.54) with mainly C14 Laves phase structure were designed and prepared to optimize the composition by an orthogonal experiment. According to the orthogonal analysis, it is found that the maximum hydrogen storage capacity and hysteresis factor mainly are controlled by the content of VFe80 in the Ti–Zr–Mn–VFe-based alloys. The over-stoichiometry of A-side governs the plateau slope, and the content of Zr decreases hydrogen plateau pressure. The optimal Ti0.9Zr0.1Mn1.44(VFe)0.44 alloy achieves a revisable hydrogen storage capacity of 1.73 wt% with low plateau hysteresis factor (0.49) and plateau slope factor (0.73) at room temperature, the dehydrogenation enthalpy and entropy values respectively are 33.92 kJ/mol and 120.64 J/(mol∙K), which exhibits the best overall hydrogen storage properties. Furthermore, the optimal alloy was successfully produced on a large scale, which provides empirical value for upscaled production of AB2 Laves-phase hydrogen alloys.