Study on hydrogen storage properties of Ti–V–Fe–Mn alloys by modifying Ti/V ratio.

The high stability of hydride phase has limited the improvement for the hydrogen storage properties of Ti–V based alloy at room temperatures. In this work, the stability of hydride was reduced by designing a low-price Ti–V–Fe–Mn alloy, and the effect of Ti/V ratio on the crystal structure and hydrogen storage properties was systematically investigated. The Ti 40- x V 40+ x Fe 15 Mn 5 (x = 0, 2, 4, 6, 8) alloys were synthesized using arc melting, and the as-prepared alloys are all composed of single BCC phase. The lattice constant and cell volume decrease linearly with a lessening in Ti/V ratio. The reduction of cell volume makes it difficult for hydrogen atoms to diffuse, resulting in a sluggish hydrogen absorption rate. The dehydrogenation plateau in PCI curve rises and corresponding thermodynamics is optimized with a decrease in the lattice constant, and the hydrogen atoms are more readily to release, especially for Ti 32 V 48 Fe 15 Mn 5 alloy with the dehydrogenation capacity of 1.83 wt% at 373 K. The result indicates the thermodynamic properties can be optimized by adjusting the lattice constant of Ti–V–Fe–Mn alloys, and hydrogen storage capacity is improved effectively. This study provides a reference for composition design of Ti–V–Fe–Mn alloys for high-density hydrogen storage. [Display omitted] • The solubility of iron for Ti–V based alloy is not less than 15 mol.%. • The Samples can absorb hydrogen after heat preservation at 623 K and 3 MPa H 2. • The substitution of V for Ti enhances the desorption capacity. [ABSTRACT FROM AUTHOR]