Abstract
The development of hydrogen storage alloys possessing high plateau pressures for three-stage metal hydride hydrogen compressors (MHHCs), is critically significant for the safe and high-efficiency re-/charging of H2 in hydrogen refueling stations (HRSs). Herein, Ti-Cr-Mn-Fe-based alloys (Ti1.04+xCr2?y-zMnyFez, x = 0.02, 0.04, 0.06, y = 0.2, 0.3, 0.4, z = 0.5, 0.6, 0.7) synthesized by vacuum arc melting, with the single structure of C14 Laves and uniform element distribution, enable the final-stage compression units up to 85 MPa for MHHCs. It is demonstrated that both unit cell volume and maximum hydrogen capacity (Cmax) increase by the rising amount of Ti or decreasing Mn and Fe in the Ti-Cr-Mn-Fe-based alloys, whereas the dissociation pressures and plateau hysteresis (Hf) at 223 K are reduced correspondingly, according to the orthogonal results. Meanwhile, as the over-stoichiometric amount of Ti increases, so does the plateau slope (Sf) of the Ti-Cr-Mn-Fe-based alloys. Under the optimized conditions conducted by the orthogonal results, Ti1.08Cr1.3Mn0.2Fe0.5 exhibits comprehensively considerable hydrogen absorption/desorption properties, rendering it possible to be one of the most promising final-stage compression materials. Notably, the dehydrogenation enthalpy and entropy for Ti1.08Cr1.3Mn0.2Fe0.5 is determined to be 22.3 ± 0.3 kJ/mol and 117.8 ± 1.0 J/(mol K), respectively, with a corresponding hydrogen absorption pressure of 14.00 ± 0.52 MPa at 298 K and a dehydriding pressure of 89.19 ± 3.21 MPa at 363 K. Furthermore, the values of Cmax, Hf,andSf are evaluated as 1.83 ± 0.01 wt%, 0.33 ± 0.01, and 0.72 ± 0.03, respectively, at 223 K.
NSTL
Elsevier