TiCrVMo alloys with high dissociation pressure for high-pressure MH tank

Abstract

High-pressure metal hydride (MH) tank is a possible hydrogen storage system for fuel cell vehicles. The merit of the high-pressure MH tank system is improved by the use of a metal hydride with high dissociation pressure. In this study, TiCrV and TiCrVMo alloys with BCC structure has been developed for the high-pressure MH tank system. The developed TiCrVMo alloy shows 2.4 mass% of effective hydrogen capacity between 0.1 MPa and 33 MPa at 298 K, which has a dissociation pressure of 2.3 MPa at 298 K. By investigating the dissociation pressures of the synthesized metal hydrides, it is found that Mo has a special effect to increase dissociation pressure of the metal hydrides. This effect is probably attributed to the large bulk modulus of Mo compared to other elements.

Surface Observation of LaNi₅ under Deuterium Atmosphere Using Small-Angle Neutron Scattering

“…The neutron wavelength, , which was monochromatized using a double-reflection Ni-Ti multilayer monochromator, 12) was 0.46 nm (long-wavelength mode). Scattered neutrons were detected using a two-dimensional position-sensitive 3 He gas detector installed at a small-angle scattering bank, and I(q) profiles were collected in the q range 0.161.6 nm ¹1 . The XRD patterns for LaNi 5 before deuteration (i.e., no activation) and after deuteration are shown in Figs.…”

In‐Operando Neutron Diffraction Studies of Transition Metal Hydrogen Storage Materials

“…The cycling performance was checked by the Sieverts' method using pressure-composition (PC) isotherm measurements at 0 ° C as a function of hydrogen pressure (1 × 10 − 4 to 20 MPa); details are described elsewhere. [ 9 ] Two samples of Ti 25 Cr 50 V 20 Mo 5 were prepared by cycling the material from 1 × 10 − 2 kPa to 20 MPa and back to 1 × 10 − 2 kPa H 2 ex-situ in a pressure-composition isotherm apparatus. The fi rst sample was subjected to one hydrogen absorption/desorption cycle (one-cycle sample) and the second to ten hydrogen absorption/desorption cycles (tencycle sample).…”

“…[ 8 ] Ti-V-Cr-Mo alloys of body-centred cubic (bcc) structure, which has high reversible hydrogen capacity (2.4 mass% H 2 ) and high dissociation pressure (2.3 MPa at 298 K), have been developed for this MH tank system. [ 9 ] So far, hydrogen storage properties of bcc alloys have been widely studied and it is known that these alloys have the highest reversible hydrogen capacity [10][11][12][13][14][15][16] among current transition metal hydrides, but the hydrogen storage capacity decreases during the absorption and desorption cycle. [17][18][19] In this communication, we report neutron diffraction studies of hydrogen absorption and desorption in a prototypic metal hydride under realistic operating conditions.…”

Enhancement of hydrogen diffusion in the body-centered tetragonal monohydride phase of the V–H system by substitutional Al studied by proton nuclear magnetic resonance

“…Solid solution alloys containing V and other transition metals are attractive hydrogen storage materials which can compactly store hydrogen [1][2][3][4][5][6][7][8][9][10]. V metal forms the hydrogen solid solution (a) phase, the monohydride (b) phase and the dihydride (c) phase by hydrogenation at ambient temperatures [11].…”