Hydrogen Isotope Effects on Absorption Properties of Ti-Cr-V Alloys

Tamura, Takuya; Kamegawa, Atsunori; Takamura, Hitoshi; Okada, Masuo

doi:10.2320/matertrans.44.641

Cited by 9 publications

(6 citation statements)

References 24 publications

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“…For the full implementation of hydrogen as an energy vector, safe and low-cost means of storing hydrogen should be available. Many ways to store hydrogen are available such as high-pressure, cryogenic liquid hydrogen, porous materials, liquid hydrogen carriers (e.g., ammonia), complex metal hydrides and intermetallic hydrides [1]. Metal hydrides are promising candidates for many stationary and mobile hydrogen storage applications.…”

Section: Introductionmentioning

confidence: 99%

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Hydrogenation Thermodynamics of Ti16V60Cr24−xFex Alloys (x = 0, 4, 8, 12, 16, 20, 24)

Ravalison,

Huot

2024

Hydrogen

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The effect of the partial substitution of Cr with Fe on the thermodynamic parameters of vanadium-rich Ti16V60Cr24-xFex alloys (x = 0, 4, 8, 12, 16, 20, 24) was investigated. For each composition, a pressure–concentration isotherm (PCI) was registered at 298, 308, and 323 K. The PCI curves revealed a reduction in plateau pressure and a decrease in desorbed hydrogen capacity with an increasing amount of Fe. For all alloys, about 50% or less of the initial hydrogen capacity was desorbed for all chosen temperatures. Entropy (ΔS) and enthalpy (ΔH) values were deducted from corresponding Van’t Hoff plots of the PCI curves: the entropy values ranged from −150 to −57 J/K·mol H2, while the enthalpy values ranged from −44 to −21 kJ/mol H2. They both decreased with an increasing amount of Fe. Plotting ΔS as function of ΔH showed a linear variation that seems to indicate an enthalpy–entropy compensation. Moreover, a quality factor analysis demonstrated that the present relationship between entropy and enthalpy is not of a statistical origin at the 99% confidence level.

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Section: Introductionmentioning

confidence: 99%

“…Another interesting family of metal hydrides is the solid solution Body-Centered Cubic (BCC) alloys. These alloys are frequently based on vanadium, and they have attracted attention due to their high maximum hydrogen capacity (~4 wt.%) [1][2][3][4][5][6][7][8]. The process of the hydrogenation of pure vanadium occurs two steps.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenation Thermodynamics of Ti16V60Cr24−xFex Alloys (x = 0, 4, 8, 12, 16, 20, 24)

Ravalison,

Huot

2024

Hydrogen

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“…The combination of both in-situ and ex-situ neutron powder diffraction studies on the hydrogenation and dehydrogenation of Ti 25 Cr 50 V 20 Mo 5 has revealed the location and nature of (a) the sequestered hydrogen that limits the hydrogen capacity of this materials system and (b) the reversible hydrogen component of the cycling process. The sequestered hydrogen is principally located in basal plane interstitial sites in the majority bct phase.…”

Section: Doi: 101002/aenm201200390mentioning

confidence: 99%

“…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).…”

Section: Doi: 101002/aenm201200390mentioning

confidence: 99%

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

Kamazawa

Aoki

Noritake

et al. 2012

Advanced Energy Materials

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Hydrogen storage is one of the most important technological issues to be resolved in the move towards a future sustainable hydrogen-based economy. [1][2][3] The multiple technological requirements of safety, durability, recyclability, energy efficiency, high hydrogen capacity and low cost place very significant constraints on the development of a commercially viable hydrogen storage material for transportation. [4][5][6] Over the past decade, many new material systems have been studied as potential hydrogen storage materials. These include complex chemical hydrides such as alanates, amides and borohydrides, molecular hydrides such as ammonia borane and its derivatives and physisorbed systems such as carbon aerogels and metal organic framework materials. [ 7 ] Despite signifi cant advances, no materials have been discovered that have substantially improved overall performance over the current generation of transition metal hydrides. As a possible hydrogen storage system for fuel cell electric vehicles (FCEV), the new highpressure metal hydride (MH) tank system has been reported. [ 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. These in operando neutron diffraction measurements mimic the hydrogen cycling behaviour in the current generation of FCEV. We clarify the detailed behaviour of hydrogen within the alloy crystal structure on absorption and desorption and identify the principal reasons for the degradation of hydrogen storage performance. Our results explain the nature of hydrogen absorption and desorption in the prototypic Ti-V-Cr-Mo transition metal hydride system and also the capacity limitations that develop on prolonged cycling of these materials. We conclude that even with this generation of transition metal hydride the degree of hydrogen sequestration on cycling may be eliminated, which in turn will lead to a higher usable gravimetric capacity. Further optimised alloy systems may reach storage capacities that will approach near-term transportation requirements for FCEV.High initial capacity and good cycling performance are two of the most signifi cant materials properties that must be understood and developed in the search for new hydrogen storage materials. The direct location and nature of hydrogen during cycling is key to this understanding and also to subsequent materials optimisation. [20][21][22][23] However, the determination of hydrogen po...

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“…24) Moreover, the present authers reported that the appearance region of the mono-dueteride was more Cr-rich compositions than that of the mono-protides. 25) For example, Ti-Cr-20V alloys containing more than 60 at%Cr absorb deuterium up to D/M = 1. Therefore, Ti-56Cr-20V alloy absorbs protium up to H/M = 1, but deuterium up to D/M = 2.…”

Section: Introductionmentioning

confidence: 99%

Isotope Effects on Protium and Deuterium Absorption Properties in Ti-56 at%Cr-20 at%V Alloy

et al. 2004

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Ti-Cr-V alloys are known to absorb protium (hydrogen atom) up to H/M = 2. However, the Cr-rich alloys, e.g. Ti-Cr-20 at%V alloys containing more than 56 at%Cr, absorb up to H/M = 1 because of the formation of the mono-protides (mono-hydrides). The appearance region of the mono-dueteride was found to be more Cr-rich compositions than that of the mono-protides. For example, Ti-Cr-20 at%V alloys containing more than 60 at%Cr absorb deuterium up to D/M = 1. Therefore, Ti-56 at%Cr-20 at%V alloy absorbs protium up to H/M = 1, but deuterium up to D/M = 2. As higher protium desorption capacity is achieved by increasing the Cr content in the region of the di-protide, there is some possibility of increasing the protium desorption capacity in Ti-Cr-V alloys using the isotope effects on absorption-desorption properties of the Ti-56 at%Cr-20 at%V alloy. This paper aims to clarify the isotope effects on protium and deuterium absorption properties in the Ti-56 at%Cr-20 at%V alloy. It was found that the memory effect for the absorption plateau pressure appears only once when deuterium was absorbed after desorbing protium, and the memory effect for the absorption capacity appears when protium was absorbed after desorbing deuterium. The protium desorption capacity after deuterium treatment, namely, after desorbing deuterium showed twice as high as that without deuterium treatment in the Ti-56 at%Cr-20 at%V alloy. Increasing protium desorption capacity for deuterium treatment was caused by increasing di-protide formation and decreasing mono-protide formation.

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Hydrogen Isotope Effects on Absorption Properties of Ti-Cr-V Alloys

Cited by 9 publications

References 24 publications

Hydrogenation Thermodynamics of Ti16V60Cr24−xFex Alloys (x = 0, 4, 8, 12, 16, 20, 24)

Hydrogenation Thermodynamics of Ti16V60Cr24−xFex Alloys (x = 0, 4, 8, 12, 16, 20, 24)

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

Isotope Effects on Protium and Deuterium Absorption Properties in Ti-56 at%Cr-20 at%V Alloy

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