Composite hydrogen storage material and preparation method thereof

Abstract

The application relates to a composite hydrogen storage material and a preparation method thereof, relates to the technical field of hydrogen storage materials, and solves the problem of limited reversible capacity of a solid solution hydrogen storage alloy. The composite hydrogen storage material comprises a hydrogen storage alloy and Mg(AlH4)2; the chemical general formula of the hydrogen storage alloy is TiV 2‑x B x or Ti 1‑ y Re y V 2‑y B x ; 0.6<=x<=1.4, B is selected from one or more of Mn, Cr, Ni, Zr, Fe, Cu and Co; 0.1<=y<=0.4, Re is selected from one or more of La, Ce, Pr, Nd, Sm and Gd. After the hydrogen storage alloy and Mg(AlH4)2 are weighed and blended, the hydrogen storage alloy and the Mg(AlH4)2 are uniformly mixed under an argon gas, hydrogen gas or mixed gas atmosphere to obtain the composite hydrogen storage material. The application is simple, fast and efficient, improves the low-temperature hydrogen storage performance of the solid solution hydrogen storage alloy, and is especially suitable for the fields of transportation systems, aerospace and energy supply.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage materials technology, specifically to a composite hydrogen storage material and its preparation method. Background Technology

[0002] As a highly efficient and clean secondary energy carrier, the core challenge for the large-scale application of hydrogen energy lies in developing safe and economical storage technologies. Among various hydrogen storage methods, solid-state hydrogen storage has become the most promising development direction due to its high volumetric density and excellent safety. Solid solution hydrogen storage alloys, in particular, have attracted much attention due to their unique reversible hydrogen absorption and desorption capabilities and tunable thermodynamic properties. These materials achieve hydrogen storage through the solid solution and desolvation of hydrogen atoms in the interstitial spaces of the metal lattice, and their crystal structures mainly include two configurations: body-centered cubic (BCC) and face-centered cubic (FCC).

[0003] However, the development of solid solution hydrogen storage alloys currently faces three major technical bottlenecks: First, the reversible capacity is generally low (usually below 2.5 wt.%), making it difficult to meet the needs of high-end applications; second, the activation process is complex and difficult; and third, the cycle stability is insufficient. These problems severely restrict their industrialization process. Taking the most widely used AB5 type rare earth nickel-based and AB2 type Laves phase alloys as examples, their actual reversible hydrogen storage capacity is mostly limited to the range of 1.8~2.0 wt.%, which is far from meeting the stringent requirements for lightweight hydrogen storage systems in applications such as fuel cell vehicles.

[0004] To overcome this limitation, researchers have turned their attention to titanium-vanadium-based BCC solid solutions and magnesium-based alloys, which have higher theoretical hydrogen storage capacities (3.5–7.6 wt.%). However, these materials also face significant challenges: while vanadium-based BCC alloys can achieve effective hydrogen absorption of over 3.5 wt.% at low temperatures, they suffer from complex activation processes, difficulties in hydrogen release at room temperature, and high costs of vanadium raw materials; magnesium-based alloys, although possessing capacity advantages, have hydrogen release temperatures mostly above 250°C, making it difficult to meet the practical requirements of vehicle systems below 100°C.

[0005] Against this backdrop, how to overcome the reversible capacity limitation of solid solution alloys through material design innovation and preparation process optimization has become a core research direction in the field of hydrogen storage materials. Summary of the Invention

[0006] To address the limitation of reversible capacity in existing solid solution hydrogen storage alloys, this invention proposes a composite hydrogen storage material and its preparation method.

[0007] The specific technical solution of the present invention is as follows:

[0008] A composite hydrogen storage material, the composite hydrogen storage material comprising a hydrogen storage alloy and Mg(AlH4)2;

[0009] The general chemical formula of the hydrogen storage alloy is:

[0010] TiV 2-x B x or Ti 1-y Re y V 2-y B x ;

[0011] In the formula, 0.6≤x≤1.4, B is selected from one or more of Mn, Cr, Ni, Zr, Fe, Cu, and Co; 0.1≤y≤0.4, Re is selected from one or more of La, Ce, Pr, Nd, Sm, and Gd.

[0012] Preferably, the mass of Mg(AlH4)2 is 1% to 20% of the mass of the hydrogen storage alloy; more preferably, it is 5% to 15%, and most preferably, it is 10%.

[0013] Preferably, the mass of Mg(AlH4)2 is 10% of the mass of the hydrogen storage alloy.

[0014] Preferably, the average particle size of the hydrogen storage alloy is 30µm to 100µm.

[0015] Preferably, the hydrogen storage alloy is TiV. 1.1 Cr 0.3 Mn 0.6 Material.

[0016] The present invention also provides a method for preparing the above-mentioned composite hydrogen storage material, comprising the following steps:

[0017] The hydrogen storage alloy and Mg(AlH4)2 are weighed in proportion, mixed, and then subjected to high-energy ball milling, planetary ball milling, mechanical stirring, crushing or grinding under argon, hydrogen or a mixture of the two atmospheres to make the hydrogen storage alloy and Mg(AlH4)2 uniformly mixed, thus obtaining a composite hydrogen storage material.

[0018] Preferably, the uniform mixing is achieved by high-energy ball milling or planetary ball milling.

[0019] Preferably, the rotational speed of the ball mill is 350 rpm to 600 rpm, and more preferably, it is 400 rpm to 550 rpm.

[0020] Preferably, the ball milling time is 60 min to 300 min, and more preferably, it is 120 min to 240 min.

[0021] Preferably, the ball-to-material mass ratio of the ball mill is 8:1 to 40:1, and more preferably, it is 15:1 to 30:1.

[0022] Compared with the prior art, the specific beneficial effects of the present invention are as follows:

[0023] 1. This invention innovatively selects Mg(AlH4)2 as a catalyst promoter for titanium-vanadium solid solution hydrogen storage alloys, overcoming the limitations of traditional inorganic catalysts (such as TiCl3, NbF5, etc.). On the one hand, Mg(AlH4)2 itself has a high theoretical hydrogen storage capacity of 9.3 wt.%, and as a supplementary hydrogen source, it can avoid the system capacity loss caused by the addition of traditional catalysts. On the other hand, the active hydrogen atoms generated by its decomposition under mild conditions (100~150°C) can effectively activate the alloy surface, and the decomposition products (MgH2 and Al) form a highly efficient catalytic layer, realizing a "self-catalytic" mechanism.

[0024] 2. This invention develops a one-step mechanochemical composite process that directly mixes titanium vanadium solid solution alloy blocks with Mg(AlH4)2 powder. Compared with the traditional multi-step method (pre-ball milling + sintering + re-ball milling), the process is expected to be shortened by 70%, equipment investment is reduced by more than 40%, and the material oxidation and thermal decomposition caused by high-temperature sintering are avoided. Uniform composite is achieved through mechanochemical effects.

[0025] 3. Verification has shown that the hydrogen storage material provided by this invention exhibits excellent low-temperature hydrogen storage performance. At 0℃, the reversible hydrogen storage capacity is increased by 47.6% compared to the unmodified alloy; the initial hydrogen absorption exceeds 2.8 wt.%, requiring no high-temperature activation treatment; reaching 95% of the maximum hydrogen absorption capacity takes only 2 minutes, a 33% improvement compared to the cast alloy (3 minutes); and the capacity retention rate after 100 cycles is >94%.

[0026] 4. This invention reduces the hydrogen molecule dissociation energy barrier by forming a nano-Al / MgH2 catalytic layer through the decomposition of the surface catalytic layer Mg(AlH4)2; the lattice defects and nanograin boundaries generated by mechanical ball milling provide efficient hydrogen diffusion channels; and the Mg-Ti-V multiphase interface promotes hydrogen overflow and accelerates hydrogen atom migration.

[0027] This invention achieves a breakthrough in the performance of titanium-vanadium solid solution hydrogen storage alloys through a combination of material system innovation and process optimization, providing a new technical solution for the engineering application of solid-state hydrogen storage materials. It is particularly suitable for cryogenic applications in transportation systems, aerospace, and other fields, and can simultaneously solve problems such as low capacity, high temperature, and slow kinetics in traditional technologies. Attached Figure Description

[0028] Figure 1 The first hydrogen absorption activation curves are for the hydrogen storage materials prepared in Examples 1-3 and Comparative Examples 1-2;

[0029] Figure 2 The hydrogen desorption PCT curves of the hydrogen storage materials prepared in Examples 1-3 and Comparative Examples 1-2 at 0°C are shown.

[0030] Figure 3The hydrogen desorption PCT curves of the hydrogen storage materials prepared in Examples 1-3 and Comparative Examples 1-2 at 50°C are shown. Detailed Implementation

[0031] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0032] Example 1.

[0033] This embodiment prepares a composite hydrogen storage material with the following expression: 95 wt.% TiV 1.1 Cr 0.3 Mn 0.6 +5wt.% Mg(AlH4)2, its preparation method is as follows:

[0034] (1) First, a titanium-vanadium solid solution alloy is prepared. The preparation method is as follows:

[0035] The vacuum arc melting furnace was evacuated to a vacuum level of 2×10. -3 After Pa, high-purity argon gas (99.99% purity, volume percentage) at 0.5 atmospheres is introduced as a protective gas. Ti metal (99.7% purity), V metal (99.9% purity), Mn metal (99.5% purity), and chromium metal (99.9% purity) are then arranged according to TiV... 1.1 Cr 0.3 Mn 0.6 After weighing the chemical formula, the alloy ingot was placed in a vacuum arc furnace for melting. The arc current was 300 A, and the melting was carried out 4 times, each time for 2 minutes. After natural cooling, the alloy ingot was removed from the furnace to obtain an alloy ingot. The alloy ingot was then crushed into 30-100 µm alloy powder to obtain titanium vanadium hydrogen storage alloy powder.

[0036] (2) Weigh the TiV obtained in step (1) precisely by weight percentage. 1.1 Cr 0.3 Mn 0.6 1.90 g of powdered material and 0.10 g of commercially available Mg(AlH4)2 material were used, with a total mass of 2.0 g. The mixture was placed in a ball mill jar within a glove box filled with high-purity argon atmosphere. Zircon balls (40 g in total mass) were added at a ball-to-material ratio of 20:1. Three sizes of zircon balls were selected: large, medium, and small, with diameters of 6 mm, 4 mm, and 2 mm, respectively. The ball mill was operated at 450 rpm for 90 min. The ball mill jar was then removed from the mill, opened in an argon atmosphere, and the composite hydrogen storage material was obtained. This material was then sealed and stored in a desiccator.

[0037] Example 2.

[0038] This embodiment prepares a composite hydrogen storage material with the following expression: 90 wt.% TiV 1.1 Cr 0.3 Mn 0.6 +10wt.% Mg(AlH4)2, the preparation method is as follows:

[0039] (1) First, a titanium-vanadium solid solution alloy is prepared. The preparation method is as follows:

[0040] The vacuum arc melting furnace was evacuated to a vacuum level of 2×10. -3 After Pa, high-purity argon gas (99.99% purity, volume percentage) at 0.5 atmospheres is introduced as a protective gas. Ti metal (99.7% purity), V metal (99.9% purity), Mn metal (99.5% purity), and chromium metal (99.9% purity) are then arranged according to TiV... 1.1 Cr 0.3 Mn 0.6 After weighing the chemical formula, the alloy ingot was placed in a vacuum arc furnace for melting. The arc current was 300 A, and the melting was carried out 4 times, each time for 2 minutes. After natural cooling, the alloy ingot was removed from the furnace to obtain an alloy ingot. The alloy ingot was then crushed into 30-100 µm alloy powder to obtain titanium vanadium hydrogen storage alloy powder.

[0041] (2) Weigh the TiV obtained in step (1) precisely by weight percentage. 1.1 Cr 0.3 Mn 0.6 1.80 g of powdered material and 0.20 g of commercially available Mg(AlH4)2 material were used, with a total mass of 2.0 g. The mixture was placed in a ball mill jar within a glove box filled with high-purity argon atmosphere. Zircon balls (40 g in total mass) were added at a ball-to-material ratio of 20:1. Three sizes of zircon balls were selected: large, medium, and small, with diameters of 6 mm, 4 mm, and 2 mm, respectively. The ball mill was operated at 450 rpm for 90 min. The ball mill jar was then removed from the mill, opened in an argon atmosphere, and the composite hydrogen storage material was obtained. This material was then sealed and stored in a desiccator.

[0042] Example 3.

[0043] This embodiment prepares a composite hydrogen storage material with the following expression: 85 wt.% TiV 1.1 Cr 0.3 Mn 0.6 +15wt.% Mg(AlH4)2, the preparation method is as follows:

[0044] (1) First, a titanium-vanadium solid solution alloy is prepared. The preparation method is as follows:

[0045] The vacuum arc melting furnace was evacuated to a vacuum level of 2×10. -3After Pa, high-purity argon gas (99.99% purity, volume percentage) at 0.5 atmospheres is introduced as a protective gas. Ti metal (99.7% purity), V metal (99.9% purity), Mn metal (99.5% purity), and chromium metal (99.9% purity) are then arranged according to TiV... 1.1 Cr 0.3 Mn 0.6 After weighing the chemical formula, the alloy ingot was placed in a vacuum arc furnace for melting. The arc current was 300 A, and the melting was carried out 4 times, each time for 2 minutes. After natural cooling, the alloy ingot was removed from the furnace to obtain an alloy ingot. The alloy ingot was then crushed into 30-100 µm alloy powder to obtain titanium vanadium hydrogen storage alloy powder.

[0046] (2) Weigh the TiV obtained in step (1) precisely by weight percentage. 1.1 Cr 0.3 Mn 0.6 1.70 g of powdered material and 0.3 g of commercially available Mg(AlH4)2 material were used, with a total mass of 2.0 g. The mixture was placed in a ball mill jar within a glove box filled with high-purity argon atmosphere. Zircon balls (40 g in total mass) were added at a ball-to-material ratio of 20:1. Three sizes of zircon balls were selected: large, medium, and small, with diameters of 6 mm, 4 mm, and 2 mm, respectively. The ball mill was operated at 450 rpm for 90 min. The ball mill jar was then removed from the mill, opened in an argon atmosphere, and the composite hydrogen storage material was obtained. This material was then sealed and stored in a desiccator.

[0047] Comparative Example 1.

[0048] A hydrogen storage material was prepared as a control sample, with the expression TiV. 1.1 Cr 0.3 Mn 0.6 Its preparation method is as follows:

[0049] The vacuum arc melting furnace was evacuated to a vacuum level of 2×10. -3 After Pa, high-purity argon gas (99.99% purity, volume percentage) at 0.5 atmospheres is introduced as a protective gas. Ti metal (99.7% purity), V metal (99.9% purity), Mn metal (99.5% purity), and chromium metal (99.9% purity) are then arranged according to TiV... 1.1 Cr 0.3 Mn 0.6 After weighing the chemical formula, the alloy ingot was placed in a vacuum arc furnace for melting. The arc current was 300 A, and the melting was carried out 4 times, each time for 2 minutes. After natural cooling, the alloy ingot was removed from the furnace to obtain an alloy ingot. The alloy ingot was then crushed into 30-100 µm alloy powder to obtain titanium vanadium hydrogen storage alloy powder.

[0050] Comparative Example 2.

[0051] A hydrogen storage material was prepared as a control sample, with the formula BM-TiV. 1.1 Cr 0.3 Mn 0.6 Its preparation method is as follows:

[0052] (1) First, a titanium-vanadium solid solution alloy is prepared. The preparation method is as follows:

[0053] The vacuum arc melting furnace was evacuated to a vacuum level of 2×10. -3 After Pa, high-purity argon gas (99.99% purity, volume percentage) at 0.5 atmospheres is introduced as a protective gas. Ti metal (99.7% purity), V metal (99.9% purity), Mn metal (99.5% purity), and chromium metal (99.9% purity) are then arranged according to TiV... 1.1 Cr 0.3 Mn 0.6 After weighing the chemical formula, the alloy ingot was placed in a vacuum arc furnace for melting. The arc current was 300 A, and the melting was carried out 4 times, each time for 2 minutes. After natural cooling, the alloy ingot was removed from the furnace to obtain an alloy ingot. The alloy ingot was then crushed into 30-100 µm alloy powder to obtain titanium vanadium hydrogen storage alloy powder.

[0054] (2) Weigh the TiV obtained in step (1) precisely by weight percentage. 1.1 Cr 0.3 Mn 0.6 2.0 g of material powder was placed in a ball mill jar inside a glove box filled with high-purity argon atmosphere. Zircon balls (total mass 40 g) were added at a ball-to-material ratio of 20:1. Three sizes of zircon balls were selected: large, medium, and small, with diameters of 6 mm, 4 mm, and 2 mm, respectively. The ball mill speed was 450 rpm, and the milling time was 90 min. The ball mill jar was then removed from the ball mill, and the jar was opened in an argon atmosphere to obtain the composite hydrogen storage material. The material was then sealed and stored in a desiccator.

[0055] Example of results.

[0056] The hydrogen storage material powders prepared in Examples 1-3 and Comparative Examples 1-2 were respectively loaded into reactors. The reactors were first evacuated for 30 minutes at 25°C. Subsequently, high-purity hydrogen gas with a purity of 99.99% (volume fraction) at 4 MPa was introduced into the reactors at the same temperature (25°C) to test the hydrogen absorption kinetics. The obtained hydrogen absorption kinetic curves at 25°C are shown below. Figure 1 As shown (horizontal axis: time / min; vertical axis: hydrogen absorption / wt.%).

[0057] Test results show that the Mg(AlH4)2-doped composite hydrogen storage materials of Examples 1-3 began to rapidly absorb hydrogen after a short incubation period of approximately 10 seconds. After 30 minutes, the hydrogen absorption rates of Comparative Examples 1-2 were all 0 wt.%, while the hydrogen absorption rates of Examples 1-3 reached 2.813 wt.%, 2.904 wt.%, and 2.960 wt.%, respectively. These data indicate that the activation performance of the material increases with the increase of Mg(AlH4)2 addition. This phenomenon is related to the reversibility of MgH2, whose decomposition and regeneration processes contribute to part of the hydrogen storage capacity.

[0058] To evaluate the hydrogen release capacity of the prepared composite hydrogen storage material, Figure 2 , 3 The diagrams show the PCT test results of samples from Examples 1-3 and Comparative Examples 1-2 at 0℃ and 50℃, respectively. The prepared composite hydrogen storage material powder was loaded into a reactor and, after undergoing the same activation treatment, subjected to hydrogen release PCT tests at 0℃ and 50℃, with a pressure range of 10... -4 MPa~5 MPa. The graph shows that the higher the temperature, the higher the hydrogen absorption / desorption plateau pressure, and the gradually decreasing plateau width. Compared to Comparative Example 1 (cast alloy) and Comparative Example 2 (its ball-milled sample), the effective hydrogen desorption capacity of the composite hydrogen storage materials in Examples 1-3 is significantly increased at 0°C and 50°C. At 0°C, the effective hydrogen desorption capacity increased from 0.316 wt.% in the comparative example to 0.603 wt.% in the examples; especially at 50°C, Example 3 (TiV) showed a significant increase. 1.1 Cr 0.3 Mn 0.6 + 15 wt.% TiV 1.1 Cr 0.3 Mn 0.6 The effective hydrogen release capacity of the sample reached 1.793 wt.%.

[0059] The aforementioned performance improvement is attributed to the fact that the doping of Mg(AlH4)2 reduces the stability of dihydrides and promotes the transformation of some dihydrides into monohydrides, thereby significantly improving the effective hydrogen desorption capacity of the material at lower temperatures.

[0060] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A composite hydrogen storage material, characterized in that, The composite hydrogen storage material includes a hydrogen storage alloy and Mg(AlH4)2; The general chemical formula of the hydrogen storage alloy is: You 1-y Re y V 2-y B x ; In the formula, 0.6≤x≤1.4, B is selected from one or more of Mn, Cr, Ni, Zr, Fe, Cu, and Co; 0.1≤y≤0.4, Re is selected from one or more of La, Ce, Pr, Nd, Sm, and Gd; The mass of Mg(AlH4)2 is 1% to 20% of the mass of the hydrogen storage alloy.

2. The composite hydrogen storage material according to claim 1, characterized in that, The mass of Mg(AlH4)2 is 10% of the mass of the hydrogen storage alloy.

3. The composite hydrogen storage material according to claim 1, characterized in that, The average particle size of the hydrogen storage alloy is 30µm~100µm.

4. The composite hydrogen storage material according to any one of claims 1 to 3, characterized in that, The hydrogen storage alloy is TiV. 1.1 Cr 0.3 Mn 0.6 Material.

5. A method for preparing a composite hydrogen storage material as described in any one of claims 1 to 4, characterized in that, Includes the following steps: The hydrogen storage alloy and Mg(AlH4)2 are weighed in proportion, mixed, and then subjected to high-energy ball milling, planetary ball milling, mechanical stirring, crushing or grinding under argon, hydrogen or a mixture of the two atmospheres to make the hydrogen storage alloy and Mg(AlH4)2 uniformly mixed, thus obtaining a composite hydrogen storage material.

6. The method for preparing the composite hydrogen storage material according to claim 5, characterized in that, The uniform mixing is achieved by high-energy ball milling or planetary ball milling.

7. The method for preparing the composite hydrogen storage material according to claim 6, characterized in that, The ball mill operates at a speed of 350 rpm to 600 rpm.

8. The method for preparing the composite hydrogen storage material according to claim 6, characterized in that, The ball milling time is 60 min to 300 min.

9. The method for preparing the composite hydrogen storage material according to claim 6, characterized in that, The ball-to-material mass ratio of the ball mill is 8:1 to 40:1.

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