High-capacity hydrogen storage V-based solid solution alloy and preparation method and application thereof

Abstract

The invention relates to a high-capacity hydrogen storage V-based solid solution alloy and a preparation method and application thereof, the component expression of the high-capacity hydrogen storage V-based solid solution alloy is V78TixCryFe3, x is greater than or equal to 0 and less than or equal to 19, y is greater than or equal to 0 and less than or equal to 19, and x + y is equal to 19. The invention further provides a preparation method and application of the hydrogen storage V-based solid solution alloy. By adjusting the components and proportion of the hydrogen storage V-based solid solution alloy, the hydrogen storage V-based solid solution alloy can have high hydrogen desorption plateau pressure, high hydrogen storage capacity and fast hydrogen absorption kinetics, and has the advantages of being high in hydrogen storage capacity, small in activation difficulty, high in hydrogen desorption plateau pressure, good in cycle performance and the like. The solid solution alloy is prepared through electric arc melting, the preparation process is simple, the preparation cost is low, and good application and industrialization prospects are achieved.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen storage materials technology, and relates to a high-capacity hydrogen storage V-based solid solution alloy, its preparation method and application. Background Technology

[0002] With the growth of the global population, massive energy consumption has led to problems such as energy crises, environmental pollution, and global warming. The development and utilization of new alternative energy sources is urgently needed. Hydrogen energy, as an efficient, sustainable, and environmentally friendly alternative energy source, has received high attention from countries around the world. However, the slow development of hydrogen storage technology seriously hinders the future development and utilization of hydrogen energy. Its main challenge is the lack of efficient and safe hydrogen storage materials. Therefore, developing efficient and safe hydrogen storage materials has become a key focus of modern scientific research.

[0003] Based on technical principles, current hydrogen storage technologies can be categorized into three types: physical processing hydrogen storage (including high-pressure gaseous hydrogen storage and cryogenic liquid hydrogen storage), physical adsorption hydrogen storage (including hydrogen storage using carbon-based materials, inorganic porous materials, and organic framework materials), and chemical reaction hydrogen storage (including hydrogen storage using metal compounds and organic liquid hydrogen storage). Based on technical form, commonly used hydrogen storage methods mainly include four categories: high-pressure gaseous hydrogen storage, solid-state hydrogen storage, cryogenic liquid hydrogen storage, and organic liquid hydrogen storage. High-pressure gaseous hydrogen storage involves compressing hydrogen under high pressure to store it in a high-density gaseous state. Solid-state hydrogen storage utilizes adsorption with solid materials to store hydrogen. Cryogenic liquid hydrogen storage involves compressing hydrogen and cooling it to below -253°C, storing it in an adiabatic vacuum reservoir. Organic liquid hydrogen storage involves reacting unsaturated organic compounds with hydrogen to achieve hydrogen storage.

[0004] The International Energy Agency (IEA) sets a hydrogen storage density standard of 5% for future novel hydrogen storage materials. The United States has set volumetric storage capacities of 45 g / L and 81 g / L for 2010 and 2015, respectively, with storage costs of $4 / (kWh) and $2 / (kWh). The U.S. Department of Energy (DOE) requires that the mass hydrogen storage density of domestic technologies reach 4.5% by 2020, 5.5% by 2025, and a final target of 6.5%. Based on the DOE's technical requirements for on-board hydrogen storage systems, improving energy density is currently a research hotspot in hydrogen storage technology. High pressure, cryogenic, and saturated adsorption are the three main technical approaches to achieving higher volumetric / mass hydrogen storage densities. These three approaches can be used independently or in combination to increase energy density. High-pressure gaseous hydrogen storage technology is the most mature and widely used, but it has essentially reached its hydrogen storage density limit. Future development will focus on reducing costs. Cryogenic liquid hydrogen storage and material adsorption hydrogen storage have higher energy density limits, but both suffer from high costs and technical complexity.

[0005] Currently, existing chemical hydrogen storage materials include alloy hydrides, light metal hydrides, complex hydrides, and ammonia borane materials. Based on their structure, hydrogen storage alloys can be classified into the following categories: AB5 type, AB3 type, AB2 type, AB type, V-based solid solutions, Mg-based alloys, and other alloys. Among these, AB5 alloys have poor storage capacity and cycle stability; AB5 alloys have low hydrogen storage capacity, with a mass hydrogen storage density of only 1.8 wt%, and are prone to activation and have poor cycle stability; AB2 type, mainly represented by TiFe, has poor gas cycle performance, as the TiH2 and TiFe2 formed during hydrogen release cannot reabsorb hydrogen; V-based solid solutions have a theoretical hydrogen absorption capacity of 3.8 wt% and can rapidly absorb and release hydrogen at room temperature; however, the high price of V and the excessive stability of the formed monohydride affect the reversible capacity of the alloy; Mg-based alloys have poor hydrogen performance, with high hydrogen release temperatures and poor kinetic performance. Therefore, there is currently no metallic hydrogen storage material that fully meets the requirements, severely limiting the development and application of hydrogen energy.

[0006] Vanadium-based solid solution hydrogen storage alloys are a promising type of hydrogen storage material. Their structure is typically body-centered cubic (BCC), and due to the numerous interstitial sites, they possess a high theoretical hydrogen storage capacity. Pure vanadium has an actual hydrogen storage capacity as high as 3.8 wt% and can store hydrogen at room temperature. However, it suffers from low reversible hydrogen storage capacity, difficulty in activation, and high cost, limiting its application in hydrogen storage. To improve the hydrogen storage performance of vanadium, researchers have employed methods such as alloying, optimizing preparation processes, and heat treatment. Alloying is an effective method, not only reducing costs but also altering the thermodynamic properties of the hydrogenation process. Currently, the developed systems mainly include single-phase systems such as V-Ti-Cr, V-Ti-Mn, V-Ti-Ni, and V-Ti-Fe. While these systems exhibit good hydrogen storage performance, the inherent passivation characteristics of vanadium alloys still require cumbersome and demanding activation conditions, such as an activation temperature of 400℃, which severely limits the practical application of these materials.

[0007] For example, Chinese patent application CN202410636328.6 provides a hydrogen storage V-based solid solution alloy, the composition expression of which is V a Ti b Cr c Fe d Mo e Wherein, 5at%≤a≤40at%, 5at%≤b≤40at%, 5at%≤c≤35at%, 5at%≤d≤35at%, 0at%≤e≤20at%, and a+b+c+d+e=100. However, the effective hydrogen storage capacity of this patent still needs further improvement to meet the industry's growing demand. Summary of the Invention

[0008] The purpose of this invention is to provide a hydrogen storage V-based solid solution alloy, its preparation method and application. By adjusting the composition and ratio of the hydrogen storage V-based solid solution alloy, the hydrogen storage V-based solid solution alloy can have a high hydrogen desorption plateau pressure, a high hydrogen storage capacity and a fast hydrogen absorption kinetics. It has the advantages of high hydrogen storage capacity, low activation difficulty, high hydrogen desorption plateau pressure and good cycle performance.

[0009] The objective of this invention can be achieved through the following technical solutions: In one aspect, the present invention provides a high-capacity hydrogen storage V-based solid solution alloy, the composition of which is expressed as V 78 Ti x Cr y Fe3, where 0≤x≤19, 0≤y≤19, and x+y=19.

[0010] Furthermore, 7.125≤x≤10.4, for example, the value of x can be 8, 9, 10, etc., or it can be an end value of this range, 8.6≤y≤11.875, for example, its value can be 9, 10, 11, etc.

[0011] Furthermore, the hydrogen storage V-based solid solution alloy has a BCC single-phase structure; the mass hydrogen storage density of the hydrogen storage V-based solid solution alloy is >3.4wt%. When the Ti / Cr ratio of the alloy changes, the lattice size of the BCC phase changes, further affecting the hydrogen storage performance of the alloy. The hydrogen storage solid solution alloy of this application has a high hydrogen storage capacity.

[0012] This invention achieves a hydrogen storage V-based solid solution alloy with high hydrogen storage capacity, low activation difficulty, fast hydrogen absorption kinetics, and good cycle performance by controlling the proportion of each raw material element. This application utilizes Ti and V to form a BCC solid solution, which effectively increases the hydrogen storage capacity; however, the addition of Ti increases the difficulty of dehydrogenation and activation. Therefore, by controlling the amount of Ti added and adding Cr, the plateau pressure of the hydrogen storage V-based solid solution alloy can be effectively increased, the stability of hydrides reduced, and the effective hydrogen storage capacity increased. Adding Fe further stabilizes the BCC phase and also increases the plateau pressure. Furthermore, this invention optimizes the BCC lattice uniformity and its lattice parameters, further enhancing the hydrogen storage performance.

[0013] In a second aspect, the present invention provides a method for preparing a hydrogen storage V-based solid solution alloy. Under an inert atmosphere, elemental V, elemental Ti, elemental Cr, and elemental Fe are smelted in stoichiometric proportions to obtain an alloy ingot. This ingot is then repeatedly smelted by turning it over to obtain a hydrogen storage V-based solid solution alloy V. 78 Ti x Cr y Fe3.

[0014] Furthermore, the inert atmosphere is provided by argon or nitrogen.

[0015] Furthermore, the smelting process is carried out in an electric arc melting furnace, in which the elemental V, elemental Ti, elemental Cr, and elemental Fe are placed separately according to their melting points from low to high, from bottom to top.

[0016] Furthermore, before melting, the electric arc melting furnace is first purged, and then evacuated to 3 Pa. Next, a gas providing an inert atmosphere is introduced into the furnace, and then the furnace is evacuated again until the vacuum level is 3 × 10⁻⁶ Pa. -3 Pa, then 0.5 bar of gas is added into the electric arc melting furnace to provide an inert atmosphere (as a protective gas).

[0017] Furthermore, during the melting process, the arc gun is adjusted to a distance of 2mm-3mm from the metal surface to initiate the arc. After successfully initiating the arc, the arc gun is raised to the melting height, specifically adjusted to a distance of 6mm-8mm from the metal surface. At the same time, the current intensity of the arc gun is slowly increased to 180A for melting, and the melting time is 2-3 minutes.

[0018] Furthermore, the number of repeated melting processes is greater than or equal to four.

[0019] Furthermore, the elemental V, elemental Ti, elemental Cr, and elemental Fe are all elements with a purity greater than 99.9%.

[0020] In a second aspect, the present invention provides an application of a hydrogen storage V-based solid solution alloy in hydrogen storage.

[0021] Furthermore, the hydrogen storage V-based solid solution alloy is activated before hydrogen storage. The activation process is as follows: the hydrogen storage V-based solid solution alloy is evacuated at 400°C for 2 hours, then hydrogen gas at a pressure of 7 MPa is introduced and maintained for 30 minutes, and finally cooled to room temperature. The above operation is repeated 2-3 times.

[0022] Compared with the prior art, the present invention has the following advantages: (1) By adjusting the ratio of the hydrogen storage V-based solid solution alloy, this application can make the hydrogen storage V-based solid solution alloy have a higher hydrogen storage capacity and faster hydrogen absorption kinetics, and has the advantages of high hydrogen storage capacity, low activation difficulty, fast hydrogen absorption kinetics and good cycle performance.

[0023] (2) This application uses an electric arc melting method to prepare hydrogen storage V-based solid solution alloys. The preparation process is simple and the preparation cost is low. It has good application and industrialization prospects in the field of new energy. Attached Figure Description

[0024] Figure 1 The hydrogen storage V-based solid solution alloy V prepared for this application 78 Ti x Cr y XRD patterns of Fe3 (x=7.125, 8.44, 9.5, 10.38); Figure 2 Hydrogen storage V-based solid solution alloy V prepared for embodiments of this application 78 Ti 8.44 Cr 10.56 SEM and EDS images of Fe3; Figure 3 Hydrogen storage V-based solid solution alloy V prepared for embodiments of this application 78 Ti 8.44 Cr 10.56 The hydrogen absorption kinetics curves of Fe3 at 30℃, 40℃, 50℃, 60℃ and 8MPa hydrogen gas; Figure 4 Hydrogen storage V-based solid solution alloy V prepared for embodiments of this application 78 Ti 8.44 Cr 10.56 PCT curves of Fe3 at 30℃, 40℃, 50℃, 60℃, and 8MPa hydrogen atmosphere. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0027] As used herein, the terms "and / or," "or / and," and "and / or" encompass any one of two or more of the related listed items, as well as any and all combinations of the related listed items. These arbitrary and all combinations include any two related listed items, any more related listed items, or a combination of all related listed items. It should be noted that when at least three items are connected using at least two conjunctions selected from "and / or," "or / and," and "and / or," it should be understood that, in this application, the technical solution undoubtedly includes solutions connected by "logical AND," and also undoubtedly includes solutions connected by "logical OR."

[0028] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0029] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0030] This document only specifically discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0031] Unless otherwise specified, the temperature parameters in this application may be either constant temperature processing or processing within a certain temperature range. The constant temperature processing allows temperature fluctuations within the precision range controlled by the instrument, such as ±5°C, ±4°C, ±3°C, ±2°C, or ±1°C.

[0032] In this document, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0033] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0034] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0035] In the description of the application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] Unless otherwise specified, all preparations and tests described herein took place at 25°C.

[0037] The terms “comprising,” “including,” “containing,” “having,” “comprising,” or other variations thereof are intended to cover non-closed inclusion, and no distinction is made between these terms. The term “comprising” means that other steps and ingredients may be added without affecting the final result. The compositions and methods / processes of the present invention comprise, consist of, and substantially consist of the essential elements and limitations described herein, as well as any additional or optional ingredients, components, steps, or limitations described herein. No distinction is made between the terms “efficacy,” “performance,” “effect,” and “potency” herein.

[0038] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions. Unless otherwise specified, all technical features and optional technical features of this application can be combined to form new technical solutions.

[0039] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, but sequentially is preferred.

[0040] Example 1: A hydrogen storage V-based solid solution alloy, the composition formula of which is V 78 Ti 8.44 Cr 10.56 Fe3. The hydrogen storage V-based solid solution alloy has a BCC single-phase structure; the mass storage density of the hydrogen storage V-based solid solution alloy is >3.4wt%.

[0041] The preparation method of the hydrogen storage V-based solid solution alloy includes the following steps: Under an argon atmosphere, elemental V (vanadium), elemental Ti (titanium), elemental Cr (chromium), and elemental Fe (iron) are smelted to obtain an alloy ingot; the alloy ingot is then repeatedly smelted by flipping it to obtain a hydrogen storage V-based solid solution alloy V. 78 Ti 8.44 Cr 10.56 Fe3.

[0042] The melting is carried out in an electric arc melting furnace; in the electric arc melting furnace, the elemental V, elemental Ti, elemental Cr, and elemental Fe are placed separately according to their melting points from low to high, from bottom to top. This effectively reduces the difficulty of melting and makes the alloy composition uniform.

[0043] During the melting process, the arc gun is ignited when the distance between it and the metal surface is adjusted to 2mm-3mm. After successful arc ignition, the arc gun is raised to the melting height, and the current of the arc gun is increased to 180A for melting. The melting time is 2 minutes.

[0044] The melting process is repeated 4 times. The current for each melting cycle is 180A, and the melting time is 2 minutes.

[0045] The elemental V, elemental Ti, elemental Cr, and elemental Fe are all elements with a purity greater than 99.9%.

[0046] Each element is pretreated as follows before use: the raw material is placed in a beaker containing alcohol for ultrasonic cleaning to remove the oxide layer on the surface of the material. After ultrasonic cleaning, it is dried in a drying oven for later use.

[0047] The vacuum degree is achieved by the following method: before starting melting, the electric arc melting furnace is purged and evacuated to 3 Pa; then argon gas is introduced into the electric arc melting furnace, and then evacuation is performed (repeated three times to remove air and water from the electric arc melting furnace), so that the vacuum degree of the electric arc melting furnace is 3 × 10⁻⁶ Pa. -3 Pa, and then 0.5 bar of argon gas is introduced into the electric arc melting furnace.

[0048] This hydrogen storage V-based solid solution alloy V 78 Ti 8.44 Cr 10.56 The XRD pattern of Fe3 is as follows: Figure 1 As shown, from Figure 1 It can be seen that the prepared hydrogen storage V-based solid solution alloy V 78 Ti 8.44 Cr 10.56 Fe3 has a BCC single-phase structure.

[0049] Figure 2 This V-based solid solution alloy V is shown. 78 Ti 8.44 Cr 10.56 SEM and EDS images of Fe3, where (a) and (b) show the particle size of the test sample, reflecting the prepared hydrogen storage-based solid solution alloy V. 78 Ti 8.44 Cr 10.56 Fe3 has a BCC single-phase structure.

[0050] Depend on Figure 1 XRD patterns Figure 2 The SEM and EDS spectra show that the prepared hydrogen storage V-based solid solution alloy V 78 Ti 8.44 Cr 10.56 Fe3 has a BCC single-phase structure and the elements are evenly distributed.

[0051] Before the hydrogen storage V-based solid solution alloy is used for hydrogen storage, it needs to be activated. The activation process is carried out by the following method: the hydrogen storage V-based solid solution alloy is evacuated at 400°C for 30 minutes, then hydrogen gas at a pressure of 8 MPa is introduced and maintained for 1 hour, and finally cooled to room temperature. The above operation is repeated twice.

[0052] Hydrogen storage V-based solid solution alloy V 78 Ti 8.44 Cr 10.56 Hydrogen storage performance test of Fe3: hydrogen storage V-based solid solution alloy V 78 Ti 8.44 Cr 10.56 Fe3+ undergoes two hydrogen absorption and desorption cycles at 400℃ to complete the hydrogen storage V-based solid solution alloy V. 78 Ti 8.44 Cr 10.56 Fe3 was activated, and then hydrogen storage performance was tested.

[0053] Figure 3 The hydrogen storage V-based solid solution alloy V prepared in this embodiment is shown. 78 Ti 8.44 Cr 10.56 The hydrogen absorption kinetics curve of Fe3 at 40℃ and 8MPa. Figure 3 As can be seen, the prepared V-based solid solution alloy V 78 Ti 8.44 Cr 10.56 Fe3 exhibits good hydrogen absorption kinetics at 40℃, and this alloy reaches 95% of its saturated hydrogen absorption capacity in 160s.

[0054] Figure 4 The hydrogen storage V-based solid solution alloy V prepared in this embodiment is shown. 78 Ti 8.44 Cr 10.56 The PCT hydrogen absorption curve of Fe3 at a temperature of 40℃ and a pressure of 8MPa is shown in the figure. Figure 4 It can be seen that the hydrogen storage V-based solid solution alloy V 78 Ti 8.44 Cr 10.56 Fe3+ exhibits good hydrogen storage performance at 40°C, with a hydrogen storage capacity of 3.74 wt.%. The aforementioned hydrogen storage capacity refers to the material's maximum hydrogen storage capacity. Furthermore, the "effective hydrogen storage capacity" mentioned below refers to the amount of hydrogen released under a specific pressure after the material reaches its maximum hydrogen storage capacity. In this invention, the effective hydrogen release capacity is calculated under a pressure of 0.01 MPa. The effective hydrogen storage capacity varies depending on the hydrogen release pressure; all effective hydrogen storage capacities calculated in this invention are based on a pressure of 0.01 MPa.

[0055] Comparative Example 1: Compared to Example 1, most aspects are the same, except that the composition of the hydrogen storage V-based solid solution alloy is adjusted to V. 70 Ti 15 Cr 12 Fe3.

[0056] The properties of the obtained solid solution alloy were tested, as follows: The effective hydrogen storage capacity is 2.1 wt%, compared to V in Example 1. 78 Ti 8.44 Cr 10.56 Fe3 (2.6wt%) was significantly lower.

[0057] Activation performance: It requires more than 5 cycles at 450°C and high vacuum to be activated, making activation extremely difficult.

[0058] Platform pressure: The platform area is severely skewed, and the effective platform pressure range is unclear.

[0059] Cyclic stability: Very poor; after 20 hydrogen adsorption / desorption cycles, the capacity decayed to 1.5 wt%.

[0060] Performance Analysis: Excessive Ti and Cr led to the precipitation of non-BCC second phases. These second phases not only failed to store hydrogen but also encapsulated the BCC main phase, hindering hydrogen diffusion and resulting in activation difficulties, capacity reduction, and deterioration of plateau characteristics. It was demonstrated that controlling x+y around 19 is crucial for obtaining a pure and easily activated single-phase BCC structure.

[0061] Comparative Example 2: Compared to Example 1, most aspects are the same except that the composition of the hydrogen storage V-based solid solution alloy is adjusted to V. 85 Ti8Cr4Fe3.

[0062] The performance of the obtained solid solution alloy was tested, and the results are as follows: the effective hydrogen storage capacity was 2.4 wt%, which is lower than that of Example 1. 78 Ti 8.44 Cr 10.56 Fe3.

[0063] Activation performance: Easy to activate, comparable to Example 1.

[0064] Platform pressure: The platform pressure is extremely low at room temperature (<0.01 MPa), and hydrogen release requires a very high temperature (>400°C).

[0065] Cyclic stability: Due to the difficulty of hydrogen desorption, the grains grow during repeated high-temperature cycling, and the capacity decreases slowly.

[0066] Performance Analysis: The solid solution strengthening and thermodynamic property tuning effects of Ti and Cr are insufficient, resulting in overly stable alloy hydrides and excessively high hydrogen desorption temperatures, rendering them impractical. This demonstrates that an appropriate amount of x+y is necessary to obtain suitable plateau pressure (i.e., thermodynamic properties).

[0067] Comparative Example 3: Compared to Example 1, most aspects are the same except that the composition of the hydrogen storage V-based solid solution alloy is adjusted to V. 76 Ti 15 CrFe3.

[0068] The properties of the obtained solid solution alloy were tested, as follows: The effective hydrogen storage capacity is 2.5 wt% (slightly lower than in Example 1).

[0069] Activation performance: Activation requires 2-3 cycles, which is more difficult than in Example 1.

[0070] Platform pressure: The platform pressure is slightly lower than that of Example 1, but the platform flatness is still acceptable.

[0071] Cyclic stability: Very poor; after 50 cycles, the capacity rapidly decayed to 2.0 wt%. Severe pulverization.

[0072] Performance Analysis: While high Ti content contributes to higher capacity and lower plateau pressure, a severe deficiency in Cr content leads to a sharp decline in the alloy's cycle stability. Cr plays a crucial role in suppressing hydrogen-induced amorphization and enhancing the alloy's resistance to pulverization. This comparative example demonstrates that even with a similar total atomic number, a lack of sufficient Cr prevents the acquisition of a long-term stable hydrogen storage alloy.

[0073] Comparative Example 4: Compared to Example 1, most of the components are the same except that the composition of the hydrogen storage V-based solid solution alloy is adjusted to V74Ti4Cr14Fe3.

[0074] The effective hydrogen storage capacity is 2.0 wt%, significantly lower than the V in Example 1. 78 Ti 8.44 Cr 10.56 Fe3.

[0075] Activation properties: Easy to activate.

[0076] Platform pressure: Excessive platform pressure, exceeding 2 MPa at room temperature, poses a safety hazard and makes hydrogen storage difficult under mild conditions.

[0077] Cyclic stability: It has good stability, but the high platform pressure greatly reduces its application value.

[0078] Performance Analysis: A low Ti content weakens its effectiveness in reducing hydride stability, leading to a surge in plateau pressure. While a high Cr content provides good kinetics and stability, it cannot compensate for the deterioration in thermodynamic properties. This comparative example demonstrates the irreplaceable role of Ti in regulating thermodynamic properties, and that the precise ratio range of the "Ti-Cr" synergistic effect (i.e., the Ti / Cr ratio of this invention) is crucial for equilibrium capacity, plateau pressure, and stability.

[0079] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A high-capacity hydrogen storage V-based solid solution alloy, characterized in that, Its component expression is V 78 Ti x Cr y Fe3, where 0≤x≤19, 0≤y≤19, and x+y=19.

2. The high-capacity hydrogen storage V-based solid solution alloy according to claim 1, characterized in that, 7.125≤x≤10.4, 8.6≤y≤11.

875.

3. The method for preparing a high-capacity hydrogen storage V-based solid solution alloy as described in claim 1 or 2, characterized in that, In an inert atmosphere, elemental V, elemental Ti, elemental Cr, and elemental Fe are smelted in stoichiometric proportions to obtain an alloy ingot. This ingot is then repeatedly smelted by turning it over to obtain a high-capacity hydrogen storage V-based solid solution alloy V. 78 Ti x Cr y Fe3.

4. The method for preparing a high-capacity hydrogen storage V-based solid solution alloy according to claim 3, characterized in that, The inert atmosphere is provided by argon or nitrogen.

5. The method for preparing a high-capacity hydrogen storage V-based solid solution alloy according to claim 3, characterized in that, The smelting process is carried out in an electric arc melting furnace, in which the elemental V, elemental Ti, elemental Cr and elemental Fe are placed separately according to their melting points from low to high, from bottom to top.

6. The method for preparing a high-capacity hydrogen storage V-based solid solution alloy according to claim 5, characterized in that, Before melting, the electric arc melting furnace is first purged, and then evacuated to 3 Pa. Next, a gas providing an inert atmosphere is introduced into the furnace, and then the furnace is evacuated again until the vacuum level reaches 3 × 10⁻⁶ Pa. -3 Pa, then 0.5 bar of gas is introduced into the electric arc melting furnace to provide an inert atmosphere.

7. The method for preparing a high-capacity hydrogen storage V-based solid solution alloy according to claim 3, characterized in that, During the melting process, the arc gun is adjusted to a distance of 2mm-3mm from the metal surface to initiate the arc. After successfully initiating the arc, the arc gun is raised to the melting height, and the current intensity of the arc gun is slowly increased to 180A for melting. The melting time is 2-3 minutes.

8. The method for preparing a high-capacity hydrogen storage V-based solid solution alloy according to claim 3, characterized in that, The number of repeated melting processes is greater than or equal to 4.

9. The application of a high-capacity hydrogen storage V-based solid solution alloy as described in claim 1 or 2 in hydrogen storage.

10. The application according to claim 9, characterized in that, Before storing hydrogen, the high-capacity hydrogen storage V-based solid solution alloy is activated. The activation process is as follows: the high-capacity hydrogen storage V-based solid solution alloy is evacuated at 400°C for 2 hours, then hydrogen gas at a pressure of 7 MPa is introduced and maintained for 30 minutes, and finally cooled to room temperature. The above operation is repeated 2-3 times.

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