A lightweight high-entropy hydrogen storage alloy, its preparation method and application

Abstract

The present application relates to a lightweight high-entropy hydrogen storage alloy and its preparation method and application. The preparation of the lightweight high-entropy hydrogen storage alloy adopts a plasma ball milling method. Through the strategy of step-by-step ball milling, a LiAlMgTiV high-entropy hydrogen storage alloy with good room temperature hydrogen storage performance is prepared. The preparation method of the lightweight high-entropy hydrogen storage alloy includes placing Ti powder and V powder in a plasma ball milling jar under an inert gas atmosphere, filling the plasma ball milling jar with an inert gas, allowing the plasma ball mill to run for a first time, then stop running for the first time, cyclically executing the process of running for the first time and then stopping running for the first time, allowing the plasma ball milling to run for more than or equal to 20 hours, and finally obtaining a TiV alloy, and other implementation steps to finally obtain a lightweight high-entropy hydrogen storage alloy, wherein Li, Al, Mg, Ti and V in the lightweight high-entropy hydrogen storage alloy are in an equiatomic ratio.

Description

Technical Field

[0001] This application relates to the field of materials science and engineering, and in particular to a lightweight high-entropy hydrogen storage alloy and its preparation method and application. Background Art

[0002] Hydrogen energy has the advantages of high energy density, rich resources, and environmental friendliness, and has attracted the attention of researchers at home and abroad. As a secondary energy source, hydrogen energy can be used as a carrier for renewable energy sources such as solar energy and wind energy to achieve the efficient utilization of clean energy. As the world's largest hydrogen-producing country, promoting the development of the entire hydrogen energy industry chain is crucial for China to further achieve the goals of carbon peak and carbon neutrality. Currently, safe and efficient hydrogen storage technology is one of the key bottlenecks in the development and utilization of hydrogen energy. Due to its high volumetric hydrogen storage density, good safety, and easy access to high-purity hydrogen, hydrogen storage alloys that store hydrogen in solid form have stood out among many hydrogen storage materials. In actual application processes, it is usually required that hydrogen storage alloys can reversibly store hydrogen at room temperature. However, room-temperature hydrogen storage alloys usually have a low gravimetric hydrogen storage density (about 2 wt%), which severely restricts the practical application of the alloys. Therefore, there is an urgent need to develop lightweight hydrogen storage alloys with higher hydrogen storage density. In recent years, the research on high-entropy hydrogen storage alloys has broadened the research field of hydrogen storage alloys. Many domestic and foreign researchers have reported high-entropy hydrogen storage alloys with room-temperature hydrogen storage capacity, but most high-entropy hydrogen storage alloys use transition metal elements and refractory metal elements, resulting in a low hydrogen storage capacity.

[0003] The densities of light metals such as Li, Al, and Mg are 0.53 / cm 3 、2.70 / cm 3 and 1.74 g / cm 3 respectively, while the densities of transition metals such as V, Cr, and Zr are 6.11 / cm 3 、7.15 / cm 3 and 6.49 g / cm 3In contrast, light metal elements such as Li, Al, and Mg usually have relatively high weight hydrogen storage densities, with their theoretical weight hydrogen storage densities reaching 12.6 wt%, 10 wt%, and 7.6 wt% respectively, which are much higher than those of refractory metals (1-3 wt%). However, due to the fact that light metals often have relatively high thermodynamic stability for hydrogen absorption and desorption or poor kinetic performance for hydrogen absorption and desorption, there are usually problems such as irreversible hydrogen absorption and desorption at room temperature and atmospheric pressure, high hydrogen desorption temperature, and slow hydrogen absorption and desorption rate. Hydrogen in such metals often exists in the form of ions, and their hydrides are usually ionic hydrides, such as MgH2 and LiH, so the binding between the metal and hydrogen is relatively strong. Although transition metals such as Ti and V have high densities and low hydrogen storage capacities, the metals or alloys they form usually have good reversibility, thermodynamic properties, or kinetic performance for hydrogen absorption and desorption; hydrogen in such alloys mainly exists in the form of atoms dissolved in the alloy, and some hydrogen atoms carry charges. After hydrogen enters the interstitial sites, lattice expansion often occurs, and the degree of lattice expansion is proportional to the dissolved hydrogen concentration, and the binding force between the metal or alloy and hydrogen is relatively weak. For example, the Ti-V and Ti-V-X (X = Fe, Mn, Co, Cr, Ni) alloys reported by Professor Akiba of the National Institute for Materials Science and Chemistry in Japan can have a weight hydrogen storage density exceeding 2 wt% and a relatively fast hydrogen absorption and desorption rate only at room temperature and under an atmospheric pressure. Therefore, many researchers have adopted the method of alloying light metals with relatively strong hydrogen binding and transition metal alloys with relatively weak hydrogen binding to improve the thermodynamic and kinetic properties of light metal elements such as Al and Mg, so as to reduce the binding energy between the material and hydrogen element. For example, adding transition elements to pure magnesium or magnesium-based alloys can generally reduce the thermal effect of the hydrogen absorption and desorption reaction and improve the kinetic performance of hydrogen absorption and desorption, such as Mg2Ni, Mg2Fe, Mg2Co, etc. However, for high-entropy alloys, it is relatively difficult to form light high-entropy alloys by combining light elements and transition metals. Due to the differences in atomic radii and electronegativity of these two types of metals, it is difficult to form a single-phase solid solution; moreover, the melting points of these two types of metals vary greatly. For example, the melting points of light elements Li and Mg are 180°C and 650°C respectively, while the melting points of transition metals Ti and V are 1668°C and 1890°C respectively, and it is difficult to prepare them by conventional methods (such as melting method and powder metallurgy method). Therefore, the latest method of mechanical alloying such as ball milling can be used to combine light elements such as Al and Mg with transition metal elements such as Ti and V. Existing research has shown that by using ball milling, with light elements such as Mg and Al as the main components, light high-entropy hydrogen storage alloys containing Mg or Al can be prepared. On this basis, the present invention further uses the Li element with a lower density, and at the same time uses light metal elements Mg and Al, and combines the oscillating plasma ball milling with better alloying effect to prepare light high-entropy hydrogen storage alloys with an atomic ratio of LiAlMgTiV and having room temperature hydrogen storage performance.

[0004] Compared with metals with higher hardness such as Ti and V, softer metals such as Mg and Al are prone to cold welding during ball milling, causing the powder to agglomerate and adhere to the wall of the ball milling tank, affecting the alloying process of pure metal powder, reducing the final alloying effect, and seriously reducing the yield of alloy powder prepared by ball milling. When high-purity Li particles and high-purity metal powders such as Al, Mg, Ti, and V are simultaneously loaded into a plasma ball milling tank under an inert gas atmosphere in a glove box, when the one-step plasma ball milling is carried out for more than 15 hours, the yield of the ball-milled alloy powder will be less than 30%, and the alloying effect of the powder is poor. Figure 1 Figure Figure 1 is the XRD pattern of the LiAlMgTiV high-entropy alloy powder prepared by one-step plasma ball milling for 15 h. It can be seen that there are no obvious diffraction peaks corresponding to the Li, Al, and Mg elements in the alloy powder in this state, indicating that the three light elements have been alloyed. In addition, in this XRD pattern, relatively obvious diffraction peaks corresponding to the Ti and V elements are observed, indicating that the Ti and V metal elements with higher melting points have not undergone solid solution. The presence of light elements such as Li, Al, and Mg causes obvious cold welding phenomena during ball milling, reducing the alloying effect of Ti and V elements during plasma ball milling. Therefore, it is impossible to achieve the alloying of Li, Al, Mg, Ti, and V elements and obtain a LiAlMgTiV light high-entropy hydrogen storage alloy by one-step plasma ball milling method. Summary of the Invention

[0005] In view of this, the embodiments of the present invention provide a light high-entropy hydrogen storage alloy, a preparation method thereof, and an application thereof.

[0006] On the one hand, the present invention provides a preparation method of a light high-entropy hydrogen storage alloy, the method comprising the following steps:

[0007] Step 1: Under an inert gas atmosphere, place Ti powder and V powder in a plasma ball milling tank, fill the plasma ball milling tank with an inert gas, make the plasma ball milling run for a first time, and then stop running for the first time. Repeat the process of running for the first time and then stopping for the first time, and make the running time of the plasma ball milling greater than or equal to 20 h to obtain a TiV alloy;

[0008] Step 2: Under an inert gas atmosphere, screen out the TiV alloy powder prepared in Step 1; take Li particles, Al powder, and Mg powder, and place the Li particles, Al powder, and Mg powder into the plasma ball milling tank under an inert gas atmosphere, and then weigh the TiV alloy powder and place it into the plasma ball milling tank; fill the plasma ball milling tank with inert gas, let the plasma ball milling run for the first time, and then stop running for the first time. Repeat the process of running for the first time and then stopping for the first time until the running time of the plasma ball milling is greater than or equal to 15 h to obtain a lightweight high-entropy hydrogen storage alloy, where Li, Al, Mg, Ti, and V in the lightweight high-entropy hydrogen storage alloy are in an equiatomic ratio.

[0009] In some alternative embodiments, H2O is less than 1 ppm and O2 is less than 1 ppm under the inert gas atmosphere in Step 1.

[0010] In some alternative embodiments, the plasma ball milling tank is filled with inert gas at 0.12 - 0.15 MPa.

[0011] In some alternative embodiments, the first time is half an hour.

[0012] In some alternative embodiments, the plasma ball milling tank is equipped with an inflation valve.

[0013] In some alternative embodiments, the ball milling medium in the plasma ball milling tank is clean 304 stainless steel grinding balls with a diameter of 5 - 20 mm.

[0014] In some alternative embodiments, the ball-to-material ratio in the ball milling tank is 50:1.

[0015] In some alternative embodiments, the inert gas is argon.

[0016] In some alternative embodiments, Li, Al, Mg, Ti, and V in the lightweight high-entropy hydrogen storage alloy are in an equiatomic ratio.

[0017] On the other hand, the present invention also provides a lightweight high-entropy hydrogen storage alloy prepared by the method as described above, where Li, Al, Mg, Ti, and V in the lightweight high-entropy hydrogen storage alloy are in an equiatomic ratio.

[0018] On yet another aspect, the present invention also provides an application of a lightweight high-entropy LiAlMgTiV alloy in hydrogen storage.

[0019] In some alternative embodiments, the lightweight high-entropy hydrogen storage alloy disclosed in the present invention is a LiAlMgTiV alloy.

[0020] The present invention has the following technical effects compared with the prior art:

[0021] After the lightweight high-entropy hydrogen storage alloy disclosed in the embodiments of the present invention is activated at 400 °C under vacuum conditions for 4 h, the room-temperature hydrogen absorption kinetic curve under a hydrogen pressure condition of 6 MPa shows that hydrogen absorption reaches saturation at 1200 s, and the maximum hydrogen storage capacity is 4.2 wt%.

[0022] The embodiments of the present invention adopt a two-step ball milling method to improve the alloying effect of elements such as Li, Al, Mg, Ti, and V, and successfully prepare a lightweight high-entropy hydrogen storage alloy, namely LiAlMgTiV alloy. Due to the large differences in melting points and electronegativities between lightweight elements such as Li, Al, and Mg and refractory metal elements such as Ti and V in the lightweight high-entropy alloy, it is impossible to obtain the lightweight high-entropy alloy by conventional alloy preparation methods (such as melting method and powder metallurgy method). Usually, the ball milling method is used to prepare the lightweight high-entropy alloy, but for refractory elements such as Ti and V, the alloying effect of the conventional planetary ball milling method is limited. During the actual planetary ball milling process, the metal powder is prone to cold welding on the inner wall of the ball milling tank, affecting the alloying of the elemental powder.

[0023] Therefore, the present invention adopts a plasma ball milling device with a more significant alloying effect, combined with an innovative step-by-step ball milling method, to successfully prepare a lightweight high-entropy alloy with the composition of LiAlMgTiV. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present application, and are used together with the specification to explain the principles of the present application.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the accompanying drawings required for use in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without creative efforts.

[0026] Figure 1 XRD pattern of the LiAlMgTiV high-entropy alloy powder prepared by one-step plasma ball milling for 15 h provided by the embodiments of the present application;

[0027] Figure 2 XRD patterns of TiV alloy powders under different plasma ball milling times provided by the embodiments of the present application;

[0028] Figure 3 SEM secondary electrons and their corresponding elemental distribution maps (EDS mapping) of the plasma ball milled TiV alloy powder provided by the embodiments of the present application;

[0029] Figure 4XRD pattern of the plasma ball-milled LiAlMgTiV lightweight high-entropy hydrogen storage alloy provided by the embodiment of the present application;

[0030] Figure 5 Bright-field phase of the plasma ball-milled LiAlMgTiV lightweight high-entropy hydrogen storage alloy provided by the embodiment of the present application;

[0031] Figure 6 Room-temperature hydrogen absorption kinetic curve of the plasma ball-milled LiAlMgTiV lightweight high-entropy hydrogen storage alloy provided by the embodiment of the present application. Detailed implementation manners

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0033] Unless otherwise specifically stated, all kinds of raw materials, reagents, instruments, and equipment used in the present application can be obtained through market purchase or can be prepared by existing methods.

[0034] The embodiment of the present invention provides a preparation method of a lightweight high-entropy hydrogen storage alloy, and the method includes the following steps:

[0035] Step 1: Under an inert gas atmosphere, place Ti powder and V powder in a plasma ball-milling tank, fill the plasma ball-milling tank with an inert gas, make the plasma ball-milling run for a first time, and then stop running for the first time. Repeat the process of running for the first time and then stopping running for the first time, and make the running time of the plasma ball-milling greater than or equal to 20 h to obtain a TiV alloy;

[0036] Step 2: Under an inert gas atmosphere, sieve out the TiV alloy powder prepared in Step 1 with a sieve; take Li particles, Al powder, and Mg powder, and place the Li particles, Al powder, and Mg powder in the plasma ball-milling tank under an inert gas atmosphere, and then weigh the TiV alloy powder and place it in the plasma ball-milling tank; fill the plasma ball-milling tank with an inert gas, make the plasma ball-milling run for the first time, and then stop running for the first time. Repeat the process of running for the first time and then stopping running for the first time, and make the running time of the plasma ball-milling greater than or equal to 15 h to obtain a lightweight high-entropy hydrogen storage alloy, where Li, Al, Mg, Ti, and V in the lightweight high-entropy hydrogen storage alloy are in an equiatomic ratio.

[0037] In some alternative embodiments, the lightweight high-entropy hydrogen storage alloy disclosed in the present invention is a LiAlMgTiV alloy.

[0038] In some alternative embodiments, a LiAlMgTiV high-entropy hydrogen storage alloy with good room-temperature hydrogen storage performance is prepared by means of plasma ball milling and a step-by-step ball milling strategy. Due to the large differences in the melting points of Li, Al, Mg, Ti, and V elements, the melting points of Li, Mg, and Al elements are 180 °C, 660 °C, and 650 °C respectively, while the melting points of Ti and V elements are 1668 °C and 1910 °C respectively. The alloy is prepared by the step-by-step ball milling method.

[0039] Next, the preparation method of the above-mentioned lightweight high-entropy hydrogen storage alloy will be described in detail with a specific embodiment.

[0040] 1. First, alloying of the higher-melting-point Ti and V elements is achieved by means of plasma ball milling. The specific experimental process is as follows:

[0041] (1) Inside a glove box under an argon atmosphere (H2O less than 1 ppm, O2 less than 1 ppm), high-purity Ti powder (-200 mesh, 99.9%) and V powder (-325 mesh, 99.9%) are weighed by an analytical balance accurate to ten-thousandths of a decimal place according to an equiatomic ratio, that is, 24.225 g of Ti powder and 25.775 g of V powder. They are placed in a plasma ball milling tank with an inflation valve, and 2.5 kg of clean 304 stainless steel grinding balls with diameters ranging from 5 to 20 mm (ball milling medium) are loaded into the ball milling tank. At this time, the ball-to-powder ratio of ball milling is 50:1. After loading the stainless steel grinding balls and the required metal powders, the ball milling tank is sealed inside the glove box.

[0042] (2) The sealed ball milling tank is taken out of the glove box, filled with argon at 0.12 - 0.15 MPa, and placed in a plasma ball mill. To reduce the ball milling temperature and avoid cold welding during ball milling, which may affect the alloying effect, the ball milling parameters are set as follows: the plasma ball mill runs for half an hour and then stops for half an hour, and this process is repeated. The total running time of the plasma ball milling is set to 20 h.

[0043] 2. After alloying of Ti and V by plasma ball milling, on this basis, the preparation of the LiAlMgTiV high-entropy alloy is carried out. The specific experimental preparation process is as follows:

[0044] (1) After the ball milling tank is taken out of the plasma ball milling equipment, it is placed in the glove box. The ball milling tank is opened, and the equiatomic ratio TiV alloy powder after ball milling is sieved out with a sieve for standby.

[0045] (2) Inside the glove box, use an analytical balance to weigh high-purity lithium particles (99.9%, 6 - 10 mm cylinders), Al powder (-200 mesh, 99.9%), and Mg powder (-200 mesh, 99.9%) in equal atomic ratios, that is, 2.21 g of Li particles, 8.59 g of Al powder, and 7.738 g of Mg powder. Then, inside the glove box, place the above three powders into a plasma ball milling tank containing clean 304 stainless steel grinding balls (ball milling media) with diameters ranging from 5 - 20 mm. Then, place 31.462 g of TiV alloy powder prepared by plasma ball milling, which was weighed, into the plasma ball milling tank as well. At this time, the total weight of the powder in the tank is 50 g, and the ball-to-powder ratio is 50:1. Seal the ball milling tank inside the glove box.

[0046] (3) Take out the sealed ball milling tank from the glove box, fill the ball milling tank with argon gas at 0.12 - 0.15 MPa, and place it in a plasma ball mill. Set the ball milling parameters as follows: the plasma ball mill runs for half an hour and then stops for half an hour, repeating this process, and set the total running time of the plasma ball milling to 15 h.

[0047] (4) Inside the glove box, open the sealed ball milling tank, and use a sieve to screen out the LiAlMgTiV lightweight high-entropy hydrogen storage alloy powder.

[0048] Optionally, the purity of the Li, Al, Mg, Ti, and V metal raw materials used can be 99.99% or higher. Optionally, the diameter of the grinding balls used in the plasma ball milling process in the embodiments of the present invention can be 2 - 40 mm.

[0049] Optionally, the first time can be 20 minutes, 25 minutes, 30 minutes, etc. That is, the ball milling running time can be set as ball milling for 20 minutes and then stopping for 20 minutes, or ball milling for 25 minutes and then stopping for 25 minutes, or ball milling for 30 minutes and then stopping for 30 minutes, etc.

[0050] The present invention innovatively adopts a two-step ball milling method to improve the alloying effect of Li, Al, Mg, Ti, and V elements, and successfully prepares a lightweight high-entropy hydrogen storage alloy, namely the LiAlMgTiV alloy. First, a TiV alloy powder with a single-phase BCC crystal structure is successfully prepared through ball milling for at least 20 h. As Figure 2 shown, after 10 h of ball milling, diffraction peaks corresponding to element Ti are significantly present in the alloy, indicating that the powder after ball milling is not fully alloyed at this time; after 15 h of ball milling, the diffraction peaks corresponding to Ti element are significantly reduced; and after 20 h of plasma ball milling, the alloy powder presents a single-phase BCC structure, indicating that the alloying effect is better at this time, and a single-phase TiV alloy is formed. By Figure 3It can be seen that the particle diameters of the TiV alloy powder after 20 h of ball milling range from several hundred nanometers to dozens of micrometers. The Ti and V elements are uniformly distributed in each alloy powder particle, indicating good alloying effect and successfully preparing the TiV alloy.

[0051] On the basis of the TiV alloy, Li, Al, and Mg elements were further added to prepare the LiAlMgTiV lightweight high-entropy hydrogen storage alloy. Figure 4 XRD pattern of the plasma ball-milled LiAlMgTiV lightweight high-entropy hydrogen storage alloy. It can be seen that the alloy powder is mainly composed of a BCC structure, indicating good alloying of the alloy. In addition, the diffraction peaks of the alloy are relatively broadened, indicating that partial amorphization occurred during the ball milling process. The above results prove that the LiAlMgTiV lightweight high-entropy hydrogen storage alloy was successfully prepared by the stepwise plasma ball milling method. Figure 5 TEM bright field image of the plasma ball-milled LiAlMgTiV lightweight high-entropy hydrogen storage alloy, indicating that the alloy powder shows an obvious cluster structure, which is the typical morphology of the alloy powder after ball milling. Figure 5 In (a) and (b) are the morphologies of the LiAlMgTiV lightweight high-entropy hydrogen storage alloy powder observed in different regions under TEM.

[0052] Figure 6 Hydrogen absorption kinetic curve at room temperature under a hydrogen pressure of 6 MPa after the plasma ball-milled LiAlMgTiV lightweight high-entropy hydrogen storage alloy was activated at 400 °C under vacuum conditions for 4 h. The alloy can complete the first hydrogen absorption at a temperature of 293 K. Although there is a short incubation period during the first hydrogen absorption process, the hydrogen absorption of the alloy reaches saturation at 1200 s, and the maximum hydrogen storage capacity is 4.2 wt%. This result shows that the LiAlMgTiV lightweight high-entropy alloy prepared by the stepwise plasma ball milling method has good room-temperature hydrogen storage performance.

[0053] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent substitution methods and are all included in the protection scope of the present invention.

[0054] The above description is only the specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A preparation method of a lightweight high-entropy hydrogen storage alloy, characterized in that, It includes the following steps: Step 1: Under an inert gas atmosphere, place Ti powder and V powder into a plasma ball milling tank, fill the plasma ball milling tank with inert gas, let the plasma ball milling tank run for a first period of time, then stop running for the first period of time, and cyclically execute the process of running for the first period of time and then stopping running for the first period of time, so that the running time of the plasma ball milling tank is greater than or equal to 20 h to obtain a TiV alloy; Step 2: Under an inert gas atmosphere, sieve out the TiV alloy powder prepared in Step 1 with a sieve; take Li particles, Al powder and Mg powder, and under an inert gas atmosphere, place the Li particles, Al powder and Mg powder into the plasma ball milling tank, and then weigh the TiV alloy powder and place it into the plasma ball milling tank; fill the plasma ball milling tank with inert gas, let the plasma ball milling tank run for the first period of time, then stop running for the first period of time, and cyclically execute the process of running for the first period of time and then stopping running for the first period of time, so that the running time of the plasma ball milling tank is greater than or equal to 15 h to obtain a light high-entropy hydrogen storage alloy, wherein Li, Al, Mg, Ti and V in the light high-entropy hydrogen storage alloy have an equal atomic ratio.

2. The preparation method of the lightweight high-entropy hydrogen storage alloy according to claim 1, characterized in that, In Step 1, under an inert gas atmosphere, H2O is less than 1 ppm and O2 is less than 1 ppm.

3. The preparation method of the lightweight high-entropy hydrogen storage alloy according to claim 1, characterized in that, Fill the plasma ball milling tank with inert gas at 0.12 - 0.15 MPa.

4. The preparation method of the lightweight high-entropy hydrogen storage alloy according to claim 2, characterized in that, The first period of time is half an hour.

5. The preparation method of the lightweight high-entropy hydrogen storage alloy according to claim 2, wherein, The plasma ball milling tank is equipped with an inflation valve.

6. The preparation method of the lightweight high-entropy hydrogen storage alloy according to claim 2, characterized in that, The ball milling medium in the plasma ball milling tank is clean 304 stainless steel grinding balls with a diameter of 5 - 20 mm.

7. The preparation method of the lightweight high-entropy hydrogen storage alloy according to claim 6, characterized in that, The ball-to-material ratio in the plasma ball milling tank is 50:

1.

8. The preparation method of the lightweight high-entropy hydrogen storage alloy according to claim 2, characterized in that, The inert gas is argon.

9. A light high-entropy hydrogen storage alloy prepared by the method according to any one of claims 1 - 8, wherein Li, Al, Mg, Ti and V in the light high-entropy hydrogen storage alloy have an equal atomic ratio.

10. An application of the light high-entropy hydrogen storage alloy according to claim 9 in hydrogen storage.

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