La-containing high-entropy alloy and preparation method of magnesium hydride hydrogen storage material of La-containing high-entropy alloy

Abstract

The invention discloses a La-containing high-entropy alloy and a preparation method thereof.The preparation method comprises the steps that smelting is conducted according to the molar ratio of Ti to Mn to Fe to Co to Ni to La being 1: 1: 1: 1: 1: 0.1, and the mass of La is additionally increased by 3 wt% of burning loss mass; meanwhile, a CoFe phase, a NiTi phase and a FeNi phase are included; and the particle size is 100-200 meshes. The invention relates to a preparation method of a magnesium hydride hydrogen storage material based on a La-containing high-entropy alloy. The preparation method comprises the step of carrying out ball milling on HEA-La and MgH2. The obtained magnesium hydride hydrogen storage material based on the La-containing high-entropy alloy is applied to the field of hydrogen storage, when the doping amount of a catalyst is 10 wt%, the initial hydrogen desorption temperature is reduced to 179.44-180.33 DEG C, and the hydrogen desorption amount reaches 6.46-6.45 wt%; under the conditions that the dehydrogenation temperature is 300 DEG C and the dehydrogenation time is 30 minutes, the hydrogen desorption amount is 6.17-6.78 wt%; under the conditions that the hydrogen pressure is 3 Mpa, the hydrogen absorption temperature is 170 DEG C and the hydrogen absorption time is 5 min, the hydrogen absorption amount is 5.23-5.24 wt%.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage materials, and in particular to a method for preparing a La-containing high-entropy alloy and a magnesium hydride hydrogen storage material thereof. Background Art

[0002] Magnesium hydride (MgH2) has a hydrogen storage density of up to 7.6 wt% and has excellent reversibility, non-toxicity, and low cost. However, it has the problems of high dehydrogenation temperature and slow kinetic performance. The current common technical solution to improve MgH2 is to use alloys as catalysts. Common alloy catalyst systems include TiFe alloy systems, TiMn alloy systems, and LaNi alloy systems. Among them, in the LaNi alloy system, LaH5 and MgH2 in situ generate Mg2Ni phase and LaH3 phase, which can effectively promote the dissociation of hydrogen molecules. For example, the existing literature 1 (Liu Yu, Zhang Jian, Pang Xiaotong, et al. Effect and mechanism of lanthanum nickel alloy on the microstructure and hydrogen storage performance of magnesium hydride [J]. Materials Guide, 2025, 39(08): 138-143.) obtained LaH3 alloy by vacuum melting, which can reduce the initial dehydrogenation temperature of MgH2 to 247 ° C, and release 6.0 wt% of hydrogen within 500 s at 300 ° C. However, the LaNi alloy catalyst obtained by this technical solution still has an initial hydrogen desorption temperature above 247°C and an activation energy greater than 80 kJ / mol, indicating poor hydrogen desorption thermodynamic performance. This is because such alloy catalysts are typically composed of two metal elements, resulting in a low entropy value (≤1.5R), i.e., a low-entropy alloy. The surface atomic arrangement and electronic structure of low-entropy alloys tend to be ordered, which leads to a reduction in surface active sites, ultimately manifesting in poor catalytic performance.

[0003] In order to solve the above problems, high entropy alloys can be prepared by adding components to further improve the hydrogen storage kinetics of MgH2. The principle of improving the hydrogen storage kinetics of high entropy alloys HEA is based on the basic characteristics of high entropy alloys, specifically the electronic structure and lattice distortion between the multi-metal elements produced by the combination of five or more metal elements in high entropy alloys. For example, in existing document 2 (Wan H, Yang X, Zhou S, et al. "Enhancing hydrogen storage properties of MgH2 using FeCoNiCrMn high entropy alloy catalysts" [J]. Journal of Materials Science & Technology, 2023, 149: 88-98.), the technical solution uses the same vacuum melting method as existing document 1 to obtain the alloy and then use a mechanical crushing process to obtain FeCoNiCrMn high entropy alloy powder, achieving the initial hydrogen desorption temperature of MgH2 reduced to 209 ° C, and 5.8wt% of hydrogen can be released at 300 ° C and within 240s. However, research and analysis show that the direct reason for the poor performance of this technical solution is that the obtained alloy is a face-centered cubic FCC solid solution phase, which directly leads to a small lattice distortion of only 3.74%. The essential reason is that the five metal elements used in this technical solution are adjacent elements, that is, the difference in atomic radius is small.

[0004] Therefore, in order to increase the degree of lattice distortion, high entropy alloys can be prepared using atomic radii with a large difference. For example, the existing document 3 (Song MC, Wu FY, Jiang YQ, et al. "Optimizing FeCoNiCrTi high-entropy alloy with hydrogen pumping effect to boost de / hydrogenation performance of magnesium hydride" [J]. Rare Metals, 2024, 43 (7): 3273-3285.) prepared FeCoNiCrTi high-entropy alloy powder, which can reduce the initial dehydrogenation temperature of MgH2 to 198 ° C, and release 6.62wt% of hydrogen at 290 ° C and within 600s. The lattice distortion of FeCoNiCrTi obtained by this technical solution is 6.62%, which is higher than that of the aforementioned comparative document 2, and the corresponding technical effect is improved.

[0005] Analysis of the aforementioned References 2 and 3 indicates that lattice distortion is also a criterion for catalytic performance. However, the catalytic performance of Reference 3 still fails to meet application requirements. This is because oxidation of the Cr element in the high-entropy alloy during the preparation process forms a Cr2O3 passivation layer, which hinders hydrogen diffusion and ultimately results in catalytic performance that fails to meet expectations. Summary of the Invention

[0006] The purpose of this patent is to provide a method for preparing La-containing high entropy alloy and its magnesium hydride hydrogen storage material.

[0007] In order to achieve the above-mentioned object of the invention, the present invention adopts the following inventive concept: in order to obtain a high-entropy alloy with a higher lattice distortion, TiMnFeCoNi is selected as the high-entropy alloy, and by adding a trace amount of La metal, the lattice distortion degree of HEA is increased from 6.22% to 15.88%, greatly improving the lattice distortion degree of HEA. At the same time, the density and stability of the surface oxide layer are destroyed, effectively reducing the effect of the initial hydrogen release performance of magnesium hydride.

[0008] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0009] A La-containing high entropy alloy is smelted with a molar ratio of Ti, Mn, Fe, Co, Ni, and La of 1:1:1:1:1:0.1, and the mass of La is increased by 3 wt% of the burnt mass;

[0010] The HEA-La high entropy alloy contains CoFe phase, NiTi phase and FeNi phase at the same time;

[0011] The particle size of the HEA-La high entropy alloy is 100-200 meshes.

[0012] A preparation method of a La-containing high entropy alloy, wherein the molar ratio of Ti, Mn, Fe, Co, Ni and La is 1:1:1:1:1:0.1, and the mass of La is increased by 3wt% by the burnt mass, and arc melting is performed under certain conditions to obtain a La-containing high entropy alloy, referred to as HEA-La. -3 Pa, argon gas pressure was 0.05 MPa as the protective gas, and the number of flipping was 5 times.

[0013] A method for preparing a magnesium hydride hydrogen storage material based on a La-containing high entropy alloy comprises the following steps: ball milling HEA-La and MgH2 under certain conditions to obtain a magnesium hydride hydrogen storage material based on a La-containing high entropy alloy, referred to as MgH2-HEA-La;

[0014] The ball milling conditions are as follows: a mass ratio of 10:90, a ball-to-material ratio of 80:1, a ball milling speed of 400 rpm, a ball milling time of 12 h, and a certain ball milling interval;

[0015] The ball milling conditions also include the existence of a ball milling interval, and the ball milling interval condition is that after each ball milling time of 12 minutes, the ball milling is paused, and the pause time is 6 minutes.

[0016] The obtained magnesium hydride hydrogen storage material based on La-containing high entropy alloy is used in the field of hydrogen storage. When the catalyst doping amount is 10wt%, the initial hydrogen desorption temperature drops to 179.44-180.33°C and the hydrogen desorption amount reaches 6.46-6.45wt%.

[0017] Under the conditions of dehydrogenation temperature of 300℃ and dehydrogenation time of 30min, the hydrogen release amount is 6.17-6.78wt%; under the conditions of hydrogen pressure of 3Mpa, hydrogen absorption temperature of 170℃ and hydrogen absorption time of 5min, the hydrogen absorption amount is 5.23-5.24wt%.

[0018] The technical effects of the present invention have been tested and the specific contents are as follows:

[0019] EDS test results show that HEA-La contains Ti, Mn, Fe, Co, and Ni. It also contains La. Furthermore, the atomic contents of Ti, Mn, Fe, Co, and Ni are similar, all approaching 20 at.%. These test results indicate that HEA-La is a high-entropy alloy.

[0020] XRD test results show that HEA-La contains characteristic peaks of CoFe phase, NiTi phase and FeNi phase.

[0021] The results of dehydrogenation thermodynamic tests show that the initial hydrogen desorption temperature is 179.44-180.33°C. When the test temperature is 300°C, the hydrogen desorption amount is 5.50-5.57wt%, reaching 83.63-82.58% of the theoretical maximum hydrogen desorption amount of 6.66wt%; the total hydrogen desorption amount reaches 6.46-6.45wt%, reaching 96.84-97.00% of the theoretical maximum hydrogen desorption amount.

[0022] The results of dehydrogenation kinetics tests show that the amount of hydrogen released is 6.17-6.78 wt% under the conditions of dehydrogenation temperature of 300°C and dehydrogenation time of 30 min.

[0023] The dehydrogenation kinetic test results show that under the conditions of hydrogen pressure of 3 MPa, hydrogen absorption temperature of 170°C and hydrogen absorption time of 5 min, the hydrogen absorption amount is 5.23-5.24 wt%.

[0024] Therefore, the present invention has the following advantages over the prior art:

[0025] 1. The present invention greatly improves the lattice distortion of HEA by doping a trace amount of La metal, generating a large number of dislocations and defects, thereby effectively destroying the density and stability of its surface oxide layer, increasing the active sites in the hydrogen storage reaction process, achieving a lower starting hydrogen desorption temperature of MgH2 and a rapid hydrogen absorption and desorption effect, thereby improving the hydrogen storage performance of MgH2.

[0026] 2. The method used to prepare the La-containing high-entropy alloy of the present invention only requires a trace amount of La metal, and has the advantages of low cost, simple preparation process, controllable reaction and easy large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is the EDS spectrum of HEA-La prepared in Example 1;

[0028] Figure 2 is the XRD pattern of HEA-La prepared in Example 1;

[0029] Figure 3 The temperature-increasing dehydrogenation curves of Example 1 and Example 2, Comparative Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4 are shown;

[0030] Figure 4 is the isothermal dehydrogenation curve of MgH2-HEA-La-10 prepared in Example 1;

[0031] Figure 5 is the isothermal dehydrogenation curve of BM-MgH2 prepared in Comparative Example 1;

[0032] Figure 6 is a graph showing the isothermal hydrogen absorption curve of MgH2-HEA-La-10 prepared in Example 1;

[0033] Figure 7 This is the isothermal hydrogen absorption curve of BM-MgH2 prepared in Comparative Example 1. DETAILED DESCRIPTION

[0034] The present invention is further described in detail through embodiments and in conjunction with the accompanying drawings, but the present invention is not limited thereto.

[0035] Example 1

[0036] A preparation method of a La-containing high-entropy alloy comprises the following steps: with the molar ratio of Ti, Mn, Fe, Co, Ni and La being 1:1:1:1:1:0.1, and the mass of La being increased by 3wt% of the burnt mass, firstly, using ethanol as a cleaning liquid for 30 minutes, ultrasonically cleaning 3.292g of Ti metal, 3.776g of Mn metal, 3.840g of Fe metal, 4.054g of Co metal, 4.036g of Ni metal and 1.000g of La metal, and then, in a vacuum degree of 2×10 -3 Pa, argon pressure 0.05MPa as the shielding gas, arc melting was carried out under the conditions of 5 flipping times,

[0037] The arc melting conditions are as follows: first, La is melted at a current intensity of 100A. After the La metal is completely melted, Ni metal, Co metal, Fe metal, Mn metal, and Ti metal are added in sequence at a current intensity of 200A and melted until completely melted. After the melting is completed, the resulting alloy is cooled in the furnace to obtain an alloy ingot. The resulting alloy ingot is polished, crushed, ground, and sieved to obtain a La-containing high entropy alloy, referred to as HEA-La.

[0038] The sieved particle size is 200 meshes.

[0039] In order to prove the composition of HEA-La, that is, to meet the requirements of high entropy alloy, EDS test was carried out. The test results are as follows Figure 1 As shown in Table 1, HEA-La contains Ti, Mn, Fe, Co, and Ni. It also contains La. Furthermore, the atomic contents of Ti, Mn, Fe, Co, and Ni are similar, all approaching 20 at.%. The test results indicate that HEA-La is a high-entropy alloy.

[0040] Table 1 Element composition of HEA-La high entropy alloy

[0041] element Wt% At% Ti 16.41 19.52 Mn 19.21 19.93 Fe 18.58 18.95 Co 19.96 19.30 Ni 20.88 20.26 La 4.96 2.03 Total amount: 100.00 100.00

[0042] In order to prove the crystal structure of HEA-La, XRD test was carried out. The test results are as follows Figure 2 As shown, HEA-La contains the characteristic peaks of CoFe phase, NiTi phase and FeNi phase.

[0043] A magnesium hydride hydrogen storage material based on a La-containing high entropy alloy comprises the following steps: ball milling is performed under the conditions of a mass ratio of HEA-La to MgH2 of 10:90, a ball-to-material ratio of 80:1, a ball milling speed of 400 rpm, a ball milling time of 12 hours, and a certain ball milling interval, to obtain a magnesium hydride hydrogen storage material based on a La-containing high entropy alloy, referred to as MgH2-HEA-La. The MgH2-HEA-La obtained in specific embodiment 1 is named MgH2-HEA-La-10 because the content of HEA-La is 10 wt.%;

[0044] The ball milling interval condition is that after each ball milling time of 12 minutes, the ball milling is paused for 6 minutes.

[0045] In order to demonstrate the thermodynamic performance of HEA-La as a catalyst for dehydrogenation, a temperature-increasing dehydrogenation test was conducted on MgH2-HEA-La-10. Figure 3 As shown, the initial hydrogen desorption temperature is 179.44°C, which is 101.6°C lower than that of pure magnesium hydride; when the test temperature is 300°C, the hydrogen desorption amount is 5.57wt%, reaching 83.63% of the theoretical maximum hydrogen desorption amount of 6.66wt%, that is, the hydrogen desorption rate reaches 83.63%; the total hydrogen desorption amount reaches 6.46wt%, reaching 97.00% of the theoretical maximum hydrogen desorption amount.

[0046] In order to demonstrate the kinetics of hydrogen absorption and desorption of HEA-La as a catalyst, isothermal dehydrogenation and isothermal hydrogen absorption tests were carried out on MgH2-HEA-La-10.

[0047] The isothermal dehydrogenation test results are as follows Figure 4 As shown, under the conditions of dehydrogenation temperature of 300 ° C and dehydrogenation time of 30 min, the amount of hydrogen released is 6.18 wt%;

[0048] The isothermal hydrogen absorption test results are as follows Figure 5 As shown, under the conditions of hydrogen pressure of 3 MPa, hydrogen absorption temperature of 170°C and hydrogen absorption time of 5 min, the hydrogen absorption amount is 5.23 wt%.

[0049] In order to demonstrate the effect of HEA-La as a catalyst on the performance of magnesium hydride, Comparative Example 1 is provided, which is a magnesium hydride hydrogen storage material prepared without doping with HEA-La.

[0050] Comparative Example 1.

[0051] A method for preparing a magnesium hydride hydrogen storage material not doped with HEA-La, wherein the steps not specifically described are the same as those in Example 1, except that no HEA-La is added. The obtained magnesium hydride hydrogen storage material is referred to as BM-MgH2.

[0052] The results of the temperature-increasing dehydrogenation test of BM-MgH2 are as follows: Figure 3 As shown, the initial hydrogen desorption temperature is 281.04°C. At a test temperature of 300°C, the amount of hydrogen released is only 0.19 wt%, reaching only 2.53% of the theoretical maximum hydrogen desorption of 7.5 wt%, or a hydrogen desorption rate of 2.53%. Compared with Example 1, the introduction of HEA-La as a catalyst significantly reduces the initial hydrogen desorption temperature from 281.04°C to 179.44°C, a decrease of 101.6°C. Furthermore, the hydrogen desorption rate significantly increases from 2.53% to 86.63%. These test results demonstrate that the addition of HEA-La as a catalyst significantly improves the thermodynamic performance of magnesium hydride during hydrogen desorption.

[0053] The isothermal dehydrogenation test results of BM-MgH2 are as follows Figure 6 As shown in Figure 1, under the conditions of a dehydrogenation temperature of 300°C and a dehydrogenation time of 30 minutes, the hydrogen release rate was 0.35 wt%. Compared with Example 1, the introduction of HEA-La as a catalyst significantly increased the hydrogen release rate from 0.35 wt% to 6.18 wt%, an increase of 1765.7%. The test results show that the addition of HEA-La as a catalyst can improve the dehydrogenation kinetics of magnesium hydride.

[0054] The isothermal hydrogen absorption test results of BM-MgH2 are as follows: Figure 7 As shown. Under the conditions of a hydrogen pressure of 3 MPa, a hydrogen absorption temperature of 170°C, and a hydrogen absorption time of 5 minutes, the hydrogen absorption capacity was 1.34 wt%. Compared with Example 1, the introduction of HEA-La as a catalyst significantly increased the hydrogen absorption capacity from 1.34 wt% to 5.23 wt% at a hydrogen absorption temperature of 170°C, an increase of 389.3%. The test results of introducing HEA-La as a catalyst show that the doping of HEA-La as a catalyst can improve the hydrogen absorption kinetics of magnesium hydride.

[0055] In order to further demonstrate the effect of the HEA-La doping amount on the performance of magnesium hydride, comparative examples 2, 3, 4 and 5 are provided, in which magnesium hydride hydrogen storage materials with HEA-La doping amounts of 3wt%, 5wt%, 7wt% and 12wt%, respectively.

[0056] Comparative Example 2

[0057] A method for preparing a magnesium hydride hydrogen storage material with a HEA-La doping amount of 3 wt%. The steps not specifically described are the same as those in Example 1, except that the HEA-La doping amount is 3 wt%. The obtained magnesium hydride hydrogen storage material is referred to as MgH2-HEA-La-3.

[0058] The results of the temperature-increasing dehydrogenation test of MgH2-HEA-La-3 are as follows: Figure 3As shown, the initial hydrogen desorption temperature is 197.88°C. At a test temperature of 300°C, the amount of hydrogen desorption is only 1.49 wt%, reaching only 20.49% of the theoretical maximum hydrogen desorption of 7.27 wt%, i.e., the hydrogen desorption rate is 20.49%. Compared with Example 1, increasing the content of HEA-La as a catalyst can significantly reduce the initial hydrogen desorption temperature from 197.88°C to 179.44°C, a decrease of 18.44°C. Furthermore, the hydrogen desorption rate is significantly increased from 20.49% to 83.63%. The test results show that increasing the content of HEA-La can reduce the initial hydrogen desorption temperature and increase the hydrogen desorption rate.

[0059] Comparative Example 3

[0060] A method for preparing a magnesium hydride hydrogen storage material doped with 5 wt% HEA-La, wherein the steps not specifically described are the same as those in Example 1, except that 5 wt% HEA-La is added and ball milled to obtain a magnesium hydride hydrogen storage material doped with 5 wt% HEA-La, referred to as MgH2-HEA-La-5.

[0061] The results of the temperature-increasing dehydrogenation test of MgH2-HEA-La-5 are as follows: Figure 3 As shown, the initial hydrogen desorption temperature is 195.87°C. At a test temperature of 300°C, the amount of hydrogen desorption is only 2.84 wt%, reaching 39.86% of the theoretical maximum hydrogen desorption of 7.12 wt%, i.e., a hydrogen desorption rate of 39.86%. Compared with Example 1, increasing the content of HEA-La as a catalyst can reduce the initial hydrogen desorption temperature from 195.87°C to 179.44°C, a decrease of 16.43°C; and significantly increase the hydrogen desorption rate from 39.86% to 86.63%. The test results are consistent with those of Comparative Example 2, indicating that increasing the content of HEA-La can reduce the initial hydrogen desorption temperature and increase the hydrogen desorption rate.

[0062] Comparative Example 4

[0063] A method for preparing a magnesium hydride hydrogen storage material doped with 7 wt% HEA-La, wherein the steps not otherwise specified are the same as those in Example 1, except that 7 wt% HEA-La is added and ball milled to obtain a magnesium hydride hydrogen storage material doped with 7 wt% HEA-La, referred to as MgH2-HEA-La-7.

[0064] The results of the temperature-increasing dehydrogenation test of MgH2-HEA-La-7 are as follows: Figure 3As shown, the initial hydrogen desorption temperature was 209.04°C. At a test temperature of 300°C, the hydrogen desorption rate was 4.35 wt%, reaching 62.37% of the theoretical maximum hydrogen desorption rate of 6.98 wt%, or a hydrogen desorption rate of 62.37%. Compared with Example 1, increasing the HEA-La catalyst content significantly reduced the initial hydrogen desorption temperature from 209.04°C to 179.44°C, a decrease of 85.9%. Furthermore, the hydrogen desorption rate significantly increased from 62.37% to 86.63%. The test results are consistent with those of Comparative Example 2, indicating that increasing the HEA-La content can reduce the initial hydrogen desorption temperature and increase the hydrogen desorption rate.

[0065] Example 2

[0066] A method for preparing a magnesium hydride hydrogen storage material doped with 12% HEA-La, wherein the steps not otherwise specified are the same as those in Example 1, except that 12% HEA-La is added and ball milled to obtain a magnesium hydride hydrogen storage material doped with 12% HEA-La, referred to as MgH2-HEA-La-12.

[0067] The results of the temperature-increasing dehydrogenation test of MgH2-HEA-La-12 are as follows: Figure 3 As shown, the initial hydrogen desorption temperature is 188.72°C. At a test temperature of 300°C, the hydrogen desorption amount is 5.30 wt%, reaching 80.30% of the theoretical maximum hydrogen desorption amount of 6.60 wt%, i.e., a hydrogen desorption rate of 80.30%. Compared with Example 1, the introduction of 10 wt% HEA-La as a catalyst can reduce the initial hydrogen desorption temperature from 188.72°C to 179.44°C, a decrease of 70.1%, and increase the hydrogen desorption rate from 80.30% to 86.63%. The test results indicate that while an excessive amount of HEA-La can further increase the hydrogen desorption rate, it can also lead to a decrease in the initial hydrogen desorption temperature.

Claims

1. A La-containing high-entropy alloy, characterized in that: The smelting is performed with a material ratio of Ti, Mn, Fe, Co, Ni and La of 1:1:1:1:1:1:0.1, and the mass of La is increased by 3 wt% of the burnt mass.

2. The La-containing high entropy alloy according to claim 1, wherein: The HEA-La high entropy alloy contains CoFe phase, NiTi phase and FeNi phase at the same time.

3. The La-containing high entropy alloy according to claim 1, wherein: The particle size of the HEA-La high entropy alloy is 100-200 meshes.

4. A method for preparing a La-containing high-entropy alloy, characterized in that: By arc melting under certain conditions with the molar ratio of Ti, Mn, Fe, Co, Ni and La being 1:1:1:1:1:0.1 and the mass of La being increased by an additional 3wt% by burnt mass, a La-containing high entropy alloy, referred to as HEA-La, can be obtained.

5. The preparation method according to claim 4, characterized in that: The arc melting conditions are as follows: -3 Pa, argon gas pressure was 0.05 MPa as the protective gas, and the number of flipping was 5 times.

6. A method for preparing a magnesium hydride hydrogen storage material based on a La-containing high entropy alloy, characterized in that The following steps are involved: By ball milling HEA-La and MgH2 under certain conditions, a magnesium hydride hydrogen storage material based on La-containing high entropy alloy can be obtained, which is referred to as MgH2-HEA-La.

7. The preparation method according to claim 6, characterized in that: The ball milling conditions are as follows: a mass ratio of 10:90, a ball-to-material ratio of 80:1, a ball milling speed of 400 rpm, a ball milling time of 12 h, and a certain ball milling interval.

8. The preparation method according to claim 7, characterized in that: The ball milling conditions also include the existence of a ball milling interval, and the ball milling interval condition is that after each ball milling time of 12 minutes, the ball milling is paused, and the pause time is 6 minutes.

9. The preparation method according to claim 7, characterized in that: The obtained magnesium hydride hydrogen storage material based on La-containing high entropy alloy is used in the field of hydrogen storage. When the catalyst doping amount is 10wt%, the initial hydrogen desorption temperature drops to 179.44-180.33°C and the hydrogen desorption amount reaches 6.46-6.45wt%.

10. The preparation method according to claim 7, characterized in that: The obtained magnesium hydride hydrogen storage material based on La-containing high-entropy alloy is used in the field of hydrogen storage. Under the conditions of dehydrogenation temperature of 300°C and dehydrogenation time of 30 minutes, the hydrogen release amount is 6.17-6.78wt%; under the conditions of hydrogen pressure of 3Mpa, hydrogen absorption temperature of 170°C and hydrogen absorption time of 5 minutes, the hydrogen absorption amount is 5.23-5.24wt%.

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