Mg2Si-based hydrogen storage material and preparation method thereof

Abstract

The invention discloses an Mg2Si-based hydrogen storage material and a preparation method thereof.The preparation method comprises the following steps that a mixture of Mg2Si powder / Ti powder and ball-milling beads are placed in a ball-milling tank, and hydrogen is inflated; a ball milling program is set as follows: the rotating speed of the ball mill is 150-400 rpm; and after the ball milling procedure is completed, the Mg2Si-based hydrogen storage material is obtained. Through Ti induction and a hydrogen-assisted high-energy ball milling technology, Mg2Si is successfully subjected to high-temperature ball milling under a mild condition; the method has the advantages that the high-efficiency hydrogenation is realized under the conditions that the pressure is 1.5 MPa H2 and an external heat source is not needed for heating, the conversion rate is as high as 76%, and the technical bottleneck that the traditional Mg2Si hydrogenation is difficult is solved; meanwhile, excellent hydrogen absorption and desorption kinetics and low-temperature hydrolysis hydrogen production performance are achieved.

Description

Technical Field

[0001] The present invention relates to the field of hydrogen energy, and in particular to a Mg 2 Si-based hydrogen storage material and preparation method thereof. Background Art

[0002] The utilization of hydrogen energy provides an important solution to the global energy crisis and environmental pollution. However, the efficient, safe and economical storage of hydrogen remains a major challenge for the industrialization of hydrogen energy. Magnesium-based hydrides (such as MgH 2 ) has been widely studied as a hydrogen storage material due to its high dehydrogenation enthalpy change (75 kJ / mol H 2 ) The dehydrogenation process requires a lot of heat, and its high dehydrogenation temperature and slow dehydrogenation kinetics limit its practical application. As a potential hydrogen storage material system, it has much lower 2 The dehydrogenation enthalpy change (36.8 kJ / mol H 2 ), showing the potential to absorb and desorb hydrogen at near room temperature, which is superior to MgH 2 Thermodynamic prediction shows that the dehydrogenation platform pressure can reach 5.44 bar at 50 °C, demonstrating excellent dehydrogenation thermodynamic performance. However, the dehydrogenation product (Mg 2 Si) faces significant obstacles in the rehydriding process, limiting its large-scale application. 2 The hydrogenation of Si still faces great challenges, including the difficulty in achieving high-pressure hydrogen pressure, difficulty in initial hydrogenation nucleation and slow hydrogenation kinetics.

[0003] Mg 2 Si is not only a potential pyrolysis hydrogen storage material, but also can react with water to efficiently produce hydrogen under mild conditions, with a theoretical hydrogen production of up to 1178.9 mL / g. Injecting hydrogen atoms after hydrogenation can further improve its hydrolysis hydrogenation efficiency. Therefore, whether it is used as a reversible hydrogen storage material or a hydrolysis hydrogen production medium, Mg 2 Si hydrogenation is crucial for practical applications.

[0004] For the above Mg 2 The technical problem of the difficulty in hydrogenating Si-based hydrogen storage materials is that the present invention provides a method different from the traditional high temperature and high pressure treatment of Mg 2 A method for hydrogenation of Si was designed to facilitate the operation and mild conditions of Mg hydrogenation. 2 Si method, a Mg 2Si-based hydrogen storage materials, compared with traditional magnesium-based hydrogen storage materials, the Mg prepared by this method 2 Si-based hydrogen storage materials have fine grains and are rich in defects. They have excellent hydrogen absorption and desorption kinetics at lower temperatures and can quickly hydrolyze hydrogen at lower temperatures (5°C). Summary of the invention

[0005] In view of the above-mentioned defects of the prior art, the technical problem to be solved by the present invention is to overcome the traditional method of hydriding Mg 2 Si requires high temperature and high pressure defects, and provides an easy-to-operate, mild condition for Mg hydride 2 The method of Si.

[0006] To achieve the above object, the present invention provides a Mg 2 The preparation method of Si-based hydrogen storage material comprises the following steps:

[0007] Mg 2 The Si powder / Ti powder mixture and ball milling beads were placed in a ball milling jar and filled with hydrogen;

[0008] The ball mill used in this patent is a planetary ball mill, and the rotation speeds mentioned in this patent are all orbital rotation speeds.

[0009] Set the ball milling program as follows: the speed of the ball mill is 150 rpm to 400 rpm;

[0010] After the ball milling process is completed, Mg 2 Si-based hydrogen storage materials.

[0011] In the present invention, the Mg 2 The molar ratio of Si powder to the Ti powder is preferably 0.5:1-2:1, more preferably 1:1.

[0012] In the present invention, the Mg 2 The particle size of Si powder can be 50 to 100 μm.

[0013] In the present invention, the particle size of the Ti powder may be 50 to 100 μm.

[0014] In the present invention, the Mg 2 The mass ratio of the Si powder / Ti powder mixture to the ball milling beads is preferably 1:50 to 1:70, for example 1:60. Experiments have shown that the less ball milling beads, the more Mg 2 The risk of Si hydrogenation failure is greater when there are too many ball milling beads and the ball milling beads are wasted.

[0015] In the present invention, the hydrogen pressure in the ball mill is preferably 10 to 30 bar, for example 15 bar.

[0016] In the present invention, the ball milling program further includes setting periodic forward and reverse rotation, for example, forward rotation for 0.2 to 0.8 hours, reverse rotation for 0.2 to 0.8 hours, and stop for 0.2 to 0.8 hours. For another example, forward rotation for 0.5 hours, reverse rotation for 0.5 hours, and stop for 0.5 hours.

[0017] In the present invention, the rotation speed of the ball mill is preferably 300 rpm-400 rpm.

[0018] The present invention also provides a Mg prepared by the above preparation method. 2 Si-based hydrogen storage materials.

[0019] In the present invention, the Mg 2 The preferred atomic ratio of Mg / Si / Ti in Si-based hydrogen storage materials is 2:1:(0.5-2), and its main phase components are MgH 2 / TiSi 2 / Mg 2 Four.

[0020] Technical Effects

[0021] High efficiency hydrogenation performance: Through Ti-induced and hydrogen-assisted high-energy ball milling technology, Mg 2 Si under mild conditions (<1.5MPa H 2 , no external heat source is required for heating) high efficiency hydrogenation, conversion rate up to 76%, solving the problem of traditional Mg 2 The technical bottleneck of Si hydrogenation is difficult.

[0022] Excellent hydrogen absorption and desorption kinetics: the prepared Mg 2 Si-based hydrogen storage materials have fine grains and are rich in grain boundary defects, containing in-situ generated ultrafine MgH 2 Nanocrystalline particles, and TiSi 2 The catalyst forms a close interface, significantly reducing the dehydrogenation starting temperature to 114.3 °C, and completely dehydrogenates within 7 minutes at 250 °C, and absorbs 1.25 wt.% of hydrogen (reaching 50% of the total capacity) within 60 minutes at room temperature, which is comparable to MgH 2 , the hydrogen absorption rate of this material increased by 8.4 times.

[0023] Low-temperature hydrolysis hydrogen production performance: After hydrogenation, the material particles have rich internal defects, and the ultrafine MgH 2 With TiSi 2 The interfacial synergistic effect significantly improves the efficiency of hydrogen production by hydrolysis. The hydrogen production reaches 580.11 mL / g at 35°C and still maintains 91.9% hydrogen production efficiency at 5°C, making it suitable for hydrogen energy applications in cold regions.

[0024] Dual-function application scenarios: The material has both thermal desorption hydrogen storage and hydrolysis hydrogen production functions, which expands its application potential in vehicle-mounted hydrogen storage systems, portable hydrogen energy equipment and industrial hydrogen sources.

[0025] 2. Performance indicators

[0026] Hydrogen storage capacity: 2.35wt.%, meeting the basic requirements of commercial hydrogen storage materials;

[0027] Dehydrogenation temperature: starting temperature ≤ 114.3℃, much lower than traditional MgH 2 (>300℃);

[0028] Hydrogen absorption rate: The hydrogen absorption amount reaches 1.23wt.% in 60 minutes at room temperature, accounting for 52.1% of the total capacity;

[0029] Hydrogen production by hydrolysis: ≥580mL / g within 1 hour at 35°C, ≥528mL / g at 5°C.

[0030] 3. Production implementation feasibility

[0031] Simple process: The preparation method only requires a ball mill and a hydrogen environment, no complex equipment or high temperature and high pressure conditions, and is easy to scale up production;

[0032] Raw materials are easily available: the main raw material is Mg 2 Si and Ti powders are low-cost and widely available;

[0033] Environmental protection: No toxic by-products are generated during the preparation process, which meets the requirements of green chemistry;

[0034] Strong compatibility: The material can be seamlessly connected with existing hydrogen storage equipment (such as hydrogen storage tanks, fuel cells), reducing the cost of industrial promotion.

[0035] 4. Prospects for industrial application

[0036] On-board hydrogen storage system: low dehydrogenation temperature and high hydrogen absorption rate characteristics adapt to the needs of fuel cell vehicles, improving driving range and hydrogen charging efficiency;

[0037] Portable hydrogen energy equipment: low-temperature and high-efficiency hydrolysis hydrogen production characteristics are suitable for outdoor emergency power supply, drones and other scenarios;

[0038] Industrial hydrogen source: high hydrogen storage capacity and rapid hydrogen absorption and release performance meet the needs of industrial hydrogen production, storage and use;

[0039] Application of hydrogen energy in cold regions: Excellent low-temperature hydrolysis performance expands the application scenarios of hydrogen energy in high-latitude regions.

[0040] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The hydrogen-assisted high-energy ball milling method for preparing Mg 2 Schematic diagram of Si-based hydrogen storage materials;

[0042] Reference numerals: ball mill gas valve 1, hydrogen 2, Ti powder 3, Mg 2 Si powder 4, stainless steel beads 5, ball mill cover 6, ball mill body 7, prepared Mg 2 Si-based hydrogen storage materials 8

[0043] Figure 2 Mg prepared in Example 1 2 Si-based hydrogen storage materials (Mg 2 XRD spectrum of Si / Ti molar ratio 1:1);

[0044] Figure 3 Mg prepared in Example 1 2 Si-based hydrogen storage materials (Mg 2 Transmission electron microscope image (a) of the Si / Ti molar ratio of 1:1, high-resolution transmission electron microscope image (b), selected area electron diffraction image (c), element distribution map (d);

[0045] Figure 4 Mg prepared in Example 1 2 Si-based hydrogen storage materials (Mg 2 Dehydrogenation performance at different temperatures (Si / Ti molar ratio of 1:1);

[0046] Figure 5 Mg prepared in Example 1 2 Si-based hydrogen storage materials (Mg 2 The hydrogen absorption performance at different temperatures (Si / Ti molar ratio of 1:1);

[0047] Figure 6 Mg prepared in Example 1 2 Si-based hydrogen storage materials (Mg 2 Si / Ti molar ratio 1:1) hydrolysis hydrogen production performance at different temperatures;

[0048] Figure 7 Mg prepared in Example 2 2 Si-based hydrogen storage materials (Mg 2 XRD spectrum of Si / Ti molar ratio 1:2);

[0049] Figure 8 Mg prepared in Example 3 2 XRD spectra of Si-based hydrogen storage materials, Mg 2The Si / Ti molar ratios are 2:1 (a), 1:1 (b), and 2:1 (c);

[0050] Fig. 9 Mg prepared in Example 3 2 Si-based hydrogen storage materials (Mg 2 The results of the programmed temperature-controlled dehydrogenation test with Si / Ti molar ratios of 2:1, 1:1, and 2:1, respectively;

[0051] Fig.10 Mg prepared in Example 4 2 Si-based hydrogen storage materials (Mg 2 XRD patterns of the steel (Si / Ti molar ratio is 1:1) at ball milling speeds of 350 rpm (a) and 175 rpm (b). DETAILED DESCRIPTION

[0052] The following describes several preferred embodiments of the present invention with reference to the drawings in the specification, so that the technical content is clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the protection scope of the present invention is not limited to the embodiments mentioned in the text.

[0053] Example 1

[0054] A Mg with excellent hydrogen absorption and desorption kinetics 2 Si-based hydrogen storage material, the preparation method thereof comprises the following steps:

[0055] S1. Weigh Mg in an inert gas environment (such as a glove box). 2 About 0.608 g of Si powder (50-100 μm particle size) and about 0.392 g of Ti powder (50-100 μm particle size) were weighed and mixed to obtain Mg 2 A mixture of Si / Ti (molar ratio 1:1) (1 g).

[0056] S2. Place 1 g of the mixture prepared in S1 into a ball mill equipped with a commercial planetary ball mill and add 60 g of stainless steel ball milling beads to ensure that the ball-to-material ratio is 60:1. Cover the lid of the ball mill and seal it with a rubber gasket. Tighten the fixing bolts (such as Figure 1 shown).

[0057] S3. Take the sealed ball mill out of the glove box and connect the ball valve on the top of the ball mill lid to the hydrogen source. Use hydrogen to clean the pipeline and the ball mill. The specific operation is as follows: close the hydrogen source valve, open the vacuum pump valve to pump the pipeline to a vacuum state, close the vacuum pump valve, open the hydrogen source valve to inject 5 bar hydrogen and then close it, open the vacuum pump valve to pump the pipeline to a vacuum state, slowly open the valve on the top of the ball mill to pump the ball mill to a vacuum state, close the vacuum pump valve, keep the valve on the top of the ball mill open, and repeat the above cleaning steps twice to ensure that the pipeline and the ball mill are cleaned with hydrogen.

[0058] S4. Fill the ball mill with 15 bar of hydrogen. The specific operations are as follows: close the vacuum pump valve, open the valve on the top of the ball mill, open the hydrogen source valve, and after the hydrogen pressure in the ball mill reaches 15 bar, close the hydrogen source valve and the valve on the top of the ball mill.

[0059] S5. After removing the ball mill jar, install it into the ball mill, lock the safety knob, and set the ball mill program as follows: total time is 24 hours, forward rotation is 0.5 hour, reverse rotation is 0.5 hour, stop rotation is 0.5 hour, and the ball mill speed is 350rpm.

[0060] S6. After the ball milling process is completed, the ball mill is removed from the ball mill and transferred to a glove box. The ball mill is opened in the glove box and the Mg 2 The Si-based hydrogen storage material was scraped off the wall of the ball mill and collected.

[0061] S7, weigh the Mg in S6 2 About 20 mg of Si-based hydrogen storage material is placed in an inert XRD sample holder that can be sealed with tape. The powder surface is flattened with a flat key. The XRD sample holder with the sample is sealed with non-diffraction tape to isolate the water and oxygen in the air. After taking it out, it is placed on the XRD instrument to detect its phase composition. Observe whether the intensity of the diffraction peak corresponding to 54.92° in the diffraction spectrum is obvious. If it is obvious, it means that Mg 2 Si was successfully hydrogenated (e.g. Figure 2 As shown). Transmission electron microscopy (TEM) test results show that the prepared powder particle size is about 0.5 microns to 1.5 microns (as shown Figure 3 (a)). The high-resolution transmission electron microscopy (HRTEM) test results show that the prepared powder particles are composed of a large number of nano-scale grains and amorphous particles, rich in a large number of grain boundary defects, and the main phase components are MgH 2 and TiSi 2 , and formed a good interface contact (such as Figure 3(b)). The selected area electron diffraction (SAED) test results show that the diffraction rings of the sample are broadened and the high-angle diffraction rings are weakened, indicating that the prepared powder is composed of a large amount of nanocrystals and amorphous materials (such as Figure 3 (c)). The element distribution spectrum shows that the Mg / Si / Ti elements are evenly distributed, indicating that the formed MgH 2 and TiSi 2 Evenly mixed (such as Figure 3 (d)).

[0062] S8, the prepared Mg 2 The Si-based hydrogen storage material was subjected to a hydrogen absorption and desorption kinetic test. The specific steps are as follows: Weigh the Mg 2 100 mg of Si-based hydrogen storage material was placed in the sample tube of the high pressure gas adsorption tester (HPSA-auto) to perform isothermal hydrogen absorption and dehydrogenation tests. The dehydrogenation test results showed that at 250°C, the material could complete dehydrogenation within 7 minutes (e.g. Figure 4 The hydrogen absorption test results show that the material can absorb hydrogen quickly at room temperature, absorbing 1.25wt.% of hydrogen within 60 minutes at room temperature, and the hydrogen absorption capacity reaches 50% of the maximum capacity (as shown in Figure 5 shown).

[0063] S9, the prepared Mg 2 The Si-based hydrogen storage material was tested for hydrogen production by hydrolysis. The specific steps are as follows: 50 mL of MgCl 2 The solution (concentration is 1 mol / L) was poured into a three-necked flat-bottomed reaction bottle, a stirrer was added, a magnetic stirring device was turned on, and then a low-temperature water bath temperature control device was connected to keep the temperature of the hydrolysis solution at 5°C. The Mg successfully hydrogenated in S7 was weighed. 2 25 mg of Si-based hydrogen storage material was put into the hydrolysis solution. Every time 5 bubbles were generated, the corresponding time and the volume of hydrogen collected were recorded, and finally the hydrogen generation rate curve was obtained. Through the low-temperature water bath device, the hydrolysis hydrogen production rate curves at 15°C, 25°C and 35°C can be obtained according to the above method, such as Figure 6 As shown, it is possible to obtain a similar rate of hydrogen production by hydrolysis at a lower temperature of 5°C as that at 35°C.

[0064] Example 2

[0065] A Mg with excellent hydrogen absorption and desorption kinetics 2 Si-based hydrogen storage material, the preparation method thereof comprises the following steps:

[0066] S1. Weigh Mg in an inert gas environment (such as a glove box). 2About 0.437 g Si powder (50-100 μm), about 0.563 g Ti powder (50-100 μm), and mixed them to obtain Mg 2 A mixture of Si / Ti (molar ratio 1:2) (1 g).

[0067] S2. Place 1 g of the mixture prepared in S1 into a ball mill jar of a commercial planetary ball mill, and add 60 g of stainless steel ball mill beads to ensure that the ball-to-material ratio is 60:1. Close the lid of the ball mill jar and seal it with a rubber gasket, and tighten the fixing bolts.

[0068] S3. Take the sealed ball mill out of the glove box and connect the ball valve on the top of the ball mill lid to the hydrogen source. Use hydrogen to clean the pipeline and the ball mill. The specific operation is as follows: close the hydrogen source valve, open the vacuum pump valve to pump the pipeline to a vacuum state, close the vacuum pump valve, open the hydrogen source valve to inject 5 bar hydrogen and then close it, open the vacuum pump valve to pump the pipeline to a vacuum state, slowly open the valve on the top of the ball mill to pump the ball mill to a vacuum state, close the vacuum pump valve, keep the valve on the top of the ball mill open, and repeat the above cleaning steps twice to ensure that the pipeline and the ball mill are cleaned with hydrogen.

[0069] S4. Fill the ball mill with 15 bar of hydrogen. The specific operations are as follows: close the vacuum pump valve, open the valve on the top of the ball mill, open the hydrogen source valve, and after the hydrogen pressure in the ball mill reaches 15 bar, close the hydrogen source valve and the valve on the top of the ball mill.

[0070] S5. After removing the ball mill jar, install it into the ball mill, lock the safety knob, and set the ball mill program as follows: total time is 24 hours, forward rotation is 0.5 hour, reverse rotation is 0.5 hour, stop rotation is 0.5 hour, and the ball mill speed is 350rpm.

[0071] S6. After the ball milling process is completed, the ball mill is removed from the ball mill and transferred to a glove box. The ball mill is opened in the glove box and the Mg 2 The Si-based hydrogen storage material was scraped off the wall of the ball mill and collected.

[0072] S7, weigh the Mg in S6 2 About 20 mg of Si-based hydrogen storage material is placed in an inert XRD sample holder that can be sealed with tape. The powder surface is flattened with a flat key. The XRD sample holder with the sample is sealed with non-diffraction tape to isolate the water and oxygen in the air. After taking it out, it is placed on the XRD instrument to detect its phase composition. Observe whether the intensity of the diffraction peak corresponding to 54.92° in the diffraction spectrum is obvious. If it is obvious, it means that Mg 2 Si was successfully hydrogenated (e.g. Figure 7If it is not obvious, recheck all the above steps to see if they meet the required conditions. Repeat the above steps after maintenance and then test again.

[0073] S8, the prepared Mg 2 The Si-based hydrogen storage material was subjected to a hydrogen absorption and desorption kinetic test. The specific steps are as follows: Weigh the Mg 2 100 mg of Si-based hydrogen storage material was placed in the sample tube of a high pressure gas adsorption tester (HPSA-auto) to perform isothermal hydrogen absorption and dehydrogenation tests.

[0074] S9, the prepared Mg 2 The Si-based hydrogen storage material was tested for hydrogen production by hydrolysis. The specific steps are as follows: 50 mL of MgCl 2 The solution (concentration is 1 mol / L) was poured into a three-necked flat-bottomed reaction bottle, a stirrer was added, a magnetic stirring device was turned on, and then a low-temperature water bath temperature control device was connected to keep the temperature of the hydrolysis solution at 5°C. The Mg successfully hydrogenated in S7 was weighed. 2 25 mg of Si-based hydrogen storage material was put into the hydrolysis solution. Every time 5 bubbles were generated, the corresponding time and the volume of hydrogen collected were recorded, and finally the hydrogen generation rate curve was obtained.

[0075] Example 3

[0076] This example aims to explore the effect of different Ti powder addition ratios on Mg 2 Influence of Si hydrogenation conversion efficiency. According to the method of Example 1, Mg 2 Si powder and Ti powder were mixed in different molar ratios (2:1, 1:1, 1:2), placed in a hydrogen atmosphere, and subjected to high-energy ball milling for 24 hours. The ball milling speed was 350 rpm, and the rotation was periodically reversed (forward for 30 minutes, reverse for 30 minutes, and stop for 30 minutes). The hydrogen atmosphere in the ball mill was maintained at 15 bar. XRD test results show that the 1:1 molar ratio of Mg 2 MgH corresponding to Si / Ti composites 2 The diffraction peak is the most obvious, indicating that the hydrogenation conversion effect of this sample is the most significant (such as Figure 8 The results of the programmed temperature dehydrogenation test also show that the 1:1 molar ratio sample has the largest dehydrogenation capacity, indicating that the Mg in this group of samples 2 Si has the best hydrogenation conversion efficiency (such as Fig. 9 In contrast, the Mg content of the samples with 2:1 and 1:2 molar ratios was 2 The conversion rate of Si hydrogenation is low, and the corresponding MgH 2 The intensity of the diffraction peak is significantly weakened, and the dehydrogenation capacity is also small. 2The samples with Si / Ti molar ratio of 1:1 showed the best performance in terms of hydrogenation conversion efficiency. The temperature programmed dehydrogenation test (TPD) showed that the dehydrogenation amount of this group of samples was at least 2.35wt.%. Assuming that Mg 2 Mg in Si / Ti (1:1) mixture 2 All Si is converted into MgH 2 and titanium silicon compounds, the theoretical maximum dehydrogenation capacity is 3.10wt.%. Therefore, the Mg content in this group of samples is 2 Conversion of Si to MgH 2 The actual conversion rate is 2.35 / 3.10=76%.

[0077] Example 4

[0078] In this example, in order to study the effect of different ball milling speeds on the hydrogenation effect, the same Mg as in Example 1 was selected. 2 Si powder and Ti powder were used as raw materials. Mg 2 After Si powder and Ti powder were mixed in a 1:1 molar ratio, they were subjected to high-energy ball milling in a hydrogen atmosphere at a speed of 175 rpm and 350 rpm, respectively. The milled materials were analyzed by XRD. The results showed that at a speed of 350 rpm, Mg 2 The hydrogenation conversion rate of Si is higher, and the XRD spectrum shows more obvious MgH 2 Diffraction peaks (such as Fig.10 In the hydrogen adsorption / desorption test, the material at 350 rpm can adsorb more hydrogen at room temperature and start to dehydrogenate at a lower temperature, and the dehydrogenation rate is significantly faster than that of the material at 175 rpm, indicating that high-speed ball milling (350 rpm) promotes the desorption of Mg 2 Si powder is transformed into MgH 2 The effect is better than that of low-speed ball milling (175rpm).

[0079] The preferred specific embodiments of the present invention are described in detail above. It should be understood that ordinary technicians in the field can make many modifications and changes based on the concept of the present invention without creative work. Therefore, all technical solutions that can be obtained by technicians in the technical field based on the concept of the present invention through logical analysis, reasoning or limited experiments on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for preparing a Mg2Si-based hydrogen storage material, characterized in that: It includes the following steps: The mixture of Mg2Si powder / Ti powder and ball milling beads are placed in a ball milling jar and filled with hydrogen; Set the ball milling program as follows: the speed of the ball mill is 150 rpm to 400 rpm; After the ball milling process is completed, the Mg2Si-based hydrogen storage material is obtained.

2. The method for preparing the Mg2Si-based hydrogen storage material according to claim 1, characterized in that: The molar ratio of the Mg2Si powder to the Ti powder is 0.5:1-2:

1.

3. The method for preparing the Mg2Si-based hydrogen storage material according to claim 2, characterized in that: The molar ratio of the Mg2Si powder to the Ti powder is 1:1-2:

1.

4. The method for preparing the Mg2Si-based hydrogen storage material according to claim 1, characterized in that: The particle size of the Mg2Si powder is 50-100 μm; the particle size of the Ti powder is 50-100 μm.

5. The method for preparing the Mg2Si-based hydrogen storage material according to claim 1, characterized in that: The mass ratio of the mixture of the Mg2Si powder / Ti powder to the ball milling beads is 1:50 to 1:

70.

6. The method for preparing the Mg2Si-based hydrogen storage material according to claim 1, characterized in that: The hydrogen pressure in the ball mill is 10 to 30 bar.

7. The method for preparing the Mg2Si-based hydrogen storage material according to claim 1, characterized in that: The ball milling program also includes setting periodic forward and reverse rotation, with forward rotation for 0.2 to 0.8 hours, reverse rotation for 0.2 to 0.8 hours, and stop for 0.2 to 0.8 hours.

8. The method for preparing the Mg2Si-based hydrogen storage material according to claim 1, characterized in that: The rotation speed of the ball mill is 300 rpm-400 rpm.

9. A Mg2Si-based hydrogen storage material prepared according to the preparation method according to any one of claims 1 to 8.

10. The Mg2Si-based hydrogen storage material according to claim 9, characterized in that: The atomic ratio of Mg / Si / Ti elements in the Mg2Si-based hydrogen storage material is 2:1:(0.5-2), and its main phase components are MgH2 / TiSi2 / Mg2Si.

Images