Mg-ni-in ternary hydrogen storage alloy and preparation method thereof

Abstract

The application belongs to the technical field of hydrogen storage materials, and discloses a Mg-Ni-In ternary hydrogen storage alloy and a preparation method thereof. The alloy contains not more than 10% of nickel element and not more than 5% of indium element in terms of weight percentage, and the balance is magnesium element, and the general formula is 90Mg-xNi-yIn. The alloy contains primary Mg phase and Mg2Ni phase, and In is solid-solved in the primary Mg phase and the Mg2Ni phase and is more inclined to be solid-solved in the Mg2Ni phase and the interface. The preparation method comprises the following steps: taking metal Mg, Mg-30Ni intermediate alloy and metal In as raw materials, vacuumizing in a vacuum furnace, filling argon protection, controlling heating power to heat to 800 DEG C, heat preservation after complete melting, and natural cooling to obtain a cast alloy; then crushing and transferring to a ball mill to carry out ball milling under inert atmosphere to obtain a powder alloy. The alloy has high hydrogen storage capacity, fast hydrogen absorption and release rate, and good reversibility, effectively solves the performance defects of the Mg-Ni alloy, and has simple preparation process, easy control parameters, low cost, and is suitable for hydrogen transportation, separation and purification, hydrogen fuel cell and heat storage fields.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen storage materials technology, specifically relating to a Mg-Ni-In ternary hydrogen storage alloy and its preparation method. Background Technology

[0002] Hydrogen energy boasts outstanding characteristics such as wide availability, high calorific value, and water as its sole byproduct. It can be produced through water electrolysis from renewable energy sources like photovoltaics and wind power, achieving a "zero-carbon cycle." It is widely recognized as an ideal medium connecting renewable energy with end-use applications, showing broad application prospects in fuel cell vehicles, distributed energy storage, and industrial hydrogen refueling. The large-scale advancement of the hydrogen energy industry chain depends on the coordinated breakthroughs in four core links: hydrogen production, storage, transportation, and utilization. Among these, hydrogen storage technology, as a crucial link between hydrogen production and consumption, directly determines the progress of hydrogen energy industrialization and is currently a core challenge that urgently needs to be overcome in the hydrogen energy field.

[0003] Currently developed hydrogen storage technologies are mainly divided into three categories: high-pressure gaseous hydrogen storage, cryogenic liquid hydrogen storage, and solid-state hydrogen storage. Each technology has its own advantages and disadvantages and is at different stages of development. High-pressure gaseous hydrogen storage has achieved initial application in short-distance transportation due to its simple equipment structure and fast hydrogen filling and discharging speed. However, it is limited by problems such as low hydrogen storage density, high safety requirements for high-pressure containers, and high transportation costs over long distances, making it difficult to meet the needs of large-scale, long-term energy storage. Although cryogenic liquid hydrogen storage can significantly improve hydrogen storage density, it requires maintaining an ultra-low temperature environment of -253°C, which not only consumes a lot of energy, but also causes hydrogen to evaporate easily, resulting in a decrease in hydrogen storage efficiency. The high cost of dedicated containers and supporting equipment further limits its commercialization.

[0004] Compared to the previous two hydrogen storage methods, solid-state hydrogen storage, which uses materials as carriers to achieve hydrogen adsorption and storage, has significant advantages such as high hydrogen storage density, good safety, strong adaptability to operating conditions, and no volatilization loss. It is considered one of the optimal technological paths for large-scale hydrogen energy storage and transportation in the future. Among various solid-state hydrogen storage materials, metal hydride hydrogen storage materials have become a research hotspot due to their ability to stably dissolve or combine hydrogen in the atomic state within the crystal lattice, exhibiting excellent reversible hydrogen storage performance and strong cycle stability. Among these, magnesium-based hydrogen storage alloys, with their abundant raw material reserves, low cost, and environmental friendliness, coupled with a theoretical mass hydrogen storage capacity of up to 7.6 wt.% and a volumetric hydrogen storage density of 110 kg / m³, are particularly noteworthy. 3Magnesium-based hydrogen storage alloys are among the highest-density metallic hydrogen storage materials discovered to date, demonstrating strong application potential among various hydrogen storage materials. However, they also suffer from problems such as high activation energy for hydrogen absorption and desorption reactions, strong thermodynamic stability, sluggish hydrogen absorption and desorption kinetics at low temperatures, and a tendency for grain growth and structural pulverization during cycling, leading to a decline in hydrogen storage performance. These issues severely restrict their transition from laboratory research to practical engineering applications. Existing Mg-Ni binary alloys cannot maintain high hydrogen storage capacity and fast hydrogen absorption and desorption rates below 300℃, further limiting practical applications. Current technologies cannot rely solely on Mg or Mg-Ni alloys to simultaneously address the issues of poor thermodynamic stability and kinetic performance. A novel ternary alloy is urgently needed to achieve a breakthrough through specific element solid solution and phase structure control. Summary of the Invention

[0005] In view of this, the purpose of this invention is to solve the problems of high thermodynamic stability, poor hydrogen absorption and desorption kinetics, and inability to maintain high hydrogen storage capacity and fast hydrogen absorption and desorption rate in magnesium-based hydrogen storage alloys in the prior art, and to provide a Mg-Ni-In ternary hydrogen storage alloy and its preparation method.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A Mg-Ni-In ternary hydrogen storage alloy, by weight percentage, comprises the following elements: nickel not exceeding 10%, indium not exceeding 5%, and the balance being magnesium, with each element's content not exceeding 0%. The alloy's crystal structure includes primary Mg and Mg₂Ni phases. In is dissolved in both the primary Mg and Mg₂Ni phases, with a greater tendency to dissolve in the Mg₂Ni phase and its interface. Ni acts as a catalyst, enhancing the hydrogen desorption kinetics. In dissolves in the Mg and Mg₂Ni phases to form a solid solution, causing cell distortion and weakening the Mg-H bond strength, further improving the hydrogen desorption kinetics and temperature. Furthermore, the hydrogen absorption and desorption processes are completely reversible, with no irreversible impurity phases generated.

[0007] Furthermore, the general formula of the Mg-Ni-In ternary hydrogen storage alloy is 90Mg-xNi-yIn, wherein the content of nickel x is 5~9.5 wt.%, the content of indium y is 0.5~5 wt.%, and the content of magnesium is 90 wt.%.

[0008] A method for preparing the Mg-Ni-In ternary hydrogen storage alloy as described above includes the following steps: A: Prepare raw materials containing Mg, Ni, and In according to the weight percentage of each element, specifically metallic Mg, Mg-Ni alloy, and metallic In; B: Place the raw materials into the vacuum furnace, evacuate the vacuum, and then fill it with the protective gas argon; by controlling the heating power, raise the temperature to 800 degrees within 30 minutes; C: Observe inside the vacuum furnace. After the raw material has completely melted, keep it at that temperature for 3 minutes. After cooling naturally inside the furnace for 40 minutes, take out the sample. D: Powdered Mg-Ni-In ternary hydrogen storage alloy was obtained by crushing and ball milling the as-cast alloy.

[0009] Furthermore, the Mg-Ni alloy mentioned in step A is a Mg-30Ni alloy.

[0010] Further, in step D, the cast alloy is crushed into powder and then transferred to a ball mill for ball milling under an inert atmosphere; the ball-to-material ratio of the ball mill is 20~40:1, the rotation speed is 250~300 rpm / min, and the time is 1~20h; the ball milling method is: alternating between forward ball milling and reverse ball milling, running for 5~15min during the ball milling period, and resting for 5~10min during the alternation period.

[0011] Furthermore, the Mg-Ni-In ternary hydrogen storage alloy prepared by the method is applied to the fields of hydrogen transportation, separation and purification.

[0012] Furthermore, the Mg-Ni-In ternary hydrogen storage alloy prepared by the method can be applied to hydrogen fuel cells or thermal storage applications.

[0013] The beneficial effects of this invention are as follows: 1. In the Mg-Ni-In ternary hydrogen storage alloy provided by this invention, Ni and In elements play a synergistic alloying role, constructing a multiphase interface structure in the Mg-based solid solution, effectively weakening the Mg-H bond strength and reducing the thermodynamic stability of the hydrogen absorption and desorption reaction. Experimental results show that, at the same temperature, compared with Mg-Ni alloys with the same Mg content, the Mg-Ni-In ternary hydrogen storage alloy has a larger saturated hydrogen absorption and desorption capacity in the same time period, effectively solving the defect of low hydrogen storage capacity in Mg-Ni alloys. Furthermore, this alloy can complete the hydrogen desorption process in 6 minutes at 275℃ and 11 minutes at 225℃, and can desorb hydrogen at 175℃, significantly improving the low-temperature hydrogen absorption and desorption kinetics performance, and solving the core problem that existing magnesium-based alloys cannot maintain a high hydrogen storage capacity and a fast hydrogen absorption and desorption rate below 300℃.

[0014] 2. The Mg-Ni-In ternary hydrogen storage alloy preparation method provided by this invention is simple, highly controllable, and uses widely available and cost-effective raw materials. Introducing high-melting-point Mg and Ni elements in the form of a Mg-Ni master alloy facilitates the thorough mixing of different elements, avoids uneven element distribution, and promotes the production of a uniformly structured ternary hydrogen storage alloy. The melting process is precisely controlled through vacuum purging with argon, heating to approximately 800°C within 30 minutes, holding at that temperature for 3 minutes after complete melting, and then allowing natural cooling in the furnace for 40 minutes, ensuring uniform alloy composition and stable phase structure. Subsequent crushing and ball milling steps are carried out under an inert atmosphere, with the ball-to-material ratio, rotation speed, time, and alternating forward and reverse milling methods further refining the particles and improving dispersibility. This makes the overall preparation operation simple and controllable, the required equipment readily available, and the preparation cost moderate, which is conducive to large-scale industrial production.

[0015] 3. This invention utilizes the positional relationship of In dissolving in the primary Mg phase and Mg2Ni phase, with a greater emphasis on dissolving in the Mg2Ni phase and the interface, to form a solid solution that affects bond length and weakens Mg-H bond strength. Simultaneously, Ni, as a highly efficient catalyst, significantly enhances the hydrogen desorption kinetics, jointly improving the hydrogen desorption temperature and kinetic performance. The hydrogen absorption and desorption process is completely reversible, with no irreversible impurity phase formation, thus improving cycle stability. The eutectic structure is refined or moderately coarsened by adjusting the In ratio, and the overall phase structure and interfacial interaction optimize the hydrogen storage platform and capacity.

[0016] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0017] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0018] Figure 1 These are SEM and EDS images of the as-cast Mg-Ni-In ternary alloy prepared in the embodiments of the present invention.

[0019] Figure 2 This is the XRD pattern of the as-cast Mg-Ni-In ternary alloy prepared in the embodiments of the present invention.

[0020] Figure 3 This is the XRD pattern of the ball-milled Mg-Ni-In ternary alloy prepared in the embodiments of the present invention.

[0021] Figure 4These are the hydrogen absorption (a) and hydrogen release (b) kinetic diagrams of 90Mg5Ni5In prepared in Example 1 of this invention.

[0022] Figure 5 This is a kinetic diagram of hydrogen absorption (c) and hydrogen release (d) of 90Mg7.5Ni2.5In prepared in Example 2 of this invention.

[0023] Figure 6 This is a kinetic diagram of hydrogen absorption (e) and hydrogen release (f) of 90Mg9.5Ni0.5In prepared in Example 3 of the present invention. Detailed Implementation

[0024] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0025] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0026] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0027] Example 1 A Mg-Ni-In ternary hydrogen storage alloy with the general formula 90Mg-5Ni-5In, wherein the content of nickel (x) is 5 wt.%, the content of indium (y) is 5 wt.%, and the content of magnesium is 90 wt.%; the crystal structure of the alloy contains primary Mg phase and Mg2Ni phase, and In is dissolved in both primary Mg phase and Mg2Ni phase, with a greater tendency to be dissolved in Mg2Ni phase and interface.

[0028] Its preparation method specifically includes the following steps: S1: Prepare raw materials containing Mg, Ni, and In according to the weight percentage of each element, specifically pure metallic Mg, master alloy Mg-30Ni, and pure metallic In; then, perform smelting in a 35Kg vacuum induction furnace, specifically by first adding 3130g of pure metallic Mg, 670g of master alloy Mg-30Ni, and 200g of pure metallic In to the furnace, and then evacuating the furnace to a vacuum of 10... -1 After the pressure reaches approximately 100 Pa, stop the vacuuming process and fill the furnace with argon as a protective gas. When the pressure inside the furnace reaches -0.06 atm, adjust the heating power to 20 KW for 10 minutes, then adjust it to 40 KW. Observe the furnace until the alloy is completely melted (about 5 minutes). After the alloy is completely melted in the furnace, hold it at that temperature for 3 minutes, then pour it into a stainless steel mold. Cool it under vacuum for 40 minutes and then remove it to obtain the as-cast alloy 90Mg-5Ni-5In.

[0029] S2: Cut the as-cast alloy prepared in step S1 into blocks, then file it into powder. Transfer the powder to a high-energy ball mill and ball mill it under argon conditions (to prevent oxidation of the prepared alloy). Add about 5g of n-heptane as a grinding aid. Use 10mm, 8mm, and 5mm stainless steel grinding balls with a mass ratio of grinding balls to as-cast alloy particles of 30:1. Weigh out two 10mm grinding balls, add 8mm grinding balls to reach the target mass, and balance the mass with 5mm grinding balls. The rotation speed is 280rpm / min. Rotate forward for 10 minutes, pause for 10 minutes, and then rotate in reverse for 10 minutes (this ball milling method avoids the problem of excessive alloy temperature during ball milling and helps to improve ball milling efficiency). After ball milling for 10 hours, the Mg-Ni-In hydrogen storage alloy 90Mg-5Ni-5In is obtained.

[0030] Example 2 A Mg-Ni-In ternary hydrogen storage alloy has the general formula 90Mg-7.5Ni-2.5In, wherein the content of nickel (x) is 7.5 wt.%, the content of indium (y) is 2.5 wt.%, and the content of magnesium is 90 wt.%; the crystal structure of the alloy contains primary Mg phase and Mg2Ni phase, and In is dissolved in both primary Mg phase and Mg2Ni phase, with a greater tendency to be dissolved in Mg2Ni phase and interface.

[0031] Its preparation method specifically includes the following steps: S1: Prepare pure Mg, master alloy Mg-30Ni, and pure In according to the weight percentage of each element; then melt them in a 35Kg vacuum induction furnace. Specifically, first put 2900g of pure Mg, 1000g of master alloy Mg-30Ni, and 100g of pure In into the furnace, and then evacuate the furnace to 1000kJ. -1 After the pressure reaches approximately 0.06 atm, stop evacuating and fill with protective argon gas. When the furnace pressure reaches -0.06 atm, adjust the heating power. By controlling the heating power, heat at 20 kW for 10 minutes and then adjust to 40 kW. Observe the furnace until the alloy is completely melted (about 5 minutes). After the alloy is completely melted in the furnace, hold it at that temperature for 3 minutes, and then pour it into a stainless steel mold. Cool it under vacuum for 40 minutes and then remove it to obtain the as-cast alloy 90Mg-7.5Ni-2.5In.

[0032] S2: Cut the as-cast alloy prepared in step S1 into blocks, then file it into powder. Transfer the powder to a high-energy ball mill and ball mill it under argon conditions (to prevent oxidation of the prepared alloy). Add about 5g of n-heptane as a grinding aid. Use 10mm, 8mm, and 5mm stainless steel grinding balls with a mass ratio of grinding balls to as-cast alloy particles of 30:1. Weigh out two 10mm grinding balls, add 8mm grinding balls to reach the target mass, and balance the mass with 5mm grinding balls. The rotation speed is 280rpm / min. Rotate forward for 10 minutes, pause for 10 minutes, and then rotate in reverse for 10 minutes (this ball milling method avoids the problem of excessive alloy temperature during ball milling and helps to improve ball milling efficiency). After ball milling for 10 hours, the Mg-Ni-In hydrogen storage alloy 90Mg-7.5Ni-2.5In can be obtained.

[0033] Example 3 A Mg-Ni-In ternary hydrogen storage alloy has the general formula 90Mg-9.5Ni-0.5In, wherein the content of nickel (x) is 9.5 wt.%, the content of indium (y) is 0.5 wt.%, and the content of magnesium is 90 wt.%; the crystal structure of the alloy contains primary Mg phase and Mg2Ni phase, and In is dissolved in both primary Mg phase and Mg2Ni phase, with a greater tendency to be dissolved in Mg2Ni phase and interface.

[0034] Its preparation method specifically includes the following steps: S1: Prepare pure Mg, master alloy Mg-30Ni, and pure In according to the weight percentage of each element; then perform melting in a 35Kg vacuum induction furnace. Specifically, first add 2710g of pure Mg, 1270g of master alloy Mg-30Ni, and 20g of pure In to the furnace, and then evacuate the furnace to 10°C. -1After the pressure reaches approximately 100 Pa, stop evacuating and fill with protective argon gas. When the pressure inside the furnace reaches -0.06 atm, adjust the heating power to 20 KW for 10 minutes, then increase it to 40 KW. Observe the furnace until the alloy is completely melted (approximately 5 minutes). After the alloy is completely melted, hold it at that temperature for 3 minutes, then pour it into a stainless steel mold. Cool it under vacuum for 40 minutes and then remove it to obtain the as-cast alloy 90Mg-9.5Ni-0.5In.

[0035] S2: Cut the as-cast alloy prepared in step S1 into blocks, then file it into powder. Transfer the powder to a high-energy ball mill and ball mill it under argon conditions (to prevent oxidation of the prepared alloy). Add about 5g of n-heptane as a grinding aid. Use 10mm, 8mm, and 5mm stainless steel grinding balls with a mass ratio of grinding balls to as-cast alloy particles of 30:1. Weigh out two 10mm grinding balls, add 8mm grinding balls to reach the target mass, and balance the mass with 5mm grinding balls. The rotation speed is 280rpm / min. Rotate forward for 10 minutes, pause for 10 minutes, and then rotate in reverse for 10 minutes (this ball milling method avoids the problem of excessive alloy temperature during ball milling and helps to improve ball milling efficiency). After ball milling for 10 hours, the Mg-Ni-In hydrogen storage alloy 90Mg-9.5Ni-0.5In can be obtained.

[0036] Performance testing 1. The morphology and composition of the Mg-Ni-In hydrogen storage alloys prepared in Examples 1 and 2 were tested. The as-cast alloy samples prepared in step S1 of Examples 1, 2, and 3 were then polished sequentially with 600-grit, 1200-grit, and 2000-grit sandpaper to prepare metallographic images. Their morphology was then observed using a Quattro S environmental scanning electron microscope at different magnifications. The corresponding experimental results are as follows: Figure 1 As shown in (a), (b), and (c). Figure 2 The images show the XRD patterns of the as-cast alloys prepared in step S1 of Examples 1, 2, and 3. Figure 2 The image shows the XRD pattern of the ball-milled alloy prepared in step S2 of Examples 1, 2, and 3.

[0037] 2. The hydrogen storage performance of the Mg-Ni-In hydrogen storage alloys prepared in Examples 1-3 was tested. First, the 90Mg-5Ni-5In hydrogen storage alloy prepared in Example 1 was subjected to five activation hydrogen absorption and desorption tests at 350°C. The activated 90Mg-5Ni-5In hydrogen storage alloy was then subjected to isothermal hydrogen absorption and desorption tests at 275°C, 250°C, 225°C, and 175°C, respectively. The experimental results are as follows: Figure 4As shown, (a) is the hydrogen absorption curve and (b) is the hydrogen desorption curve. Similarly, the 90Mg-7.5Ni-2.5In and 90Mg-9.5Ni-0.5In hydrogen storage alloys from Examples 2 and 3, after the above activation, were subjected to isothermal hydrogen absorption and desorption tests at 275℃, 250℃, 225℃, and 175℃. The experimental results are as follows. Figure 5 , 6 As shown in Table 1, the test results of the three activated alloys are plotted in a table.

[0038] Table 1

[0039] Through the Figures 4-6 The comprehensive analysis of Table 1 shows that the Mg-Ni-In hydrogen storage alloy prepared by this invention has high hydrogen storage performance and excellent hydrogen absorption and desorption performance. The hydrogen storage capacity can still reach 5.57 wt.% at 175℃, absorb 3.3 wt.% of hydrogen in 30s at 250℃ and release 3.6 wt.% of hydrogen in 45min, and release 5.1 wt.% of hydrogen in 15min at 225℃.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A Mg-Ni-In ternary hydrogen storage alloy, characterized in that, The content of each element in the Mg-Ni-In ternary hydrogen storage alloy by weight percentage is as follows: the content of nickel is not more than 10%, the content of indium is not more than 5%, and the balance is magnesium, and the content of each element is not 0%; the crystal structure of the alloy contains primary Mg phase and Mg2Ni phase, and In is dissolved in primary Mg phase and Mg2Ni phase, and is more inclined to be dissolved in Mg2Ni phase and interface.

2. The Mg-Ni-In ternary hydrogen storage alloy according to claim 1, characterized in that, The general formula of the Mg-Ni-In ternary hydrogen storage alloy is 90Mg-xNi-yIn, wherein the content of nickel x is 5~9.5wt.%, the content of indium y is 0.5~5wt.%, and the content of magnesium is 90wt.%.

3. A method for preparing a Mg-Ni-In ternary hydrogen storage alloy as described in any one of claims 1 to 2, characterized in that, Includes the following steps: A: Prepare raw materials containing Mg, Ni, and In according to the weight percentage of each element, specifically metallic Mg, Mg-Ni alloy, and metallic In; B: Place the raw materials into the vacuum furnace, evacuate the vacuum, and then fill it with the protective gas argon; by controlling the heating power, raise the temperature to 800 degrees within 30 minutes; C: Observe inside the vacuum furnace. After the raw material has completely melted, keep it at that temperature for 3 minutes. After cooling naturally inside the furnace for 40 minutes, take out the sample. D: Powdered Mg-Ni-In ternary hydrogen storage alloy was obtained by crushing and ball milling the as-cast alloy.

4. The preparation method according to claim 3, characterized in that, The Mg-Ni alloy mentioned in step A is a Mg-30Ni alloy.

5. The preparation method according to claim 3, characterized in that, In step D, the cast alloy is crushed into powder and then transferred to a ball mill for ball milling under an inert atmosphere. The ball-to-material ratio of the ball mill is 20-40:1, the rotation speed is 250-300 rpm / min, and the time is 1-20 h. The ball milling method is as follows: forward ball milling and reverse ball milling are alternated, with a running time of 5-15 min during the ball milling period and a resting time of 5-10 min during the alternation period.

6. The preparation method according to claim 3, characterized in that, The Mg-Ni-In ternary hydrogen storage alloy prepared by the method is used for hydrogen transportation, separation and purification.

7. The preparation method according to claim 3, characterized in that, The Mg-Ni-In ternary hydrogen storage alloy prepared by the method is applied to hydrogen fuel cells or thermal storage.

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