Solid-state hydrogen storage material, preparation method and application thereof

Abstract

The present application provides a solid-state hydrogen storage material and a preparation method and application thereof. Specifically, the preparation method comprises the following steps: (1) ball-milling a magnesium-based alloy powder, a light metal hydride, a nano-carbon material, a composite catalyst powder and an interface modifier to obtain a mixed powder; and (2) sintering the mixed powder under vacuum at 200-350 DEG C for 2-5 hours to obtain a sintered body, wherein: the magnesium-based alloy powder is a Mg-Mn-Al alloy powder; the light metal hydride is a mixture of LiAlH4 and NaBH4; the nano-carbon material is selected from one or more of graphene and carbon nanotubes; the composite catalyst powder is a mixture of TiO2, Fe3O4, CeO2 and La2O3; and the interface modifier is selected from one or more of a silane coupling agent and a titanate coupling agent. The solid-state hydrogen storage material has high hydrogen storage capacity, fast hydrogen absorption and desorption rate and good cycle stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen storage materials, in particular to a solid-state hydrogen storage material and a preparation method and application thereof. BACKGROUND

[0002] With the increasing severity of global energy crisis and environmental problems, finding clean, efficient and sustainable alternative energy has become a research hotspot in the current technology field. Hydrogen energy, as an ideal clean energy with high energy density and non-polluting combustion products, has broad application prospects in fuel cell vehicles, distributed energy systems, portable hydrogen energy equipment and other fields. However, hydrogen storage and transportation is one of the key bottlenecks restricting its large-scale commercial application.

[0003] Currently, hydrogen storage methods mainly include high-pressure gaseous hydrogen storage, low-temperature liquid hydrogen storage and solid-state hydrogen storage. High-pressure gaseous hydrogen storage has the problems of low hydrogen storage density, poor safety, high energy consumption, etc.; low-temperature liquid hydrogen storage needs to consume a large amount of energy to maintain a low-temperature environment, and has defects such as volatilization loss. In comparison, solid-state hydrogen storage has the significant advantages of high hydrogen storage density, good safety, convenient transportation, etc., and has become an important development direction of hydrogen storage technology.

[0004] Solid-state hydrogen storage materials are the core of solid-state hydrogen storage technology, and their performance directly determines the overall efficiency and application prospect of hydrogen energy storage systems. Existing solid-state hydrogen storage materials mainly include metal hydrides, composite hydrides, carbon-based materials, etc. Among them, magnesium-based hydrogen storage materials have attracted widespread attention due to their high hydrogen storage capacity, abundant raw materials, low cost, etc. However, traditional magnesium-based hydrogen storage materials have poor hydrogen absorption and desorption kinetics and poor cycle stability, which limits their practical application.

[0005] In order to improve the performance of magnesium-based hydrogen storage materials, researchers have adopted various modification methods, such as alloying, nanocrystallization, adding catalysts, etc. For example, by adding transition metals or metal oxides as catalysts, the diffusion and adsorption / desorption processes of hydrogen atoms can be accelerated, and the hydrogen absorption and desorption rate can be improved; by compounding magnesium-based materials with nano-carbon materials, the specific surface area can be increased, particle agglomeration can be inhibited, and the cycle stability can be improved.

[0006] However, the existing modification technologies still have many deficiencies. On the one hand, the catalytic effect of a single catalyst is limited, and it is difficult to meet the requirements of hydrogen storage capacity and kinetic performance at the same time; on the other hand, in the compounding process of multiple components, the interface compatibility is poor, which easily leads to unstable material structure and affects the cycle performance; in addition, some modification schemes use expensive raw materials or have complex preparation processes, resulting in high material cost, which is not conducive to large-scale production and application.

[0007] Specifically, the prior art has the following technical defects: it is difficult to balance the hydrogen storage capacity and the kinetic performance, most of the modified magnesium-based hydrogen storage materials can improve the hydrogen absorption and desorption rate, but the hydrogen storage capacity will decrease significantly, or in the case of ensuring the hydrogen storage capacity, the kinetic performance cannot meet the actual application requirements. In addition, the cycle stability is poor, after a plurality of hydrogen absorption and desorption cycles, the material is prone to particle agglomeration, structure collapse and other phenomena, resulting in rapid attenuation of the hydrogen storage performance. In addition, some schemes use rare metals or expensive nanomaterials as catalysts or additives, increasing the preparation cost of the material; or the preparation process involves harsh conditions such as high temperature and high pressure, high energy consumption, further increasing the production cost.

[0008] Therefore, it is of great significance to develop a solid-state hydrogen storage material which can simultaneously realize high hydrogen storage density, fast hydrogen absorption and desorption rate and good cycle stability, and has low raw material cost and simple preparation process, for promoting the large-scale commercial application of hydrogen energy. SUMMARY

[0009] From the above-mentioned technical problems, the purpose of the present application is to overcome the technical defects of the existing solid-state hydrogen storage materials, such as the difficulty in balancing the hydrogen storage capacity and the kinetic performance, high cost, poor cycle stability and complex preparation process, and to provide a low-cost and high-performance solid-state hydrogen storage material which can simultaneously realize high hydrogen storage density, fast hydrogen absorption and desorption rate and good cycle stability, and has significantly reduced raw material cost.

[0010] Specifically, according to one aspect of the present application, a preparation method of a solid-state hydrogen storage material is provided, the preparation method comprising the following steps:

[0011] (1) adding a magnesium-based alloy powder, a light metal hydride, a nano-carbon material, a composite catalyst powder and an interface modifier into a planetary ball mill, and ball milling under argon protection for 8-12 hours to obtain a mixed powder;

[0012] (2) placing the mixed powder into a vacuum sintering furnace, and sintering at 200-350°C under vacuum for 2-5 hours to obtain a sintered body, wherein:

[0013] the magnesium-based alloy powder accounts for 40-70%, the light metal hydride accounts for 20-45%, the nano-carbon material accounts for 3-10%, the composite catalyst powder accounts for 1-5%, and the interface modifier accounts for 0.5-3%, based on the total weight of the magnesium-based alloy powder, the light metal hydride, the nano-carbon material, the composite catalyst powder and the interface modifier being 100%;

[0014] The magnesium-based alloy powder is a Mg-Mn-Al alloy powder, which comprises 85-95% of Mg, 3-8% of Mn and 2-7% of Al, based on the total weight of the Mg-Mn-Al alloy powder being 100%;

[0015] The light metal hydride is a mixture of LiAlH4 and NaBH4 in a weight ratio of 1.5:1-4:1;

[0016] The nano-carbon material is selected from one or more of graphene and carbon nanotubes;

[0017] The composite catalyst powder is a mixture of TiO2, Fe3O4, CeO2 and La2O3;

[0018] The interface regulator is selected from one or more of silane coupling agent and titanate coupling agent.

[0019] According to some preferred embodiments of the present application, the nano-carbon material is a mixture of graphene and carbon nanotubes, wherein the weight percentage of graphene is 30-50% and the weight percentage of carbon nanotubes is 50-70%.

[0020] According to some preferred embodiments of the present application, the nano-carbon material is a mixture of graphene and carbon nanotubes, wherein the weight percentage of graphene is 35-45% and the weight percentage of carbon nanotubes is 55-65%.

[0021] According to some preferred embodiments of the present application, the composite catalyst powder comprises 30-50% of TiO2, 20-30% of Fe3O4, 15-25% of CeO2 and 10-20% of La2O3, based on the total weight thereof.

[0022] According to some preferred embodiments of the present application, the composite catalyst powder comprises 35-45% of TiO2, 22-28% of Fe3O4, 18-22% of CeO2 and 12-18% of La2O3, based on the total weight thereof.

[0023] According to some preferred embodiments of the present application, the interface regulator is a mixture of silane coupling agent and titanate coupling agent in a weight ratio of 1:1-3:1, preferably 2:1-3:1.

[0024] According to some preferred embodiments of the present application, the magnesium-based alloy powder accounts for 50-60%, the light metal hydride accounts for 30-40%, the nano-carbon material accounts for 5-8%, the composite catalyst powder accounts for 2-4% and the interface regulator accounts for 0.8-2%, based on the total weight of the magnesium-based alloy powder, the light metal hydride, the nano-carbon material, the composite catalyst powder and the interface regulator being 100%.

[0025] According to some preferred embodiments of the present application, the Mg-Mn-Al alloy powder comprises 88-92% of Mg, 4-6% of Mn and 4-6% of Al, based on the total weight of the Mg-Mn-Al alloy powder being 100%.

[0026] According to some preferred embodiments of the present application, the weight percentage of LiAlH4 in the light metal hydride is 65-75%, and the weight percentage of NaBH4 in the light metal hydride is 25-35%.

[0027] According to some preferred embodiments of the present application, the magnesium-based alloy powder is prepared by mixing Mg, Mn and Al metal powders in proportion, smelting at 700-800°C for 30-60 minutes under argon protection, and crushing to a particle size of 50-100 μm after cooling.

[0028] According to some preferred embodiments of the present application, the light metal hydride is prepared by mixing LiAlH4 and NaBH4 in proportion in an argon atmosphere glove box for 30-60 minutes.

[0029] According to some preferred embodiments of the present application, the nano-carbon material is prepared by mixing graphene and carbon nanotubes in proportion, and treating under argon atmosphere at a plasma power of 100-200 W for 10-20 minutes.

[0030] According to some preferred embodiments of the present application, the composite catalyst powder is prepared by mixing TiO2, Fe3O4, CeO2 and La2O3 powders in proportion, ball-milling in ethanol as a dispersion medium for 2-4 hours and drying.

[0031] According to some preferred embodiments of the present application, the step (2) comprises:

[0032] The mixed powder is placed in a vacuum sintering furnace, and heated from room temperature to 200°C at a heating rate of 5°C / min under a vacuum of 1 x 10 -3 -5 x 10 -3 Pa, and held for 60-90 minutes; heated from 200°C to 350°C at a heating rate of 3°C / min and held for 120-180 minutes; and cooled to room temperature at a cooling rate of 4°C / min.

[0033] According to some preferred embodiments of the present application, the preparation method further comprises, after step (2):

[0034] (3) crushing the sintered body from step (2) to a particle size of 20-50 μm.

[0035] According to another aspect of the present invention, a solid hydrogen storage material is provided, which is prepared by the method described above.

[0036] According to certain preferred embodiments of the present invention, the solid hydrogen storage material is a porous particle with a particle size in the range of 20-50 μm.

[0037] According to another aspect of the present invention, a solid hydrogen storage material is provided for use in hydrogen energy supply for fuel cell vehicles, hydrogen energy storage in distributed energy systems, energy storage for long-distance hydrogen pipeline transportation, or portable hydrogen energy devices, wherein the solid hydrogen storage material is the solid hydrogen storage material described above.

[0038] The beneficial effects of the present invention are that the solid hydrogen storage material according to the present invention has high hydrogen storage capacity, fast hydrogen absorption and desorption rate and good cycle stability. Attached Figure Description

[0039] The accompanying drawings are provided in this specification to more clearly explain the technical solutions of the present invention; however, the art is not limited thereto.

[0040] Figure 1 An overview image of a transmission electron microscope (SEM) image of a solid hydrogen storage material prepared according to Example 1 of the present invention is shown.

[0041] Figure 2 A magnified image of a single particle of the solid hydrogen storage material prepared according to Example 1 of the present invention is shown. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. It will be understood that other embodiments may be implemented without departing from the scope or spirit of the invention. Therefore, the following detailed description is non-limiting.

[0043] Unless otherwise specified, all figures used in this specification to represent characteristic dimensions, quantities, and physical properties should be understood to be modified by the term "about" in all cases. Therefore, unless otherwise stated, the numerical parameters listed in the foregoing specification are approximations, and those skilled in the art can appropriately modify these approximations to obtain the desired properties using the teachings disclosed herein.

[0044] As mentioned above, existing solid-state hydrogen storage materials mainly suffer from the following problems: First, it is difficult to balance hydrogen storage capacity and kinetic performance. Most modified materials show a significant decrease in hydrogen storage capacity when increasing the hydrogen absorption and desorption rate, or the kinetic performance cannot meet application requirements while maintaining the capacity. Second, they have poor cycle stability. After multiple hydrogen absorption and desorption cycles, particle agglomeration and structural collapse easily occur, leading to a sharp decline in hydrogen storage performance. Third, they are costly. Some solutions use rare metals, expensive nanomaterials, or require harsh preparation conditions such as high temperature and high pressure, which drives up production costs. Fourth, the preparation process is complex, with cumbersome steps and high equipment requirements, making it difficult to achieve large-scale production. This invention aims to solve the above problems.

[0045] Specifically, according to one aspect of the present invention, a method for preparing a solid hydrogen storage material is provided, the method comprising the following steps:

[0046] (1) Add magnesium-based alloy powder, light metal hydride, nano carbon material, composite catalyst powder and interface modifier to a planetary ball mill and ball mill for 8-12 hours under argon protection to obtain mixed powder;

[0047] (2) The mixed powder is placed in a vacuum sintering furnace and sintered under vacuum at 200-350°C for 2-5 hours to obtain a sintered body, wherein:

[0048] Based on the total weight of the magnesium-based alloy powder, the light metal hydride, the nano-carbon material, the composite catalyst powder, and the interface modifier as 100%, the magnesium-based alloy powder accounts for 40-70%, the light metal hydride accounts for 20-45%, the nano-carbon material accounts for 3-10%, the composite catalyst powder accounts for 1-5%, and the interface modifier accounts for 0.5-3%.

[0049] The magnesium-based alloy powder is a Mg-Mn-Al alloy powder, wherein, based on the total weight of the Mg-Mn-Al alloy powder as 100%, it contains 85-95% Mg, 3-8% Mn and 2-7% Al.

[0050] The light metal hydride is a mixture of LiAlH4 and NaBH4 in a weight ratio of 1.5:1 to 4:1;

[0051] The nano-carbon material is selected from one or more of graphene and carbon nanotubes;

[0052] The composite catalyst powder is a mixture of TiO2, Fe3O4, CeO2 and La2O3;

[0053] The interface modifier is selected from one or more of silane coupling agents and titanate coupling agents.

[0054] According to the technical solution of the present invention, the magnesium-based alloy powder is a Mg-Mn-Al ternary alloy with a weight ratio of 85-95% Mg, 3-8% Mn, and 2-7% Al, preferably 88-92% Mg, 4-6% Mn, and 4-6% Al. Mg, as the core contributor to hydrogen storage capacity, can provide the basic hydrogen storage capacity of the material due to its high theoretical hydrogen storage density (7.6 wt%). The introduction of Mn can refine the alloy grains, reduce the diffusion resistance of hydrogen atoms, and simultaneously inhibit the excessive growth of MgH2, thus improving the hydrogen absorption and desorption kinetics. Al can form stable intermetallic compound phases (such as Mg) with Mg and Mn. 17 Al 12 This phase can serve as a "bridge" for hydrogen atom adsorption and diffusion, further optimizing the kinetic properties.

[0055] According to the technical solution of the present invention, the light metal hydride is a mixture of LiAlH4 and NaBH4 with a weight ratio of 1.5:1-4:1, preferably a mixture of 65-75% LiAlH4 and 25-35% NaBH4. LiAlH4 and NaBH4 form a synergistic hydrogen storage system: LiAlH4 has a high hydrogen storage capacity but a high hydrogen desorption temperature and poor kinetics, while NaBH4 has a fast hydrogen desorption rate but a low hydrogen storage capacity. By mixing the two in a specific ratio, the boron element produced by the decomposition of NaBH4 can form a Li-BH mesophase with LiAlH4, reducing the hydrogen desorption activation energy of LiAlH4. Simultaneously, the high capacity of LiAlH4 compensates for the capacity deficiency of NaBH4, achieving a balance between "high capacity and fast kinetics". Furthermore, this mixture forms a "metal hydride-magnesium-based alloy" composite system with Mg-Mn-Al alloy powder, allowing hydrogen atoms to migrate rapidly between the two interfaces, further improving the overall hydrogen storage efficiency.

[0056] According to the technical solution of the present invention, the nano-carbon material is selected from one or more of graphene and carbon nanotubes. Preferably, the nano-carbon material is a mixture of 30-50% graphene and 50-70% carbon nanotubes, more preferably a mixture of 35-45% graphene and 55-65% carbon nanotubes. Graphene has an ultra-large specific surface area and excellent electronic conductivity, and can serve as an adsorption site for hydrogen atoms and an electron transport channel, accelerating the hydrogen adsorption / desorption reaction. Carbon nanotubes have a one-dimensional hollow structure, which not only provides a fast diffusion channel for hydrogen atoms, but also inhibits the agglomeration of magnesium-based alloy particles in the hydrogen adsorption / desorption cycle through spatial confinement effect. When the two are combined in a specific ratio, the sheet structure of graphene and the tubular structure of carbon nanotubes intertwine to form a three-dimensional conductive network. On the one hand, this improves the electronic conduction rate of the material and reduces the charge transfer resistance of hydrogen adsorption / desorption; on the other hand, it inhibits particle agglomeration through physical barrier effect and improves cycle stability.

[0057] Preferably, before preparing the solid-state hydrogen storage material, the nano-carbon material is treated with 100-200W plasma power for 10-20 minutes. This process can introduce active functional groups such as hydroxyl and carboxyl groups on the surface of the carbon material, enhancing its interfacial bonding with magnesium-based alloy powder and light metal hydrides, and avoiding performance degradation caused by interfacial separation. At the same time, plasma treatment can remove impurities from the surface of the carbon material, further improving its conductivity and specific surface area, and enhancing the hydrogen storage performance.

[0058] According to the technical solution of the present invention, the composite catalyst powder is a mixture of TiO2, Fe3O4, CeO2, and La2O3. Preferably, the weight ratio of each component is 35-45% TiO2, 22-28% Fe3O4, 18-22% CeO2, and 12-18% La2O3, so that the four oxides form a multi-component synergistic catalytic system. TiO2 has high catalytic activity, and its surface oxygen vacancies can serve as adsorption sites for hydrogen atoms. It can also form a Mg-Ti-O solid solution with Mg, reducing the decomposition activation energy of MgH2. Fe3O4 is a magnetic catalyst that can accelerate the migration of hydrogen atoms through a magnetic field effect. Simultaneously, Fe can form Mg2FeH6 with Mg, and this hydride has good kinetic performance, promoting the overall hydrogen release rate. CeO2 has excellent oxygen storage / release capacity, and its Ce... 3+ / Ce 4+ Valence state transitions can regulate the electronic states on the catalyst surface, enhancing its activation capacity for hydrogen molecules. La₂O₃, as a rare earth oxide, can form stable composite oxide phases with other components, improving the catalyst's structural stability. Simultaneously, the lanthanide contraction effect of La optimizes the distribution of active sites on the catalyst surface. When the four components work synergistically, they not only exert their individual catalytic functions but also form a TiO₂-Fe₃O₄-CeO₂-La₂O₃ composite interface. The electron transfer efficiency of this interface is significantly higher than that of a single catalyst, simultaneously accelerating the entire process of hydrogen molecule adsorption, dissociation, diffusion, and desorption, thus solving the problem that a single catalyst cannot simultaneously achieve high catalytic efficiency in multi-step reactions.

[0059] According to the technical solution of the present invention, the interface modifier is one or more of a silane coupling agent or a titanate coupling agent. The interface modifier is a mixture of a silane coupling agent and a titanate coupling agent in a weight ratio of 1:1-3:1, preferably 2:1-3:1. Magnesium-based alloys, lightweight metal hydrides, and nano-carbon materials have significantly different surface properties and poor interfacial compatibility, easily leading to problems such as component separation and loose structure during the composite process. The organic functional groups of the silane coupling agent can react with the active groups on the surface of the carbon material, while the inorganic functional groups can form chemical bonds with metals or metal hydrides; the titanate coupling agent can bind to the hydroxyl groups on the surface of the metal hydride through transesterification, and its long-chain alkyl groups are compatible with organic phases. When the two are mixed in a specific ratio, an interfacial layer with a synergistic effect of "chemical bonds and intermolecular forces" can be formed at the interfaces of different components, reducing the interfacial energy, improving the binding tightness of each component, and avoiding structural collapse caused by interfacial peeling during cycling; at the same time, the interfacial layer can serve as a hydrogen atom transport channel, further optimizing kinetic performance.

[0060] According to the technical solution of the present invention, in the raw materials used to prepare solid hydrogen storage materials, magnesium-based alloy powder accounts for 40-70%, light metal hydrides account for 20-45%, nano-carbon materials account for 3-10%, composite catalyst accounts for 1-5%, and interface modifier accounts for 0.5-3%. This ratio design is based on the synergistic principle of "hydrogen storage core - performance enhancement - structural stability". Specifically, magnesium-based alloy powder, as the core hydrogen storage component, will result in a decrease in kinetic performance if its proportion is too high, and insufficient hydrogen storage capacity if its proportion is too low; the optimized proportion of 40-70% can provide sufficient distribution space for other functional components while ensuring high capacity. When the proportion of light metal hydrides is 20-45%, its kinetic synergistic effect can be fully utilized without causing material structural embrittlement due to an excessive proportion. When the proportion of nano-carbon materials is 3-10%, a complete three-dimensional conductive network can be formed; if the proportion is too low, the network will be discontinuous, and if the proportion is too high, it will crowd out the space of the hydrogen storage components and reduce the hydrogen storage capacity. When the composite catalyst accounts for 1-5%, sufficient distribution of active sites can be ensured. Too high a proportion will increase costs and may lead to catalyst agglomeration, while too low a proportion will result in insignificant catalytic effects. When the interface modifier accounts for 0.5-3%, effective optimization of interface compatibility can be achieved. Too high a proportion will form a thick barrier at the interface, affecting hydrogen atom transport, while too low a proportion will not effectively improve interface bonding.

[0061] Preferably, the magnesium-based alloy powder is prepared by the following method: Mg, Mn and Al metal powders are mixed in proportion, melted at 700-800℃ for 30-60 minutes under argon protection, cooled and then pulverized to a particle size of 50-100μm;

[0062] The light metal hydride is prepared by the following method: LiAlH4 and NaBH4 are mixed in proportion for 30-60 minutes in an argon atmosphere glove box;

[0063] The nano-carbon material is prepared by the following method: graphene and carbon nanotubes are mixed in a certain proportion and treated with 100-200W plasma power for 10-20 minutes under an argon atmosphere;

[0064] The composite catalyst powder is prepared by the following method: TiO2, Fe3O4, CeO2 and La2O3 powders are mixed in proportion, ethanol is used as the dispersion medium, ball milled for 2-4 hours and then dried.

[0065] Preferably, step (2) includes:

[0066] The mixed powder was placed in a vacuum sintering furnace at a temperature of 1×10⁻⁶. -3 -5×10 -3 Under a vacuum of Pa, the temperature is increased from room temperature to 200℃ at a heating rate of 5℃ / min and held for 60-90 minutes; then increased from 200℃ to 350℃ at a heating rate of 3℃ / min and held for 120-180 minutes; and finally cooled to room temperature at a cooling rate of 4℃ / min.

[0067] Preferably, the preparation method further includes the following steps after step (2):

[0068] (3) The sintered body from step (2) is crushed to a particle size of 20-50 μm.

[0069] According to another aspect of the present invention, a solid hydrogen storage material is provided, which is prepared by the method described above. Preferably, the solid hydrogen storage material is porous particles with a particle size in the range of 20-50 μm.

[0070] According to another aspect of the present invention, a solid hydrogen storage material is provided for use in hydrogen energy supply for fuel cell vehicles, hydrogen energy storage in distributed energy systems, energy storage for long-distance hydrogen pipeline transportation, or portable hydrogen energy devices, wherein the solid hydrogen storage material is the solid hydrogen storage material described above.

[0071] The solid-state hydrogen storage material of this invention possesses adaptability and advantages in various hydrogen energy application scenarios due to its high hydrogen storage capacity, rapid hydrogen absorption and desorption rate, and good cycle stability. In the field of hydrogen energy supply for fuel cell vehicles, its high hydrogen storage density can meet the vehicle's range requirements, its rapid hydrogen absorption and desorption characteristics are suitable for the vehicle's refueling efficiency requirements, and its cycle stability ensures long-term performance, solving the problems of insufficient capacity and slow refueling associated with traditional hydrogen storage methods. In distributed energy systems, this material can efficiently store hydrogen energy produced from renewable energy sources, balancing energy supply and demand fluctuations. In long-distance hydrogen pipeline transportation and supporting energy storage scenarios, it can serve as a "buffer energy storage unit" for pipeline transportation, adjusting the spatial and temporal differences between hydrogen transportation and use, and ensuring the stability of the transportation system. In the field of portable hydrogen energy devices, the material's high hydrogen storage efficiency and structural stability can improve the device's range and lifespan, promoting the miniaturization and practical application of portable hydrogen energy devices.

[0072] The present invention will now be described in more detail with reference to embodiments. It should be noted that these descriptions and embodiments are intended to facilitate understanding of the present invention and are not intended to limit the invention.

[0073] Example

[0074] In this invention, unless otherwise specified, all reagents used are commercially available products and are used directly without further purification. Furthermore, "%" refers to "weight %" and "parts" refers to "parts by weight".

[0075] Table 1 below lists specific information about the raw materials used in the embodiments and comparative examples of the present invention.

[0076] Table 1 List of Experimental Materials

[0077]

[0078] Table 2 below lists specific information about the experimental equipment used in the embodiments and comparative examples of the present invention.

[0079] Table 2 List of Experimental Equipment

[0080]

[0081] Example 1

[0082] Preparation of magnesium-based alloy powder: Mg, Mn and Al metal powders were mixed in a weight percentage ratio of 90%Mg, 5%Mn and 5%Al, and melted at 750℃ for 45 minutes under argon protection. After cooling, the mixture was pulverized to a particle size of 50-100μm to obtain Mg-Mn-Al alloy powder.

[0083] Preparation of light metal hydrides: In an argon-atmospheric glove box, LiAlH4 and NaBH4 were mixed at a weight ratio of 70:30 for 45 minutes to obtain light metal hydrides.

[0084] Preparation of carbon nanomaterials: Graphene and carbon nanotubes were mixed at a weight ratio of 40:60 and treated with a plasma processor (SPC-200) at a plasma power of 150W for 15 minutes under an argon atmosphere to obtain carbon nanomaterials.

[0085] Preparation of composite catalyst powder: TiO2, Fe3O4, CeO2 and La2O3 powders were mixed at a weight percentage of 40% TiO2, 25% Fe3O4, 20% CeO2 and 15% La2O3, with ethanol as the dispersion medium, a ball-to-particle ratio of 25:1, a rotation speed of 350 rpm, and ball milled for 3 hours and then dried to obtain composite catalyst powder.

[0086] Preparation of interface modifier: Silane coupling agent KH550 and titanate coupling agent NDZ-101 were mixed at a weight ratio of 2:1 to obtain the interface modifier.

[0087] Ball milling and mixing: The components are added to a planetary ball mill in the following proportions by weight: 55% magnesium-based alloy powder, 35% light metal hydride, 6% nano-carbon material, 3% composite catalyst powder and 1% interface modifier. The mixture is then ball-milled for 10 hours under argon protection to obtain a mixed powder.

[0088] Vacuum sintering: The mixed powder is placed in a vacuum sintering furnace and sintered at 3×10⁻⁶ ℃. -3 Under a vacuum of Pa, the temperature was increased from room temperature to 200°C at a heating rate of 5°C / min and held for 75 minutes; then the temperature was increased from 200°C to 350°C at a heating rate of 3°C / min and held for 150 minutes; and then the temperature was decreased to room temperature at a cooling rate of 4°C / min to obtain the sintered body.

[0089] Crushing: The sintered body is crushed to a particle size of about 30μm to obtain a solid hydrogen storage material.

[0090] Figure 1 An overview image of the transmission electron microscope (SEM) image of the solid hydrogen storage material prepared in Example 1 is shown, and Figure 2 A magnified view of a single particle is shown. (See image.) Figure 1 and Figure 2 As shown in the figure, the obtained solid hydrogen storage material has a porous particle morphology.

[0091] Example 2

[0092] Preparation of magnesium-based alloy powder: Mg, Mn and Al metal powders were mixed at a weight percentage of 88%Mg, 6%Mn and 6%Al, and melted at 700℃ for 60 minutes under argon protection. After cooling, the mixture was pulverized to a particle size of 50-100μm to obtain Mg-Mn-Al alloy powder.

[0093] Preparation of light metal hydrides: LiAlH4 and NaBH4 were mixed at a weight ratio of 65:35 for 60 minutes in an argon atmosphere glove box to obtain light metal hydrides.

[0094] Preparation of carbon nanomaterials: Graphene and carbon nanotubes were mixed at a weight ratio of 35:65 and treated with a plasma processor (SPC-200) at a plasma power of 100W for 20 minutes under an argon atmosphere to obtain carbon nanomaterials.

[0095] Preparation of composite catalyst powder: TiO2, Fe3O4, CeO2 and La2O3 powders were mixed at a weight percentage of 35% TiO2, 28% Fe3O4, 22% CeO2 and 15% La2O3, with ethanol as the dispersion medium, a ball-to-particle ratio of 20:1, a rotation speed of 300 rpm, and ball milled for 4 hours and then dried to obtain composite catalyst powder.

[0096] Preparation of interface modifier: Silane coupling agent KH550 and titanate coupling agent NDZ-101 were mixed at a weight ratio of 3:1 to obtain the interface modifier.

[0097] Ball milling and mixing: The components are added to a planetary ball mill in the following proportions by weight: 50% magnesium-based alloy powder, 40% light metal hydride, 5% nano-carbon material, 4% composite catalyst powder and 1% interface modifier. The mixture is then ball-milled for 8 hours under argon protection to obtain a mixed powder.

[0098] Vacuum sintering: The mixed powder is placed in a vacuum sintering furnace and sintered at a temperature of 1×10⁻⁶ mm. -3 Under a vacuum of Pa, the temperature was increased from room temperature to 200°C at a heating rate of 5°C / min and held for 60 minutes; then increased from 200°C to 350°C at a heating rate of 3°C / min and held for 180 minutes; and finally cooled to room temperature at a cooling rate of 4°C / min to obtain a sintered body.

[0099] Crushing: The sintered body is crushed to a particle size of about 20μm to obtain a solid hydrogen storage material.

[0100] Example 3

[0101] Preparation of magnesium-based alloy powder: Mg, Mn and Al metal powders were mixed at a weight percentage of 92%Mg, 4%Mn and 4%Al, and melted at 800℃ for 30 minutes under argon protection. After cooling, the mixture was pulverized to a particle size of 50-100μm to obtain Mg-Mn-Al alloy powder.

[0102] Preparation of light metal hydrides: In an argon-atmospheric glove box, LiAlH4 and NaBH4 were mixed at a weight ratio of 75:25 for 30 minutes to obtain light metal hydrides.

[0103] Preparation of carbon nanomaterials: Graphene and carbon nanotubes were mixed at a weight ratio of 45:55 and treated with a plasma processor (SPC-200) at a plasma power of 200W for 10 minutes under an argon atmosphere to obtain carbon nanomaterials.

[0104] Preparation of composite catalyst powder: TiO2, Fe3O4, CeO2 and La2O3 powders were mixed at a weight percentage of 45% TiO2, 22% Fe3O4, 18% CeO2 and 15% La2O3, with ethanol as the dispersion medium, a ball-to-particle ratio of 30:1, a rotation speed of 400 rpm, and ball milled for 2 hours and then dried to obtain composite catalyst powder.

[0105] Preparation of interface modifier: Silane coupling agent KH550 and titanate coupling agent NDZ-101 were mixed at a weight ratio of 2:1 to obtain the interface modifier.

[0106] Ball milling: The components are added to a planetary ball mill in the following proportions by weight: 60% magnesium-based alloy powder, 30% light metal hydride, 8% nano-carbon material, 1.2% composite catalyst powder and 0.8% interface modifier. The mixture is then ball-milled for 12 hours under argon protection to obtain a mixed powder.

[0107] Vacuum sintering: The mixed powder is placed in a vacuum sintering furnace and sintered at 5×10⁻⁶ ℃. -3 Under a vacuum of Pa, the temperature was increased from room temperature to 200°C at a heating rate of 5°C / min and held for 90 minutes; then increased from 200°C to 350°C at a heating rate of 3°C / min and held for 120 minutes; and finally cooled to room temperature at a cooling rate of 4°C / min to obtain a sintered body.

[0108] Pulverization: The sintered body is pulverized to a particle size of about 50 μm to obtain a solid hydrogen storage material.

[0109] Example 4

[0110] Preparation of magnesium-based alloy powder: Mg, Mn and Al metal powders were mixed in a weight percentage ratio of 90%Mg, 5%Mn and 5%Al, and melted at 750℃ for 45 minutes under argon protection. After cooling, the mixture was pulverized to a particle size of 50-100μm to obtain Mg-Mn-Al alloy powder.

[0111] Preparation of light metal hydrides: In an argon-atmospheric glove box, LiAlH4 and NaBH4 were mixed at a weight ratio of 70:30 for 45 minutes to obtain light metal hydrides.

[0112] Preparation of carbon nanomaterials: Graphene alone was used as the carbon nanomaterial and treated with a plasma processor (SPC-200) at a plasma power of 120W for 18 minutes under an argon atmosphere to obtain carbon nanomaterials.

[0113] Preparation of composite catalyst powder: TiO2, Fe3O4, CeO2 and La2O3 powders were mixed at a weight percentage of 40% TiO2, 25% Fe3O4, 20% CeO2 and 15% La2O3, with ethanol as the dispersion medium, a ball-to-particle ratio of 25:1, a rotation speed of 350 rpm, and ball milled for 3 hours and then dried to obtain composite catalyst powder.

[0114] Preparation of interface modifier: Silane coupling agent KH550 was used alone as the interface modifier.

[0115] Ball milling and mixing: The components are added to a planetary ball mill in the following proportions by weight: 55% magnesium-based alloy powder, 35% light metal hydride, 6% nano-carbon material, 3% composite catalyst powder and 1% interface modifier. The mixture is then ball-milled for 10 hours under argon protection to obtain a mixed powder.

[0116] Vacuum sintering: The mixed powder is placed in a vacuum sintering furnace and sintered at 3×10⁻⁶ ℃. -3 Under a vacuum of Pa, the temperature was increased from room temperature to 200°C at a heating rate of 5°C / min and held for 75 minutes; then the temperature was increased from 200°C to 350°C at a heating rate of 3°C / min and held for 150 minutes; and then the temperature was decreased to room temperature at a cooling rate of 4°C / min to obtain the sintered body.

[0117] Crushing: The sintered body is crushed to a particle size of about 30μm to obtain a solid hydrogen storage material.

[0118] Example 5

[0119] Preparation of magnesium-based alloy powder: Mg, Mn and Al metal powders were mixed in weight percentages of 95%Mg, 3%Mn and 2%Al, and melted at 780℃ for 35 minutes under argon protection. After cooling, the mixture was pulverized to a particle size of 50-100μm to obtain Mg-Mn-Al alloy powder.

[0120] Preparation of light metal hydrides: In an argon-atmospheric glove box, LiAlH4 and NaBH4 were mixed at a weight ratio of 70:30 for 45 minutes to obtain light metal hydrides.

[0121] Preparation of carbon nanomaterials: Carbon nanotubes were used alone as carbon nanomaterials and treated with a plasma processor (SPC-200) at a plasma power of 180W for 12 minutes under an argon atmosphere to obtain carbon nanomaterials.

[0122] Preparation of composite catalyst powder: TiO2, Fe3O4, CeO2 and La2O3 powders were mixed at a weight percentage of 35% TiO2, 28% Fe3O4, 22% CeO2 and 15% La2O3, with ethanol as the dispersion medium, a ball-to-particle ratio of 20:1, a rotation speed of 300 rpm, and ball milled for 4 hours and then dried to obtain composite catalyst powder.

[0123] Preparation of interface modifier: Titanate coupling agent NDZ-101 was used alone as interface modifier.

[0124] Ball milling and mixing: The components are added to a planetary ball mill in the following proportions by weight: 70% magnesium-based alloy powder, 20% light metal hydride, 3% nano-carbon material, 5% composite catalyst powder and 2% interface modifier. The mixture is then ball-milled for 11 hours under argon protection to obtain a mixed powder.

[0125] Vacuum sintering: The mixed powder is placed in a vacuum sintering furnace and sintered at 4×10⁻⁶ ℃. -3 Under a vacuum of Pa, the temperature was increased from room temperature to 200°C at a heating rate of 5°C / min and held for 85 minutes; then increased from 200°C to 350°C at a heating rate of 3°C / min and held for 130 minutes; and finally cooled to room temperature at a cooling rate of 4°C / min to obtain a sintered body.

[0126] Crushing: The sintered body is crushed to a particle size of about 45μm to obtain a solid hydrogen storage material.

[0127] Comparative Example 1 (Composite catalyst lacking TiO2)

[0128] Comparative Example 1 was carried out in a manner similar to Example 1, except that TiO2 was not added in the preparation of the composite catalyst powder. Specifically, Fe3O4, CeO2 and La2O3 powders were mixed in a weight percentage of 41.7% Fe3O4, 33.3% CeO2 and 25% La2O3, with ethanol as the dispersion medium, a ball-to-particle ratio of 25:1, a rotation speed of 350 rpm, and ball milled for 3 hours and then dried to obtain the composite catalyst powder.

[0129] Comparative Example 2 (Composite catalyst lacking Fe3O4)

[0130] Comparative Example 2 was carried out in a manner similar to Example 1, except that Fe3O4 was not added in the preparation of the composite catalyst powder. Specifically, in the step of preparing the composite catalyst powder, TiO2, CeO2 and La2O3 powders were mixed in a weight percentage of 53.3% TiO2, 26.7% CeO2 and 20% La2O3, with ethanol as the dispersion medium, a ball-to-particle ratio of 25:1, a rotation speed of 350 rpm, and ball milled for 3 hours and then dried to obtain the composite catalyst powder.

[0131] Comparative Example 3 (Composite catalyst lacking CeO2)

[0132] Comparative Example 3 was carried out in a manner similar to Example 1, except that CeO2 was not added in the preparation of the composite catalyst powder. Specifically, in the step of preparing the composite catalyst powder, TiO2, Fe3O4 and La2O3 powders were mixed at a weight percentage of 50% TiO2, 31.25% Fe3O4 and 18.75% La2O3, with ethanol as the dispersion medium, a ball-to-powder ratio of 25:1, a rotation speed of 350 rpm, for 3 hours and then dried to obtain the composite catalyst powder.

[0133] Comparative Example 4 (La2O3 missing from composite catalyst)

[0134] Comparative Example 4 was carried out in a manner similar to Example 1, except that La2O3 was not added in the preparation of the composite catalyst powder. Specifically, in the step of preparing the composite catalyst powder, TiO2, Fe3O4 and CeO2 powders were mixed at a weight percentage of 47.1% TiO2, 29.4% Fe3O4 and 23.5% CeO2, with ethanol as the dispersion medium, a ball-to-powder ratio of 25:1, a rotation speed of 350 rpm, for 3 hours and then dried to obtain the composite catalyst powder.

[0135] Comparative Example 5 (Single Catalyst TiO2)

[0136] Comparative Example 5 was carried out in a manner similar to that of Example 1, except that a single catalyst TiO2 was used. Specifically, in the step of preparing the catalyst powder, TiO2 powder was ball-milled for 3 hours with ethanol as the dispersion medium at a ball-to-powder ratio of 25:1 and a rotation speed of 350 rpm, and then dried to obtain a single catalyst powder.

[0137] Comparative Example 6 (Catalyst-free powder)

[0138] Comparative Example 6 was carried out in a similar manner to Example 1, except that no catalyst powder was added. That is, in the ball milling mixing step, the components were added to a planetary ball mill in the proportion of 56.7% magnesium-based alloy powder, 36.1% light metal hydride, 6.2% nano-carbon material and 1% interface modifier by weight, and ball milled for 10 hours under argon protection to obtain a mixed powder.

[0139] Comparative Example 7 (Conventional Magnesium-Based Hydrogen Storage Materials)

[0140] Comparative Example 7 was carried out in a manner similar to Example 1, except that a magnesium-based hydrogen storage material was prepared by the following conventional method: pure Mg powder and Ni powder were mixed at a weight ratio of 95:5, ball-milled for 10 hours under argon protection, and then vacuum sintered at 300°C for 3 hours to obtain a conventional Mg-Ni-based hydrogen storage material.

[0141] Performance Testing and Result Analysis

[0142] The solid hydrogen storage materials prepared in Examples 1-5 and Comparative Examples 1-7 were subjected to performance tests, including hydrogen storage capacity, hydrogen absorption / desorption rate, and cycle stability. The test methods are as follows:

[0143] Hydrogen storage capacity test:

[0144] Based on the Sieverts method (volumetric method), the hydrogen storage capacity (expressed as a percentage by weight) is calculated by measuring the volume change of hydrogen adsorbed by the material under specific temperature and pressure. The test was conducted using a Sieverts-type hydrogen storage performance tester (PCT-4SDWIN, manufactured by Suzuki Shokan, Japan).

[0145] Specifically, the solid hydrogen storage materials to be tested (from Examples 1-5 and Comparative Examples 1-7) were dried to constant weight to avoid moisture adsorption affecting the hydrogen adsorption capacity. 0.5 g of the dried sample was weighed, placed into the sample tube of the testing instrument, sealed, and then evacuated until the system pressure was ≤1×10⁻⁶. -3 To remove air and residual impurities from the sample tube, the sample tube was then placed in a constant temperature environment, heated to 300℃ and held for 30 minutes to stabilize the sample temperature (to avoid temperature fluctuations affecting hydrogen adsorption equilibrium). Subsequently, high-purity hydrogen (purity ≥ 99.999%) was introduced into the system, and the hydrogen pressure was stabilized at 3 MPa. The hydrogen adsorption process was then recorded. System pressure changes were continuously monitored; when the pressure did not decrease significantly within 1 hour (pressure fluctuation ≤ 0.01 MPa), adsorption equilibrium was considered reached. Finally, based on the Sieverts equation, combined with the system calibration volume, hydrogen pressure, temperature, and sample mass, the mass of hydrogen adsorbed in the sample was calculated. The final result was calculated as "Hydrogen storage capacity (weight %) = (mass of adsorbed hydrogen / sample mass) × 100%".

[0146] Hydrogen absorption / desorption rate test:

[0147] The hydrogen absorption and desorption kinetics are quantified by recording the time required for a material to reach 90% of its maximum hydrogen storage capacity (hydrogen absorption) or to release to 10% of its maximum hydrogen storage capacity (hydrogen release) under specific temperature and pressure conditions. The shorter the time, the faster the rate.

[0148] Specifically, the test steps and conditions for the hydrogen absorption rate are the same as the "sample loading-vacuuming-heating" steps for the hydrogen storage capacity test described above. The sample tube is heated to 300℃ and held at that temperature until stable. Then, hydrogen gas is introduced until the system pressure stabilizes at 3MPa, and a timer is started simultaneously. The change in hydrogen adsorption amount of the sample is monitored and recorded in real time. When the adsorption amount reaches 90% of the sample's "maximum hydrogen storage capacity (determined through hydrogen storage capacity testing)," the timer is stopped, and the time at this point is recorded as t. 90 Hydrogen absorption (unit: min).

[0149] Furthermore, regarding the hydrogen release rate test procedure and conditions, first, the sample is subjected to hydrogen adsorption at 300℃ and 3MPa until saturation (reaching maximum hydrogen storage capacity) according to the hydrogen absorption rate test conditions. Then, the sample temperature is kept stable at 300℃, and the system pressure is slowly reduced to 0.1MPa (at ambient pressure), while simultaneously starting the timer. The change in hydrogen release from the sample is monitored and recorded in real time. When the release reaches "10% of the maximum hydrogen storage capacity", the timer is stopped, and the time at this point is recorded as t. 90 Hydrogen emission (unit: min).

[0150] Cyclic stability test:

[0151] Cyclic stability testing simulates the repeated hydrogen absorption and desorption scenarios during actual use of materials. Cyclic stability is evaluated by assessing the degree of hydrogen storage capacity decay after multiple cycles, with "hydrogen storage capacity retention rate after cycling" as the evaluation criterion.

[0152] Specifically, an alternating "hydrogen absorption-hydrogen release" cycle mode is adopted, and the single cycle process is as follows:

[0153] Hydrogen adsorption stage: Hydrogen is adsorbed to saturation at 300℃ and 3MPa (reaching the maximum hydrogen storage capacity of the sample in its first test);

[0154] Hydrogen release phase: Hydrogen is released at 300℃ and 0.1MPa until the remaining capacity is 10% of the maximum hydrogen storage capacity;

[0155] Cycle count: Perform 50 consecutive "hydrogen absorption-hydrogen release" cycles, with temperature and pressure controlled according to the above operating conditions for each cycle;

[0156] Capacity recording: Record the hydrogen storage capacity after the first cycle (1st cycle) and each subsequent cycle;

[0157] Retention rate calculation: Cycle stability is expressed as the "hydrogen storage capacity retention rate after 50 cycles", and the calculation formula is: Retention rate (%) = (hydrogen storage capacity after 50 cycles / hydrogen storage capacity after 1 cycle) × 100%. The higher the retention rate, the better the cycle stability.

[0158] The test results are shown in Table 3 below:

[0159] Table 3 Performance test results of Examples 1-5 and Comparative Examples 1-7

[0160]

[0161] As can be seen from the results in Table 3 above, regarding hydrogen storage capacity, the hydrogen storage capacities of Examples 1-5 are all between 6.3 wt% and 6.8 wt%, significantly higher than those of Comparative Examples 1-7. Example 1 exhibits the highest hydrogen storage capacity, reaching 6.8 wt%, which is attributed to the optimized ratio and synergistic effect of the components. Comparative Examples 1-4, due to the absence of one component in the composite catalyst, have hydrogen storage capacities reduced to 5.0 wt%-5.3 wt%, a decrease of approximately 22%-26% compared to Example 1, a significant difference. Comparative Example 5, using a single TiO2 catalyst, has a hydrogen storage capacity of only 4.8 wt%, further demonstrating that the synergistic effect of the composite catalyst is superior to that of a single catalyst. Comparative Example 6, without a catalyst, has a hydrogen storage capacity reduced to 4.5 wt%, indicating that the catalyst is crucial for improving hydrogen storage capacity. The conventional magnesium-based hydrogen storage material in Comparative Example 7 has a hydrogen storage capacity of only 3.8 wt%, far lower than the examples of this invention.

[0162] Furthermore, regarding the hydrogen absorption and desorption rates, the hydrogen absorption t in Examples 1-5... 90 Between 12 and 18 minutes, hydrogen is released. 90 It exhibits excellent kinetic performance between 8 and 12 minutes. Example 1 shows the fastest hydrogen absorption and desorption rates, with a hydrogen absorption t... 90 For 12 minutes, hydrogen is released. 90 The time was 8 minutes. The hydrogen absorption time for Comparative Examples 1-4 was... 90 Between 35 and 40 minutes, hydrogen is released. 90 The hydrogen absorption time was significantly longer than in Example 1, ranging from 28 to 32 minutes, indicating that the absence of any component in the composite catalyst leads to a decrease in catalytic activity and a deterioration in hydrogen absorption / desorption kinetics. Comparative Example 5 showed a significantly longer hydrogen absorption time of t0. 90 For 45 minutes, hydrogen is released. 90 After 35 minutes, the kinetic performance further deteriorated, demonstrating the synergistic catalytic effect of the composite catalyst. Comparative Example 6, without catalyst, showed a hydrogen absorption t... 90 For up to 55 minutes, hydrogen was released. 90 The hydrogen absorption time was 42 minutes, exhibiting the worst kinetic performance. Comparatively, the hydrogen absorption time of the conventional Mg-Ni-based hydrogen storage material in Example 7 was [not specified]. 90 For 60 minutes, hydrogen is released.90 The time was 48 minutes, and the dynamic performance was far inferior to that of the embodiments of the present invention.

[0163] Regarding cycle stability, the hydrogen storage capacity retention rates after 50 cycles in Examples 1-5 ranged from 88% to 92%, with Example 1 showing the highest retention rate at 92%, indicating that the solid-state hydrogen storage material of the present invention exhibits good cycle stability. This is attributed to the addition of Al, the dispersion effect of nano-carbon materials, and the improved interfacial compatibility through interface modifiers, effectively suppressing particle agglomeration and structural collapse. The hydrogen storage capacity retention rates after 50 cycles in Comparative Examples 1-4 ranged from 72% to 75%, a decrease of approximately 18% to 22% compared to Example 1. This is because the synergistic effect of the composite catalyst was disrupted, affecting not only kinetic performance but also leading to a decrease in material structural stability and accelerated decay of hydrogen storage performance during cycling. The cycle retention rates of Comparative Example 5 were 68% and Comparative Example 6 was 65%, both lower than Comparative Examples 1-4, further demonstrating the importance of the composite catalyst. The conventional Mg-Ni-based hydrogen storage material in Comparative Example 7 exhibited a cycle retention rate of only 55%, demonstrating poor cycle stability and failing to meet practical application requirements.

[0164] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from the spirit and scope of this disclosure. Therefore, if such modifications and variations fall within the scope of this invention, this disclosure is also intended to include such modifications and variations.

Claims

1. A method for preparing a solid hydrogen storage material, characterized in that, The preparation method includes the following steps: (1) Add magnesium-based alloy powder, light metal hydride, nano carbon material, composite catalyst powder and interface modifier to a planetary ball mill and ball mill for 8-12 hours under argon protection to obtain mixed powder; (2) The mixed powder is placed in a vacuum sintering furnace and sintered under vacuum at 200-350°C for 2-5 hours to obtain a sintered body, wherein: Based on the total weight of the magnesium-based alloy powder, the light metal hydride, the nano-carbon material, the composite catalyst powder, and the interface modifier as 100%, the magnesium-based alloy powder accounts for 40-70%, the light metal hydride accounts for 20-45%, the nano-carbon material accounts for 3-10%, the composite catalyst powder accounts for 1-5%, and the interface modifier accounts for 0.5-3%. The magnesium-based alloy powder is a Mg-Mn-Al alloy powder, wherein, based on the total weight of the Mg-Mn-Al alloy powder as 100%, it contains 85-95% Mg, 3-8% Mn and 2-7% Al. The light metal hydride is a mixture of LiAlH4 and NaBH4 in a weight ratio of 1.5:1 to 4:1; The nano-carbon material is selected from one or more of graphene and carbon nanotubes; The composite catalyst powder is a mixture of TiO2, Fe3O4, CeO2 and La2O3; The interface modifier is selected from one or more of silane coupling agents and titanate coupling agents.

2. The method for preparing solid hydrogen storage material according to claim 1, characterized in that, The nano-carbon material is a mixture of graphene and carbon nanotubes, wherein the weight percentage of graphene is 30-50% and the weight percentage of carbon nanotubes is 50-70%.

3. The method for preparing solid hydrogen storage material according to claim 1, characterized in that, The composite catalyst powder contains 30-50% TiO2, 20-30% Fe3O4, 15-25% CeO2 and 10-20% La2O3 by weight.

4. The method for preparing solid hydrogen storage material according to claim 1, characterized in that, The interface modifier is a mixture of silane coupling agent and titanate coupling agent in a weight ratio of 1:1 to 3:

1.

5. The method for preparing solid hydrogen storage material according to claim 1, characterized in that, The magnesium-based alloy powder is prepared by the following method: Mg, Mn and Al metal powders are mixed in proportion, melted at 700-800℃ for 30-60 minutes under argon protection, cooled and then pulverized to a particle size of 50-100μm. The light metal hydride is prepared by the following method: LiAlH4 and NaBH4 are mixed in proportion for 30-60 minutes in an argon atmosphere glove box; The nano-carbon material is prepared by the following method: graphene and carbon nanotubes are mixed in a certain proportion and treated with 100-200W plasma power for 10-20 minutes under an argon atmosphere; The composite catalyst powder is prepared by the following method: TiO2, Fe3O4, CeO2 and La2O3 powders are mixed in proportion, ethanol is used as the dispersion medium, ball milled for 2-4 hours and then dried.

6. The method for preparing solid hydrogen storage material according to claim 1, characterized in that, Step (2) includes: The mixed powder was placed in a vacuum sintering furnace at a temperature of 1×10⁻⁶. -3 -5×10 -3 Under a vacuum of Pa, the temperature is increased from room temperature to 200℃ at a heating rate of 5℃ / min and held for 60-90 minutes; then increased from 200℃ to 350℃ at a heating rate of 3℃ / min and held for 120-180 minutes; and finally cooled to room temperature at a cooling rate of 4℃ / min.

7. The method for preparing solid hydrogen storage material according to claim 1, characterized in that, The preparation method further includes the following steps after step (2): (3) The sintered body from step (2) is crushed to a particle size of 20-50 μm.

8. A solid hydrogen storage material, characterized in that, The solid hydrogen storage material is prepared by the method according to any one of claims 1-7.

9. The solid hydrogen storage material according to claim 8, characterized in that, The solid hydrogen storage material is a porous particle with a particle size in the range of 20-50 μm.

10. A solid hydrogen storage material for use in hydrogen energy supply for fuel cell vehicles, hydrogen energy storage in distributed energy systems, energy storage for long-distance hydrogen pipeline transportation, or portable hydrogen energy devices, characterized in that, The solid hydrogen storage material is the solid hydrogen storage material according to claim 8 or 9.

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