A graphene nanosolid hydrogen storage material and its manufacturing process

Abstract

This invention discloses a graphene nano-solid hydrogen storage material and its manufacturing process. Raw materials include nano-magnesium powder, graphene, nano-Y2O3, and nano-La2O3. Through steps such as proportioning, raw material processing, and ball milling, the nano-magnesium powder is physically modified while simultaneously encapsulated and adsorbed by graphene to obtain a graphene nano-solid hydrogen storage material with a stable sandwich structure. By using graphene to prevent the agglomeration of nano-magnesium powder, it not only promotes hydrogen storage and release but also improves the reversibility of hydrogen storage and release, allowing for a high number of cycles, low reuse cost, and a high volumetric energy density, far exceeding the hydrogen storage capacity per unit volume at a pressure of 20 MPa. Furthermore, its solid state at room temperature reduces transportation costs. Additionally, the hybridization of magnesium with rare earth materials and the high carrier mobility and high thermal conductivity of graphene lower the temperature during hydrogen storage and release, reducing the risk of leakage and explosion during the process.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage materials, specifically to a graphene nanosolid hydrogen storage material and its manufacturing process. Background Technology

[0002] As people pay increasing attention to energy and environmental issues, the development and utilization of clean energy has become an important direction for development in countries around the world. Hydrogen has a high mass energy density; its energy density is almost three times that of other fossil fuels, such as gasoline, diesel, and natural gas. Currently, due to its advantages such as zero pollution, high efficiency, abundant sources, and wide range of applications, many countries regard hydrogen energy as the "energy of the future."

[0003] High-pressure hydrogen storage technology is currently the most commonly used and relatively mature hydrogen storage technology. However, this technology has the potential for leakage and explosion, and its safety performance is poor. Furthermore, the commonly used pressure of high-pressure hydrogen storage tanks is 20 MPa, and its density is only 15.3 g / L, making transportation costs extremely high. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a graphene nano-solid-state hydrogen storage material and its manufacturing process. The technical solution provided by this invention is as follows:

[0005] A manufacturing process for graphene nano-solid-state hydrogen storage materials includes the following steps:

[0006] S1: Prepare raw materials, including nano-magnesium powder, graphene, and rare earth materials. The rare earth materials include nano-Y2O3 and nano-La2O3, and mix them in a ratio of nano-magnesium powder: graphene: nano-Y2O3: nano-La2O3 = 1000:50~100:1~5:1~5. The graphene used has a purity of at least 99.9%, 1~3 layers, and a thickness of 0.335~1.1 nanometers. The nano-magnesium powder used has a purity of at least 99.9% and a particle size of 50~500nm. The nano-Y2O3 used has a purity of at least 99.9% and a particle size of 10~30nm. The nano-La2O3 used has a purity of at least 99.9% and a particle size of 10~30nm.

[0007] S2: Mixing raw materials. Place the raw materials prepared in S1 into a high-speed mixer and mix them. The mixer speed is 2000-5000 rpm, and the mixing time is 10-30 minutes to ensure that the nano magnesium powder, graphene, nano Y2O3 and nano La2O3 are evenly dispersed. The four raw materials are evenly mixed under micron-scale observation. Micron-scale observation is observed under a microscope at 1000x magnification to check the dispersion uniformity. If the dispersion is not uniform enough during observation, it needs to be put back into the mixer for further mixing.

[0008] S3: Ball milling raw material. After the raw material mixed in S2 is cooled to room temperature, it is ball milled in a high-speed ball mill at a speed of 400-500 rpm for 30-100 hours. The smaller the particle size of the raw material, the shorter the ball milling time. The high-speed ball mill contains wear-resistant grinding balls in three sizes: large (10-15 mm), medium (6-8 mm), and small (3-5 mm). The three types of grinding balls are filled together, greatly improving the efficiency of the ball mill. The high-speed ball mill extrudes nano-magnesium powder, flattening it to a thickness of 3-20 nm. The high-speed ball mill also extrudes nano-Y2O3 and nano-La2O3, crushing them to a particle size of 2-10 nm. Under the mutual collision and extrusion of the grinding balls, the high-purity magnesium powder fuses with graphene and rare earth materials to form a stable sandwich structure, obtaining the finished graphene nano-solid hydrogen storage material.

[0009] It should be noted that each step, namely raw material metering, conveying, mixing, testing and ball milling, must be carried out in an atmosphere with argon as the protective gas to ensure that there is no direct contact with air.

[0010] Preferably, the ratio of the prepared raw materials is nano magnesium powder: graphene: nano Y2O3: nano La2O3 = 1000:80:3:3.

[0011] Based on the same concept, the present invention also provides a graphene nano-solid hydrogen storage material, which is prepared according to the methods described in S1-S3 above. The finished graphene nano-solid hydrogen storage material has a sandwich structure. Specifically, the finished graphene nano-solid hydrogen storage material has a sandwich structure of (nano-magnesium powder-rare earth material)-graphene-(nano-magnesium powder-rare earth material).

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0013] 1. This invention involves ball milling a mixture of nano-magnesium powder and nano-scale rare earth materials to physically modify the nano-magnesium powder, breaking down the passivation layer on its surface and exposing a fresh magnesium surface. Simultaneously, ball milling with alloying elements forms a transition layer on the surface of the nano-magnesium powder, promoting its hydrogen storage and release. Furthermore, based on the modified magnesium-based material, graphene effectively encapsulates and adsorbs the nano-scale magnesium powder, creating a stable sandwich structure of graphene, nano-magnesium powder, and rare earth materials. The tensile strength of graphene is over 1000 times that of pure magnesium. During hydrogen storage and release, graphene not only effectively prevents the agglomeration of nano-magnesium particles from affecting hydrogen storage and release performance but also ensures a high number of cycles for hydrogen storage and release, resulting in low reuse costs.

[0014] 2. Furthermore, in the process of hydrogen storage and release, this invention, based on the promoting effect of physical modification of the nano-magnesium powder on hydrogen storage and release, also utilizes the quantum effect generated by the ultra-high carrier mobility of graphene (approximately 15000 cm² / (V·s) at room temperature), which results in a low hydrogen storage and release temperature for the graphene nano-solid hydrogen storage material. Moreover, the added nano-Y₂O₃ and nano-La₂O₃ rare earth materials are integrated into the nano-magnesium powder, hybridizing it and altering its atomic structure, thus providing excellent catalytic effects and reducing the temperature to only 180°C during hydrogen storage and release.

[0015] It is understood that this invention, by using graphene to prevent the agglomeration of nano-magnesium powder, not only promotes the hydrogen storage and release of magnesium, but also ensures good reversibility of hydrogen storage and release, allowing for a high number of cycles, low cost of reuse, and high volumetric energy density, far exceeding the amount of hydrogen stored per unit volume at a pressure of 20 MPa. Furthermore, it is a solid at room temperature, which not only reduces transportation costs, but also reduces the temperature of hydrogen storage and release by hybridizing magnesium with rare earth materials and by using the high carrier mobility and high thermal conductivity of graphene. This also reduces the risk of leakage and explosion during the hydrogen storage and release process. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0017] Figure 1 This is a flowchart of the manufacturing process of the graphene nano-solid hydrogen storage material of the present invention.

[0018] Figure 2 This is a schematic diagram of the microstructure of the graphene nanosolid hydrogen storage material of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] For examples, please refer to Figure 1-2 A manufacturing process for graphene nano-solid-state hydrogen storage materials includes the following steps:

[0021] S1: In an atmosphere protected by argon, prepare raw materials, including nano-magnesium powder, graphene, and rare earth materials. The rare earth materials used include nano-Y2O3 and nano-La2O3, and mix them in a ratio of nano-magnesium powder: graphene: nano-Y2O3: nano-La2O3 = 1000:50~100:1~5:1~5. The graphene used has a purity of at least 99.9%, 1~3 layers, and a thickness of 0.335~1.1 nm. The nano-magnesium powder used has a purity of at least 99.9% and a particle size of 50~500 nm. The nano-Y2O3 used has a purity of at least 99.9% and a particle size of 10~30 nm. The nano-La2O3 used has a purity of at least 99.9% and a particle size of 10~30 nm.

[0022] S2: In an atmosphere protected by argon, the raw materials prepared in S1 are placed in a high-speed mixer for mixing. The mixer speed is 2000-5000 rpm, and the mixing time is 10-30 minutes to ensure uniform dispersion of nano-magnesium powder, graphene, nano-Y2O3, and nano-La2O3. The four raw materials are observed to be uniformly mixed at the micron level. Micron-level observation refers to observing the dispersion uniformity under a microscope at 1000x magnification. It should be noted that if the dispersion is not uniform enough during observation, it needs to be placed back into the mixer for further mixing. The speed and time are controlled according to actual needs.

[0023] S3: After cooling the mixed raw materials from S2 to room temperature in an argon-protected atmosphere, they are then ball-milled in a high-speed ball mill under the same argon-protected atmosphere. The milling speed is 400-500 rpm, and the milling time is 30-100 hours. The smaller the particle size of the raw material, the shorter the milling time. The high-speed ball mill contains wear-resistant grinding balls in three sizes: large (10-15mm diameter), medium (6-8mm diameter), and small (3-5mm diameter). These three types of grinding balls are interleaved, greatly improving the efficiency of the ball mill. The high-speed ball mill extrudes... Nano-magnesium powder, with a thickness of 3-20 nm, is flattened and then extruded using a high-speed ball mill to crush nano-Y2O3 and nano-La2O3, reducing their particle size to 2-10 nm. The collision and compression of the grinding balls physically modify the surface of the nano-magnesium powder. Mechanical ball milling destroys the passivation layer on the surface of the nano-magnesium powder, exposing a fresh surface of magnesium. Simultaneously, it is mixed with alloying elements and ball-milled, forming a transition layer on the surface of the nano-magnesium powder, which promotes hydrogen storage and release. High-purity magnesium powder is then fused with graphene and rare earth materials to form a stable sandwich structure, yielding the finished graphene nano-solid-state hydrogen storage material.

[0024] This invention also provides a graphene nano-solid-state hydrogen storage material, namely, a finished graphene nano-solid-state hydrogen storage material prepared according to the methods described in S1-S3 above. The finished graphene nano-solid-state hydrogen storage material has a sandwich structure, specifically, as shown below. Figure 2 As shown, the finished graphene nano-solid-state hydrogen storage material has a sandwich structure of (nano-magnesium powder-rare earth material)-graphene-(nano-magnesium powder-rare earth material). The minimum thickness of the graphene used is only 0.335 nm, and the specific surface area reaches 2630 m². 2 / g, can effectively encapsulate and adsorb nano-sized magnesium powder. Graphene, magnesium powder, and rare earth materials form a sandwich structure. Meanwhile, the tensile strength of pure magnesium is only 115MPa, while the tensile strength of graphene is as high as 130GP, which is more than 1000 times that of pure magnesium. Since nano-sized particles are easy to aggregate, graphene effectively prevents the agglomeration of magnesium powder during hydrogen storage and release, ensuring that the number of hydrogen storage and release cycles is more than 2000.

[0025] During hydrogen storage, based on the principle of interconversion between Mg and MgH2, that is... Both nano-magnesium powder and MgH2 are solids. Nano-magnesium powder has a melting point of 648.8℃, while MgH2 decomposes at 180℃ and above, ensuring that it is a solid at room temperature, thus enabling the storage of hydrogen.

[0026] When releasing hydrogen, graphene exhibits excellent thermal conductivity, with a single-layer graphene thermal conductivity reaching 5300 W / mK. Furthermore, graphene's carrier mobility at room temperature is approximately 15000 cm² / (V·s), exceeding ten times that of silicon and more than twice that of indium antimonide (InSb), the known material with the highest carrier mobility. Graphene's electron mobility is less affected by temperature changes, and this extremely high carrier mobility facilitates efficient heat exchange, thus lowering the hydrogen storage and release temperature of the graphene nano-solid-state hydrogen storage material. Moreover, the addition of nano-Y₂O₃ and nano-La₂O₃ rare earth materials integrated into the nano-magnesium powder creates a hybridization effect. This hybridization improves the hydrogen storage kinetics of the MgH₂ system, altering the atomic structure of the nano-magnesium. This catalytic effect lowers the temperature during hydrogen storage and release, acting as a catalyst. The catalytic mechanism is believed to be that the heterogeneous interface between MgH₂ and the nanoparticles promotes Mg nucleation and provides channels for H atom diffusion, keeping the temperature as low as 180℃.

[0027] Ideally, the ratio of the prepared raw materials should be nano-magnesium powder: graphene: nano-Y2O3: nano-La2O3 = 1000:80:3:3, so that the mass ratio of magnesium is as high as 92%, and the theoretical hydrogen storage capacity per unit mass is 7.2wt%. Due to the influence of hydrogen purity, the actual hydrogen storage capacity is 5.5-6wt%.

Claims

1. A manufacturing process for graphene nano-solid-state hydrogen storage materials, characterized in that, Includes the following steps: S1: Prepare raw materials, including nano magnesium powder, graphene and rare earth materials, wherein the rare earth materials include nano Y2O3 and nano La2O3, and mix them in a ratio of nano magnesium powder: graphene: nano Y2O3: nano La2O3 = 1000: 50~100: 1~5: 1~5; S2: Mixing raw materials. Place the raw materials prepared in S1 into a high-speed mixer and mix them. The speed of the mixer is 2000~5000 rpm and the mixing time is 10~30 minutes to make the nano magnesium powder, graphene, nano Y2O3 and nano La2O3 evenly dispersed. If the dispersion is not even enough, it is necessary to continue to put them into the mixer for further mixing. S3: Ball milling raw material. After the raw material mixed in S2 is cooled to room temperature, it is ball milled in a high-speed ball mill at a speed of 400-500 rpm for 30-100 hours. The high-speed ball mill extrudes nano-magnesium powder, flattening the thickness to 3-20 nm. The high-speed ball mill also extrudes nano-Y2O3 and nano-La2O3, crushing them and reducing their particle size to 2-10 nm to obtain the finished graphene nano solid hydrogen storage material. The graphene has a purity of at least 99.9%, has 1 to 3 layers, and a thickness of 0.335 to 1.1 nanometers; The purity of the nano-magnesium powder is at least 99.9%, and the particle size is 50~500nm.

2. The manufacturing process of graphene nano-solid-state hydrogen storage material according to claim 1, characterized in that, The purity of the nano-Y2O3 is at least 99.9%, and the particle size is 10~30nm; The purity of the nano-La2O3 is at least 99.9%, and the particle size is 10~30nm.

3. The manufacturing process of graphene nano-solid-state hydrogen storage material according to claim 2, characterized in that, In step S2, the four raw materials are mixed evenly under micron-scale observation, which means observing the dispersion uniformity under a microscope at a magnification of 1000x.

4. The manufacturing process of graphene nano-solid hydrogen storage material according to claim 2, characterized in that, In step S3, the smaller the particle size of the raw material used, the shorter the ball milling time.

5. The manufacturing process of graphene nano-solid-state hydrogen storage material according to claim 2, characterized in that, In step S3, the high-speed ball mill used contains wear-resistant grinding balls. The grinding balls come in three sizes: large grinding balls with a diameter of 10-15 mm, medium grinding balls with a diameter of 6-8 mm, and small grinding balls with a diameter of 3-5 mm.

6. The manufacturing process of graphene nano-solid-state hydrogen storage material according to claim 1, characterized in that, In each step, including raw material metering, conveying, mixing, testing, and ball milling, it is necessary to ensure that the raw materials are in an atmosphere with argon as the protective gas and that they do not come into direct contact with air.

7. The manufacturing process of graphene nano-solid-state hydrogen storage material according to claim 1, characterized in that, The proportions of the prepared raw materials are: nano magnesium powder: graphene: nano Y2O3: nano La2O3 = 1000:80:3:

3.

8. A graphene nano-solid-state hydrogen storage material, characterized in that, The graphene nano-solid hydrogen storage material is prepared by the process described in any one of claims 1-7, and the finished product has a sandwich structure.

9. The graphene nanosolid-state hydrogen storage material according to claim 8, characterized in that, The finished graphene nano-solid hydrogen storage material has a sandwich structure of nano-magnesium powder / rare earth material-graphene-nano-magnesium powder / rare earth material.

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