Liquid metal gallium and hollow glass microsphere composite hydrogen storage material

Abstract

This invention relates to a composite hydrogen storage material of liquid gallium metal and hollow glass microspheres. The material is produced by etching the glass microspheres with dilute hydrofluoric acid to create defects on their surface, followed by mixing and stirring with liquid gallium metal to form a gallium-coated glass microsphere composite powder. This material achieves efficient hydrogen storage under mild conditions, with hydrogen storage density meeting various application requirements. The preparation method is simple and suitable for large-scale production. The composite hydrogen storage material achieves hydrogen storage densities of 1.61 wt% and 3.14 wt% at 100℃ and 200℃, and 5 MPa hydrogen pressure, respectively. Liquid gallium metal effectively lowers the reaction energy barrier for hydrogen molecule cracking and hydrogen atom recombination, improving hydrogen storage kinetics and thermodynamics. The composite hydrogen storage material Ga@HGMs provided by this invention exhibits excellent performance, offering a new solution for the field of hydrogen storage and is expected to play an important role in stationary and mobile hydrogen storage devices. Furthermore, the material's considerable hydrogen storage capacity and rapid adsorption kinetics give it significant advantages in practical applications and are expected to promote the development of hydrogen storage technology.

Description

Technical Field

[0001] This invention belongs to the field of novel solid hydrogen storage materials, and relates to a composite hydrogen storage material of liquid gallium metal and hollow glass microspheres and its preparation method. Background Technology

[0002] Hydrogen energy, as a clean and efficient energy form, is receiving increasing global attention. Its uniqueness lies in its versatility: it can be used as fuel to power vehicles and power plants, and also as an energy carrier to facilitate the interconversion of electricity, heat, and hydrogen energy. In the field of large-scale energy storage, hydrogen energy's advantages are particularly prominent. It has a large storage capacity and can be charged and discharged at any time, providing a stable energy storage solution for intermittent energy sources such as wind and solar power. However, the widespread application of hydrogen energy faces a major challenge: hydrogen storage technology. As a low-density gas that is difficult to liquefy, hydrogen storage and transportation are challenging. Currently, the main methods of hydrogen storage include compressed hydrogen and liquid hydrogen. However, both methods have certain technological bottlenecks. For example, hydrogen compression and liquefaction consume a lot of energy, and the small atomic and molecular size of hydrogen makes it prone to leakage from containers. Therefore, how to achieve high-density, safe, and efficient storage and transportation of hydrogen is the focus and challenge of current hydrogen storage technology research.

[0003] To address this challenge, researchers are actively exploring novel hydrogen storage materials and technologies. The emergence of new materials such as metal-organic frameworks and carbon nanotubes has brought new opportunities for the development of hydrogen storage technology. Furthermore, utilizing renewable energy sources such as solar and wind power for water electrolysis to produce hydrogen is also one of the future directions for hydrogen storage technology development.

[0004] In the field of hydrogen storage technology, while traditional high-pressure gas cylinders and liquid hydrogen storage technologies meet the hydrogen storage needs to some extent, they have significant shortcomings in terms of safety, economy, and convenience. High-pressure gas cylinder storage of hydrogen typically requires a high-pressure environment, which not only places high demands on the pressure resistance of the storage containers but also increases safety hazards during storage and transportation. While liquid hydrogen storage technology can achieve high hydrogen storage densities, it requires extremely low temperatures, which not only increases the cost and difficulty of storage and transportation but also places extremely high demands on the thermal insulation performance of the storage containers. Furthermore, the evaporation of liquid hydrogen leads to energy loss, thus affecting its economic viability. To overcome these shortcomings, solid hydrogen storage materials have become a research hotspot.

[0005] Compared to high-pressure gas cylinders and liquid hydrogen storage technologies, solid hydrogen storage materials offer higher safety performance, better hydrogen storage density, and more convenient operation and transportation methods. Solid hydrogen storage materials typically have higher hydrogen storage density, achieving both high mass and volumetric hydrogen storage densities. Furthermore, the operation process for solid hydrogen storage materials is relatively simple, giving them a greater advantage in practical applications. Among solid hydrogen storage technologies, glass microsphere hydrogen storage technology has attracted considerable attention due to its unique advantages. Glass microsphere hydrogen storage primarily utilizes micron-sized glass spheres as a carrier to store hydrogen through physical or chemical adsorption. This technology boasts advantages such as high safety performance, high hydrogen storage density, simple operation, and convenient transportation. However, the development of glass microsphere hydrogen storage technology also faces some challenges. Further increasing hydrogen storage capacity is a key issue. Fundamental issues such as adsorption and desorption mechanisms, kinetics, and temperature effects involved in the hydrogen storage process still require in-depth research. Summary of the Invention

[0006] This invention provides a composite hydrogen storage material of liquid gallium metal and hollow glass microspheres. First, glass microspheres are etched in hydrofluoric acid. Next, liquid gallium metal is mixed and stirred with the glass microspheres, causing the liquid metal to coat the surface of the glass microspheres, resulting in a composite solid powder of gallium and glass microspheres. This powder is then used as a solid hydrogen storage material for direct high-pressure adsorption and storage of hydrogen.

[0007] Furthermore, the commercially available glass microspheres are sieved to select hollow glass microspheres with a diameter of less than 50 micrometers, thereby making the synthesized composite material more uniform, less prone to breakage, and ultimately resulting in a more stable composite material.

[0008] Furthermore, moderate etching of glass microspheres with dilute hydrofluoric acid can provide more surface defects, thereby achieving uniform bonding of liquid metal and facilitating hydrogen diffusion.

[0009] Furthermore, the composite hydrogen storage material achieves a hydrogen storage density of 1.61 wt% under conditions of hydrogen pressure of 5 MPa and temperature of 100°C.

[0010] Furthermore, the composite hydrogen storage material achieves a hydrogen storage density of 3.14 wt% under conditions of hydrogen pressure of 5 MPa and temperature of 200°C.

[0011] Furthermore, liquid gallium plays a role in splitting hydrogen molecules and conducting hydrogen atoms, which can lower the reaction energy barrier of hydrogen molecule splitting and hydrogen atom recombination, thereby improving the slow hydrogen storage kinetics of hollow glass microspheres.

[0012] This invention also provides a method for preparing a composite hydrogen storage material of liquid gallium metal and hollow glass microspheres, the steps of which are as follows:

[0013] Step 1: Prepare concentrated hydrofluoric acid and dilute it into a low-concentration hydrofluoric acid aqueous solution.

[0014] Step 2: After sieving the purchased hollow glass microsphere powder, add it to dilute hydrofluoric acid and stir for 15 minutes.

[0015] Step 3: Wash the acid-etched hollow glass microspheres with deionized water until neutral, filter them, and dry them in a vacuum oven at 60°C.

[0016] Step 4: Mix the treated hollow glass microspheres with an appropriate amount of liquid gallium in a glass bottle.

[0017] Step 5: Stir the mixture overnight using a magnetic stirrer to obtain a light gray sample powder Ga@HGMs.

[0018] The composite hydrogen storage material of liquid gallium and hollow glass microspheres provided by this invention is denoted as Ga@HGMs. This composite material is a hollow glass microsphere powder with gallium loaded on its surface, the powder particle size being 10-50 micrometers, wherein the content of liquid gallium accounts for 50% of the total composite material. Gallium is loaded on the surface of the hollow glass microspheres in the form of metal droplets, playing a role in catalyzing hydrogen reactions and promoting hydrogen atom diffusion.

[0019] The novel solid hydrogen storage material prepared by this invention has the following advantages:

[0020] 1) This method is simple to operate, operates under mild conditions, and is suitable for large-scale preparation;

[0021] 2) The Ga@HGMs prepared by this invention can store hydrogen under operating conditions slightly above room temperature, and the hydrogen storage density meets the application requirements of both stationary and mobile devices.

[0022] 3) The Ga@HGMs prepared by this invention have considerable hydrogen adsorption and storage capacity and rapid hydrogen adsorption kinetics, which have significant advantages in practical applications. Attached Figure Description

[0023] Figure 1 This is a schematic diagram illustrating the structural characteristics and preparation process of Ga@HGMs obtained in this invention;

[0024] Figure 2 These are scanning electron microscope images of Ga@HGMs etched with 2% hydrofluoric acid obtained in this invention at different magnifications.

[0025] Figure 3 Transmission electron microscope images of Ga@HGMs etched with 2% hydrofluoric acid obtained in this invention at different magnifications.

[0026] Figure 4The hydrogen adsorption kinetics curves of commercial hollow glass microspheres at different temperatures;

[0027] Figure 5 The hydrogen adsorption kinetics curve of the hollow glass microspheres after hydrofluoric acid etching obtained in this invention is shown.

[0028] Figure 6 The hydrogen adsorption kinetics curve of the hollow glass microspheres and liquid gallium composite material obtained in this invention without hydrofluoric acid etching was tested under low temperature conditions.

[0029] Figure 7 The hydrogen adsorption kinetics curve of the hollow glass microspheres and liquid gallium composite material obtained in this invention without hydrofluoric acid etching was tested under high temperature conditions.

[0030] Figure 8 The hydrogen adsorption kinetics curve of Ga@HGMs hollow glass microsphere composite material etched with 2% hydrofluoric acid obtained in this invention was tested under low temperature conditions.

[0031] Figure 9 The hydrogen adsorption kinetics curve of Ga@HGMs hollow glass microsphere composite material etched with 2% hydrofluoric acid obtained in this invention was tested under high temperature conditions.

[0032] Figure 10 The hydrogen adsorption kinetic curves of Ga@HGMs hollow glass microsphere composite material etched with 5% hydrofluoric acid obtained in this invention are obtained under two consecutive test conditions at 100°C.

[0033] Figure 11 The hydrogen adsorption kinetic curves of Ga@HGMs hollow glass microsphere composite material etched with 5% hydrofluoric acid obtained in this invention are obtained under two consecutive test conditions at 200°C. Detailed Implementation

[0034] The present invention will be further described below with reference to the accompanying drawings and embodiments. Example 1

[0035] The preparation method of the liquid gallium metal and hollow glass microsphere composite material of the present invention includes the following steps:

[0036] 1) Prepare hollow glass microspheres: The hollow glass microspheres purchased directly are in the form of white powder. The powder is sieved through a 300-mesh sieve.

[0037] 2) Cleaning and drying: The hollow glass microspheres are washed in deionized water and separated by vacuum filtration to remove surface impurity ions. Finally, the hollow glass microspheres are dried in a vacuum oven at 60°C.

[0038] 3) Mixing with liquid gallium: After cooling the treated hollow glass microspheres to room temperature, mix them with an equal weight of liquid gallium. Ensure this process is performed in a glass bottle or suitable container to prevent gallium from reacting with other materials.

[0039] 4) Overnight stirring: The mixture was stirred overnight on a magnetic stirrer to ensure sufficient contact between the hollow glass microspheres and liquid gallium. During this process, gallium was uniformly loaded onto the surface of the hollow glass microspheres. A light gray sample powder, Ga@HGMs (gallium-coated hollow glass microspheres), was observed to have formed.

[0040] The structural features and hydrogen storage performance of the Ga@HGMs prepared in Example 1 are described below with reference to the accompanying drawings.

[0041] Figure 1 The preparation process and key structural parameters of Ga@HGMs prepared in Example 1 are shown. The Ga@HGMs prepared in Example 1 are characterized by droplet-shaped metallic gallium loaded on the outside of micron-sized hollow glass microspheres.

[0042] Figure 4 The kinetics of hydrogen isobaric adsorption on the original hollow glass microspheres (HGMs) are shown. At room temperature, there is almost no hydrogen storage capacity, with an equilibrium hydrogen adsorption capacity of 0.02 wt%. Even at higher temperatures (100°C and 200°C), the hydrogen adsorption capacity remains low, at 0.3 wt% and 0.4 wt%, respectively.

[0043] Figure 6 The kinetics of hydrogen isobaric adsorption on Ga@HGMs (a composite material of hollow glass microspheres and gallium) are shown at 100°C. The initial hydrogen adsorption at 100°C yielded 1.0 wt%; after hydrogen desorption at the same temperature, the second test showed 1.1 wt% hydrogen adsorption. This demonstrates that the composite material exhibits good reversible hydrogen storage and a certain degree of activation.

[0044] Figure 7 The kinetics of hydrogen isobaric adsorption on Ga@HGMs are shown at temperatures of 150°C, 200°C, and 250°C. The hydrogen adsorption capacity was 1.5 wt% at 150°C, 1.8 wt% at 200°C, and 2.5 wt% at 250°C. This demonstrates that the composite material exhibits a higher hydrogen storage density at higher temperatures. Example 2

[0045] The preparation method of the composite material of liquid gallium metal and lightly etched hollow glass microspheres of the present invention includes the following steps:

[0046] 1) Diluting hydrofluoric acid: Use deionized water as a diluent to dilute 40% concentrated hydrofluoric acid to a concentration of 2%. Specifically, add 20 ml of precisely measured concentrated hydrofluoric acid to 980 ml of deionized water and stir for 5 minutes to ensure thorough mixing;

[0047] 2) Prepare hollow glass microspheres: The hollow glass microspheres purchased directly are in the form of white powder. The powder is sieved through a 300-mesh sieve.

[0048] 3) Acid etching treatment: Mix an appropriate amount of diluted hydrofluoric acid with hollow glass microsphere powder, ensuring the hollow glass microspheres are completely immersed in the acid. Stir the mixture for 15 minutes to ensure sufficient contact between the hydrofluoric acid and the glass microspheres. The purpose of this step is to etch defects onto the outer layer of the glass microspheres;

[0049] 4) Cleaning and Drying: The acid-etched hollow glass microspheres are separated from the acid solution by vacuum filtration. The microspheres are then rinsed with plenty of deionized water to remove residual hydrofluoric acid and other impurity ions. This washing process is repeated several times until the pH of the rinsing solution is close to neutral. Finally, the hollow glass microspheres are dried in a vacuum oven at 60°C.

[0050] 5) Mixing with liquid gallium: After cooling the treated hollow glass microspheres to room temperature, mix them with an equal weight of liquid gallium. Ensure this process is performed in a glass bottle or suitable container to prevent gallium from reacting with other materials.

[0051] 6) Overnight stirring: The mixture was stirred overnight on a magnetic stirrer to ensure sufficient contact between the hollow glass microspheres and liquid gallium. During this process, gallium was uniformly loaded onto the surface of the hollow glass microspheres. A light gray sample powder, Ga@2%HF-HGMs (gallium-coated acid-etched hollow glass microspheres), was observed to have formed.

[0052] The structural features and hydrogen storage performance of the Ga@2%HF-HGMs prepared in Example 2 are described below with reference to the accompanying drawings.

[0053] Figure 2 Scanning electron microscope (SEM) images of different regions of hollow glass microspheres etched with 2% hydrofluoric acid at different magnifications are shown. It can be seen that the glass microspheres are generally uniform in size, with some mixed glass microsphere fragments present in the sample. The surface of the glass microspheres is loaded with some irregularly shaped liquid gallium metal.

[0054] Figure 3Transmission electron microscope images of hollow glass microspheres etched with 2% hydrofluoric acid at different magnifications are shown. It can be seen that a large number of liquid gallium droplets are distributed on the surface of the glass microspheres.

[0055] Figure 8 The kinetics of hydrogen isobaric adsorption on Ga@2%HF-HGMs hollow glass microspheres etched with 2% hydrofluoric acid are shown at temperatures of 23°C and 100°C. The hydrogen adsorption capacity obtained at 23°C was relatively low, at 0.8 wt%. The initial hydrogen adsorption capacity at 100°C was 1.5 wt%; after hydrogen desorption at 100°C, the second test at 100°C yielded a hydrogen adsorption capacity of 1.6 wt%. This demonstrates that the composite material exhibits good reversible hydrogen storage and a certain degree of activation.

[0056] Figure 9 The kinetics of hydrogen isobaric adsorption on Ga@2%HF-HGMs hollow glass microspheres etched with 2% hydrofluoric acid are shown. The initial hydrogen adsorption capacity at 200°C was 2.3 wt%; after hydrogen desorption at 200°C, the second test at 200°C yielded a hydrogen adsorption capacity of 2.3 wt%. This demonstrates that the composite material exhibits good reversible hydrogen storage, and the activation phenomenon is not significant under high-temperature conditions. Example 3

[0057] The preparation method of the composite material of liquid gallium metal and heavily etched hollow glass microspheres of the present invention includes the following steps:

[0058] 1) Diluting hydrofluoric acid: Use deionized water as a diluent to dilute 40% concentrated hydrofluoric acid to a 5% concentration. Specifically, add 50 ml of precisely measured concentrated hydrofluoric acid to 950 ml of deionized water and stir for 5 minutes to ensure thorough mixing;

[0059] 2) Prepare hollow glass microspheres: The hollow glass microspheres purchased directly are in the form of white powder. The powder is sieved through a 300-mesh sieve.

[0060] 3) Acid etching treatment: Mix an appropriate amount of diluted hydrofluoric acid with hollow glass microsphere powder, ensuring the hollow glass microspheres are completely immersed in the acid. Stir the mixture for 15 minutes to ensure sufficient contact between the hydrofluoric acid and the glass microspheres. The purpose of this step is to etch defects onto the outer layer of the glass microspheres;

[0061] 4) Cleaning and Drying: The acid-etched hollow glass microspheres are separated from the acid solution by vacuum filtration. The microspheres are then rinsed with plenty of deionized water to remove residual hydrofluoric acid and other impurity ions. This washing process is repeated several times until the pH of the rinsing solution is close to neutral. Finally, the hollow glass microspheres are dried in a vacuum oven at 60°C.

[0062] 5) Mixing with liquid gallium: After cooling the treated hollow glass microspheres to room temperature, mix them with an equal weight of liquid gallium. Ensure this process is performed in a glass bottle or suitable container to prevent gallium from reacting with other materials.

[0063] 6) Overnight stirring: The mixture was stirred overnight on a magnetic stirrer to ensure sufficient contact between the hollow glass microspheres and liquid gallium. During this process, gallium was uniformly loaded onto the surface of the hollow glass microspheres. A light gray sample powder, Ga@5%HF-HGMs (gallium-coated acid-etched hollow glass microspheres), was observed to have formed.

[0064] The structural features and hydrogen storage performance of the Ga@5%HF-HGMs prepared in Example 3 are described below with reference to the accompanying drawings.

[0065] Figure 10 The kinetics of hydrogen isobaric adsorption on Ga@5%HF-HGMs hollow glass microspheres etched with 5% hydrofluoric acid are shown at 100°C. The initial hydrogen adsorption capacity at 100°C was 1.4 wt%; after hydrogen desorption at 100°C, the second test at 100°C yielded 1.6 wt% hydrogen adsorption. This demonstrates that the composite material exhibits good reversible hydrogen storage and a certain degree of activation.

[0066] Figure 11 The kinetics of hydrogen isobaric adsorption on Ga@5%HF-HGMs in hollow glass microspheres etched with 5% hydrofluoric acid are shown. The initial hydrogen adsorption capacity at 200°C was 2.8 wt%; after hydrogen desorption at 200°C, the second test at 200°C yielded 3.1 wt% hydrogen adsorption. This demonstrates that the composite material exhibits good reversible hydrogen storage and a certain degree of activation.

[0067] Comparative examples 1-3 also show that the composite hydrogen storage material synthesized using hollow glass microspheres etched with hydrofluoric acid exhibits a higher hydrogen storage density. Appropriate acid etching and suitable operating temperature are key to the high hydrogen storage density of the composite material.

[0068] This invention can change the type and ratio of liquid metal to obtain composite materials of different hollow glass microspheres and liquid metal, all of which can achieve good near-room temperature and high temperature hydrogen storage performance.

[0069] For those skilled in the art, various modifications and improvements can be made to the embodiments of the present invention without departing from the inventive concept of the present invention, and these modifications and improvements all fall within the protection scope of the present invention.

Claims

1. A composite hydrogen storage material of liquid gallium metal and hollow glass microspheres, characterized in that, The composite hydrogen storage material is a composite material in which liquid gallium metal is modified on the surface of hollow glass microspheres. The gallium is attached to the surface of the glass microspheres in the form of droplets. The gallium content is 50 wt%, and the diameter of the glass microspheres is 10-50 micrometers. The hollow glass microspheres are etched with hydrofluoric acid at a concentration of 2% or 5%.

2. The use of the liquid gallium metal and hollow glass microsphere composite hydrogen storage material as described in claim 1 in hydrogen adsorption and storage.

3. The use according to claim 2, characterized in that, The operating temperature for hydrogen adsorption and storage is 100℃ or 200℃, and the hydrogen pressure is 5MPa.

4. A method for preparing the liquid gallium metal and hollow glass microsphere composite hydrogen storage material as described in claim 1, characterized in that, Includes the following steps: (1) Dilute concentrated hydrofluoric acid to a 2% or 5% aqueous solution of hydrofluoric acid; (2) Add the hollow glass microsphere powder to the dilute hydrofluoric acid obtained in step (1) and stir for 15 minutes; (3) The acid-etched hollow glass microspheres were filtered, washed with deionized water, and dried in a vacuum oven at 60°C; (4) Mix the hollow glass microspheres processed in step (3) with liquid gallium metal at a mass ratio of 1:1; (5) Stir the mixture overnight using a magnetic stirrer to obtain a light gray powder, which is the composite hydrogen storage material.

5. The preparation method according to claim 4, characterized in that, The hollow glass microsphere powder described in step (2) is used after being sieved, with a sieve mesh size of 300 mesh.

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