Preparation process of calcium-magnesium-aluminum-based porous solid hydrogen storage material and hydrogen adsorption application
By preparing calcium-magnesium-zinc based porous solid hydrogen storage materials, and utilizing the synergistic effect of CaMg2 intermetallic compounds and zinc-based solid solutions, combined with hierarchical porous structures and transition metal oxides, the problem of insufficient hydrogen storage performance of existing hydrogen storage materials under mild conditions was solved, achieving efficient and stable hydrogen adsorption and release.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 新疆理工学院
- Filing Date
- 2026-02-27
- Publication Date
- 2026-05-19
AI Technical Summary
Existing calcium-based and magnesium-based hydrogen storage materials suffer from problems such as slow hydrogen absorption and desorption kinetics, poor cycle stability, low specific surface area, and complex and costly preparation in practical applications, making it difficult to achieve efficient hydrogen storage under mild conditions.
A calcium-magnesium-zinc based porous solid hydrogen storage material is used. Through specific element combinations and microstructure regulation, CaMg2 intermetallic compounds and zinc-based solid solutions are formed. Combined with hierarchical porous structures and transition metal oxides, the hydrogen storage performance is optimized.
The material significantly improves hydrogen storage capacity and kinetic performance under mild conditions, maintains stability during multiple cycles, and is suitable for fuel cells and portable hydrogen storage devices, reducing system energy consumption and safety risks.
Smart Images
Figure CN122059375A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of solid hydrogen storage materials technology, specifically to a preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material. Background Technology
[0002] Solid-state hydrogen storage materials have become a key technology for hydrogen energy storage and utilization due to their high hydrogen storage density, safety, and reversibility. Among them, calcium-based and magnesium-based hydrogen storage materials have attracted widespread attention due to their abundant resources and high theoretical hydrogen storage capacity (e.g., the theoretical capacity of MgH2 reaches 7.6 wt%). However, existing calcium-based or magnesium-based materials still have significant shortcomings in practical applications: First, magnesium-based materials have slow hydrogen absorption and desorption kinetics, usually requiring high temperatures (>300℃) to achieve effective hydrogenation / dehydrogenation, and their cycle stability is poor; second, although calcium-based materials have high thermodynamic stability, they easily form stable hydrides, making hydrogen desorption difficult, and their low specific surface area limits their actual hydrogen storage capacity. In addition, traditional single-metal hydrogen storage materials often suffer from poor activation performance and severe volume expansion.
[0003] To improve performance, researchers have attempted to develop multi-component alloys or porous materials. For example, introducing zinc can form solid solutions or intermetallic compounds (such as CaMg2) to modulate thermodynamic properties and promote hydrogen diffusion; constructing porous structures can increase specific surface area and hydrogen diffusion pathways, thereby improving kinetics. However, existing porous hydrogen storage materials (such as metal-organic frameworks or carbon materials) are often complex to prepare, costly, and while they have large specific surface areas, their hydrogen storage capacity is limited, especially under mild conditions (such as medium-low temperature and medium-low pressure), where their performance is poor. In addition, materials prepared by simple mechanical alloying often have a single pore structure (only at the micrometer or nanometer scale), making it difficult to achieve both high capacity and fast kinetics.
[0004] Therefore, there is an urgent need in this field to develop a novel porous solid hydrogen storage material that combines high specific surface area, hierarchical pores (micron-nano composite), suitable phase composition, and mild operating conditions to overcome the bottlenecks of existing materials in terms of hydrogen storage capacity, kinetics, and practicality. Summary of the Invention
[0005] The purpose of this invention is to provide a preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material. Through specific element combinations, microstructure regulation and preparation process, a novel solid hydrogen storage material with high specific surface area, hierarchical porous structure and excellent hydrogen storage performance is obtained.
[0006] To achieve the above objectives, this invention provides a preparation process and hydrogen adsorption application for a calcium-magnesium-aluminum based porous solid hydrogen storage material. The active components of this calcium-magnesium-zinc based porous solid hydrogen storage material are composed of calcium, magnesium, and zinc elements. This combination aims to utilize the synergistic effect of each element to optimize hydrogen storage performance. The CaMg2 intermetallic compound formed in the material provides a stable crystal framework, facilitating reversible hydrogen adsorption, while the zinc-based solid solution enhances surface reactivity by regulating the electronic structure. The material possesses a hierarchical porous structure, including micron-sized macropores and nano-sized mesopores. This design promotes rapid hydrogen diffusion and efficient storage: the micron-sized macropores act as hydrogen transport channels, reducing diffusion resistance; the nano-sized mesopores provide a large specific surface area, increasing adsorption sites. The BET specific surface area is controlled between 30 and 100 square meters per gram. This range ensures that the material has sufficient surface area for hydrogen adsorption while maintaining mechanical stability and preventing structural collapse.
[0007] Furthermore, the atomic ratio of calcium, magnesium, and zinc is precisely controlled within the range of 1:1.5-2.5:0.5-1.5. When the magnesium ratio is between 1.5 and 2.5, it is conducive to the formation of sufficient CaMg2 intermetallic compounds, which are the main active components for hydrogen storage. The zinc ratio, within the range of 0.5 to 1.5, can form a suitable zinc-based solid solution, regulating the electronic properties of the material and improving the hydrogen adsorption barrier. If the zinc content is too low, it may lead to insufficient solid solution, affecting reaction kinetics; if it is too high, it may introduce impurity phases, reducing hydrogen storage efficiency. Similarly, deviations in the magnesium ratio will change the amount of CaMg2 formed, thus affecting the overall structural stability. Therefore, this atomic ratio range ensures that the material has a balanced capacity, reversibility, and cycle life during hydrogen storage.
[0008] Furthermore, 5% to 15% of transition metal oxides, specifically titanium dioxide or zirconium dioxide or a mixture thereof, are added to the material by mass. These oxides are uniformly dispersed in the matrix at the nanoscale, playing multiple positive roles: they can act as catalytic sites, lowering the activation energy for hydrogen molecule dissociation and adsorption, thereby increasing the reaction rate; simultaneously, the high stability of the oxides enhances the structural integrity of the material, preventing pore structure degradation during repeated hydrogen adsorption and desorption cycles. Uniform dispersion is crucial; the preparation process is optimized to ensure that oxide particles do not agglomerate, thus maximizing their surface effect. The addition amount is controlled between 5-15% because too low a amount may result in insignificant catalytic effect, while too high a amount may clog pores or reduce the proportion of active components. This design significantly improves the hydrogen storage kinetics and durability of the material without excessively affecting the overall performance.
[0009] Furthermore, the preparation process includes four key steps: First, calcium, magnesium, and zinc powders are weighed according to a predetermined atomic ratio and uniformly mixed with transition metal oxide powders. This step ensures sufficient contact between the components at the microscale, laying the foundation for subsequent reactions. The uniformity of mixing directly affects the phase composition and properties of the final material. Second, the mixed powders are ball-milled under a protective atmosphere. The ball-milling process induces powder refinement, alloying, and activation through mechanical energy, forming a uniform precursor. Then, the ball-milled powder is pressed into a green body. The pressing process imparts preliminary shape and density to the material, facilitating subsequent processing. Finally, the green body is sintered under a controlled temperature under a protective atmosphere. During sintering, a solid-state reaction occurs, forming the desired CaMg2 phase and zinc-based solid solution, and establishing a porous structure. After cooling, the final material is obtained. The entire process emphasizes controlled conditions to avoid oxidation and phase separation.
[0010] Furthermore, the process parameters for high-energy ball milling are: milling speed of 300 to 500 rpm, ball-to-powder ratio of 20:1 to 40:1, and milling time of 5 to 20 hours. A milling speed within the 300-500 rpm range provides sufficient impact energy to break up powder particles, promoting inter-element diffusion and alloying, while avoiding overheating or contamination due to excessively high speeds. A ball-to-powder ratio (mass ratio of grinding balls to powder) controlled between 20:1 and 40:1 ensures more effective collision and mixing, resulting in finer and more uniform powder; however, an excessively high ratio may increase energy consumption and equipment wear. A milling time of 5-20 hours ensures sufficient powder refinement and the formation of a uniform precursor; too short a time may lead to uneven mixing or incomplete reaction, while too long a time may cause over-processing or phase transformation. These parameters work synergistically to determine the particle size, specific surface area, and activity of the powder, thereby affecting the hydrogen storage performance of the final material.
[0011] Furthermore, the temperature-controlled sintering process is divided into two stages: The first stage involves heating to 300-400 degrees Celsius at a rate of 3-10 degrees Celsius per minute and holding at that temperature for 0.5-2 hours. This stage primarily removes adsorbed water, gases, and impurities from the powder surface, while simultaneously initiating a preliminary solid-phase reaction that fosters bonding between powder particles. The holding time allows for uniform heat distribution, preventing localized overheating that could lead to structural defects. The second stage involves heating to 450-550 degrees Celsius at a slower rate of 2-5 degrees Celsius per minute and holding at that temperature for 2-5 hours. This high-temperature stage is crucial for the formation of the CaMg2 intermetallic compound and the zinc-based solid solution. The slow heating prevents thermal stress from damaging the structure, while the long holding time ensures complete reaction and promotes the stable formation of a porous structure. The entire sintering process optimizes the phase composition and pore structure through temperature control, thereby enhancing the hydrogen storage properties of the material.
[0012] Furthermore, the sintering process is carried out under a protective atmosphere, specifically a mixture of argon and hydrogen, with the hydrogen component controlled between 1% and 10%. Argon acts as an inert carrier, preventing the material from being oxidized at high temperatures and maintaining the reduced state of the components. The addition of hydrogen has specific functions: it can reduce the oxide layer on the powder surface, improving the purity and reactivity of the material; simultaneously, hydrogen may participate in surface reactions, promoting the migration of metal atoms and the formation of pore structures; in addition, an appropriate amount of hydrogen helps to regulate the electronic environment of the material and optimize the hydrogen adsorption barrier. If the hydrogen concentration is too low, the reduction effect may be insufficient; if it is too high, it may cause over-reduction or safety issues. Therefore, the 1%-10% range is a result that balances effectiveness and safety. This atmosphere design ensures the chemical stability and structural integrity of the material during the sintering process.
[0013] Furthermore, this calcium-magnesium-zinc based porous solid-state hydrogen storage material is specifically designed for hydrogen adsorption and storage applications. Due to its hierarchical porous structure and high specific surface area, the material can efficiently adsorb and release hydrogen molecules: micron-sized macropores allow hydrogen to diffuse rapidly into the material's interior, while nano-sized mesopores provide abundant surface sites for physico- and chemi-adsorption. Simultaneously, the presence of the CaMg2 intermetallic compound and zinc-based solid solution ensures good reversibility and cycle stability, allowing the material to maintain its performance during repeated hydrogen adsorption and desorption processes. This application is based on the material's mild operating conditions and safety; compared to high-pressure gaseous hydrogen storage, the solid form reduces the risk of leakage, making it suitable for applications requiring a stable hydrogen source.
[0014] Furthermore, the hydrogen storage material operates within a temperature range of 50 to 150 degrees Celsius and a pressure range of 1 to 6 MPa. These conditions are optimized based on the material's adsorption characteristics: at 50-150 degrees Celsius, the material possesses a moderate adsorption enthalpy, making the hydrogen adsorption and desorption processes easily controllable; excessively low temperatures may lead to slow kinetics and a decreased adsorption rate, while excessively high temperatures may cause material sintering or performance degradation. The pressure range of 1-6 MPa provides sufficient driving force for hydrogen molecules to enter the pores and adsorb onto the active sites, while avoiding the equipment complexity and safety risks associated with excessively high pressures. Under these mild conditions, the material can achieve high hydrogen storage capacity and rapid response, making it suitable for practical systems such as stationary hydrogen storage devices or mobile applications, ensuring practicality and economy.
[0015] Furthermore, this hydrogen storage material can be widely used in hydrogen source systems for fuel cells or portable hydrogen storage devices. In fuel cell systems, the material serves as a stable and continuous hydrogen source, and its porous structure allows for rapid hydrogen release, meeting the dynamic power requirements of the fuel cell, while its solid-state form avoids the risks associated with high-pressure hydrogen storage. In portable devices, such as power banks or small equipment, the material's high volumetric energy density and safety make it easy to integrate and carry, supporting the application of hydrogen energy in distributed energy. This application not only improves the accessibility of hydrogen energy technology but also promotes the popularization of clean energy, suitable for outdoor activities, emergency power supplies, and other scenarios, demonstrating the material's practical value and adaptability.
[0016] This invention provides a preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material, which has the following beneficial effects: 1. This hydrogen storage material is composed of calcium, magnesium, and zinc in an atomic ratio of 1:(1.5-2.5):(0.5-1.5), and its phases include an intermetallic compound CaMg2 and a zinc-based solid solution. This specific composition and phase structure enable the material to form stable hydrides during hydrogen adsorption, thereby significantly improving its hydrogen storage capacity. The CaMg2 phase provides strong hydrogen bonding ability, while the zinc-based solid solution enhances the material's toughness and anti-pulverization properties, preventing structural degradation during repeated hydrogen adsorption and desorption cycles. Furthermore, the introduction of zinc modulates the electronic interactions between calcium and magnesium, promoting rapid diffusion of hydrogen atoms, enabling the material to achieve efficient hydrogen storage under mild conditions (such as medium temperature and medium pressure). This optimized composition not only increases the material's gravimetric hydrogen storage density but also extends its service life, making it suitable for long-term cyclic operation.
[0017] The material possesses a hierarchical porous structure, including micron-sized macropores and nano-sized mesopores, with a BET specific surface area controlled between 30 and 100 m² / g. The micron-sized macropores serve as channels for hydrogen transport, reducing diffusion resistance, while the nano-sized mesopores provide numerous adsorption sites, significantly increasing the hydrogen adsorption capacity. This multi-scale porous structure works synergistically, enabling rapid hydrogen permeation into the material's interior and shortening the hydrogen adsorption / desorption kinetics time. Simultaneously, the high specific surface area ensures greater contact between the active surface and hydrogen, improving the hydrogen storage efficiency per unit mass of material. The hierarchical porosity also enhances the material's structural stability, preventing pore collapse due to volume changes during cycling, thus maintaining long-term performance.
[0018] The material contains 5-15% uniformly dispersed transition metal oxides (such as TiO2 or ZrO2). These oxides act as catalyst promoters, lowering the dissociation energy barrier of hydrogen molecules and accelerating the hydrogen adsorption and desorption reaction kinetics. The high dispersion of the transition metal oxides prevents the aggregation of active sites, ensuring uniform and effective catalysis. Furthermore, the oxide particles act as structural supports, inhibiting particle growth or phase separation in the calcium-magnesium-zinc matrix during cycling, thereby reducing capacity decay. This modification not only improves the material's hydrogen storage performance at low temperatures but also enhances its resistance to poisoning and oxidation, enabling stable output even in practical application environments (such as hydrogen containing impurities).
[0019] The preparation process achieves precise control over the material composition and pore structure through a combination of high-energy ball milling (parameters such as milling speed 300-500 rpm, ball-to-material ratio 20:1-40:1) and programmed temperature-controlled sintering (segmented heating to 300-550℃ and holding at that temperature). High-energy ball milling ensures uniform mixing of calcium, magnesium, and zinc powders with oxides and induces mechanical alloying to form the desired CaMg2 phase and solid solution. Programmed sintering, under a protective atmosphere (such as an argon-hydrogen mixture), promotes densification and pore structure formation through a slow heating process, avoiding component volatilization or oxidation. This process route is simple, highly controllable, easy to scale up for production, and the resulting material exhibits a consistent hierarchical porous structure and chemical homogeneity, ensuring batch-to-batch reproducibility and reliability.
[0020] This hydrogen storage material operates efficiently under mild conditions of 50-150°C and 1-6 MPa, making it ideal for integration into fuel cell hydrogen source systems or portable hydrogen storage devices. Compared to traditional high-pressure hydrogen storage, this medium-temperature, medium-pressure operation reduces system energy consumption and safety risks, eliminating the need for complex cooling or pressurization equipment. The material's high hydrogen storage density and rapid kinetics allow for the design of more compact hydrogen storage units suitable for mobile devices or distributed energy systems. Furthermore, the material's stability and durability ensure continued performance even in practical scenarios with frequent start-stop cycles, providing a reliable solution for clean energy applications. Attached Figure Description
[0021] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.
[0022] Figure 1 This is a flowchart illustrating the overall preparation and application process of the present invention; Figure 2 This is a flowchart illustrating the material composition and porous structure design of the present invention. Figure 3 This is a flow chart of the high-energy ball milling pretreatment process of the present invention; Figure 4 This is a flowchart of the temperature-controlled sintering process of the present invention; Figure 5 This is a flowchart illustrating the operating conditions and application fields of hydrogen storage according to the present invention. Detailed Implementation
[0023] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses consistent with some aspects of this disclosure as detailed in the appended claims.
[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0025] Example 1 This embodiment provides a calcium-magnesium-zinc based porous solid-state hydrogen storage material and its preparation method. The active components of the material are composed of calcium, magnesium, and zinc elements, with their atomic ratio strictly controlled at 1:2:1. The specific preparation process is as follows: First, high-purity calcium powder, magnesium powder, and zinc powder are accurately weighed according to the calcium, magnesium, and zinc atomic ratio of 1:2:1. The weighed metal powders are placed in a vacuum glove box and preliminarily mixed manually to ensure the initial uniformity.
[0026] Next, high-energy ball milling is performed. The pre-mixed powder and grinding balls are loaded into a high-energy ball mill jar. The grinding balls are made of cemented carbide, and the ball-to-powder ratio is set at 30:1. After the ball mill jar is sealed, it is filled with high-purity argon as a protective atmosphere. The ball milling process is carried out on a planetary ball mill, with the milling speed controlled at 400 rpm, and the milling time lasting for 10 hours. This process aims to achieve atomic-level interdiffusion and mixing of calcium, magnesium, and zinc elements through mechanical alloying, and to lay the structural foundation for the formation of specific intermetallic compounds.
[0027] After ball milling, the resulting powder was removed from a glove box and pressed into cylindrical green bodies with a diameter of 10 mm using a tablet press at a pressure of 200 MPa. The green bodies were then subjected to programmed temperature-controlled sintering. Sintering was carried out in a tube furnace with a mixed atmosphere of argon and hydrogen, where hydrogen comprised 5%. The sintering program was as follows: heating from room temperature to 350°C at a heating rate of 5°C / min and holding at that temperature for 1 hour; then, heating to 500°C at a heating rate of 3°C / min and holding at that temperature for 3 hours. After holding, the furnace was cooled to room temperature to obtain a bulk porous solid hydrogen storage material.
[0028] Testing revealed that the main phases of the material obtained in this embodiment comprise CaMg2 intermetallic compounds and zinc-based solid solutions. The material exhibits a hierarchical porous structure, combining micron-sized macropores and nano-sized mesopores, with a BET specific surface area of 65 m² / g. Hydrogen storage tests conducted at 80°C and a hydrogen pressure of 3 MPa demonstrated excellent adsorption performance, making it suitable for use as a hydrogen source storage unit in small fuel cell systems.
[0029] Example 2 The main difference between this embodiment and Embodiment 1 is that the atomic ratio of the metal elements was adjusted and transition metal oxides were added. In this embodiment, the atomic ratio of calcium, magnesium, and zinc was set to 1:1.8:0.8. Furthermore, during the raw material mixing stage, titanium dioxide (TiO2) powder, accounting for 10% of the total mass of the materials, was added. The specific steps were as follows: after weighing the calcium powder, magnesium powder, and zinc powder according to the atomic ratio, they were placed together with the required amount of TiO2 powder in a mixer and thoroughly dry-mixed to ensure that the oxides were uniformly dispersed in the metal powder.
[0030] The high-energy ball milling process parameters were adjusted to: a ball-to-material ratio of 25:1, a ball milling speed of 350 rpm, and a ball milling time extended to 15 hours, in order to more uniformly embed TiO2 particles into the metal matrix while forming the alloy phase. The pressing pressure was 250 MPa. During the programmed temperature-controlled sintering stage, the hydrogen gas fraction in the furnace mixture was adjusted to 3%. The sintering program was set as follows: first, the temperature was increased to 380℃ at a rate of 4℃ / min and held for 1.5 hours; then, the temperature was increased to 520℃ at a rate of 4℃ / min and held for 4 hours.
[0031] In the resulting material, TiO2 nanoparticles exist in a highly dispersed state within a matrix composed of CaMg2 intermetallic compounds and a zinc-based solid solution. This composite structure further refines the material's pore structure, increasing its BET specific surface area to approximately 85 m² / g. The dispersed TiO2 is believed to provide more hydrogen adsorption sites and potentially improve hydrogen adsorption / desorption kinetics. This material is suitable for applications with slightly higher operating temperatures, exhibiting high hydrogen storage capacity and cycle stability at 100°C and 4 MPa, making it suitable for portable devices requiring continuous hydrogen supply.
[0032] Example 3 This embodiment focuses on the impact of higher zinc content on the material's structure and properties. The atomic ratio of calcium, magnesium, and zinc was set to 1:2.2:1.2. No transition metal oxides were added. High-energy ball milling was employed with a high energy input: a milling speed of 450 rpm, a ball-to-material ratio of 35:1, and a milling time of 8 hours, aiming to promote more complete solid solution of zinc.
[0033] After pressing, the sintering process employs a two-stage heating method: first, the temperature is raised to 320℃ at a rate of 6℃ / min and held for 0.5 hours to allow some low-melting-point components to initially diffuse; then, the temperature is raised to 480℃ at a slow rate of 2℃ / min and held at this temperature for an extended period of 5 hours to ensure the full formation of the CaMg2 phase and the establishment of a stable porous framework. An argon-hydrogen mixture with a hydrogen integral of 8% is used during sintering; the higher hydrogen partial pressure helps maintain the reduced state of the metal elements and prevents oxidation.
[0034] In the hydrogen storage material obtained in this embodiment, the proportion of zinc-based solid solution is relatively high. Phase analysis confirmed that the CaMg2 phase is the main crystalline phase, with most of the zinc element dissolved in a specific phase. The material exhibits significant porosity, with well-developed macropore channels and uniform mesopore distribution, resulting in a BET specific surface area of approximately 45 m² / g. This material demonstrates considerable hydrogen adsorption capacity under relatively mild conditions (e.g., 60°C, 2 MPa) and exhibits a rapid hydrogen adsorption / desorption rate, making it suitable for applications sensitive to operating conditions and requiring rapid response, such as hydrogen storage modules in certain emergency power supplies.
[0035] Example 4 This embodiment explores the role of another transition metal oxide and its suitable sintering regime. The atomic ratio of calcium, magnesium, and zinc is 1:1.5:1.5. The added transition metal oxide is zirconium dioxide (ZrO2), and its addition amount is 8% of the total mass of the material. The preparation process is the same as in Example 2, that is, the metal powder and ZrO2 powder are first uniformly mixed.
[0036] The high-energy ball milling parameters were set as follows: milling speed 380 rpm, ball-to-material ratio 30:1, and milling time 12 hours. After pressing and molding, the product underwent programmed temperature-controlled sintering. The sintering atmosphere was an argon-hydrogen mixture containing 1% hydrogen. The sintering program was specially designed as follows: heating to 400℃ at a slow rate of 3℃ / min and holding for 2 hours to allow for more sufficient interaction between ZrO2 and the metal matrix interface; then heating to 550℃ at a rate of 5℃ / min and holding for 2 hours to obtain a more perfect crystal structure and pore structure.
[0037] In the final material, high-hardness ZrO2 particles are uniformly dispersed within the matrix, playing a role in refining grain size and enhancing structural stability. The material exhibits a well-connected three-dimensional hierarchical porous network with a BET specific surface area of approximately 95 m² / g. This material demonstrates superior hydrogen storage performance at relatively high temperatures (120℃) and pressures (5 MPa), exhibiting good structural stability and making it suitable for application exploration in on-board fuel cell hydrogen storage systems with certain mechanical vibration requirements.
[0038] Example 5 This embodiment aims to optimize process efficiency and explore material preparation with a relatively short ball milling time. The atomic ratio of calcium, magnesium, and zinc is set to 1:2.5:0.5. A mixed oxide of TiO2 and ZrO2 is also added, each accounting for 4% of the total material mass, for a total of 8%. After preliminary mixing of the metal powder and oxide powder, high-energy ball milling is performed.
[0039] The ball milling process parameters were as follows: a relatively high ball milling speed of 480 rpm and a large ball-to-material ratio of 40:1 were used to compensate for the shortened ball milling time, which was controlled to be 5 hours. After pressing, the sintering process was carried out in an argon-hydrogen mixed atmosphere containing 10% hydrogen. The sintering procedure was as follows: the temperature was increased to 300℃ at a relatively rapid rate of 10℃ / min without holding; then the temperature was increased to 450℃ at a rate of 5℃ / min and held for 3 hours.
[0040] Despite the short ball milling time, sufficient mechanical alloying of the raw materials was achieved under high rotational speed and a large ball-to-material ratio. The resulting material contains a CaMg2 phase and a zinc-based solid solution, while a mixture of TiO2 and ZrO2 oxides provides dispersion and strengthening. The pore structure of the material is predominantly nanoscale mesopores, with a small number of micron-sized macropores, and a BET specific surface area of approximately 35 m² / g. This material exhibits practical hydrogen storage capacity under moderate conditions (90℃, 3.5 MPa), and due to its relatively short preparation cycle, it has a potential cost advantage, making it suitable for large-scale stationary hydrogen storage devices or specific types of portable hydrogen storage containers where cost is a primary concern.
[0041] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material, comprising calcium, magnesium, and zinc elements, characterized in that: The active components of the material are composed of calcium, magnesium and zinc elements, and its phases include CaMg2 intermetallic compounds and zinc-based solid solutions. The material has a hierarchical porous structure, including micron-sized macropores and nano-sized mesopores, and its BET specific surface area is between 30 and 100 m² / g.
2. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 1, characterized in that: The atomic ratio range of the calcium, magnesium, and zinc is 1: (1.5-2.5): (0.5-1.5).
3. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 1 or 2, characterized in that: The material also contains 5-15% transition metal oxides by mass, which are selected from one or a mixture of two of TiO2 or ZrO2.
4. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 1, characterized in that, Includes the following steps: a) Weigh calcium powder, magnesium powder and zinc powder according to the predetermined atomic ratio, and mix them evenly with transition metal oxide powder; b) The mixed powder was subjected to high-energy ball milling under a protective atmosphere; c) Press the ball-milled powder into shape to obtain a green body; d) The green blank is sintered under a controlled temperature under a protective atmosphere, and the porous solid hydrogen storage material is obtained after cooling.
5. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 4, characterized in that: The process parameters for the high-energy ball milling in step b) are: ball milling speed 300-500 rpm, ball-to-material ratio 20:1 to 40:1, and ball milling time 5-20 hours.
6. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 4, characterized in that: The temperature-controlled sintering process described in step d) is as follows: first, the temperature is increased to 300-400℃ at a rate of 3-10℃ / min and held for 0.5-2 hours, then the temperature is increased to 450-550℃ at a rate of 2-5℃ / min and held for 2-5 hours.
7. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 4, characterized in that: The sintering atmosphere in step d) is a mixture of argon and hydrogen, wherein the hydrogen component is 1%-10%.
8. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to any one of claims 1-3, characterized in that: Application of the calcium-magnesium-zinc based porous solid hydrogen storage material in hydrogen adsorption and storage.
9. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 8, characterized in that: The hydrogen storage material operates at a temperature of 50-150℃ and a pressure of 1-6 MPa.
10. The preparation process and hydrogen adsorption application of a calcium-magnesium-aluminum based porous solid hydrogen storage material according to claim 8, characterized in that: The hydrogen storage material is used in the hydrogen source system of fuel cells or in portable hydrogen storage devices.