Method for preparing Na-Al-H4 hydrogen storage material by using multi-metal catalyst activated aluminum alloy strip

Abstract

The invention relates to the technical field of hydrogen storage material preparation, in particular to a method for preparing a Na-Al-H4 hydrogen storage material by using an aluminum alloy strip activated by a multi-metal catalyst. The invention provides a method for preparing a Na-Al-H4 hydrogen storage material by using an aluminum alloy strip activated by a multi-element metal catalyst, which comprises the following steps of: in an inert atmosphere, smelting an aluminum simple substance and the multi-element metal catalyst to obtain a multi-element aluminum alloy cast ingot, and then melting and rapidly quenching the multi-element aluminum alloy cast ingot to obtain a multi-element aluminum alloy strip; the multi-metal catalyst at least comprises elemental titanium and elemental cerium; and in a hydrogen-containing reducing atmosphere, the multi-element aluminum alloy strip and sodium hydride are subjected to ball milling and hydrogenation, and the Na-Al-H4 hydrogen storage material is obtained. According to the invention, titanium and cerium are used as multi-element metal catalysts, and the sodium aluminum hydrogen tetra-hydrogen storage material with excellent hydrogen storage / desorption performance and good cycle stability is obtained by utilizing the synergistic effect between titanium and cerium.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage material preparation technology, specifically to a method for preparing sodium aluminum hydrogen (NH4H) storage material using aluminum alloy strips activated by a multi-metal catalyst. Background Technology

[0002] Hydrogen energy, as a widely available, clean, and low-carbon secondary energy source, can accelerate the global energy structure transformation through large-scale applications, including wind and solar power curtailment, grid peak shaving, and cross-regional energy storage. Efficient and safe storage and transportation of hydrogen is a crucial aspect of the hydrogen economy and also one of the bottlenecks restricting its development. Among various hydrogen storage technologies, solid-state hydrogen storage technology, which utilizes the physical adsorption or chemical reaction between the storage material and hydrogen to generate metal or coordinated metal hydrides, has attracted significant attention due to its high safety and storage capacity. Compared to other solid-state hydrogen storage materials, such as metal borohydrides, aluminum hydrides offer advantages such as high hydrogen storage density, low hydrogen release temperature, high purity, and low cost.

[0003] NaAlH4 has a hydrogen storage density of 7.5 wt%, making it one of the solid hydrogen storage materials with relatively high hydrogen storage density. The enthalpy changes of the first and second hydrogen release reactions are 37 and 47 kJ / mol, respectively, and it has good thermodynamic reversibility. Kinetically, due to the high activation energies of its two hydrogen release steps, 128 and 159 kJ / mol, respectively, its actual hydrogen release temperature is high and the hydrogen release rate is slow.

[0004] To improve the hydrogen storage kinetics of NaAlH4, increase the hydrogen absorption and release rates, lower its hydrogen absorption and desorption temperatures, and enhance its reversible cycling performance, current research focuses on three main strategies: catalyst addition, nano-sizing, and constructing hydride-based systems. In 1997, Bogdanovic and Schwickardi et al. creatively improved the hydrogen absorption and desorption rates of the NaAlH4 system by adding a Ti catalyst. Due to its high hydrogen release capacity, low desorption temperature, and relatively excellent cycling performance, it attracted widespread research attention. (Bogdanovic...) (Borislav, and Manfred Schwickardi. Ti-doped alkali metal aluminum hydrides as potential novel reversible hydrogen storage materials. Journal of Alloys and Compounds, 1997, 253: 1-9.). In 2013, R. Pramoch et al. studied the effects of different titanium compounds on the reversible hydrogen absorption and desorption of NaAlH4. They found that although TiCl3 could significantly increase the hydrogen absorption and desorption rate of NaAlH4, its byproduct NaCl led to a decrease in the reversible hydrogen storage capacity of NaAlH4. In contrast, TiO2, as a catalyst, avoided the formation of byproducts and exhibited a similar reversible hydrogen storage capacity to TiCl3, with a faster hydrogen absorption rate. This may be related to the Ti on the surface of TiO2. 3+ The defect sites are related to promoting hydrogen dissociation. Ti-doped NaAlH4 exhibits the worst performance, with a reversible hydrogen storage capacity of only 1 wt% (Pramoch Rangsunvigit et al, Effects of Different Ti-compounds on the Reversibility of NaAlH4. International Journal of Energy Research, 2013, 37:713-719).

[0005] Furthermore, although Ti doping can improve the hydrogen storage kinetics of NaAlH4, after multiple cycles, some Al and Ti irreversibly form Al-Ti alloys, leading to a decrease in cycle performance. Subsequent researchers have attempted to use other elemental metal powders as catalysts, such as Ce, Sc, and Nb. Compared to metal compounds like TiF3, TiC, TiN, ScCl3, CeCl3, Ti-Al, and CeAl, elemental metals as catalysts can avoid the formation of inert byproducts, but their catalytic activity is significantly reduced. In 2025, Ke Wang et al. prepared a composite TiVCMXene catalyst and doped it with NaAlH4 using a solid-state ball milling composite method. In the TiVC catalyst, Ti and V exist in multiple valence states. This multi-valence state and the modulating effect of V on the electronic structure of Ti significantly reduced the initial hydrogen desorption temperature of NaAlH4 to 90 °C, achieving a hydrogen desorption capacity of 4.74 wt% (Ke Wang et al, TiVCMXene mediated enhancement in hydrogen storage performance of NaAlH4 and the related mechanisms. International Journal of Hydrogen Energy, 2025, 119:194-203.). However, most nanoscale catalysts currently available are complex to prepare, and crystal structure defects easily occur during the nanoscale process. These defects affect the catalyst's activity, making it difficult to maintain a stable structure. After several hydrogen adsorption / desorption cycles, the capacity retention decreases, failing to meet the practical requirements of long-term cycling. Similarly, multi-metal composite catalysts also suffer from uneven distribution of active metal materials and complex preparation processes.

[0006] Therefore, there is an urgent need for a hydrogen storage material that possesses both excellent hydrogen storage / desorption performance and reversible cyclic hydrogen absorption / desorption performance to meet higher demands. Summary of the Invention

[0007] The present invention aims to overcome the shortcomings of existing technologies in which hydrogen storage / desorption performance and reversible cyclic hydrogen absorption / desorption performance cannot be simultaneously satisfied. It provides a method for preparing sodium aluminum hydrogen (NH4H4) hydrogen storage materials using aluminum alloy strips activated by multi-metal catalysts to overcome the above-mentioned shortcomings.

[0008] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing sodium aluminum hydrogen tetrahydrogen (NH4H) storage materials using aluminum alloy strips activated by a multi-metal catalyst, comprising: S1. Under an inert atmosphere, elemental aluminum and a multi-element metal catalyst are smelted to obtain a multi-element aluminum alloy ingot, which is then rapidly melt-quenched to obtain a multi-element aluminum alloy strip; the multi-element metal catalyst includes at least elemental titanium and elemental cerium. S2. Under a reducing atmosphere containing hydrogen, a multi-element aluminum alloy strip and sodium hydride are ball-milled and hydrogenated to obtain a sodium-aluminum-hydrogen four-element hydrogen storage material.

[0009] This invention first melts aluminum, titanium, and cerium to obtain an alloy ingot. During this process, multiple metal catalysts are coupled together; and the multi-metal catalyst is integrated with aluminum, resulting in the in-situ generation of an intermetallic compound catalyst, Al. n M (where M is a single metal or multiple metal, such as Ti, Ce, La, or Sc) plays a catalytic and matrix grain refinement role. Specifically, introducing titanium alone yields sodium-aluminum-hydrogen (SAH) 4-metal storage materials with excellent hydrogen storage / depletion performance but poor cycle stability, while introducing cerium or lanthanum alone yields SAH 4-metal storage materials with good cycle stability but poor hydrogen storage / depletion performance. This invention uses titanium and cerium (or lanthanum) as catalysts in conjunction with aluminum to obtain SAH 4-metal storage materials with excellent hydrogen storage / depletion performance and good cycle stability. However, it was ultimately found that only a combination of titanium and cerium yields SAH 4-metal storage materials with both excellent hydrogen storage / depletion performance and good cycle stability; this demonstrates a synergistic effect between titanium and cerium, resulting in optimal performance of the SAH 4-metal storage material.

[0010] During the rapid quenching process, the multi-metal catalyst is dispersed in the alloy strip, and some of the catalyst forms binary or multi-metal intermetallic compounds with aluminum in situ. During rapid quenching, the alloy droplets immediately come into contact with the copper roller; the high cooling rate significantly shortens the atomic diffusion time, reduces the segregation of the catalyst in the alloy, and ensures uniform dispersion of the catalyst metal elements in the Al alloy. Furthermore, the rapid cooling process promotes the Al... n The formation of M crystal nuclei, which serve as heterogeneous nucleation centers, provides a large number of nucleation sites through diffuse distribution, reducing the energy barrier required for Al nucleation, refining Al grains, and enabling the grain size of aluminum alloys to be controlled at the nanoscale, thereby obtaining activated multi-element aluminum alloy ribbons.

[0011] Multi-element aluminum alloy strips and sodium hydride are subjected to high-energy ball milling reaction in a hydrogen atmosphere. High-energy ball milling introduces high-density lattice defects (such as dislocations and vacancies), refines the particles and dynamically reconstructs the surface to generate nano-metal intermetallic compound catalytic interfaces, which further promotes multiphase interface reactions, thereby promoting the synthesis of sodium aluminum hydrogen hydride four-phase hydrogen storage materials doped with multi-element metal catalysts.

[0012] The resulting sodium-aluminum-hydrogen tetrahydrogen (NaAlH4) material exhibits high NaAlH4 purity and low levels of other phase impurities. It possesses a low hydrogen desorption temperature, and the in-situ generated multi-metal catalyst lowers the overall hydrogen desorption activation energy, thus accelerating the hydrogen desorption rate. Furthermore, it maintains the NaAlH4 particle size during hydrogen absorption and desorption cycles, improving cycle stability. Experimental verification revealed that this NaAlH4 hydrogen storage material demonstrates excellent hydrogen storage / desorption performance, with a hydrogen desorption capacity ≥4.5 wt.% and a capacity retention rate of 92.3% after 10 cycles, proving its extremely strong cycle stability.

[0013] Preferably, in step S1, the inert atmosphere includes argon.

[0014] Preferably, the aluminum element is aluminum elemental particles.

[0015] Compared to aluminum powder, aluminum particles have less surface oxide layer and no safety hazard of dust explosion, making them a better choice.

[0016] Preferably, the elemental titanium is in the form of elemental titanium particles.

[0017] Preferably, the cerium element is in the form of cerium elemental particles.

[0018] Preferably, the multi-metal catalyst is in particulate form.

[0019] Preferably, in S1, the amount of the multi-metal catalyst is 4 to 10 wt% of the total mass of elemental aluminum and the multi-metal catalyst.

[0020] Preferably, in the multi-metal catalyst, the mass ratio of titanium to cerium is (0.9~1.1):1.

[0021] Preferably, the multi-metal catalyst further includes at least one of the lanthanides and scandium from the third subgroup of metals.

[0022] The inventors discovered that sodium-aluminum-hydrogen tetrahydrogen (Na-AH) materials obtained using titanium and cerium as multi-metal catalysts simultaneously exhibit excellent hydrogen storage / depletion performance and cycle stability. Therefore, further exploration revealed that by combining other metal catalysts with excellent hydrogen storage / depletion performance and / or excellent cycle stability with this approach, it is still possible to obtain Na-AH materials with both excellent hydrogen storage / depletion performance and cycle stability. Furthermore, by adjusting the proportions of each individual metal catalyst, the overall performance can be further optimized.

[0023] Preferably, in S1, the smelting chamber pressure is ≤ -0.05 MPa.

[0024] Preferably, during smelting, a vacuum is first drawn and then an inert gas is introduced.

[0025] Preferably, the vacuum is evacuated to a vacuum degree of ≤0.003 Pa.

[0026] Preferably, inert gas is introduced until the chamber pressure is -0.05 to -0.1 MPa.

[0027] Preferably, the aluminum element and the multi-metal catalyst are melted and then further melted under stirring to obtain a multi-metal aluminum alloy ingot.

[0028] Preferably, cooling to a solid state after melting constitutes one melting process, and the number of melting processes is at least five.

[0029] Preferably, the smelting equipment is a vacuum electric arc melting furnace.

[0030] Preferably, in step S1, during rapid quenching of the melt, a vacuum is first drawn and then an inert gas is introduced.

[0031] Preferably, the vacuum is evacuated to a vacuum degree ≤ 0.003 Pa.

[0032] Preferably, an inert gas is introduced until the internal pressure is -0.05 to -0.1 MPa.

[0033] Preferably, the inert gas injection pressure is 0.05~0.15 MPa.

[0034] Preferably, the rotation speed during rapid melting and quenching is 1000~3000 rpm.

[0035] Preferably, the heating power during rapid melting and quenching is 1~2 Kw, and the holding time is 5~20 s.

[0036] Preferably, the equipment for rapid melting and quenching is a high-vacuum suspension melting and spinning furnace.

[0037] Preferably, in step S2, under a reducing atmosphere containing hydrogen, a multi-element aluminum alloy belt is wet-milled to obtain multi-element aluminum alloy powder, and then the multi-element aluminum alloy powder and sodium hydride are ball-milled and hydrogenated to obtain sodium aluminum hydrogen hydride (SO4) storage material.

[0038] During the wet pre-ball milling process of multi-element aluminum alloy strips, the wet milling media act as a protective agent to prevent the alloy strips from cold-welding and sticking together, and the Al grains and intermetallic compounds... n The size of M is further reduced, while Al is made nThe M-distribution is more uniform, providing a large number of reactive sites in the high-energy ball milling reaction. Subsequently, the multi-element aluminum alloy powder obtained by wet pre-ball milling is reacted with sodium hydride in a hydrogen-containing atmosphere through high-energy ball milling. High-energy ball milling introduces high-density lattice defects (such as dislocations and vacancies), refines the particles, and dynamically reconstructs the surface to form a nano-intermetallic compound catalytic interface, further promoting the multiphase interface reaction, accelerating the reaction rate, and obtaining a sodium-aluminum-hydrogen tetrahydrogen storage material with highly dispersed nano-catalyst. The highly dispersed catalyst allows the sodium-aluminum-hydrogen tetrahydrogen storage material to reduce the initial hydrogen release temperature to 81 °C after re-hydrogenation, and the capacity retention can be increased from 92.3% to 99.7%.

[0039] Preferably, the medium used for wet pre-ball milling is an inert ball milling medium.

[0040] Preferably, the inert ball milling media is n-hexane, cyclohexane, anhydrous ethanol, or acetone.

[0041] Preferably, during wet pre-ball milling, the ratio of inert ball milling media to multi-element aluminum alloy belt is 1 mL: (1500~2000) mg.

[0042] Preferably, the conditions for wet pre-ball milling are: ball-to-material ratio of 100~150:1, rotation speed of 300~500 rpm / min, and time of 3~9h.

[0043] Preferably, the multi-element aluminum alloy powder is obtained by wet pre-ball milling followed by drying.

[0044] Preferably, the drying temperature is 50~90℃ and the drying time is 1~5 h.

[0045] Preferably, in S2, the molar ratio of aluminum to sodium hydride in the multi-element aluminum alloy strip is 1:1.

[0046] Preferably, the ball milling conditions are: ball-to-material ratio of 100~150:1, rotation speed of 300~500 rpm / min, and time of 20~40 h.

[0047] Longer ball milling time promotes the formation of effective NaAlH4, but the conversion rate improvement is limited after excessively extending the ball milling time. From a time-saving perspective, a ball milling time of 20-40 hours can achieve a good conversion rate. However, it should be considered that ball milling times exceeding 40 hours are substantially the same as the scheme of this invention and are still within the protection scope of this invention.

[0048] Preferably, the hydrogen content in the reducing atmosphere containing hydrogen is ≥99.0%.

[0049] Preferably, the hydrogen pressure of the reducing atmosphere containing hydrogen is 20 to 60 bar.

[0050] This invention provides a sodium aluminum hydrogen four-component hydrogen storage material, which comprises NaAlH4 and Na3AlH6; the content of NaAlH4 is above 85 wt% based on the weight of the sodium aluminum hydrogen four-component hydrogen storage material.

[0051] Preferably, the content of NaAlH4 is above 90 wt% based on the weight of the sodium aluminum hydrogen 4 (NaAlH4) hydrogen storage material.

[0052] The multi-element aluminum alloy strip prepared by this invention can effectively introduce two or more metal catalysts and couple them together. The catalyst elements are uniformly dispersed in the aluminum alloy, and the multi-element metal catalysts are integrated with aluminum, resulting in the in-situ formation of intermetallic compound catalysts Al. n M, in aluminum alloy strips, can act as a grain refiner, refining aluminum grains to the nanoscale. The refining and catalytic effects of multi-metal catalysts synergistically promote the hydrogenation reaction of sodium hydride and Al, with different types of Al... n M has different abilities to promote hydrogenation reactions and provides different functions in the process of hydrogen absorption and desorption of products.

[0053] Sodium-aluminum-hydrogen tetrahydrogen (SoAH) materials synthesized by reacting multi-element aluminum alloy strips with sodium hydride exhibit low hydrogen desorption temperatures. The in-situ generated catalyst lowers the activation energy for hydrogen desorption, primarily due to the multi-element metal catalyst effectively refining the aluminum alloy grains and providing numerous hydrogen dissociation sites. Different types of Al... n M interacts with NaAlH4 atoms, jointly promoting electron transfer and hydrogen dissociation. M atoms enter the NaAlH4 lattice, replacing Na / Al atoms and altering the electronic structure of NaAlH4, thus promoting H dissociation. - The loss of electrons destabilizes and breaks the Al-H bond, accelerating the hydrogen desorption process of NaAlH4. Simultaneously, the in-situ generated active Al... n M dispersed on the surface of NaAlH4 accelerates the dissociation and adsorption of H, providing nucleation sites for the precipitation of Al and NaH.

[0054] Furthermore, sodium aluminum hydrogen tetrahydrogen (NaHH4) materials exhibit excellent cycling stability, which stems from the synergistic effect of multi-scale structures: rapid cooling after melting forms nanocrystalline or amorphous Al. n M, with its atomically uniform distribution suppressing component segregation, and short-range ordered defects in the amorphous phase constructing active sites, while high-energy ball milling introduces high-density lattice defects (such as dislocations and vacancies), refining particles and dynamically reconstructing the surface to generate nano-intermetallic catalytic interfaces. Different types of Al... n There may be synergistic effects between M species, and some types of Al... n The M-structure is stable and can provide stable catalytic activity, and some types of Al... nM exhibits a phenomenon of thermal decomposition and regeneration upon cooling, providing more nucleation sites during cycling, stabilizing grain size, limiting particle agglomeration and growth, and improving the cycling stability of the product NaAlH4.

[0055] This invention provides a hydrogen storage material, including sodium aluminum hydrogen tetrahydrogen storage material.

[0056] This invention provides a hydrogen storage device that uses sodium aluminum hydrogen tetrahydrogen (NH4H4) material.

[0057] Based on the hydrogen storage / desorption performance and reversible cyclic hydrogen absorption / desorption performance of the aforementioned sodium aluminum hydrogen 4 hydrogen storage material, it can be used as a component in hydrogen storage materials or as a raw material for hydrogen storage devices.

[0058] Therefore, the present invention has the following beneficial effects: (1) This invention uses titanium and cerium as multi-metal catalysts and utilizes the synergistic effect between titanium and cerium to obtain sodium aluminum hydrogen 4 hydrogen storage material with excellent hydrogen storage / desorption performance and good cycle stability.

[0059] (2) This invention introduces a multi-metal catalyst through smelting to obtain a multi-element aluminum alloy ingot, and then rapidly melts and quenches the alloy ingot to obtain a multi-element aluminum alloy strip, thus obtaining a sodium aluminum hydrogen tetrahydrogen storage material with excellent performance. The entire process adopts a solid-solid reaction preparation method, and the raw materials are simple and readily available. The use of organic solvents is avoided in the process, the operation is simple, and it is suitable for large-scale factory preparation.

[0060] (3) In this invention, the multi-element aluminum alloy strip is converted into multi-element aluminum alloy powder by wet ball milling, and then ball milled with sodium hydride to obtain sodium aluminum hydrogen four-element hydrogen storage material. The powder increases the contact reaction between the multi-element aluminum alloy and sodium hydride, accelerates the reaction rate, and obtains sodium aluminum hydrogen four-element hydrogen storage material with highly dispersed nano-scale catalyst.

[0061] (4) The aluminum alloy strip with refined grains and uniform distribution of multi-element catalysts obtained by smelting and rapid melting in this invention plays a key role in subsequent material synthesis. On the one hand, the multifunctional nano-Al formed by different metal catalysts... n M, as an active site for hydrogen dissociation and adsorption, lowers the kinetic energy barrier of the hydrogenation reaction; on the other hand, nano-Al generated in situ during the melt quenching process... n M, acting as a heterogeneous nucleation center, refines the Al grains, shortens the diffusion distance of hydrogen atoms, and further improves the kinetics of hydrogen absorption and desorption reactions; in addition, the intermetallic catalysts Al formed by different metal catalysts... n M exhibits a certain synergistic effect, with its electronic structure influencing each other, further lowering the kinetic energy barrier of the hydrogenation reaction.

[0062] (5) The present invention uses aluminum particles and metal element particles for smelting, which can avoid the problem of aluminum powder explosion, and can also simplify the complex preparation process of multi-metal catalysts. It can selectively combine different functional catalyst metals, regulate the synergistic effect between different catalyst metals, and make the multi-metal catalyst nano-sized and more uniformly distributed in the alloy, thereby obtaining sodium aluminum hydrogen 4 hydrogen storage material with ideal performance.

[0063] (6) The sodium-aluminum-hydrogen tetrahydrogen (NaAlH4) hydrogen storage material obtained by this invention has high NaAlH4 purity and contains few other phase impurities. The in-situ generated multi-metal catalyst exhibits a synergistic effect of different metals, ensuring a hydrogen release capacity ≥4.5 wt% while reducing the hydrogen release activation energy of the entire system, thus lowering the hydrogen release temperature and accelerating the hydrogen release rate. It also improves the cycle stability of the sodium-aluminum-hydrogen tetrahydrogen (NaAlH4) hydrogen storage material. Based on these properties, the obtained sodium-aluminum-hydrogen tetrahydrogen (NaAlH4) hydrogen storage material has broad application prospects. This invention provides new ideas and new basic materials for other hydrogen storage research. Attached Figure Description

[0064] Figure 1 XRD patterns of alloy strips prepared by arc melting and rapid quenching of titanium-cerium doped aluminum particles in different proportions according to Example 1 of the present invention and Comparative Example 1; Figure 2 SEM images of alloy strips after arc melting and rapid quenching of different proportions of titanium-cerium-doped aluminum particles in Examples 1, 1, 3 and 4 of the present invention, where a~f are the copper roller contact surfaces of different proportions of TiCe-doped Al alloy strips, and g~l are the non-contact surfaces of different proportions of TiCe-doped Al alloy strips. Figure 3 The images shown are TEM images, HRTEM images, and corresponding EDX energy dispersive spectra of the Al-3Ti3Ce alloy strip in Example 1 of this invention. Among them, a~b are TEM images at different scales, c is an HRTEM image, d is the lattice fringes of the corresponding selected area in c, and e is the EDX image of Al, Ce, and Ti. Figure 4 The XRD patterns of sodium aluminum hydrogen 4 hydrogen storage materials prepared in Example 1 and Comparative Example 1 of this invention are shown below. Figure 5 The hydrogen desorption curves of sodium aluminum hydrogen 4 hydrogen storage materials prepared in Example 1 and Comparative Example 1 of this invention are shown as temperature-dependent hydrogen desorption curves. Figure 6 The TPD curves of sodium aluminum hydrogen 4-hydrogen storage materials prepared in Example 1 and Comparative Example 1 of this invention are shown. Figure 7 The hydrogen release curves of sodium aluminum hydrogen 4 storage material prepared by Al-3Ti3Ce alloy strip in Example 1 of this invention under different cycles with temperature are shown. Figure 8The images show the XRD patterns of the sodium aluminum hydrogen 4 storage material prepared by Al-3Ti3Ce alloy strip in Example 1 of this invention after ball milling, after the second cycle of hydrogen absorption, and after the tenth cycle of hydrogen absorption. bm represents the result after ball milling, abs 2 represents the result after the second cycle of hydrogen absorption, and abs 10 represents the result after the tenth cycle of hydrogen absorption. Figure 9 The images show the fine XPS Ti 2p spectra of the sodium aluminum hydrogen 4 storage material prepared by Al-3Ti3Ce alloy strip in Example 1 of this invention after ball milling, after the first cycle of hydrogen absorption, and after the tenth cycle of hydrogen absorption. BM represents the hydrogen storage material after ball milling, Reh 01 represents the hydrogen absorption after the first cycle, and Reh 10 represents the hydrogen absorption after the tenth cycle. Figure 10 The images show the fine XPS Ce 3d spectra of the sodium aluminum hydrogen 4 storage material prepared by Al-3Ti3Ce alloy strip in Example 1 of this invention after ball milling, after the first cycle of hydrogen absorption, and after the tenth cycle of hydrogen absorption. BM represents the result after ball milling, Reh 01 represents the result after the first cycle of hydrogen absorption, and Reh 10 represents the result after the tenth cycle of hydrogen absorption. Figure 11 The XRD patterns of the Al-3Ti3Ce alloy strip in Example 1, and the aluminum alloy strips prepared in Comparative Example 3 and Comparative Example 4 of this invention are shown. Figure 12 The XRD patterns of the sodium aluminum hydrogen 4 storage materials prepared by Al-3Ti3Ce alloy strip in Example 1, Comparative Example 3, and Comparative Example 4 of this invention are shown. Figure 13 The hydrogen release diagrams of sodium aluminum hydrogen 4 hydrogen storage materials prepared by Al-3Ti3Ce alloy strip in Example 1, Comparative Example 3, and Comparative Example 4 are shown as temperature-dependent hydrogen release diagrams. Figure 14 The TPD curves of the sodium aluminum hydrogen tetrahydrogen storage materials prepared by Al-3Ti3Ce alloy strip in Example 1, Comparative Example 3, and Comparative Example 4 of this invention are shown. Figure 15 The hydrogen desorption curves of the sodium aluminum hydrogen 4 hydrogen storage material prepared in Comparative Example 3 of this invention under different cycles with temperature are shown. Figure 16 The hydrogen desorption curves of the sodium aluminum hydrogen 4 hydrogen storage material prepared in Comparative Example 4 of this invention under different cycles with temperature are shown. Figure 17 The XRD patterns of the aluminum alloy strips prepared in Comparative Example 2 and Comparative Example 1 of this invention are shown. Figure 18 The image shows an SEM image of the aluminum alloy strip prepared in Comparative Example 2 of this invention, where a is the contact surface of the alloy strip with the copper roller and b is the non-contact surface of the alloy strip with the copper roller. Figure 19 The XRD pattern of the sodium aluminum hydrogen 4 hydrogen storage material prepared in Comparative Example 2 of this invention; Figure 20The hydrogen desorption curve of the sodium aluminum hydrogen 4 hydrogen storage material prepared in Comparative Example 2 of this invention is shown as a function of temperature. Figure 21 The XRD patterns are of the Al-3Ti3Ce alloy strip in Example 1 and the sodium aluminum hydrogen 4 hydrogen storage material prepared in Example 2 of this invention. Figure 22 The figures show the hydrogen release at different temperatures for the Al-3Ti3Ce alloy strip in Example 1 and the sodium aluminum hydrogen 4 hydrogen storage material prepared in Example 2 of this invention. Figure 23 The hydrogen release curves of the sodium aluminum hydrogen 4 hydrogen storage material prepared in Comparative Example 5 of this invention under different cycles with temperature are shown. Figure 24 The hydrogen release curves of sodium aluminum hydrogen 4 storage material prepared by Al-5Ti1Ce alloy strip in Comparative Example 1 of this invention under different cycles with temperature are shown. Detailed Implementation

[0065] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0066]

Example

[0067] Table 1 Dosage Table

[0068] Step 2: Rapid quenching after melting. Take 5-8 g of the above aluminum-titanium-cerium alloy ingot and place it in a quartz crucible installed in a high-vacuum suspension melting and spinning furnace. After evacuating to a vacuum degree of 0.003 Pa, fill the furnace with argon atmosphere to achieve a pressure of -0.05 MPa. Adjust the argon injection casting pressure to 0.1 MPa, set the copper roller speed to 2000 rpm, and increase the heating power to 1.5-2 Kw. Hold for 10 s before injection casting to obtain aluminum-titanium-cerium alloy strip (Al- x Ti y The Ce and TiCe ratios were 5:1, 1:1, and 1:5, respectively.

[0069] Step 3: Sodium hydride and aluminum from the aforementioned aluminum-titanium alloy strip, in different molar ratios of 1:1, are loaded into a ball mill jar with a ball-to-material ratio of 120:1. Stainless steel grinding balls are used. The jar is placed in an argon-filled glove box and sealed. The jar is then removed, evacuated, and filled with 50 bar of hydrogen before being placed in a planetary ball mill for grinding. Milling parameters: alternating forward and reverse rotation, 500 rpm / min, 12 min rotation, 6 min pause, milling for 12 h. After milling, the jar is removed, the material is scraped to loosen it, and 50 bar of hydrogen is added again. The same milling parameters are used for another 12 h of milling. This process is repeated twice for a total of 36 h to obtain the prepared sodium-aluminum-hydrogen tetrahydrogen composite hydrogen storage material, denoted as NaH / Al- x Ti y Ce ( x:y =5:1,1:1,1:5).

[0070] Example 2 In this embodiment, the metal catalyst doping amount is 6 wt% of the total mass of aluminum particles and metal catalyst. The two metal catalysts selected are Ti and Ce metal particles, with a mass ratio of Ti to Ce of 1:1.

[0071] Step 1: Arc melting and mixing. Weigh 32.9 g of aluminum particles, 1.05 g of titanium particles, and 1.05 g of cerium particles, and place them in a vacuum arc melting furnace. Close the furnace door and evacuate to a vacuum level of 0.003 Pa. Introduce an argon atmosphere into the furnace to bring the furnace pressure to -0.05 MPa. Turn on the arc gun and use the pre-placed titanium and cerium particles in the furnace to ignite the arc and melt them. After cooling and no obvious color change, melt the prepared aluminum-titanium-cerium particles. Increase the current to melt them, then turn on magnetic stirring to further melt them. Then cool them to a solid state, flip them over, and repeat the above operation 5 times to obtain an aluminum-titanium-cerium alloy ingot.

[0072] Step 2: Rapid quenching after melting. Take 5-8 g of the above aluminum-titanium-cerium alloy ingot and place it in a quartz crucible installed in a high-vacuum electric arc melting furnace. After evacuating to a vacuum degree of 0.003 Pa, fill the furnace with argon atmosphere to bring the pressure inside the chamber to -0.05 MPa. Adjust the argon injection casting pressure to 0.1 MPa, set the copper roller speed to 2000 rpm, and set the heating power to 1.5-2 Kw. Hold for 10 s and then inject the casting solution to obtain an aluminum-titanium-cerium alloy strip, denoted as Al-3Ti3Ce.

[0073] Step 3: Wet ball milling pretreatment. Take 800 mg of the above-mentioned aluminum-titanium-cerium alloy strip and 0.5 mL of n-hexane and place them in a ball mill jar, ensuring the hexane fully wets the alloy strip. The ball-to-material ratio is 120:1. The grinding balls are stainless steel balls. The ball mill jar is placed in an argon-filled glove box and sealed. The jar is then removed and evacuated, and after being filled with 30 bar of hydrogen, it is placed on a planetary ball mill for milling. Milling parameters: alternating forward and reverse operation, rotation speed 400 rpm / min, 12 min rotation, 6 min pause, milling for 3 h. After milling, remove the jar, scrape the material to loosen it, add 0.5 mL of n-hexane again, and fill with 30 bar of hydrogen. Mill again using the same parameters for 3 h. Repeat the milling operation twice, for a total of 9 h. Then, place the obtained milled powder in a quartz boat and dry it in a vacuum tube furnace at 80 ℃ for 2 h to obtain the prepared aluminum-titanium-cerium alloy strip powder, denoted as Al-3Ti3Ce-B.

[0074] Step 4: Sodium hydride and aluminum from the aforementioned aluminum-titanium-lanthanum alloy powder were sampled and loaded into a ball mill jar at a molar ratio of 1:1 (ball-to-material ratio 120:1). Stainless steel grinding balls were used. The jar was placed in an argon-filled glove box and sealed. The jar was then removed, evacuated, and filled with 50 bar of hydrogen before being placed in a planetary ball mill for grinding. The grinding parameters were: alternating forward and reverse rotation at 500 rpm / min for 12 minutes followed by a 6-minute pause. After grinding for 12 hours, the jar was removed, the material was scraped to loosen it, and 50 bar of hydrogen was added again. The same grinding parameters were used for another 12 hours of grinding. This process was repeated twice for a total of 36 hours to obtain the prepared sodium-aluminum-hydrogen tetrahydrogen composite hydrogen storage material, denoted as NaH / Al-3Ti3Ce-B.

[0075] Comparative Example 1 This comparative example is basically the same as Example 1, except that no cerium particles and titanium particles are added, and the resulting product is denoted as NaH / Al (or Al).

[0076] Comparative Example 2 This comparative example is basically the same as Example 1, except that the cerium particles are replaced with lanthanum particles of equal mass, and the resulting product is denoted as NaH / Al-3Ti3La.

[0077] Comparative Example 3 This comparative example is basically the same as Example 1, except that the cerium particles are replaced with titanium particles of equal mass, and the resulting product is denoted as NaH / Al-6Ti.

[0078] Comparative Example 4 This comparative example is basically the same as Example 1, except that the titanium particles are replaced with cerium particles of equal mass, and the resulting product is denoted as NaH / Al-6Ce.

[0079] Comparative Example 5 This comparative example is basically the same as Example 1, except that the titanium particles and cerium particles are replaced with lanthanum particles, and the amount of lanthanum particles added is 8 wt% of the total mass of aluminum particles and lanthanum particles. The resulting product is denoted as NaH / Al-8La.

[0080] [Performance Testing] 1. Appearance Testing Al- with different TiCe ratios obtained in Example 1 x Ti y XRD analysis was performed on Ce alloy ribbons and pure Al alloy ribbons prepared in Comparative Example 1, and the results are as follows: Figure 1 As shown in the XRD pattern, the addition of Ti and Ce elements resulted in the presence of Al, Al3Ti, and Al in the alloy. 11 Ce3, Al4Ce and Ti2Al 20 The diffraction peaks of the Ce phase, including Ti2Al 20 Ce phase diffraction peaks were detected only in Al-5Ti1Ce and Al-3Ti3Ce. Comparing the Al peaks of the three alloy bands, the intensity of the Al phase diffraction peak in Al-3Ti3Ce was found to be approximately two-thirds lower than the other two alloy bands. This may be due to the different phase compositions and contents of the generated intermetallic compounds, resulting in varying degrees of Al grain refinement. In Al-3Ti3Ce, there is a large amount of Ti2Al. 20 The Ce phase is formed, which acts as a grain refiner, providing numerous nucleation sites to promote Al nucleation and thus refining Al grains. However, in Al-5Ti1Ce and Al-1Ti5Ce, the former only produces a small amount of Ti2Al. 20 The Ce phase has relatively few heterogeneous nucleation centers, resulting in limited refinement of Al grains; the latter did not form Ti2Al. 20 Instead of Ce phase, a large amount of Al is generated. 11 Ce3 and a small amount of Al4Ce have a less refined effect than Ti2Al. 20 Ce phase. Compared with pure Al alloy ribbons, the introduction of multi-component TiCe catalysts significantly reduced the intensity of Al diffraction peaks, indicating that the coupling of TiCe catalysts led to a significant reduction in Al grain size.

[0081] Figure 2Al- with different TiCe ratios x Ti y The copper roller contact surface of Ce alloy strip and pure Al alloy strip ( Figure 2 a~f) and non-contact surfaces ( Figure 2 Morphological characterization of g~l revealed that the catalyst elements on the two unit aluminum alloys and three multi-element aluminum alloys were uniformly dispersed, with the copper roller contact surface ( Figure 2 (a~f) exhibits a characteristic where the morphology transitions from granular to network-like as Ti content decreases and Ce content increases, rather than at the non-contact surfaces ( Figure 2 Both g~l) exhibit a relatively large particle structure. Comparing the multi-element aluminum alloy ribbon with titanium-aluminum and cerium-aluminum alloy ribbons, the multi-element titanium-cerium-aluminum alloy ribbon combines the characteristics of both unitary aluminum alloy ribbons. Ti refines Al into granular particles, while Ce is uniformly dispersed throughout the Al grains, mostly concentrated near the grain interfaces. The Al grain size in the titanium-aluminum alloy and cerium-aluminum alloy ribbons is between 400 and 800 nm, while the size in the multi-element titanium-cerium-aluminum alloy ribbon is between 200 and 900 nm, indicating that Ti2Al 20 The refining effect of Ce phase on Al3Ti and Al 11 The synergistic effect of Ce3 further refined the Al grains. Comparing the morphological characteristics of the three multi-component titanium-cerium-aluminum alloy ribbons, the Al-3Ti3Ce catalytic phase was uniformly dispersed with no obvious grain boundary segregation. The aluminum matrix grain size was 200–900 nm, the smallest among the three multi-component titanium-cerium-aluminum alloy ribbons. This is consistent with the lowest peak intensity of the Al phase diffraction peak in XRD, further confirming the large amount of Ti2Al generated in situ. 20 Ce has a superior grain-refining effect compared to Al.

[0082] Figure 3 These are TEM, HRTEM, and EDX images of Al-3Ti3Ce. The HRTEM image reveals three types of crystals corresponding to Ti2Al. 20 Ce, Al3Ti, and Al phases. EDX spectrum ( Figure 3 e) Two types of bright and dark regions are shown: the darker region is the Al matrix, and the brighter lamellar region is the Al-Ti-Ce material, which is uniformly dispersed and its size can be reduced to 50 nm. This demonstrates the nano-dispersion characteristics of the catalyst in the obtained Al-3Ti3Ce sample.

[0083] Figure 4 Al- with different TiCe ratios x Ti y XRD patterns of sodium-aluminum-hydrogen 4 (NaAlH4) hydrogen storage materials prepared by ball milling Ce and pure Al alloy strips with NaH hydrogenation. After ball milling of the three proportions of multi-element aluminum alloy strips with NaH hydrogenation, NaAlH4 was the main component of the product with similar peak intensities, and all contained Ti2Al. 20In the Ce catalytic phase, the NaH / Al-1Ti5Ce phase exhibits the lowest peak intensity corresponding to the NaAlH4 diffraction peak at 32.655 °. Due to the low Ti content, the Ti2Al catalytic phase... 20 The Ce content is relatively low; Al is mainly formed by the eutectic reaction of Ce and Al. 11 Ce3 is the main catalytic phase. This change is mainly related to the content of Al-Ti-Ce generated during the process. In the NaH / Al-5Ti1Ce sample, Ti is mainly present in Ti2Al. 20 In the presence of Ce, Al3Ti reacts with Ce to form Ti2Al. 20 Ce, failed to detect the Al3Ti phase; in the NaH / Al-3Ti3Ce sample, Ti2Al 20 The Ce content increased. After ball milling of titanium-aluminum alloy strips and cerium-aluminum alloy strips with NaH hydrogenation, NaAlH4 became the main component of the product, but its peak intensity was stronger than that of the ball-milled product from the titanium-cerium-aluminum alloy strip. This indicates the interaction between Ti, Ce, and Al in situ generated intermetallic catalysts in the titanium-cerium-aluminum alloy strip and the interaction between Ti2Al and the cerium-aluminum alloy strip. 20 The refining effect of Ce further refines the particle size of NaAlH4. In contrast, the hydrogenation ball milling product of NaH / Al produces a large amount of Na3AlH6 phase and no NaAlH4 phase, indicating that the coupling introduction of the multi-component TiCe catalyst and the refinement of Al grains significantly improve the reactivity of Al alloys, promoting the three-phase reaction of NaH, Al and H2.

[0084] Figure 11 XRD analysis of the alloy ribbons prepared in Example 1 (Al-3Ti3Ce), Comparative Example 3, and Comparative Example 4 clearly shows that the introduction of TiCe into the Al alloy in a 1:1 ratio not only generates the in-situ Al3Ti intermetallic catalytic phase, but also generates a large amount of Ti2Al at the reduction sites. 20 Compared to Al-Ti and Al-Ce alloys, the coupling of the two catalytic phases in the Ce intermetallic catalytic phase further reduces the intensity of the Al diffraction peak and significantly refines the Al grains.

[0085] Figure 12 The images show the XRD patterns of the sodium-aluminum-hydrogen 4 (NaAlH4) hydrogen storage materials prepared in Example 1 (Al-3Ti3Ce), Comparative Example 3, and Comparative Example 4. After hydrogenation ball milling, the catalytic phase of all three materials was retained to a certain extent, and a large amount of NaAlH4 phase and a small amount of Na3AlH6 phase were generated.

[0086] Figure 17 The XRD patterns of the alloy ribbons prepared in Comparative Example 2 and Comparative Example 1 show that when Ti and La catalysts are introduced in a 1:1 ratio, only the in-situ intermetallic compound phase Al is formed in the Al alloy ribbon. 11The intensity of the La3 and Al diffraction peaks also decreased, indicating that Al 11 La3 also has a grain-refining effect on Al grain size.

[0087] Figure 18 The copper roller contact surface of the alloy strip prepared for Comparative Example 2 ( Figure 18 a) and non-contact surfaces ( Figure 18 b) Morphological characterization shows that the Al grains have been refined to a certain extent, which is consistent with the XRD results. Although the metal catalyst is not completely segregated at the grain boundaries, it is mainly distributed around the grain boundaries.

[0088] Figure 19 The image shows the XRD pattern of the sodium-aluminum-hydrogen tetrahydrogen storage material prepared in Comparative Example 2. After co-introduction with the TiLa catalyst, NaAlH4 was successfully synthesized, with only a small amount of Na3AlH6 present. The catalytic phase Al... 11 La3 remained stable after ball milling and promoted the reaction.

[0089] Figure 21 The XRD patterns of the Al-3Ti3Ce hydrogen storage materials prepared in Example 1 and the sodium aluminum hydrogen tetrahydrogen materials prepared in Example 2 show that after the aluminum titanium cerium alloy strip powder was hydrogenated and ball-milled with NaH, Ti2Al 20 The Ce phase exists stably and forms Al. 11 Ce3 and NaAlH4 phases remain the main products, but the diffraction peak intensity of the Na3AlH6 phase is slightly higher than that of NaH / Al-3Ti3Ce. This is due to the in-situ formation of Al... 11 Ce3 consumes some of the active Al, which is caused by Ce3.

[0090] 2. Hydrogen storage / discharge performance The hydrogen absorption and desorption properties of sodium aluminum hydrogen tetraproducts prepared by ball milling three alloy strips with NaH were tested. Figure 5 It is NaH / Al- x Ti y The hydrogen desorption curves of Ce (Example 1) and NaH / Al (Comparative Example 1) with temperature show that, compared to NaH / Al, NaH / Al- x Ti y Ce exhibited superior hydrogen storage capacity and significantly improved overall hydrogen desorption kinetics, indicating that Ti2Al... 20 The catalytic effect of Ce phase and Al3Ti, Al 11The synergistic effect of Ce3 enhanced the hydrogen storage performance of the sodium-aluminum-hydrogen tetraproducts. Among the sodium-aluminum-hydrogen tetraproducts prepared from three multi-component titanium-cerium-aluminum alloy strips, NaH / Al-5Ti1Ce and NaH / Al-3Ti3Ce exhibited excellent hydrogen desorption performance, initiating hydrogen desorption at 102.6 ℃ and 103.1 ℃, respectively, with the second step of hydrogen desorption starting at 136.9 ℃ and 139.9 ℃, and ending at 178.9 ℃ and 182.1 ℃, respectively, releasing a total of 4.75 wt% and 4.73 wt% of hydrogen. In contrast, the NaH / Al-1Ti5Ce sample showed an initial hydrogen desorption temperature of 112.9 ℃, with the second step of hydrogen desorption starting at 155.1 ℃ and ending at 193.1 ℃, releasing a total of 4.88 wt% of hydrogen. This indicates that the large amount of Ti2Al synthesized in situ... 20 The Ce phase is more effective in promoting hydrogen desorption from the sodium aluminum hydrogen tetrahydrogen product. In comparison, the sodium aluminum hydrogen tetrahydrogen product with a Ti / Ce mass ratio of 1:1 and 5:1 exhibits superior hydrogen desorption performance; while the hydrogen desorption temperature is higher and the performance is slightly worse when the Ti / Ce mass ratio is 1:5.

[0091] Figure 6 NaH / Al- x Ti y The TPD curves of Ce (Example 1) and NaH / Al (Comparative Example 1) show that, compared with NaH / Al without catalyst, the co-introduction of TiCe catalyst makes NaH / Al... x Ti y The peak temperatures of the two-step hydrogen desorption in Ce products were significantly reduced. Specifically, the peak temperatures of the two-step hydrogen desorption in NaH / Al-5Ti1Ce and NaH / Al-3Ti3Ce decreased to 124.4 ℃ and 151.5 ℃, and 127.9 ℃ and 151.9 ℃, respectively, all lower than the peak temperatures of 142.8 ℃ and 168.4 ℃ for NaH / Al-1Ti5Ce. In the sodium aluminum hydrogen tetraproducts prepared by ball milling with a titanium-cerium-aluminum alloy belt, a large amount of in-situ synthesized Ti2Al was dispersed. 20 The excellent catalytic performance of Ce phase and Al3Ti, Al 11 The excellent synergistic catalytic effect of Ce3 enhances the hydrogen desorption kinetics of NaAlH4.

[0092] Figure 7The hydrogen desorption curves of NaH / Al-3Ti3Ce under different cycles are shown. In the first hydrogen desorption process, the initial hydrogen desorption temperature was 107.4 °C, and the hydrogen desorption amount was 4.73 wt%. In the second hydrogen desorption process after hydrogen absorption, the initial hydrogen desorption temperature dropped to 86.3 °C, a decrease of 21.1 °C compared to the first hydrogen desorption temperature, and the hydrogen desorption amount was 4.41 wt%. After ten cycles of hydrogen absorption and desorption, the initial hydrogen desorption temperature remained at 89.7 °C, and the final hydrogen desorption temperature dropped to 168.4 °C, a decrease of 13.7 °C compared to the first final hydrogen desorption temperature, with a hydrogen desorption amount of 4.37 wt% and a capacity retention of 92.39%. Meanwhile, NaH / Al-5Ti1Ce, with a similar hydrogen desorption rate, showed the following after ten hydrogen absorption and desorption cycles: Figure 24 As shown, its capacity retention rate is only 79.58%. Considering both hydrogen storage / depletion performance and cycle performance, it can be seen that only when the Ti / Ce mass ratio is 1:1 can it possess both excellent hydrogen storage / depletion performance and cycle stability.

[0093] XRD analysis was performed on the NaH / Al-3Ti3Ce sample after hydrogenation ball milling and subsequent hydrogen absorption and desorption cycles. Figure 8 The XRD patterns of the sample after ball milling, the second hydrogen absorption cycle, and the tenth hydrogen absorption cycle are shown below. A comparison reveals that the peak intensities of the Na3AlH6 and Al diffraction peaks are slightly enhanced after the second hydrogen absorption cycle. This may be because some Al particles agglomerate and grow during the cycle, losing their activity and preventing some Na3AlH6 from reacting with Al to form NaAlH4. After the tenth cycle, the main substances in the hydrogenated sample are still NaAlH4 and Al, with the catalytic phase Ti2Al... 20 The stable presence of Ce during cycling indicates that the catalyst can stably promote the hydrogen adsorption and desorption kinetics of NaAlH4 and improve the cycle capacity retention rate by maintaining the stable refinement of NaAlH4 crystal size.

[0094] Figure 9 , Figure 10 XPS spectra of Ti2p and Ce3d in the products after hydrogenation ball milling and cycling hydrogen adsorption / desorption of NaH / Al-3Ti3Ce samples, respectively. In the XPS spectrum of Ti2p ( Figure 9 The ball-milled sample showed Ti-corresponding values ​​at 453.5 eV and 457.5 eV. 0 The spin orbital peak of the sample did not show a significant change in peak intensity after the second hydrogen absorption cycle, indicating that the intermetallic compound Ti2Al formed during the cyclic process... 20 The Ce content and oxidation state remain unchanged. However, for Ce( Figure 10 After ten cycles, the peak position was similar to that measured on the sample after hydrogenation and ball milling. Overall, this indicates that Ti2Al... 20The stable existence of the Ce catalytic phase in doped NaAlH4 is the most important reason why the sample has good cycling stability.

[0095] Figure 13 for Figure 6 The figures show the hydrogen expulsion as a function of temperature for NaH / Al-3Ti3Ce (Example 1), NaH / Al-6Ti (Comparative Example 3), and NaH / Al-6Ce (Comparative Example 4). The NaH / Al-6Ti sample exhibits a low initial hydrogen expulsion temperature of 103.2 °C, demonstrating excellent kinetic performance, with an initial hydrogen expulsion capacity of 4.84 wt%. The NaH / Al-6Ce sample shows a higher initial hydrogen expulsion capacity of 4.88 wt%, but its initial hydrogen expulsion temperature is 115.6 °C, indicating poorer hydrogen expulsion kinetics. The NaH / Al-3Ti3Ce sample, utilizing the properties of Ti, has a lower initial hydrogen expulsion temperature of 103.15 °C, exhibiting superior hydrogen storage performance.

[0096] Figure 14 The TPD curves for NaH / Al-3Ti3Ce (Example 1), NaH / Al-6Ti (Comparative Example 3), and NaH / Al-6Ce (Comparative Example 4) show that compared with NaH / Al-6Ti and NaH / Al-6Ce, which only added elemental catalyst metal, the peak temperatures of the two-step hydrogen desorption in NaH / Al-3Ti3Ce are significantly reduced to 127.9 ℃ and 151.9 ℃, respectively. In contrast, the peak temperatures of the two-step hydrogen desorption in NaH / Al-6Ti are only 131.9 ℃ and 163.7 ℃, respectively, and the peak temperatures of the two-step hydrogen desorption in NaH / Al-6Ce are 151.6 ℃ and 167.7 ℃, respectively. In the sodium aluminum hydrogen tetramer prepared by ball milling with a titanium-cerium-aluminum alloy belt, the Ti catalyst provides excellent kinetic performance for the first hydrogen desorption step of NaAlH4. The synergistic effect of the Ti and Ce bimetals further reduces the peak temperature of the second hydrogen desorption step of NaAlH4, enhancing hydrogen diffusion within the matrix. This further confirms the in-situ synthesis of a large amount of Ti2Al 20 The excellent catalytic performance of Ce phase and Al3Ti, Al 11 Ce3 exhibits excellent synergistic catalytic effects.

[0097] 3. Cyclic stability Figure 15 and Figure 16The figures show the hydrogen desorption curves as a function of temperature at different cycle numbers after ten hydrogen adsorption / desorption cycles for NaH / Al-6Ti (Comparative Example 3) and NaH / Al-6Ce (Comparative Example 4). It can be seen that after ten cycles, the initial hydrogen desorption temperature of NaH / Al-6Ti decreased from 103 °C to 75 °C, and the final hydrogen desorption temperature decreased from 187 °C to 173 °C. This is attributed to the good catalytic effect of Ti on the kinetic performance of NaAlH4. After ten hydrogen adsorption / desorption cycles, its hydrogen desorption capacity decreased from 4.84 wt% to 4.40 wt%, with a capacity retention of only 84.8%. The significant decrease in hydrogen storage capacity is due to the limited dispersion of Al3Ti in the Al matrix, making local enrichment difficult to avoid, and the lack of effective grain boundary pinning, resulting in less inhibition of Al grain aggregation and growth, and poor cycle stability. After ten cycles, the initial hydrogen desorption temperature of NaH / Al-6Ce decreased from 115 °C to 108 °C, and the final hydrogen desorption temperature decreased from 197 °C to 178 °C. The hydrogen desorption rate decreased from 4.88 wt% to 4.66 wt%, while the capacity retention rate remained as high as 95.5%. This excellent cycling stability is attributed to the pinning effect of Ce on Al, which restricts the aggregation and growth of Al particles. Furthermore, its catalytic phase Al... 11 Ce3 further improved the kinetic performance of NaAlH4 in the cycle.

[0098] Figure 20 The hydrogen release curve for ten cycles of Comparative Example 2 is shown. The initial hydrogen release temperature of this sample was 126 °C, and the final hydrogen release temperature was 185 °C. The initial hydrogen release amount was 4.93 wt%. In subsequent hydrogen release processes, the initial hydrogen release temperature dropped slightly to 104 °C, but the hydrogen storage capacity decreased to 3.79 wt%, and the capacity retention rate was only 76.8%. Figure 23 The hydrogen release curve for 100 cycles versus temperature, as shown in Comparative Example 5, reveals that NaH / Al-8La, obtained using La as a metal catalyst, still exhibits extremely high stability. While Ce and La also possess extremely high cycling stability, only when combined with Ti as a multi-metal catalyst can a sodium-aluminum-hydrogen (NaH / Al-8La) material with excellent hydrogen storage / desorption performance and good cycling stability be obtained. This demonstrates a synergistic effect between titanium and cerium, resulting in optimal performance of the NaH / Al-8La hydrogen material.

[0099] Figure 22 The figures show the hydrogen release curves of the sodium aluminum hydrogen tetroxide (NaH / Al-3Ti3Ce) and the sodium aluminum hydrogen tetroxide (NaH / Al-3Ti3Ce-B) prepared in Example 1 and Example 2, respectively, under different temperatures. After pre-ball milling, the initial hydrogen release temperature of NaH / Al-3Ti3Ce-B increased, but the initial hydrogen release temperature of its re-hydrogenation decreased to 81℃ compared to 86.3℃ of the NaH / Al-3Ti3Ce sample. The hydrogen storage capacity of the re-hydrogenation also increased from 4.37 wt% to 4.46 wt%, and the capacity retention rate increased from 92.3% to 99.7%.

Claims

1. A method for preparing sodium aluminum hydride four hydrogen storage material using aluminum alloy strip activated by a multi-element metal catalyst, characterized in that, The application relates to a sodium-aluminum-hydrogen four hydrogen storage material and a preparation method thereof. S1. Melting aluminum single substance and a multi-metal catalyst under an inert atmosphere to obtain a multi-aluminum alloy ingot, and then melt-spun quenching the multi-aluminum alloy ingot to obtain a multi-aluminum alloy strip; the multi-metal catalyst at least comprises titanium single substance and cerium single substance; S2. Ball-milling and hydrogenating the multi-aluminum alloy strip and sodium hydride under a reducing atmosphere containing hydrogen to obtain the sodium-aluminum-hydrogen four hydrogen storage material.

2. The method of claim 1, wherein, In S1, the inert atmosphere comprises argon; Preferably, the aluminum single substance is aluminum single substance particles; Preferably, the titanium single substance is titanium single substance particles; Preferably, the cerium single substance is cerium single substance particles; Preferably, the multi-metal catalyst is in a particle state.

3. The method of claim 1 or 2, wherein, In S1, the amount of the multi-metal catalyst is 4-10 wt% of the total mass of the aluminum single substance and the multi-metal catalyst; Preferably, in the multi-metal catalyst, the mass ratio of titanium to cerium is (0.9-1.1):1; Preferably, the multi-metal catalyst further comprises at least one of lanthanum in the third subgroup of elements and scandium.

4. The method of claim 1, wherein, In S1, the furnace pressure during melting is less than or equal to -0.05 MPa; Preferably, vacuum is first extracted and then the inert gas is introduced during melting; Preferably, the vacuum degree is less than or equal to 0.003 Pa; Preferably, the inert gas is introduced to a furnace pressure of -0.05 to -0.1 MPa; Preferably, the aluminum single substance and the multi-metal catalyst are further melted under stirring after being melted to obtain the multi-aluminum alloy ingot; Preferably, the cooling to solid state after melting is 1-time melting, and the number of times of melting is at least 5; Preferably, the melting equipment is a vacuum arc melting furnace.

5. The method of claim 1, wherein, In S1, vacuum is first extracted and then the inert gas is introduced during melt-spun quenching; Preferably, the vacuum degree is less than or equal to 0.003 Pa; Preferably, the inert gas is introduced to an internal pressure of -0.05 to -0.1 MPa; Preferably, the inert gas spraying pressure is 0.05-0.15 MPa; Preferably, the rotating speed during melt-spun quenching is 1000-3000 rpm; Preferably, the heating power during melt-spun quenching is 1-2 Kw, and the maintaining time is 5-20 s; Preferably, the melt-spun quenching equipment is a high-vacuum suspension melting strip casting furnace.

6. The method of claim 1, wherein, In S2, the multi-aluminum alloy strip is pre-ball-milled in a wet method under a reducing atmosphere containing hydrogen to obtain a multi-aluminum alloy powder, and then the multi-aluminum alloy powder and sodium hydride are ball-milled and hydrogenated to obtain the sodium-aluminum-hydrogen four hydrogen storage material; Preferably, the medium for the wet pre-ball-milling is an inert ball-milling medium; Preferably, the inert ball-milling medium is n-hexane, cyclohexane, anhydrous ethanol or acetone; Preferably, the amount ratio of the inert ball-milling medium to the multi-aluminum alloy strip during the wet pre-ball-milling is 1 mL:(1500-2000) mg; Preferably, the wet pre-ball-milling conditions are as follows: the ball-to-material ratio is 100-150:1, the rotating speed is 300-500 rpm / min, and the time is 3-9 h; Preferably, the multi-aluminum alloy powder is obtained after the wet pre-ball-milling and drying; Preferably, the drying temperature is 50-90 DEG C, and the drying time is 1-5 h.

7. The method of claim 1 or 6, wherein, In S2, the molar ratio of aluminum in the multi-aluminum alloy strip to sodium hydride is 1:

1. Preferably, the ball milling conditions are: ball-to-material ratio 100-150:1, rotation speed 300-500 rpm / min, time 20-40 h; Preferably, the hydrogen content in the hydrogen-containing reducing atmosphere is ≥99.0%; Preferably, the hydrogen pressure in the hydrogen-containing reducing atmosphere is 20-60 bar.

8. The sodium aluminum hydride IV hydrogen storage material prepared according to the method of any one of claims 1 to 7, wherein the sodium aluminum hydride IV hydrogen storage material has a hydrogen storage capacity of at least 4.5 wt% at 25°C and 1 atmosphere of hydrogen. The sodium aluminum hydride four hydrogen storage material comprises NaAlH4 and Na3AlH6; the content of the NaAlH4 is above 85wt% based on the weight of the sodium aluminum hydride four hydrogen storage material.

9. A hydrogen storage material, characterized by, The sodium aluminum hydride four hydrogen storage material prepared by the method of any one of claims 1-7 or the sodium aluminum hydride four hydrogen storage material of claim 8.

10. A hydrogen storage device, characterized by, The sodium aluminum hydride four hydrogen storage material prepared by the method of any one of claims 1-7 or the sodium aluminum hydride four hydrogen storage material of claim 8.

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