Solid hydrogen storage alloy adsorption bed containing hierarchical pore structure, preparation method and application

Abstract

The invention belongs to the technical field of solid hydrogen storage materials, and relates to a solid hydrogen storage alloy adsorption bed containing a hierarchical pore structure, a preparation method and application, urea is decomposed at a high temperature to form tiny pores, and soluble salt is removed through water dissolution to form macropores, so that accurate regulation and control of the hierarchical pore structure are realized; a heat conduction channel is formed by adding a high heat conduction phase into hydrogen storage alloy powder, the heat exchange efficiency in the hydrogen absorption and desorption process is remarkably improved, a heat conduction network is formed by adding a high heat conduction phase material, and the heat conduction performance of the adsorption bed is improved; due to the addition of the binder, the formability of the mixed powder is improved, and the uniformity and mechanical strength of a green body in the cold pressing process are ensured; the adsorption bed with a multi-stage pore structure is constructed by combining cold press molding with multi-stage template removal. According to the porous solid hydrogen storage alloy structure, the specific surface area of the adsorption bed is increased, the diffusion path of hydrogen in the material is optimized, and the mass transfer efficiency is remarkably improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid hydrogen storage materials and relates to a solid hydrogen storage alloy adsorption bed with a multi-level pore structure, a preparation method and an application thereof. Background Art

[0002] Solid-state hydrogen storage technology is considered one of the core links in the large-scale application of hydrogen energy due to its high safety and volumetric hydrogen storage density advantages. As the mainstream solid-state hydrogen storage material, hydrogen storage alloys have hydrogen absorption and desorption kinetics and mass transfer efficiency that are highly dependent on the porous structure characteristics of the material. Traditional porosification methods (such as powder metallurgy foaming, chemical etching, or 3D printing) face significant bottlenecks: the foaming method requires high-temperature sintering (>800°C), which can easily cause alloy grain coarsening, oxidation, and hydrogen storage capacity degradation; although chemical etching can form pores, the strong acid / alkali environment will cause alloy surface passivation and reduce cycle stability; and 3D printing technology is limited by high equipment cost and small molding size, making it difficult to meet the needs of large-scale applications such as on-board hydrogen storage systems. In addition, the above methods have insufficient control over porosity (usually <40%), pore size distribution (discreteness >50%), and pore connectivity, which seriously restricts the diffusion rate of hydrogen in the adsorption bed. In recent years, template methods (such as polymer templates) have attracted much attention due to their ability to precisely design pore structures. However, template removal often relies on high-temperature pyrolysis or organic solvent dissolution, which poses challenges such as high energy consumption, heavy pollution, and residual impurities that affect alloy activity. Therefore, developing a low-temperature, environmentally friendly process for preparing porous hydrogen storage alloys with controllable pore structures is of urgent importance for overcoming the difficult mass transfer-strength trade-off in the engineering application of solid-state hydrogen storage technology. Summary of the Invention

[0003] In response to the problems existing in the prior art, the present invention provides a solid hydrogen storage alloy adsorption bed with a multi-level pore structure, a preparation method and an application. This porous solid hydrogen storage alloy structure not only increases the specific surface area of ​​the adsorption bed, but also optimizes the diffusion path of hydrogen in the material, significantly improving the mass transfer efficiency.

[0004] The present invention is achieved through the following technical solutions:

[0005] A method for preparing a solid hydrogen storage alloy adsorption bed containing a multi-level pore structure, comprising:

[0006] S1, hydrogen storage alloy powder, soluble salt, urea and high thermal conductivity phase material are mixed in proportion, and a binder is added to obtain a mixed powder;

[0007] S2, preparing the mixed powder into a green body through a cold pressing process,

[0008] S3, placing the green body in an inert atmosphere for urea pyrolysis treatment, immersing the green body after pyrolysis in deionized water for desalination treatment, and removing the urea to form a three-dimensional interconnected macroporous structure in the green body, thereby obtaining a green body after template removal;

[0009] S4, drying the green body after the template is removed to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0010] Preferably, the binder addition ratio accounts for 1wt%-5wt% of the mass fraction of the mixed powder, the urea addition ratio accounts for 0.1wt%-2wt% of the mass fraction of the mixed powder, the high thermal conductivity phase material addition ratio accounts for 0.01wt%-0.1wt% of the mass fraction of the mixed powder, the hydrogen storage alloy powder accounts for 70wt%-93wt% of the total mass of the mixed powder; and the soluble salt accounts for 5wt%-25wt% of the total mass of the mixed powder.

[0011] Preferably, the hydrogen storage alloy powder is one of LaNi5, TiMn2, Mg2Ni, TiFe and ZrMn2, and has a particle size range of 10-100 μm.

[0012] Preferably, the soluble salt is one of NaCl, KCl, Na2SO4 and K2SO4, and has a particle size range of 50-500 μm.

[0013] Preferably, the high thermal conductivity phase material is at least one of copper powder, aluminum powder, graphene and carbon nanotubes.

[0014] Preferably, the binder is one of polyvinyl alcohol and polyethylene glycol.

[0015] Preferably, the mixing process in S1 is ball milling, the mixing time is 30-60 min, and the mixing speed is 200-500 rpm; the pressure range of the cold pressing process in S2 is 50-200 MPa, and the holding time is 5-30 min.

[0016] Preferably, the urea pyrolysis temperature in S3 is 100-200°C, the pyrolysis time is 2-6 hours, and the inert atmosphere is argon or nitrogen; the desalination treatment method is deionized water immersion assisted by ultrasonic or magnetic stirring, the desalination time is 4-12 hours, and the deionized water is replaced every 30-60 minutes.

[0017] A solid hydrogen storage alloy adsorption bed containing a multi-level pore structure is prepared based on the preparation method of the solid hydrogen storage alloy adsorption bed containing a multi-level pore structure.

[0018] Application of a solid hydrogen storage alloy adsorption bed with a multi-level pore structure The solid hydrogen storage alloy adsorption bed with a multi-level pore structure is applied to vehicle-mounted hydrogen storage systems and distributed hydrogen energy storage scenarios.

[0019] Compared with the prior art, the present invention has the following beneficial technical effects:

[0020] The present invention provides a method for preparing a porous solid-state hydrogen storage alloy adsorption bed based on a combination of a soluble salt template method and a urea template method. This method combines cold pressing with multi-stage template removal to create an adsorption bed with a hierarchical pore structure. Urea decomposes at high temperatures to form micropores, while the soluble salt is removed through water dissolution to form macropores, enabling precise control of the hierarchical pore structure. Furthermore, the addition of a highly thermally conductive phase to the hydrogen storage alloy powder creates heat conduction channels, significantly improving heat exchange efficiency during hydrogen absorption and desorption. The hydrogen storage alloy powder serves as the main material of the adsorption bed, while the soluble salt and urea serve as dual template materials. The hierarchical pore structure is constructed by thermally decomposing the urea to form micropores and dissolving the soluble salt to form macropores. The addition of the highly thermally conductive phase forms a heat-conducting network, enhancing the thermal conductivity of the adsorption bed. The addition of a binder improves the formability of the mixed powder and ensures uniformity and mechanical strength of the blank during cold pressing. This porous solid-state hydrogen storage alloy structure not only increases the specific surface area of ​​the adsorption bed but also optimizes the diffusion pathways of hydrogen within the material, significantly improving mass transfer efficiency. The multi-level pore structure enables the adsorption bed to respond quickly during the hydrogen absorption and desorption process, thereby improving the hydrogen storage capacity and hydrogen absorption rate. By adding a high thermal conductivity phase material to the hydrogen storage alloy powder, the present invention forms an efficient heat conduction channel between the alloy particles. These heat conduction channels can quickly transfer the heat generated during the hydrogen absorption and desorption process, avoiding local overheating or uneven temperature. The introduction of a high thermal conductivity network improves the thermal conductivity of the adsorption bed, significantly improves the heat exchange efficiency during the hydrogen absorption and desorption process, and shortens the hydrogen absorption and desorption cycle time. At the same time, the efficient heat exchange capacity reduces the thermal stress of the alloy particles during the hydrogen absorption and desorption process, suppresses pulverization and structural collapse, and thus improves the cycle stability of the adsorption bed.

[0021] Furthermore, this design is applicable to a variety of hydrogen storage alloy materials (such as LaNi5, TiMn2, Mg2Ni, etc.), and can meet the requirements of mass transfer efficiency and hydrogen storage performance in different application scenarios.

[0022] Furthermore, the present invention adopts a process combining cold forming and template removal to avoid the damage to the performance of hydrogen storage alloys caused by high-temperature treatment, while reducing energy consumption and equipment costs. Both urea pyrolysis and soluble brine are green processes with no pollution emissions. Compared with traditional porous methods (such as foaming method, 3D printing), the production cost of the present invention is reduced and has significant economic benefits. In addition, the cold forming and template removal process is easy to realize continuous and automated production, and the single processing capacity can reach 100-200kg / h, which is suitable for large-scale application scenarios such as on-board hydrogen storage systems and distributed hydrogen energy storage stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of a method for preparing a solid hydrogen storage alloy adsorption bed with a multi-level pore structure. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to specific embodiments, which are intended to explain the present invention rather than to limit it.

[0025] The present invention provides a method for preparing a porous solid-state hydrogen storage alloy adsorption bed based on a combination of a soluble salt template method and a urea template method. By combining cold pressing with multi-stage template removal, an adsorption bed with a multi-level pore structure is constructed. Urea decomposes at high temperatures to form tiny pores, while soluble salts are removed by water dissolution to form macropores, thereby achieving precise control of the multi-level pore structure. At the same time, by adding a high thermal conductivity phase (such as copper powder, graphene, aluminum powder, carbon nanotubes) to the hydrogen storage alloy powder, a heat conduction channel is formed, which significantly improves the heat exchange efficiency during the hydrogen absorption and desorption process. Figure 1 As shown, the following is a detailed description of the technical solution:

[0026] Step 1: Mixing and pretreatment of raw materials. Mix hydrogen storage alloy powder, soluble salt, urea and high thermal conductivity phase material in proportion, and add an appropriate amount of binder. Hydrogen storage alloy powder is used as the main material of the adsorption bed, and soluble salt and urea are used as dual template materials to form large pores and micro pores, respectively. The addition of high thermal conductivity phase material is intended to form a thermal conductive network and improve the thermal conductivity performance of the adsorption bed. The addition of binder improves the formability of the mixed powder and ensures the uniformity and mechanical strength of the blank during the cold pressing process. The mixing process must be fully uniform to avoid problems such as uneven density or discontinuous pore structure distribution during subsequent pressing.

[0027] Step 2: Cold pressing. The mixed powder is placed in a mold and a green body is prepared by cold pressing. During the cold pressing process, the hydrogen storage alloy powder is densely packed under pressure, while the soluble salt particles are distributed between the alloy particles as a placeholder phase, forming a preliminary pore structure framework. The advantage of the cold pressing process is that it avoids the damage to the properties of the hydrogen storage alloy caused by high-temperature treatment (such as grain coarsening, oxidation or pulverization). At the same time, by adjusting the pressure and holding time, the density and mechanical strength of the green body can be precisely controlled.

[0028] Step 3: Multi-stage template removal. Urea pyrolysis: The green body is placed in a high-temperature argon atmosphere, where urea pyrolyzes to generate gas and form micropores. Salt template removal: The pyrolyzed green body is immersed in deionized water to dissolve away the soluble salt template. Ultrasonic assistance or mechanical stirring can be used to accelerate the dissolution process and ensure complete removal of salt particles. After dissolution is complete, a three-dimensional interconnected macroporous structure is formed in the green body.

[0029] Step 4: Drying. The green body after the template is removed is dried to remove residual moisture or pyrolysis products and stabilize the pore structure. The drying process is carried out under vacuum or inert atmosphere to avoid oxidation of the alloy surface. By controlling the drying temperature and time, the mechanical properties and pore connectivity of the adsorption bed can be further optimized. The dried porous hydrogen storage alloy adsorption bed has a multi-level pore structure (micropores + macropores), high porosity and good mechanical strength, and is suitable for application scenarios such as on-board hydrogen storage systems and distributed hydrogen energy storage.

[0030] In step 1, the hydrogen storage alloy powder is one of LaNi5, TiMn2, Mg2Ni, TiFe, and ZrMn2, with a particle size range of 10-100 μm, and the hydrogen storage alloy powder accounts for 70wt% to 93wt% of the total mass of the mixed powder.

[0031] Wherein, the soluble salt in step 1 is one of NaCl, KCl, Na2SO4, and K2SO4, with a particle size range of 50-500 μm, and the soluble salt accounts for 5wt% to 25wt% of the total mass of the mixed powder.

[0032] Wherein, in step 1, the high thermal conductivity phase material is one of graphene, carbon nanotubes, copper powder and aluminum powder, and the addition ratio accounts for 0.01wt%-0.1wt% of the mass fraction of the mixed powder.

[0033] Wherein, the addition ratio of urea in step 1 is 0.1wt% to 2wt% of the mass fraction of the mixed powder;

[0034] Wherein, the binder in step 1 is one of polyvinyl alcohol (PVA) and polyethylene glycol (PEG), and the addition ratio accounts for 1wt%-5wt% of the mass fraction of the mixed powder.

[0035] Wherein, the mixing process in step 1 is ball milling, the mixing time is 30-60 min, and the mixing speed is 200-500 rpm.

[0036] In step 2, the cold pressing pressure range is 50-200 MPa, and the holding time is 5-30 min;

[0037] In step 3, the urea pyrolysis temperature is 100-200° C., the pyrolysis time is 2-6 hours, the atmosphere is argon or nitrogen protection, and the oxygen content is ≤10 ppm.

[0038] In step 3, the desalting method is deionized water immersion assisted by ultrasonic or magnetic stirring, the desalting time is 4-12 hours, and the deionized water is replaced every 30-60 minutes.

[0039] Wherein, in step 4, the drying temperature is 50-80° C., the drying time is 6-24 hours, the drying atmosphere is vacuum or argon, nitrogen, and the oxygen content is ≤10 ppm.

[0040] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0041] Example 1: Multi-level pore structure LaNi5 hydrogen storage adsorption bed

[0042] Step 1: 85.95wt% LaNi5 powder (particle size 50μm), 10wt% NaCl particles (particle size 200μm), urea (1wt%) and graphene (0.05wt%) were mixed in proportion and added polyethylene glycol (3wt%), and mixed to obtain a mixed powder, wherein the mixing process is ball milling, the mixing time is 50min, and the mixing speed is 350rpm;

[0043] Step 2: The mixed powder is loaded into a mold and a green body is prepared by a cold pressing process with a pressure of 150 MPa and a holding time of 15 min.

[0044] Step 3: The green body is placed in an argon atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 150°C for 4 hours. After cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 8 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 40 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and a green body after template removal is obtained.

[0045] Step 4: The green body after the template is removed is placed in a vacuum dryer at 60° C. for 18 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0046] Performance characterization: The LaNi5 hydrogen storage adsorption bed has a porosity of 70%, with micropores accounting for 30% and macropores for 40%. Thermal conductivity is increased by 150% compared to a bed without the addition of a high-thermal-conductivity phase. The hydrogen absorption rate is shortened from 120 minutes for a conventional block to 25 minutes at 298K to 90% saturation. After 100 cycles, the capacity retention rate is 95%, and the compressive strength is 90 MPa.

[0047] Example 2:

[0048] Hierarchical pore structure TiMn2 hydrogen storage adsorption bed

[0049] Step 1: 81.97 wt% TiMn2 powder (particle size 50 μm), 15 wt% KCl particles (particle size 150 μm), urea (1 wt%), and carbon nanotubes (0.03 wt%) were mixed in proportion, and polyvinyl alcohol (PVA, 2 wt%) was added to obtain a mixed powder. The mixing process was ball milling, the mixing time was 60 min, and the mixing speed was 200 rpm.

[0050] Step 2: The mixed powder is loaded into a mold and a green body is prepared by a cold pressing process with a pressure of 120 MPa and a holding time of 20 min.

[0051] Step 3: The green body is placed in an argon atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 160°C for 3 hours. After cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 6 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 30 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and a green body after template removal is obtained.

[0052] Step 4: The green body after the template is removed is placed in a vacuum dryer at 70° C. for 12 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0053] Performance Characterization: The TiMn2 hydrogen storage adsorption bed has a porosity of 65%, with macropores accounting for 45% and micropores for 20%. Its thermal conductivity is 14.5 W / (m·K). At 298K and 2 MPa, the time required to achieve 90% saturation hydrogen absorption is 20 minutes. After 100 cycles, the capacity retention rate is 92%, and the compressive strength is 85 MPa.

[0054] Example 3: Multi-level pore structure Mg2Ni hydrogen storage adsorption bed

[0055] Step 1: 82.4 wt% Mg2Ni powder (particle size 30 μm), 12 wt% NaCl particles (particle size 100 μm), urea (1.5 wt%), and copper powder (0.1 wt%) were mixed in proportion, and polyethylene glycol (PEG, 4 wt%) was added to obtain a mixed powder. The mixing process was ball milling, the mixing time was 30 min, and the mixing speed was 500 rpm.

[0056] Step 2: The mixed powder is placed in a mold and a green body is prepared by cold pressing at 100 MPa with a holding pressure of 10 min.

[0057] Step 3: The green body is placed in a nitrogen atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 140°C for 5 hours. After cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 10 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 30 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and a green body after template removal is obtained.

[0058] Step 4: The green body after the template is removed is placed in a vacuum dryer at 50° C. for 24 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0059] Performance Characterization: The Mg2Ni hydrogen storage bed has a porosity of 58%, primary channel pores of 50-200 μm, and secondary channels of 0.5-5 μm. The thermal conductivity is 12.8 W / (m·K). The hydrogen absorption rate is 1.8 wt% / min at 300°C. Structural integrity remains good after 50 cycles, and hydrogen absorption activity is demonstrated at 150°C.

[0060] Example 4: Multi-level pore structure TiFe hydrogen storage adsorption bed

[0061] Step 1: Mix 85.72wt% TiFe powder (particle size 40μm), 10wt% Na2SO4 particles (particle size 300μm), urea (1.2wt%) and aluminum powder (0.08wt%) in proportion and add polyethylene glycol (3wt%), and mixed to obtain a mixed powder, wherein the mixing process is ball milling, the mixing time is 40min, and the mixing speed is 400rpm;

[0062] Step 2: The mixed powder is placed in a mold and a green body is prepared by cold pressing at 180 MPa and holding pressure for 25 minutes.

[0063] Step 3: The green body is placed in a nitrogen atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 170 ° C for 4 hours; after cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 8 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 60 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and a green body after template removal is obtained;

[0064] Step 4: The green body after the template is removed is placed in a vacuum dryer at 80° C. for 12 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0065] Performance characterization: The porosity of the TiFe hydrogen storage adsorption bed is 62%, and the pore connectivity exceeds 95%. The hydrogen storage capacity is 1.85wt%, the hysteresis coefficient is 0.08, and the volumetric hydrogen storage density is 55kg / m 3, CO tolerance is increased by 3 times. The thermal response time is shorter than 90 seconds, and the thermal conductivity anisotropy ratio is 1.2:1.

[0066] Example 5: Multi-level pore structure ZrMn2 hydrogen storage adsorption bed

[0067] Step 1: Mix 75.72% ZrMn2 powder (particle size 80μm), 20wt% K2SO4 particles (particle size 300μm), urea (1.2wt%) and aluminum powder (0.08wt%) in proportion and add polyethylene glycol (3wt%), and mixed to obtain a mixed powder, wherein the mixing process is ball milling, the mixing time is 50min, and the mixing speed is 300rpm;

[0068] Step 2: The mixed powder is placed in a mold and a green body is prepared by cold pressing at 180 MPa and holding pressure for 25 minutes.

[0069] Step 3: The green body is placed in a nitrogen atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 170 ° C for 4 hours; after cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 8 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 60 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and a green body after template removal is obtained;

[0070] Step 4: The green body after the template is removed is placed in a vacuum dryer at 80° C. for 12 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0071] Performance characterization: The porosity deviation of the ZrMn2 hydrogen storage adsorption bed is controlled within ±3%, and the pore structure retention rate is greater than 90% at 400°C. The hydrogen absorption rate is 1.2wt% / min at -20°C. The hydrogen storage density is 1.92wt%, and the capacity decay rate after 500 cycles is 7%. The permeability is 1.5×10 -12 m 2 , the surface has a 50μm dense protective layer.

[0072] Example 6: Multi-level pore structure ZrMn2 hydrogen storage adsorption bed

[0073] Step 1: 70% ZrMn2 powder (particle size 100 μm), 25 wt% K2SO4 particles (particle size 300 μm), urea (2 wt%), and carbon nanotubes (0.01 wt%) were mixed in proportion, and polyvinyl alcohol (2.99 wt%) was added to obtain a mixed powder. The mixing process was ball milling, the mixing time was 30 minutes, and the mixing speed was 500 rpm.

[0074] Step 2: The mixed powder is placed in a mold and a green body is prepared by cold pressing at 200 MPa with a holding pressure of 5 minutes.

[0075] Step 3: The green body is placed in a nitrogen atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 100 ° C for 6 hours. After cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 12 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 60 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and the green body after template removal is obtained.

[0076] Step 4: The green body after the template is removed is placed in a vacuum dryer at 80° C. for 12 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0077] Performance characterization: The porosity deviation of the ZrMn2 hydrogen storage adsorption bed is controlled within ±3%, and the pore structure retention rate is greater than 90% at 400°C. The hydrogen absorption rate is 1.1wt% / min at -20°C. The hydrogen storage density is 1.87wt%, and the capacity decay rate is 7% after 500 cycles. The permeability is 1.5×10 -12 m 2 , the surface has a 70μm dense protective layer.

[0078] Example 7: Multi-level pore structure TiFe hydrogen storage adsorption bed

[0079] Step 1: 93 wt% TiFe powder (particle size 10 μm), 5 wt% Na2SO4 particles (particle size 50 μm), urea (0.1 wt%), and graphene (0.1 wt%) were mixed in proportion, and polyvinyl alcohol (1.8 wt%) was added to obtain a mixed powder. The mixing process was ball milling, the mixing time was 60 min, and the mixing speed was 500 rpm.

[0080] Step 2: The mixed powder is placed in a mold and a green body is prepared by cold pressing at 50 MPa and holding pressure for 30 minutes.

[0081] Step 3: The green body is placed in a nitrogen atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 200 ° C for 4 hours; after cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 4 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 30 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and the green body after template removal is obtained;

[0082] Step 4: The green body after the template is removed is placed in a vacuum dryer at 80° C. for 12 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0083] Performance characterization: The porosity of the TiFe hydrogen storage adsorption bed is 63%, and the pore connectivity exceeds 93%. The hydrogen storage capacity is 1.74wt%, the hysteresis coefficient is 0.07, and the volumetric hydrogen storage density is 57kg / m 3 , CO tolerance is increased by 3 times. The thermal response time is shorter than 90 seconds, and the thermal conductivity anisotropy ratio is 1.3:1.

[0084] Example 8: Multi-level pore structure Mg2Ni hydrogen storage adsorption bed

[0085] Step 1: 77.9 wt% Mg2Ni powder (particle size 100 μm), 15 wt% NaCl particles (particle size 500 μm), urea (2 wt%), and copper powder (0.1 wt%) were mixed in proportion, and polyethylene glycol (PEG, 5 wt%) was added to obtain a mixed powder. The mixing process was ball milling, the mixing time was 30 min, and the mixing speed was 500 rpm.

[0086] Step 2: The mixed powder is placed in a mold and a green body is prepared by cold pressing at 100 MPa with a holding pressure of 10 min.

[0087] Step 3: The green body is placed in a nitrogen atmosphere (oxygen content ≤ 10 ppm) for urea pyrolysis treatment. The urea pyrolysis treatment condition is to keep the temperature at 100 ° C for 6 hours. After cooling, the pyrolyzed green body is immersed in deionized water for desalination treatment. The desalination time is 8 hours by static deionized water immersion assisted by magnetic stirring at room temperature. The deionized water is replaced every 30 minutes. After removal, a three-dimensional interconnected macroporous structure is formed in the green body, and the green body after template removal is obtained.

[0088] Step 4: The green body after the template is removed is placed in a vacuum dryer at 50° C. for 24 hours to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

[0089] Performance Characterization: The Mg2Ni hydrogen storage bed has a porosity of 68%, primary channel pore sizes of 100-500 μm, and secondary channels of 0.8-9 μm. Its thermal conductivity is 13.4 W / (m·K). Its hydrogen absorption rate is 1.9 wt% / min at 300°C. Structural integrity remains good after 50 cycles, and hydrogen absorption activity is demonstrated at 150°C.

[0090] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or are inherent to these processes, methods, products or apparatuses.

[0091] It should be noted that when a component is referred to as being "fixed to" another component, it may be directly on the other component or there may be a central component. When a component is referred to as being "connected to" another component, it may be directly connected to the other component or there may be a central component. When a component is referred to as being "disposed on" another component, it may be directly disposed on the other component or there may be a central component.

[0092] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification of the present invention are for the purpose of describing specific embodiments only and are not intended to limit the present invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0093] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in this industry can smoothly implement the present invention as shown in the drawings and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with this profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing a solid hydrogen storage alloy adsorption bed containing a multi-level pore structure, characterized in that: include, S1, hydrogen storage alloy powder, soluble salt, urea and high thermal conductivity phase material are mixed in proportion, and a binder is added to obtain a mixed powder; S2, preparing the mixed powder into a green body through a cold pressing process; S3, placing the green body in an inert atmosphere for urea pyrolysis treatment, immersing the green body after pyrolysis in deionized water for desalination treatment, after which soluble salts are removed, a three-dimensional interconnected macroporous structure is formed in the green body, and a green body after template removal is obtained; S4, drying the green body after the template is removed to obtain a solid hydrogen storage alloy adsorption bed with a multi-level pore structure.

2. The method for preparing a solid hydrogen storage alloy adsorption bed containing a multi-level pore structure according to claim 1, characterized in that: The binder addition ratio accounts for 1wt%-5wt% of the mass fraction of the mixed powder, the urea addition ratio accounts for 0.1wt%-2wt% of the mass fraction of the mixed powder, the high thermal conductivity phase material addition ratio accounts for 0.01wt%-0.1wt% of the mass fraction of the mixed powder, the hydrogen storage alloy powder accounts for 70wt%-93wt% of the total mass of the mixed powder; and the soluble salt accounts for 5wt%-25wt% of the total mass of the mixed powder.

3. The method for preparing a solid hydrogen storage alloy adsorption bed containing a multi-level pore structure according to claim 1, characterized in that: The hydrogen storage alloy powder is one of LaNi5, TiMn2, Mg2Ni, TiFe and ZrMn2, and has a particle size range of 10-100 μm.

4. The method for preparing a solid hydrogen storage alloy adsorption bed with a multi-level pore structure according to claim 1, characterized in that: The soluble salt is one of NaCl, KCl, Na2SO4 and K2SO4, and has a particle size range of 50-500 μm.

5. The method for preparing a solid hydrogen storage alloy adsorption bed with a multi-level pore structure according to claim 1, characterized in that: The high thermal conductivity phase material is at least one of copper powder, aluminum powder, graphene and carbon nanotubes.

6. The method for preparing a solid hydrogen storage alloy adsorption bed containing a multi-level pore structure according to claim 1, characterized in that: The binder is one of polyvinyl alcohol and polyethylene glycol.

7. The method for preparing a solid hydrogen storage alloy adsorption bed with a multi-level pore structure according to claim 1, characterized in that: The mixing process in S1 is ball milling, the mixing time is 30-60 min, and the mixing speed is 200-500 rpm; the pressure range of the cold pressing process in S2 is 50-200 MPa, and the holding time is 5-30 min.

8. The method for preparing a solid hydrogen storage alloy adsorption bed with a multi-level pore structure according to claim 1, characterized in that: The urea pyrolysis temperature in S3 is 100-200°C, the pyrolysis time is 2-6 hours, and the inert atmosphere is argon or nitrogen. The desalination treatment method is deionized water immersion assisted by ultrasonic or magnetic stirring, the desalination time is 4-12 hours, and the deionized water is replaced every 30-60 minutes.

9. A solid hydrogen storage alloy adsorption bed containing a multi-level pore structure, prepared based on the preparation method of a solid hydrogen storage alloy adsorption bed containing a multi-level pore structure according to any one of claims 1 to 8.

10. The use of a solid hydrogen storage alloy adsorption bed with a multi-level pore structure according to claim 9, characterized in that: The solid-state hydrogen storage alloy adsorption bed containing a multi-level pore structure is applied to vehicle-mounted hydrogen storage systems and distributed hydrogen energy storage scenarios.

Images