High-thermal-conductivity, anti-cracking and pulverization composite hydrogen storage briquette and preparation method thereof

Abstract

The application discloses a kind of high thermal conductivity, anti-cracking pulverization composite hydrogen storage briquettes and preparation method thereof, to solve the problem that existing hydrogen storage briquettes are difficult to simultaneously meet the comprehensive needs of high thermal conductivity, high porosity and long cycle anti-pulverization.The composition of the composite hydrogen storage briquette comprises 85-90% hydrogen storage alloy powder, 2-5% binder, 2-5% expanded graphite and 5-8% negative expansion material by mass percentage, and the composite hydrogen storage briquette is formed by sequentially mixing hydrogen storage alloy powder, binder, expanded graphite and negative expansion material and then cold pressing.The application uses expanded graphite to build a heat conduction network, uses a binder to improve mechanical strength, and introduces a negative expansion material to generate a compression prestress to offset the hydrogen absorption expansion of the alloy, achieving a synergistic optimization of high thermal conductivity, high packing density and excellent anti-pulverization performance, and being suitable for solid-state hydrogen storage devices.

Description

Technical Field

[0001] This invention relates to a hydrogen storage alloy briquette, specifically to a composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization, and its preparation method. Background Technology

[0002] Hydrogen energy, as a clean and efficient secondary energy source, relies heavily on storage and transportation as key links in the hydrogen energy industry chain. Solid-state hydrogen storage technology has attracted significant attention due to its high volumetric hydrogen storage density and good safety. Among these technologies, hydrogen storage alloy powders have important application value in hydrogen storage devices due to their advantages such as low cost, good activation performance, and fast hydrogen absorption and desorption kinetics. However, in practical applications, hydrogen storage alloy powders face the dual bottlenecks of low thermal conductivity (approximately 1 W / (m·K)) and poor stability during hydrogen absorption and desorption cycles (i.e., cracking and pulverization). Furthermore, when pressed into hydrogen storage blocks, their mechanical strength and formability deteriorate, which severely restricts the heat transfer efficiency and service life of reactors in hydrogen storage devices.

[0003] To address the issue of low thermal conductivity, existing technologies involve adding highly thermally conductive fillers such as expanded graphite to hydrogen storage alloy powder. Expanded graphite can construct a thermally conductive network within the alloy matrix, thereby significantly improving heat transfer performance. However, the amount of expanded graphite added must be strictly controlled. If the amount is too low, an effective thermal conductive pathway cannot be formed; if the amount is too high, it will reduce porosity and hinder hydrogen diffusion.

[0004] To address the issues of mechanical strength and formability, existing technologies typically introduce binders such as silicone into hydrogen storage alloy powder. This allows for the molding of hydrogen storage briquettes at lower molding pressures, thereby improving the mechanical strength of the briquettes. However, the specific amount of binder added is difficult to control. Too little binder can lead to briquette breakage, while too much binder can clog the active sites of the briquettes, reducing the hydrogen storage kinetics of the hydrogen storage alloy.

[0005] The so-called cracking and pulverization problem refers to the cracking and pulverization of the hydrogen storage briquettes during hydrogen absorption and desorption cycles, caused by the approximately 15-20% volume expansion of the briquettes during hydrogen absorption. Repeated cycles generate accumulated internal stress, leading to cracking and pulverization of the briquettes. Cracked and pulverized alloy particles not only have reduced thermal conductivity but may also cause valve blockage and reactor failure in the hydrogen storage device. To address this problem, Chinese invention patent CN121085216A discloses a hydrogen storage material, its preparation method, and a hydrogen storage system. The hydrogen storage material is prepared by combining hydrogen storage alloy powder, a volume expansion buffer, a thermally conductive material, and a silane coupling agent / polyimide, followed by cold pressing and heat treatment in an inert atmosphere at 110-150°C. While this hydrogen storage material uses a covalent bond interface formed by the polymer buffer and coupling agent to suppress alloy cracking and pulverization, it has the following drawbacks:

[0006] (1) Hydrogen storage materials rely solely on the elastic buffering of polymer buffers to offset expansion stress, which cannot fundamentally compensate for the positive expansion of the alloy absorbing hydrogen. If the cycle continues for a long time, there is still a risk of interface debonding.

[0007] (2) The heat treatment process during preparation increases the preparation process and energy consumption, thereby increasing the complexity of the process;

[0008] (3) No negative expansion material was introduced in the preparation process, so the volume cannot be accurately compensated by the prestress field, resulting in a lack of synergy between anti-cracking and pulverization and thermal conductivity.

[0009] In summary, existing technologies can only improve thermal conductivity, strength, or inhibit alloy cracking and pulverization in a single aspect, but cannot achieve synergistic effects of multiple properties. Therefore, it is difficult to simultaneously meet the comprehensive requirements of high thermal conductivity, high porosity, and long-cycle resistance to pulverization of hydrogen storage blocks. Summary of the Invention

[0010] The purpose of this invention is to solve the technical problem that existing hydrogen storage blocks cannot simultaneously meet the comprehensive requirements of high thermal conductivity, high porosity and long-cycle anti-pulverization, and to provide a composite hydrogen storage block with high thermal conductivity and anti-cracking and anti-pulverization and its preparation method.

[0011] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0012] A composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization, characterized by:

[0013] The composition, by weight percentage, includes 85% to 90% hydrogen storage alloy powder, 2% to 5% binder, 2% to 5% expanded graphite, and 5% to 8% negative expansion material.

[0014] In this invention, the mass percentage of hydrogen storage alloy powder is set to 85%~90%. This ratio can ensure that the composite hydrogen storage briquettes have a high volumetric hydrogen storage density and also leave sufficient space for functional additives.

[0015] The mass percentage of the binder is set at 2% to 5%. This ratio is the critical amount to maintain the mechanical strength of the composite hydrogen storage block. If the content is too low, the composite hydrogen storage block will be easily broken. If it is too high, it will easily block the active sites on the alloy surface and reduce the hydrogen storage kinetics.

[0016] Expanded graphite accounts for 2% to 5% of the mass. It can build a preliminary thermally conductive network in the alloy matrix, increasing the thermal conductivity from about 1 W / (m·K) of the pure alloy to 3 to 5 W / (m·K). However, excessive addition should be avoided to prevent excessive reduction in porosity.

[0017] The mass percentage of the negative expansion material is set at 5% to 8%, a key ratio derived from bulk modulus matching calculations. At this addition level, the negative expansion modulus of the negative expansion material and the hydrogen absorption expansion modulus of the hydrogen storage alloy powder achieve optimal matching. The resulting compressive prestress can precisely offset approximately 15% to 20% of the volume expansion of the hydrogen storage alloy during hydrogen absorption, controlling the net expansion rate of the composite hydrogen storage briquettes to within 8%, thus fundamentally suppressing cracking and pulverization during hydrogen absorption and desorption cycles. When the addition level is below 5%, the negative expansion compensation is insufficient, the prestress field is weak, and it cannot effectively constrain the expansion of the hydrogen storage alloy, making the briquettes prone to microcracks and pulverization. When the addition level is above 8%, the mismatch between the bulk modulus of the negative expansion material and the hydrogen storage alloy intensifies, the interfacial stress increases significantly, and the effective volume of the hydrogen storage alloy is squeezed, leading to a decrease in hydrogen storage density and deterioration of mechanical properties. Therefore, a mass percentage of 5% to 8% for the negative expansion material represents the optimal range for balancing stress compensation, mechanical strength, and hydrogen storage performance. The compressive stress generated by this addition can effectively offset the internal stress caused by the hydrogen absorption expansion of the hydrogen storage alloy, keeping the net expansion within 8%, thereby significantly inhibiting cracking and pulverization during the cycling process.

[0018] Furthermore, the hydrogen storage alloy powder is selected from either AB2 series alloy powder or AB5 series alloy powder.

[0019] Furthermore, the AB2 series alloy powder is selected from TiMn2 powder; the AB5 series alloy powder is selected from LaNi5 powder.

[0020] Furthermore, the adhesive is selected as X-1910 silicone; the negative expansion material is selected as ZrW2O8 or Al2W3O. 12 .

[0021] Furthermore, the adhesive is selected from any one of V-1510 silicone, polyurethane, and epoxy resin; the negative expansion material is selected from ZrW2O8 or Al2W3O. 12 .

[0022] Furthermore, the mass percentages of the hydrogen storage alloy powder, binder, expanded graphite, and negative expansion material are 86%:5%:3%:6%.

[0023] Meanwhile, this invention also provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, characterized by the following steps:

[0024] Step 1: Prepare hydrogen storage alloy powder, binder, expanded graphite and negative expansion material according to the mass percentage;

[0025] Step 2: Place the hydrogen storage alloy powder and binder in a container and stir evenly to obtain the first mixture;

[0026] In this invention, the hydrogen storage alloy powder is first premixed with a binder because the binder needs to uniformly coat the surface of the hydrogen storage alloy powder to form a continuous adhesive layer. This step uses a "dry mixing" method, utilizing the adhesive properties of the binder to ensure uniform adhesion to the surface of the hydrogen storage alloy, laying the foundation for the subsequent addition of other components.

[0027] Step 3: Add expanded graphite to the first mixture and stir until homogeneous to obtain the second mixture;

[0028] The reason for adding expanded graphite in the first mixture formed by the binder and hydrogen storage alloy is that expanded graphite has a layered structure and a high specific surface area. If it is added at the same time as the hydrogen storage alloy, it is easily selectively encapsulated by the binder and cannot effectively build a heat conduction network. The subsequent addition strategy allows the expanded graphite to be partially embedded in the interparticle gaps of the hydrogen storage alloy that has been adhered to the binder, and partially exposed on the surface to form a "bridging" structure, maximizing its heat conduction channel effect.

[0029] Step 4: Add the negative expansion material to the second mixture, stir evenly, and let stand for 2-5 minutes to obtain the pressed block blank;

[0030] This step employs the final addition and settling of the negative expansion material: the negative expansion material (such as ZrW2O8) is added last due to its high hardness (Mohs hardness 5~6) and high density (5.8 g / cm³). Adding it earlier would wear down other components during prolonged stirring and would easily cause sedimentation and stratification. Adding it later and stirring for 2~5 minutes utilizes the electrostatic self-assembly effect between its particles, allowing the negative expansion material to form a uniformly distributed skeletal structure within the viscous matrix, rather than agglomerates. This skeletal structure is a three-dimensional synergistic structure of negative expansion skeleton + thermally conductive network + binder layer, demonstrating a synergistic effect of 1+1>2. It provides rigid constraint in subsequent pressing and hydrogen absorption / desorption cycles, leveraging its negative expansion characteristics (e.g., ZrW2O8 is -8.7×10⁻⁸). -6 K -1 It generates continuous compressive prestress, counteracts the hydrogenation expansion of the alloy, and achieves a comprehensive effect that a single additive cannot achieve.

[0031] Step 5: Add the briquette blank into the pre-prepared mold and cold press to obtain a composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization.

[0032] Furthermore, the stirring time in steps 2, 3, and 4 is 3 to 10 minutes. The stirring time in step 2 is designed based on the kinetic balance of powder mixing. If the time is too short, the silica gel will be unevenly distributed, which may lead to local strength differences in the compressed block. If the time is too long, energy consumption will increase and too much air may be introduced. The stirring time in step 3 can ensure that the expanded graphite is evenly dispersed in the viscous system without being excessively broken, thereby protecting the integrity of its layered structure.

[0033] Furthermore, in step 5, the cold pressing molding is achieved by pressing the mold containing the compact blank at room temperature to 100MPa~300MPa using a tablet press, and then holding the pressure for 1~3 minutes to press and form the compact.

[0034] This step uses a pressing pressure range of 100MPa to 300MPa, which is an optimized choice that balances density and porosity. If the pressure is below 100MPa, the compaction strength will be insufficient and it will be prone to powdering. If the pressure is above 300MPa, the porosity will be too low (<15%), which will hinder hydrogen diffusion and reduce reaction kinetics. After that, the pressure is maintained for 1 to 3 minutes to allow the stress to be fully transferred and released, avoiding expansion and cracking after demolding. This results in a composite hydrogen storage compact that has the comprehensive properties of high thermal conductivity (expanded graphite network), high mechanical strength (silicone bonding), and resistance to cracking and powdering (stress compensation of negative expansion material).

[0035] The present invention has the following beneficial effects:

[0036] 1. The present invention provides a composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization, which has better hydrogen storage effect and higher packing density than hydrogen storage alloy powder, and can be applied in large hydrogen storage alloy reactors.

[0037] 2. The composite hydrogen storage block with high thermal conductivity and anti-cracking and pulverization provided by the present invention incorporates a binder (preferably X-1910 silicone), which can improve the mechanical strength of the composite hydrogen storage block, maintain its shape stability, and reduce the pressure required during pressing, thereby reducing equipment energy consumption and mold wear.

[0038] 3. The composite hydrogen storage block with high thermal conductivity and crack resistance provided by the present invention incorporates a negative expansion material (preferably ZrW2O8). It is not a simple functional superposition, but generates compressive prestress through negative expansion, forming a three-dimensional synergy with the expanded graphite thermal conductive network and silicone bonding system, thereby fundamentally inhibiting the expansion and cracking of the composite hydrogen storage block due to hydrogen absorption.

[0039] 4. In the composite hydrogen storage block with high thermal conductivity and crack resistance provided by the present invention, X-1910 silicone and ZrW2O8 form a stress buffer system. The compressive prestress provided by ZrW2O8 ensures that the silicone adhesive layer always bears compressive stress rather than tensile stress during hydrogen absorption, giving full play to the compressive strength of silicone and avoiding the interfacial failure caused by tensile shear of traditional adhesives. The combination of the two materials enables the composite hydrogen storage block to achieve structural stability while maintaining flexibility.

[0040] 5. In the composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization provided by the present invention, the negative expansion characteristics of ZrW2O8 and the positive expansion of hydrogen storage alloy powder form a volume compensation effect, which enables the thermally conductive network constructed by expanded graphite to maintain geometric stability during hydrogen absorption and desorption cycles, avoids graphite sheet peeling and interruption of thermal conduction pathways caused by alloy expansion, and achieves cycle stability of thermal conductivity.

[0041] 6. The present invention provides a method for preparing a composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization. First, hydrogen storage alloy powder is premixed with a binder to form a continuous adhesive layer on the surface of the hydrogen storage alloy powder. Then, expanded graphite is added, so that the expanded graphite is partially embedded in the gaps between the hydrogen storage alloy powder with the binder already adhered, and partially exposed on the surface to form a bridging structure, maximizing its thermal conductivity channel effect. Then, a negative expansion material is added, and the electrostatic self-assembly effect between its particles is used to allow the negative expansion material to form a uniformly distributed skeleton structure in the viscous matrix, thereby providing rigid constraints in subsequent pressing and hydrogen absorption / desorption cycles to counteract the hydrogenation expansion of the alloy. Finally, the composite hydrogen storage briquette is pressed and formed, achieving simultaneous improvement in thermal conductivity, strength, and resistance to pulverization, and solving the bottleneck of existing technologies that cannot simultaneously achieve multiple performances.

[0042] 7. Unlike traditional approaches that attempt to suppress alloy expansion, this invention utilizes the negative expansion of ZrW2O8 to generate an isotropic compressive prestress field, transforming the disordered expansion of the alloy into ordered elastic strain energy storage. This "softness overcomes hardness" strategy results in the compact exhibiting low expansion on a macroscopic scale, while the alloy maintains complete hydrogen absorption activity on a microscopic scale, thus avoiding the adverse effects of mechanical constraints on hydrogen storage kinetics. Attached Figure Description

[0043] Figure 1 A comparison of the kinetic curves of pure alloy powder, pure alloy powder briquettes, and composite hydrogen storage briquettes obtained by pressing them to 200 MPa using a briquetting machine according to Example 1 of this invention.

[0044] Figure 2 PCT curve of pure alloy powder;

[0045] Figure 3 PCT curve of pure alloy powder briquettes obtained by pressing to 200 MPa using a briquetting machine;

[0046] Figure 4 The PCT curve of the composite hydrogen storage block prepared in Example 1 of this invention is shown.

[0047] Figure 5 Comparison of the pulverization and cracking states of pure alloy powder compacts and composite hydrogen storage compacts prepared in Example 1 of this invention after one hydrogen absorption and desorption kinetic test.

[0048] Figure 6The left image shows the kinetic curve of the composite hydrogen storage block prepared in Example 1 of the present invention after 60 cycles, and the right image shows its state after cycling.

[0049] Figure 7 The diagram shows a comparison of the kinetic curves of the composite hydrogen storage blocks and pure metal powder blocks prepared in Examples 1, 4, 5, 6, and 7 of this invention. Detailed Implementation

[0050] To make the objectives, advantages, and features of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0051] Example 1

[0052] This embodiment provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, specifically including the following steps:

[0053] Step 1: Prepare TiMn2 powder (8.6g), X-1910 silica gel (0.5g), expanded graphite (0.3g), and ZrW2O8 negative expansion material (0.6g) with a mass percentage of 86%:5%:3%:6%.

[0054] Step 2: Place the weighed TiMn2 powder in a beaker, add the weighed X-1910 silica gel, and stir vigorously with a stirring rod for 3 minutes until fully mixed to obtain the first mixture.

[0055] Step 3: Add the weighed expanded graphite to the first mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous, thus obtaining the second mixture.

[0056] Step 4: Add the weighed ZrW2O8 negative expansion material to the second mixture, and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed. Then let it stand for 2 minutes to obtain the pressed block blank.

[0057] Step 5: Pour the compressed block blank into a cylindrical mold, place the cylindrical mold in a tablet press, press the tablet press to 200 MPa at room temperature, and hold the pressure for 1 minute to obtain the composite hydrogen storage block.

[0058] Figure 1 As shown in the figure, the kinetic curves of pure alloy (TiMn2) powder, pure metal powder briquettes, and the composite hydrogen storage briquettes obtained in this embodiment are compared. As can be seen from the figure, the hydrogen absorption rate of the composite hydrogen storage briquettes obtained in this embodiment is close to that of pure metal powder and significantly better than that of pure metal powder briquettes. This proves that the thermal conductivity network and pore design of the composite hydrogen storage briquettes do not hinder hydrogen diffusion.

[0059] Figure 2 The intrinsic PCT curve of the pure alloy powder is used as a performance benchmark.

[0060] Figure 3 The figure shows the PCT curve of pure alloy powder briquettes. Due to the densification of the pure alloy powder briquettes, the hydrogen storage platform deteriorates and the kinetics slow down.

[0061] Figure 4 The PCT curve of the composite hydrogen storage block prepared in this embodiment shows that its performance is close to that of the powder, indicating that it did not sacrifice hydrogen storage performance.

[0062] also, Figure 5 This also visually demonstrates the state of the composite hydrogen storage briquette prepared in this embodiment after one hydrogen absorption / desorption kinetics test. After the test, the pure alloy powder briquette severely pulverized and cracked, while the composite hydrogen storage briquette remained largely intact. Meanwhile, as... Figure 6 As shown, after 60 hydrogen absorption and desorption cycles, the hydrogen storage capacity retention rate of the composite hydrogen storage block in this embodiment is >96%, and the mass retention rate is 97.75%, thus proving that the composite hydrogen storage block obtained in this embodiment has excellent long-cycle stability.

[0063] Depend on Figure 7 It can be seen that the hydrogen storage capacity of the composite hydrogen storage briquette prepared in this embodiment is significantly higher than that of the pure metal powder briquette, thus verifying the effectiveness of the technical solution in this embodiment in improving the high thermal conductivity and crack resistance of the composite hydrogen storage briquette.

[0064] Example 2

[0065] This embodiment provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, specifically including the following steps:

[0066] Step 1: Prepare LaNi5 powder (8.5g), X-1910 silica gel (0.5g), expanded graphite (0.3g), and ZrW2O8 negative expansion material (0.7g) with a mass percentage of 85%:5%:3%:7%.

[0067] Step 2: Place the weighed LaNi5 powder in a beaker, add the weighed X-1910 silica gel, and stir vigorously with a stirring rod for 3 minutes until fully mixed to obtain the first mixture.

[0068] Step 3: Add the weighed expanded graphite to the first mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous, thus obtaining the second mixture.

[0069] Step 4: Add the weighed ZrW2O8 negative expansion material to the second mixture, and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed. Then let it stand for 2 minutes to obtain the pressed block blank.

[0070] Step 5: Pour the compressed block blank into a cylindrical mold, and place the cylindrical mold inside the tablet press. Press the tablet press to 300 MPa at room temperature and hold the pressure for 1 minute to obtain the composite hydrogen storage block.

[0071] Example 3

[0072] This embodiment provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, specifically including the following steps:

[0073] Step 1: Prepare TiMn2 powder (9.0g), X-1910 silica gel (0.2g), expanded graphite (0.3g), and ZrW2O8 negative expansion material (0.5g) with a mass percentage of 90%:2%:3%:5%.

[0074] Step 2: Place the weighed TiMn2 powder in a beaker, add the weighed X-1910 silica gel, and stir vigorously with a stirring rod for 3 minutes until fully mixed to obtain the first mixture.

[0075] Step 3: Add the weighed expanded graphite to the first mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous, thus obtaining the second mixture.

[0076] Step 4: Add the weighed ZrW2O8 negative expansion material to the second mixture, and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed. Then let it stand for 2 minutes to obtain the pressed block blank.

[0077] Step 5: Pour the compressed block blank into a cylindrical mold, and place the cylindrical mold inside the tablet press. Press the tablet press to 200 MPa at room temperature and hold the pressure for 1 minute to obtain the composite hydrogen storage block.

[0078] Example 4

[0079] This embodiment provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, specifically including the following steps:

[0080] Step 1: Prepare LaNi5 powder (9.0g), polyurethane (0.2g), expanded graphite (0.3g), and ZrW2O8 negative expansion material (0.5g) in a mass percentage ratio of 90%:2%:3%:5%.

[0081] Step 2: Place the weighed LaNi5 powder in a beaker, add the weighed polyurethane, and stir vigorously with a stirring rod for 3 minutes until fully mixed to obtain the first mixture.

[0082] Step 3: Add the weighed expanded graphite to the first mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous, thus obtaining the second mixture.

[0083] Step 4: Add the weighed ZrW2O8 negative expansion material to the second mixture, and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed. Then let it stand for 2 minutes to obtain the pressed block blank.

[0084] Step 5: Pour the compressed block blank into a cylindrical mold, and place the cylindrical mold inside the tablet press. Press the tablet press to 200 MPa at room temperature and hold the pressure for 1 minute to obtain the composite hydrogen storage block.

[0085] Example 5

[0086] This embodiment provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, specifically including the following steps:

[0087] Step 1: Prepare TiMn2 powder (8.7g), epoxy resin (0.2g), expanded graphite (0.5g), and ZrW2O8 negative expansion material (0.6g) with a mass percentage of 87%:2%:5%:6%.

[0088] Step 2: Place the weighed TiMn2 powder in a beaker, add the weighed epoxy resin, and stir vigorously with a stirring rod for 3 minutes until fully mixed to obtain the first mixture.

[0089] Step 3: Add the weighed expanded graphite to the first mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous, thus obtaining the second mixture.

[0090] Step 4: Add the weighed ZrW2O8 negative expansion material to the second mixture, and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed. Then let it stand for 2 minutes to obtain the pressed block blank.

[0091] Step 5: Pour the compressed block blank into a cylindrical mold, and place the cylindrical mold inside the tablet press. Press the tablet press to 200 MPa at room temperature and hold the pressure for 1 minute to obtain the composite hydrogen storage block.

[0092] Example 6

[0093] This embodiment provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, specifically including the following steps:

[0094] Step 1: Prepare LaNi5 powder (8.7g), epoxy resin (0.2g), expanded graphite (0.3g), and Al2W3O in a mass percentage ratio of 87%:2%:3%:8%. 12 Negative expansion material (0.8g).

[0095] Step 2: Place the weighed LaNi5 powder in a beaker, add the weighed epoxy resin, and stir vigorously with a stirring rod for 3 minutes until fully mixed to obtain the first mixture.

[0096] Step 3: Add the weighed expanded graphite to the first mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous, thus obtaining the second mixture.

[0097] Step 4, weigh the Al2W3O 12 Add the negative expansion material to the second mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous. Then let it stand for 2 minutes to obtain the pressed block blank.

[0098] Step 5: Pour the compressed block blank into a cylindrical mold, and place the cylindrical mold inside the tablet press. Press the tablet press to 300 MPa at room temperature and hold the pressure for 1 minute to obtain the composite hydrogen storage block.

[0099] Example 7

[0100] This embodiment provides a method for preparing composite hydrogen storage blocks with high thermal conductivity and resistance to cracking and pulverization, specifically including the following steps:

[0101] Step 1: Prepare TiMn2 powder (8.7g), V-1510 silica gel (0.2g), expanded graphite (0.3g), and Al2W3O in a mass percentage ratio of 87%:2%:3%:8%. 12 Negative expansion material (0.8g).

[0102] Step 2: Place the weighed TiMn2 powder in a beaker, add the weighed V-1510 silica gel, and stir vigorously with a stirring rod for 3 minutes until fully mixed to obtain the first mixture.

[0103] Step 3: Add the weighed expanded graphite to the first mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous, thus obtaining the second mixture.

[0104] Step 4, weigh the Al2W3O 12 Add the negative expansion material to the second mixture and continue to stir vigorously with a stirring rod for 3 minutes until it is fully mixed and homogeneous. Then let it stand for 2 minutes to obtain the pressed block blank.

[0105] Step 5: Pour the compressed block blank into a cylindrical mold, and place the cylindrical mold inside the tablet press. Press the tablet press to 100 MPa at room temperature and hold the pressure for 1 minute to obtain the composite hydrogen storage block.

[0106] Figure 7 The diagram shows a comparison of the kinetic curves of the composite hydrogen storage blocks prepared in Examples 1, 4, 5, 6, and 7 with those of pure metal powder blocks (i.e., pure alloy powder blocks). As can be seen from the diagram, the composite hydrogen storage block prepared in Example 1 has the best hydrogen storage capacity. The composite hydrogen storage block prepared in Example 5 has a relatively weaker hydrogen storage capacity compared to the composite hydrogen storage blocks in the other examples, but it is still better than the pure metal powder blocks.

[0107] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein, and such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization, characterized in that: The composition, by weight percentage, includes 85% to 90% hydrogen storage alloy powder, 2% to 5% binder, 2% to 5% expanded graphite, and 5% to 8% negative expansion material.

2. The composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization according to claim 1, characterized in that: The hydrogen storage alloy powder is selected from either AB2 series alloy powder or AB5 series alloy powder.

3. The composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization according to claim 2, characterized in that: The AB2 series alloy powder is selected from TiMn2 powder; the AB5 series alloy powder is selected from LaNi5 powder.

4. The composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization according to claim 1, characterized in that: The adhesive is X-1910 silicone; The negative expansion material is selected from ZrW2O8 or Al2W3O. 12 .

5. The composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization according to claim 1, characterized in that: The adhesive is selected from any one of V-1510 silicone, polyurethane, and epoxy resin; The negative expansion material is selected from ZrW2O8 or Al2W3O. 12 .

6. The composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization according to claim 1, characterized in that: The mass percentages of the hydrogen storage alloy powder, binder, expanded graphite, and negative expansion material are 86%:5%:3%:6%.

7. A method for preparing a composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization, used to prepare the composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization as described in any one of claims 1-6; characterized in that, Includes the following steps: Step 1: Prepare hydrogen storage alloy powder, binder, expanded graphite and negative expansion material according to the mass percentage; Step 2: Place the hydrogen storage alloy powder and binder in a container and stir evenly to obtain the first mixture; Step 3: Add expanded graphite to the first mixture and stir until homogeneous to obtain the second mixture; Step 4: Add the negative expansion material to the second mixture, stir evenly, and let stand for 2-5 minutes to obtain the pressed block blank; Step 5: Add the briquette blank into the pre-prepared mold and cold press to obtain a composite hydrogen storage briquette with high thermal conductivity and resistance to cracking and pulverization.

8. The method for preparing the high thermal conductivity and crack-resistant pulverization-resistant composite hydrogen storage briquettes according to claim 7, characterized in that: In steps 2, 3, and 4, the stirring time is 3 to 10 minutes.

9. The method for preparing the high thermal conductivity and crack-resistant pulverization-resistant composite hydrogen storage briquettes according to claim 8, characterized in that: In step 5, the cold pressing molding is achieved by pressing the mold containing the compact blank to 100~300MPa at room temperature using a tablet press, and then holding the pressure for 1~3 minutes to press and form the compact.

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