A hydrogen storage alloy bulk material for filling a solid-state hydrogen storage device and a method for preparing the same

Abstract

The application discloses a kind of solid-state hydrogen storage device filling hydrogen storage alloy bulk material and preparation method thereof, the hydrogen storage alloy bulk material includes hydrogen storage alloy powder, binder, additive and heat conductor, via mixing, water spraying stirring, cold-pressing forming, drying preparation in sequence, the preparation method of the application is simple, the hydrogen storage alloy block prepared has higher hydrogen storage capacity and better platform characteristics, has the characteristics of structure stability, not easy to powder, good cyclic stability in repeated hydrogen absorption and release process.The application is suitable for preparing solid-state hydrogen storage device filling hydrogen storage alloy bulk material.

Description

Technical Field

[0001] This invention belongs to the field of solid-state hydrogen storage technology, and relates to a hydrogen storage alloy block material for filling solid-state hydrogen storage devices and its preparation method. Background Technology

[0002] Hydrogen energy is green and pollution-free, and its development will greatly contribute to achieving the "dual carbon" goals. A key aspect of hydrogen energy applications lies in hydrogen storage. Solid-state hydrogen storage technology, among other hydrogen storage technologies, requires no high pressure, consumes little energy, offers good safety, and has a high volumetric hydrogen storage density, making it a promising area for stationary hydrogen storage and energy storage applications where weight is not a major concern.

[0003] Among numerous hydrogen storage materials, hydrogen storage alloys, with their mild operating conditions and high hydrogen storage capacity, have attracted widespread attention as the core active material for hydrogen storage devices. Hydrogen storage alloys typically store hydrogen in the interstices of their tetrahedral or octahedral crystal lattices. During repeated hydrogen absorption and desorption, hydrogen causes significant lattice stress within the alloy, leading to pulverization and the formation of fine hydrogen storage alloy powder. This fine powder disturbs the device during hydrogen charging and discharging, causing instability in mass and heat transfer, hindering heat management during hydrogen absorption and desorption, and affecting stable operation. In severe cases, the repeated hydrogen absorption and desorption expansion of the alloy and the disturbance of the fine powder within the device can damage the internal structure, shortening the device's lifespan.

[0004] Based on this, we continue to develop a hydrogen storage alloy bulk material for solid hydrogen storage to overcome existing technical problems. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a hydrogen storage alloy block material for filling solid hydrogen storage devices and its preparation method. The hydrogen storage alloy block material comprises hydrogen storage alloy powder, binder, additives, and thermal conductive agent, which are prepared sequentially by mixing, water spraying and stirring, cold pressing, and drying. The preparation method is simple, and the prepared hydrogen storage alloy block has a high hydrogen storage capacity and good plateau characteristics. It exhibits structural stability, is not prone to pulverization, and has good cycle stability during repeated hydrogen absorption and desorption.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A hydrogen storage alloy block material for filling a solid hydrogen storage device, comprising, by weight, 90-99 parts of hydrogen storage alloy powder, 1-5 parts of binder, 0.1-2 parts of additives, and 0.2-5 parts of thermal conductive agent.

[0008] In this invention, hydrogen storage alloy powder, as the active component in the bulk material, plays the role of absorbing and desorbing hydrogen. The polymer binder connects the alloy powder and acts as a buffer against volume expansion during hydrogen absorption and desorption, reducing the squeezing and stress between the alloy powder particles, maintaining the initial shape of the hydrogen storage alloy bulk material, and preventing it from shattering. Additives can inhibit the formation of intra- or inter-chain hydrogen bonds in the polymer binder. The edge sulfur atoms in the additives can form thiol groups, which interact strongly with the hydroxyl groups in the binder, inhibiting molecular chain movement and improving the thermal stability of the binder. In addition to mechanical strength, hydrogen storage alloys often contain a certain amount of transition metal components (this is necessary for regulating the hydrogen pressure balance and hydrogen absorption / desorption kinetics of the active components). These transition metals generally have empty orbitals in their electronic structure, which can coordinate with the thiol groups formed by the additives (sulfide additives) and polymer binders, as well as unreacted hydroxyl groups. This makes the bond between the hydrogen storage alloy, binder, and additives tighter, maintaining the bulk shape during hydrogen absorption / desorption. This is crucial for the hydrogen absorption / desorption of hydrogen storage alloys and their practical applications, directly affecting their performance and lifespan. A significant amount of heat is generated during the hydrogen absorption / desorption of the hydrogen storage alloy bulk. Thermal conductive agents, which are materials with good thermal conductivity, provide heat conduction, allowing heat to be dissipated quickly and preventing heat accumulation and the resulting deformation of the hydrogen storage alloy bulk.

[0009] As a limitation of the present invention, the hydrogen storage alloy powder is one or more of AB5 type, AB2 type, and superlattice hydrogen storage alloy; the binder is one or more of polyvinyl alcohol, hydroxymethyl cellulose, and hydroxypropyl cellulose; the additive is one or two of molybdenum disulfide and tungsten disulfide; and the thermal conductive agent is one or more of natural graphite powder, expanded graphite powder, aluminum nitride, aluminum powder, and hexagonal boron nitride.

[0010] As a further limitation of the present invention, the particle size of the hydrogen storage alloy powder is less than 20 mesh, the particle size of the binder is less than 300 mesh, and the particle size of the thermal conductive agent is less than 300 mesh.

[0011] The particle size of the materials described above has a significant impact on the preparation, molding, and performance of the final hydrogen storage alloy block material. Specifically, the particle size of the hydrogen storage alloy powder affects the density of the alloy block and the compactness of the briquettes; the particle size of the binder affects the uniformity and sufficiency of the binder filling between alloy particles; and the particle size of the thermal conductive agent affects its uniformity of filling between alloy particles and the thermal conductivity of the molded hydrogen storage alloy block.

[0012] This invention also provides a method for preparing a hydrogen storage alloy bulk material for filling a solid hydrogen storage device, characterized by the following steps being performed sequentially:

[0013] (2) Mix the hydrogen storage alloy powder, binder, additives and thermal conductive agent evenly to obtain A;

[0014] (2) Spray water evenly on the surface of A and turn it over to stir evenly to obtain B;

[0015] (3) The mixed powder of B is cold-pressed to form a hydrogen storage alloy block, thus obtaining C;

[0016] (4) Place C in a drying oven for vacuum drying to obtain solid hydrogen storage alloy block material for filling hydrogen storage device.

[0017] As a limitation of the preparation method of the present invention, in step (2), the amount of water sprayed is 0.1-2% of the weight of A.

[0018] As a second limitation of the preparation method of the present invention, in step (3), the cold pressing pressure is 5-25 MPa.

[0019] As a third limitation of the preparation method of the present invention, in step (4), the temperature of vacuum drying is 40-100℃ and the time is 0.5-10h.

[0020] In this invention, spraying water onto the surface of the mixed powder and stirring it evenly allows the water-soluble binder to be fully wetted, resulting in good adhesion between the binder and the alloy powder and thermal conductive agent. The prepared hydrogen storage alloy block material needs to be heat-treated at 40-100℃ for 0.5-10 hours. Vacuum heat treatment at 40-100℃ can remove moisture from the mixture, preventing slight oxidation of the alloy surface due to prolonged wetting. At the same time, heat treatment can also strengthen the adhesion between the mixed powders. If the hydrogen absorption and desorption reaction is carried out directly after cold pressing without heat treatment, the hydrogen storage alloy block will break.

[0021] The above-described technical solution of the present invention is a whole in which each step is interconnected and mutually influential, and cannot be separated.

[0022] The above technical solution has the following advantages or beneficial effects:

[0023] (1) The hydrogen storage alloy block material provided by the present invention has a reasonable compatibility. On the one hand, the additive can improve the thermal stability and mechanical strength of the binder. On the other hand, it can undergo coordination reaction with the mercapto groups and unreacted hydroxyl groups formed by the polymer binder, making the combination between the hydrogen storage alloy, the binder and the additive more compact. The block shape remains unchanged during the hydrogen absorption and desorption process. It does not produce serious pulverization during repeated hydrogen charging and desorption. The hydrogen absorption and desorption capacity does not decrease significantly, and it maintains good cycle stability.

[0024] (2) The hydrogen storage alloy bulk material provided by the present invention has good hydrogen storage performance, such as high hydrogen storage capacity and good hydrogen absorption and desorption platform performance.

[0025] (3) The preparation method provided by the present invention is simple, the process and operating conditions are convenient, the reaction conditions are stable and controllable, and the raw materials are readily available and inexpensive.

[0026] This invention is applicable to the preparation of hydrogen storage alloy bulk materials for filling solid hydrogen storage devices.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0028] Figure 1 The PCT curves of the compressed hydrogen storage alloy of the present invention are shown, wherein: (a) - Example 1, (b) - Example 2, (c) - Example 3, (d) - Example 4, (e) - Example 5, (f) - Example 6, (g) - Comparative Example 1, (h) - Comparative Example 2, (i) - Comparative Example 3, (j) - Comparative Example 4, (k) - Comparative Example 5;

[0029] Figure 2 This is a graph showing the change in hydrogen release capacity of the compressed hydrogen storage alloy in Example 1 of the present invention with the number of cycles;

[0030] Figure 3 The images shown are photographs of the compressed hydrogen storage alloy of the present invention before and after hydrogen absorption and desorption, wherein: (a) - bottom photo of the cylindrical block before cycling in Example 1, (b) - side photo of the cylindrical block before cycling in Example 1, (c) - bottom photo of the cylindrical block after cycling in Example 1, (d) - side photo of the cylindrical block after cycling in Example 1, (e) - bottom photo of the cylindrical block after cycling in Example 2, (f) - bottom photo of the cylindrical block after cycling in Example 3, (g) - bottom photo of the cylindrical block after cycling in Example 4, (h) - bottom photo of the cylindrical block after cycling in Example 5, (i) - bottom photo of the cylindrical block after cycling in Example 6, (j) - bottom photo of the cylindrical block after cycling in Comparative Example 1, (k) - bottom photo of the cylindrical block after cycling in Comparative Example 1, (m) - bottom photo of the cylindrical block after cycling in Comparative Example 1, (n) - bottom photo of the cylindrical block after cycling in Comparative Example 1, (p) - bottom photo of the cylindrical block after cycling in Comparative Example 1. Detailed Implementation

[0031] The following embodiments are merely some, not all, of the embodiments of the present invention. Therefore, the detailed descriptions of the embodiments provided below are not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] In this invention, unless otherwise specified, all equipment and raw materials are commercially available or commonly used in the industry. The methods described in the following embodiments are conventional methods in the art, unless otherwise specified.

[0033] In some specific embodiments, the sintering heat treatment is carried out in a protective atmosphere, such as Ar gas.

[0034] Example 1

[0035] 96g of AB2 type Ti-based hydrogen storage alloy (molecular formula: Ti) was used. 0.83 Zr 0.17 Mn 0.94 Cr 0.87 Fe 0.10 The hydrogen storage alloy was prepared by smelting according to the melting method mentioned in the thesis "Research on AB2 Type Alloy and Composite Alloy Anode Material of MH / Ni Battery" (Yanshan University, 2004). The powder was mechanically ground to 100-400 mesh and mixed evenly with 2g of commercially available polyvinyl alcohol powder (less than 300 mesh; the particle size of the binder described below is less than 300 mesh), 1g of molybdenum disulfide powder, and 1g of commercially available 300-mesh natural graphite powder. Water was sprayed evenly onto the surface (the amount of water was 0.5% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 10MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and vacuum-dried at 60℃ for 4 hours. It was then naturally cooled to room temperature and removed to obtain the hydrogen storage alloy block material.

[0036] The hydrogen storage alloy bulk material prepared above was subjected to hydrogen storage performance testing. The prepared hydrogen storage alloy bulk material is easily activated, and can be fully activated in the second week. Figure 1 As shown in Figure (a), the hydrogen desorption capacity of the prepared hydrogen storage alloy bulk material is approximately 1.61 wt% according to the pressure-composition isotherm (PCT) curve, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy bulk material, revealing that its hydrogen absorption / desorption capacity remained constant over 50 cycles. Figure 2 As shown. The hydrogen storage alloy block material was removed after the hydrogen absorption / desorption cycle, and photos of the block before and after the hydrogen absorption / desorption cycle were compared. Figure 3 (Comparison of Figures a, b and c, d) reveals that after 50 hydrogen absorption and desorption cycles, the material of the hydrogen storage alloy block does not change significantly, with only a few cracks appearing at the bottom edge.

[0037] Example 2

[0038] 99g of AB5 type rare earth hydrogen storage alloy (molecular formula: LaNi) was used. 3.55 Mn 0.35 Co0.20 Al 0.20 Cu 0.85 According to the preparation method in the Chinese Journal of Physical Chemistry, 2010, 26(08):2144, the hydrogen storage alloy was mechanically ground to 20-400 mesh and mixed evenly with 0.5g of commercially available hydroxymethyl cellulose powder, 0.5g of hydroxypropyl cellulose (HPMC) powder, 0.1g of tungsten disulfide powder, 0.1g of commercially available 500-mesh natural graphite powder, and 0.1g of commercially available 1-micron hexagonal boron nitride powder. Water was sprayed onto the surface of the mixed powder (the amount of water sprayed was 0.1% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to make the water spraying uniform. The mixture was cold-pressed into a cylindrical block under a pressure of 15MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 40℃ for 10h. Then it was naturally cooled to room temperature and removed to obtain the hydrogen storage alloy block material.

[0039] The hydrogen storage performance of the prepared hydrogen storage alloy bulk material was tested. For example... Figure 1 As shown in Figure (b), the prepared hydrogen storage alloy bulk material is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy bulk material is approximately 1.51 wt% according to the pressure-composition isotherm (PCT) curve, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy bulk material, revealing that its hydrogen absorption / desorption capacity remained unchanged after 50 cycles. Comparing photographs of the hydrogen storage alloy bulk material after the cycles showed no significant changes, although a small number of cracks appeared on the bottom surface. Figure 3 As shown in Figure (e).

[0040] Example 3

[0041] 90g of a superlattice rare earth-magnesium-nickel hydrogen storage alloy (molecular formula: Sm) was used. 0.60 Y 0.20 Mg 0.20 Ni 2.90 Al 0.10According to the method in the literature (Rare Earth, 2023, 44:148), the material was mechanically ground to below 100 mesh and mixed evenly with 3g of commercially available polyvinyl alcohol (PVA) powder, 2g of molybdenum disulfide powder, 4.5g of commercially available 1000-mesh natural graphite powder, and 0.5g of 1-micron aluminum powder. Water was sprayed onto the surface of the mixed powder (the amount of water sprayed was 1.2% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 20MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 40℃ for 10h. Then it was naturally cooled to room temperature and removed to obtain the hydrogen storage alloy block material.

[0042] The hydrogen storage performance of the prepared hydrogen storage alloy bulk material was tested. For example... Figure 1 As shown in Figure (c), the prepared hydrogen storage alloy bulk material is easily activated, reaching full activation in the second week. The hydrogen release capacity of the pressure-composition isotherm (PCT) curve of the prepared hydrogen storage alloy bulk material is approximately 1.49 wt%, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy bulk material, revealing that its hydrogen absorption / desorption capacity remained unchanged within 50 cycles. Comparing photographs of the hydrogen storage alloy bulk material after the hydrogen absorption / desorption cycles before and after showed that no significant changes occurred, and no obvious cracks appeared. Figure 3 As shown in Figure (f).

[0043] Example 4

[0044] 97.5g of AB5 type rare earth hydrogen storage alloy (molecular formula: LaNi) was used. 3.55 Mn 0.35 Co 0.20 Al 0.20 Cu 0.75 Fe 0.10 According to the preparation method in the Chinese Journal of Physico-Chimica, 2010, 26(08):2144, the hydrogen storage alloy block was mechanically ground to 20-300 mesh and mixed evenly with 1g of commercially available hydroxymethyl cellulose (CMC) powder, 1g of tungsten disulfide powder and 0.5g of commercially available 1-micron aluminum nitride powder. Water was sprayed onto the surface of the mixed powder (the amount of water sprayed was 0.8% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to make the water spraying uniform. The block was cold-pressed into a cylindrical block under a pressure of 15MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 90℃ for 2h. Then it was naturally cooled to room temperature and taken out to obtain the hydrogen storage alloy block material.

[0045] The hydrogen storage performance of the prepared hydrogen storage alloy bulk material was tested. For example... Figure 1As shown in Figure (d), the prepared hydrogen storage alloy bulk material is easily activated, reaching full activation in the second week. The hydrogen release capacity of the pressure-composition isotherm (PCT) curve of the prepared hydrogen storage alloy bulk material is approximately 1.45 wt%, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy bulk material, revealing that its hydrogen absorption / desorption capacity remained unchanged within 50 cycles. Comparing photographs of the hydrogen storage alloy bulk material after the hydrogen absorption / desorption cycles showed no significant changes or cracks after 50 cycles. Figure 3 As shown in Figure (g).

[0046] Example 5

[0047] 94g of AB2 type Ti-based hydrogen storage alloy (molecular formula: Zr) was added. 0.9 Ti 0.1 Ni 1.0 Mn 0.7 V 0.3 Si 0.10 The hydrogen storage alloy was prepared according to the preparation method described in the thesis "Research on AB2 type alloy and its composite alloy anode material of MH / Ni battery" (Yanshan University, 2004). The powder was mechanically ground to 100-400 mesh and mixed evenly with 1g of commercially available 1000-mesh polyvinyl alcohol (PVA) powder, 2g of commercially available 500-mesh hydroxypropyl cellulose (HPMC) powder, 0.5g of molybdenum disulfide powder, 0.5g of tungsten disulfide powder, 1.9g of commercially available 300-mesh natural graphite powder, and 0.1g of 1-micron hexagonal boron nitride. Water was sprayed onto the surface of the mixed powder (the amount of water was 0.5% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 25 MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 80°C for 3 hours. It was then naturally cooled to room temperature and removed to obtain the hydrogen storage alloy block material.

[0048] The hydrogen storage performance of the prepared hydrogen storage alloy bulk material was tested. For example... Figure 1 As shown in Figure (e), the prepared hydrogen storage alloy bulk material is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy bulk material is approximately 1.48 wt% according to the pressure-composition isotherm (PCT) curve, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy bulk material, revealing that its hydrogen absorption / desorption capacity remained unchanged after 50 cycles. Comparing photographs of the hydrogen storage alloy bulk material after the cycles showed no significant changes or cracks after 50 cycles. Figure 3 As shown in Figure (h).

[0049] Example 6

[0050] 91g of AB2 type Ti-based hydrogen storage alloy (molecular formula: Zr) was added. 0.9 Ti 0.1 Ni 1.0 Mn 0.7 V 0.3 Cr 0.10 The hydrogen storage alloy was prepared according to the preparation method described in the thesis "Research on AB2 type alloy and its composite alloy anode material of MH / Ni battery" (Yanshan University, 2004). The mixture was mechanically ground to below 50 mesh and then mixed evenly with 5g of commercially available 1000-mesh hydroxypropyl cellulose (HPMC) powder, 2g of molybdenum disulfide powder, and 2g of commercially available 1000-mesh natural graphite powder. The mixed powder was sprayed with water (2% of the powder weight), and the powder was continuously turned and stirred during the spraying process to ensure uniform water distribution. The mixture was then cold-pressed into a cylindrical block under 5MPa pressure. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 100℃ for 0.5h, then naturally cooled to room temperature to obtain the hydrogen storage alloy block material.

[0051] The hydrogen storage performance of the prepared hydrogen storage alloy bulk material was tested. For example... Figure 1 As shown in Figure (f), the prepared hydrogen storage alloy bulk material is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy bulk material is approximately 1.48 wt% according to the pressure-composition isotherm (PCT) curve, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy bulk material, revealing that its hydrogen absorption / desorption capacity remained unchanged within 50 cycles. Comparing photographs of the hydrogen storage alloy bulk material after the hydrogen absorption / desorption cycles before and after showed that no significant changes occurred after 50 cycles, and no obvious cracks appeared. Figure 3 As shown in Figure (i).

[0052] Comparative Example 1

[0053] 96g of AB2 type Ti-based hydrogen storage alloy (alloy as in Example 1) was mechanically ground to below 100 mesh. Water was sprayed evenly on its surface (the amount of water sprayed was 0.5% of the weight of the raw material mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 10MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 60°C for 4 hours. Then it was naturally cooled to room temperature and removed.

[0054] The hydrogen storage performance of the hydrogen storage alloy block prepared above was tested. For example... Figure 1 As shown in Figure (g), the prepared hydrogen storage alloy block is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy block's pressure-composition isotherm (PCT) curve is approximately 1.62 wt%, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy block, revealing a decrease in hydrogen absorption / desorption capacity of approximately 10% within 50 cycles. Comparing the photos before and after the hydrogen absorption / desorption cycles after removing the hydrogen storage alloy reveals… Figure 3 As shown in Figure J: After 50 hydrogen absorption and desorption cycles, the hydrogen storage alloy was in powder form. This is mainly because the hydrogen storage alloy pulverizes during the hydrogen absorption and desorption process. There is no interconnecting material or related interaction between the particles, and the resulting fine powder is scattered randomly, which disrupts the mass and heat transfer stability during the hydrogen absorption and desorption process. Some fine powder even escapes outside the test sample room under the action of the hydrogen gas flow, causing a significant loss of capacity. The test results show that its cycle stability is poor.

[0055] Comparative Example 2

[0056] 96g of AB2 type Ti-based hydrogen storage alloy (alloy as in Example 1) was mechanically ground to below 100 mesh and mixed evenly with 2g of commercially available 1000 mesh polyvinyl alcohol (PVA) powder and 1g of commercially available 300 mesh natural graphite powder. Water was sprayed evenly on the surface of the mixture (the amount of water sprayed was 0.5% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 10MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 60°C for 4 hours, and then naturally cooled to room temperature before being removed.

[0057] The hydrogen storage performance of the hydrogen storage alloy block prepared above was tested. For example... Figure 1 As shown in Figure (h), the prepared hydrogen storage alloy block is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy block's pressure-composition isotherm (PCT) curve is approximately 1.50 wt%, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy block, revealing a decrease in hydrogen absorption / desorption capacity of approximately 8% within 50 cycles. Comparing photographs of the hydrogen storage alloy block before and after the hydrogen absorption / desorption cycles after removal reveals… Figure 3As shown in Figure K): After 50 hydrogen absorption and desorption cycles, most of the hydrogen storage alloy block had turned into powder, with only a small portion remaining in the center. This is mainly because the bonding effect of using only polyvinyl alcohol as a binder is weak, failing to effectively prevent particle pulverization during hydrogen absorption and desorption, and unable to effectively resist the internal stress generated by the expansion and compression between particles. Consequently, most of the hydrogen storage alloy becomes fine powder during hydrogen absorption and desorption, resulting in phenomena such as disturbance and disruption of mass and heat transfer, as well as effective mass loss, as seen in Comparative Example 1, leading to poor cycle stability.

[0058] Comparative Example 3

[0059] 96g of AB2 type Ti-based hydrogen storage alloy (alloy as in Example 1) was mechanically ground to below 100 mesh and mixed with 2g of commercially available 1000 mesh polyvinyl alcohol (PVA) powder and 1g of commercially available 300 mesh molybdenum disulfide powder. Water was sprayed evenly on the surface of the mixture (the amount of water sprayed was 0.5% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 10MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 60°C for 4 hours. Then it was naturally cooled to room temperature and removed.

[0060] The hydrogen storage performance of the hydrogen storage alloy block prepared above was tested. For example... Figure 1 As shown in Figure (i), the prepared hydrogen storage alloy block is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy block's pressure-composition isotherm (PCT) curve is approximately 1.40 wt%, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy block, revealing a decrease in hydrogen absorption / desorption capacity of approximately 15% within 50 cycles. Comparing photographs of the hydrogen storage alloy block before and after the hydrogen absorption / desorption cycles after removal reveals… Figure 3 (As shown in Figure m): After 50 hydrogen absorption / desorption cycles, the hydrogen storage alloy block exhibited severe volume expansion and numerous cracks, even showing signs of fracture from the center. This is primarily because the hydrogen storage alloy experiences significant thermal effects during hydrogen absorption / desorption. Without a heat conductor, the generated heat cannot be dissipated through circulation, leading to a substantial localized temperature rise within the alloy block. This high temperature significantly weakens the bonding effect, resulting in numerous cracks. Furthermore, the lack of a heat conductor means that both the exothermic reaction during hydrogen absorption and the endothermic reaction during hydrogen desorption inhibit the reaction, reducing the measured hydrogen storage capacity and demonstrating poor cycle stability.

[0061] Comparative Example 4

[0062] 96g of AB2 type Ti-based hydrogen storage alloy (alloy as in Example 1) was mechanically ground to below 200 mesh and mixed with 2g of commercially available 800 mesh natural graphite powder and 1g of commercially available 300 mesh molybdenum disulfide powder. Water was sprayed evenly on the surface of the mixture (the amount of water sprayed was 0.5% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 10MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 60°C for 4 hours. Then it was naturally cooled to room temperature and removed.

[0063] The hydrogen storage performance of the hydrogen storage alloy block prepared above was tested. For example... Figure 1 As shown in Figure (j), the prepared hydrogen storage alloy block is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy block's pressure-composition isotherm (PCT) curve is approximately 1.52 wt%, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy block, revealing a decrease in hydrogen absorption / desorption capacity of approximately 10% within 50 cycles. Comparing photographs of the hydrogen storage alloy block before and after the hydrogen absorption / desorption cycles after removal reveals… Figure 3 (As shown in Figure n): After 50 hydrogen absorption and desorption cycles, the hydrogen storage alloy block had completely turned into powder. This is mainly because using only thermal conductive agents and additives does not produce an adhesive effect on the alloy particles, causing the hydrogen storage alloy powder to exhibit the pulverization phenomenon seen in Comparative Example 1, which in turn leads to its poor cycle stability.

[0064] Comparative Example 5

[0065] 96g of AB2 type Ti-based hydrogen storage alloy (alloy as in Example 1) was mechanically ground to below 100 mesh and mixed evenly with 2g of commercially available 1000 mesh polyvinyl alcohol (PVA) powder. Water was sprayed evenly on the surface of the mixture (the amount of water sprayed was 0.5% of the weight of the mixed powder). During the water spraying process, the mixed powder was continuously turned and stirred to ensure uniform water spraying. The mixture was then cold-pressed into a cylindrical block under a pressure of 10MPa. The cold-pressed hydrogen storage alloy block was placed in a vacuum drying oven and heat-treated at 60°C for 4 hours. Then it was naturally cooled to room temperature and removed.

[0066] The hydrogen storage performance of the hydrogen storage alloy block prepared above was tested. For example... Figure 1As shown in Figure (k), the prepared hydrogen storage alloy block is easily activated, reaching full activation in the second week. The hydrogen release capacity of the prepared hydrogen storage alloy block's pressure-composition isotherm (PCT) curve is approximately 1.55 wt%, exhibiting a flat hydrogen absorption / desorption plateau and minimal hysteresis. Repeated hydrogen absorption / desorption tests were conducted on the hydrogen storage alloy block, revealing a decrease in hydrogen absorption / desorption capacity of approximately 7% within 50 cycles. Comparing photographs of the hydrogen storage alloy block before and after the hydrogen absorption / desorption cycles after removal reveals… Figure 3 (As shown in Figure p): After 50 hydrogen absorption and desorption cycles, the hydrogen storage alloy block has mostly turned into powder. This is mainly because it is difficult to form an effective bond for the hydrogen storage alloy particles using only a binder, and there is still a relatively serious phenomenon of hydrogen storage alloy pulverization, which leads to its poor cycle stability.

[0067] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A hydrogen storage alloy bulk material for filling a solid-state hydrogen storage device, characterized by, The hydrogen storage alloy bulk material comprises hydrogen storage alloy powder 90-99 parts by weight, binder 1-5 parts by weight, additive 0.1-2 parts by weight, and heat-conducting agent 0.2-5 parts by weight; The hydrogen storage alloy powder is one or more of AB5 type, AB2 type, and superlattice hydrogen storage alloy; the binder is one or more of polyvinyl alcohol, hydroxymethyl cellulose, and hydroxypropyl cellulose; the additive is one or both of molybdenum disulfide and tungsten disulfide; and the heat-conducting agent is one or more of natural graphite powder, expanded graphite powder, aluminum nitride, aluminum powder, and hexagonal boron nitride; The particle size of the hydrogen storage alloy powder is less than 20 mesh, the particle size of the binder is less than 300 mesh, and the particle size of the heat-conducting agent is less than 300 mesh.

2. The method of claim 1, wherein the hydrogen storage alloy bulk material is prepared by the steps of: preparing a master alloy by mixing a magnesium-based alloy and a rare earth metal-based alloy; and adding a transition metal-based alloy to the master alloy. The steps are performed in the following order: (1) hydrogen storage alloy powder, binder, additive, and heat-conducting agent are mixed uniformly to obtain A; (2) water is sprayed on the surface of A, and A is stirred and mixed uniformly to obtain B; (3) the mixed powder of B is cold-pressed to form a hydrogen storage alloy bulk, to obtain C; (4) C is placed in a drying box for vacuum drying, to obtain a solid hydrogen storage device filling hydrogen storage alloy bulk material.

3. The method of claim 2, wherein the hydrogen storage alloy bulk material is prepared by the steps of: preparing a master alloy by mixing a magnesium-based alloy and a rare earth metal-based alloy; and adding a transition metal-based alloy to the master alloy. In step (2), the amount of water sprayed is 0.1-2% of the weight of A.

4. The method of claim 2, wherein the hydrogen storage alloy bulk material is prepared by the steps of: preparing a master alloy by mixing a magnesium-based alloy and a rare earth metal-based alloy; and adding a transition metal-based alloy to the master alloy. In step (3), the cold-pressing pressure is 5-25 MPa.

5. The method of claim 2-4, wherein the hydrogen storage alloy bulk material is prepared by the following steps: (1) preparing a master alloy by mixing a magnesium alloy and a rare earth element alloy; (2) preparing a hydrogen storage alloy bulk material by mixing the master alloy with a magnesium alloy and a rare earth element alloy. In step (4), the temperature of the vacuum drying is 40-100℃, and the time is 0.5-10 h.

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