Composite hydrogen storage material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of hydrogen storage materials, and particularly relates to a composite hydrogen storage material and a preparation method and application thereof. The invention relates to a composite hydrogen storage material, which is formed by compounding an AB2 type Laves phase alloy and a BCC structure vanadium-based solid solution alloy, wherein the AB2 type Laves phase alloy and the BCC structure vanadium-based solid solution alloy are mutually independent in structure; the AB2 type Laves phase alloy is a Zr-Ti-Mn-Cr series intermetallic compound, the general formula of the AB2 type Laves phase alloy is Zr < 1-x > Ti < x > MnCr, and x is larger than or equal to 0 and smaller than or equal to 0.5; the BCC structure vanadium-based solid solution alloy is a V-Ti-Cr-Fe system quaternary solid solution alloy, the general formula of the BCC structure vanadium-based solid solution alloy is VyTizCrmFen, y is larger than or equal to 0.5 and smaller than or equal to 0.8, z is larger than or equal to 0.1 and smaller than or equal to 0.2, and 1lt is larger than or equal to 0.1. M is less than or equal to 0.2, and n is the balance.

Description

Technical Field

[0001] This invention belongs to the field of hydrogen storage materials technology, and particularly relates to a composite hydrogen storage material, its preparation method and application. Background Technology

[0002] Hydrogen energy, as a widely available, high-energy-density, and environmentally friendly secondary energy source, plays a crucial role in the global energy structure transformation and the achievement of carbon neutrality. Safe, efficient, and low-cost hydrogen storage technology is the core element driving hydrogen energy from the laboratory to large-scale commercial applications. Among numerous hydrogen storage technologies, solid-state hydrogen storage technology based on metal hydrides is considered a key solution with great potential in areas such as on-board hydrogen storage and renewable energy coupled energy storage, due to its significant advantages including high hydrogen storage volume density, good safety, and low operating pressure.

[0003] Currently, the more mature hydrogen storage alloys mainly include several categories such as AB5-type, AB2-type Laves phase, and BCC-structured vanadium-based solid solutions. However, these single-system alloys often have irreconcilable performance defects. For example, although AB2-type Laves phase alloys have structural stability and good low-temperature hydrogen desorption kinetics, their hydrogen storage capacity is usually low, making it difficult to meet the increasing demand for driving range. On the other hand, BCC-structured alloys, represented by vanadium-based solid solutions, although theoretically capable of storing more than 3 wt% hydrogen, exhibit a sharp deterioration in hydrogen absorption and desorption performance at low temperatures, with excessively high plateau pressure and poor cycle stability. In particular, the pulverization and activity degradation problems in pure V-Ti systems severely restrict their application under varying real-world operating conditions.

[0004] Therefore, existing single-component hydrogen storage alloys struggle to simultaneously meet multiple performance requirements, including high hydrogen storage capacity, a wide operating temperature range, and long cycle life. This has become a technical bottleneck limiting their widespread application in hydrogen energy systems requiring dynamic, wide-temperature-range operation, such as fuel cell vehicles and solar-coupled hydrogen storage. In light of this, overcoming the inherent contradictions between capacity, low-temperature performance, and cycle stability in single-alloy materials, and developing a hydrogen storage material that can achieve high-capacity hydrogen storage, stably and efficiently perform reversible hydrogen absorption and desorption operations over a wide temperature range, and maintain a long service life, is a pressing technical challenge in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned shortcomings and provide a composite hydrogen storage material, its preparation method, and its application.

[0006] Firstly, a composite hydrogen storage material employs the following technical solution: A composite hydrogen storage material is composed of an AB2-type Laves phase alloy and a BCC-structured vanadium-based solid solution alloy; wherein, the AB2-type Laves phase alloy and the BCC-structured vanadium-based solid solution alloy are structurally independent of each other; The AB2-type Laves phase alloy is a Zr-Ti-Mn-Cr series intermetallic compound with the general formula Zr 0.02 , Ti x MnCr, where 0 ≤ x ≤ 0.5; The BCC-structured vanadium-based solid solution alloy is a V-Ti-Cr-Fe series quaternary solid solution alloy with the general formula V y Ti z Cr m Fe n , where 0.5 ≤ y ≤ 0.8, 0.1 ≤ z ≤ 0.2, 0 < m ≤ 0.2, and n is the balance.

[0007] Furthermore, the chemical formula of the AB2-type Laves phase alloy is Zr 0.8 Ti 0.2 MnCr.

[0008] Furthermore, the chemical formula of the BCC-structured vanadium-based solid solution alloy is V 0.75 Ti 0.11 Cr 0.12 Fe 0.02 .

[0009] Furthermore, the mass ratio of the AB2-type Laves phase alloy to the BCC-structured vanadium-based solid solution alloy is 20:80 to 40:60.

[0010] Furthermore, the mass ratio of the AB2-type Laves phase alloy to the BCC-structured vanadium-based solid solution alloy is 20:80.

[0011] Second, a preparation method of a composite hydrogen storage material adopts the following technical solution: A preparation method of a composite hydrogen storage material is characterized by comprising the following steps: Step (1), respectively prepare the AB2-type Laves phase alloy and the BCC-structured vanadium-based solid solution alloy by arc melting method, and perform annealing treatment after melting; Step (2), respectively mechanically ball-mill the annealed AB2-type Laves phase alloy and the BCC-structured vanadium-based solid solution alloy to obtain AB2-type Laves phase alloy powder and BCC-structured vanadium-based solid solution alloy powder; Step (3) involves mechanically mixing the AB2 type Laves phase alloy powder and the BCC structure vanadium-based solid solution alloy powder obtained in step (2) under an inert atmosphere to obtain the composite hydrogen storage material.

[0012] Further, in step (1), the AB2 type Laves phase alloy is annealed at a temperature of 900℃~1200℃ after melting; the BCC structure vanadium-based solid solution alloy is annealed at a temperature of 1300℃~1500℃ after melting.

[0013] Furthermore, in step (2), the ball milling speed is 300 rpm to 500 rpm, the ball milling time is 4 h to 8 h, and the particle size of the AB2 type Laves phase alloy powder and the BCC structure vanadium-based solid solution alloy powder is ≤75 μm.

[0014] Further, in step (3), the mechanical mixing is ball milling, the ball-to-material ratio is 8~12:1, and the mixing temperature is ≤40℃.

[0015] Thirdly, the application of a composite hydrogen storage material employs the following technical solution: An application of a composite hydrogen storage material, wherein the composite hydrogen storage material is applied to a hydrogen energy system that performs reversible hydrogen storage and release operations within a wide temperature range of 5℃ to 70℃, wherein the hydrogen energy system is a fuel cell vehicle hydrogen storage system or a solar-coupled hydrogen storage system.

[0016] The beneficial effects of this invention are: This invention provides a composite hydrogen storage material by combining a specific AB2-type Laves phase alloy with excellent low-temperature hydrogen release kinetics and structural stability with a specific BCC-structured vanadium-based solid solution alloy with high hydrogen storage capacity. The two phases are structurally independent and functionally complementary, overcoming the performance bottlenecks of single hydrogen storage materials. This composite hydrogen storage material utilizes the stable hydrogen release capability of the AB2 phase in the low-temperature region to compensate for the low-temperature kinetic lag of the BCC phase, while simultaneously leveraging the high capacity characteristics of the BCC phase to overcome the limitation of insufficient hydrogen storage capacity of the AB2 phase. This synergistic effect enables the final composite material to achieve a comprehensive hydrogen storage capacity far exceeding that of a single component. More importantly, it significantly widens the material's operating temperature window, allowing for continuous and stable reversible hydrogen absorption and desorption within a dynamic temperature range from low to high temperatures, while maintaining excellent cycle stability. This perfectly solves the technical challenge of existing hydrogen storage materials that struggle to simultaneously achieve high capacity, wide temperature range, and long lifespan. Attached Figure Description

[0017] Figure 1 The image shows a comparison of the hydrogen desorption PCT curves of the composite hydrogen storage material prepared in Example 1 of this invention at 5°C and 70°C.

[0018] Figure 2 The graph shows the hydrogen absorption kinetics of the composite hydrogen storage material prepared in Example 1 of this invention at 20°C.

[0019] Figure 3 The diagram shows the reversible hydrogen absorption and desorption capacity of the composite hydrogen storage material prepared in Example 1 of this invention after 10 cycles at 25°C.

[0020] Figure 4 For Comparative Example 1, AB2 type alloy (Zr) 0.8 Ti 0.2 PCT curves of hydrogen desorption of MnCr at 5~70℃.

[0021] Figure 5 For Comparative Example 1, AB2 type alloy (Zr) 0.8 Ti 0.2 The hydrogen absorption kinetics curve of MnCr at 20℃.

[0022] Figure 6 For Comparative Example 2, the BCC type alloy (V 0.75 Ti 0.11 Cr 0.12 Fe 0.02 Hydrogen release curves at 5~70℃. Detailed Implementation

[0023] The following detailed description, in conjunction with embodiments, illustrates a composite hydrogen storage material, its preparation method, and its applications according to the present invention. For the sake of simplicity, this document cannot exhaustively list all alternative technical features and implementation schemes included in the present invention. Therefore, those skilled in the art should understand that any technical feature and implementation scheme within these embodiments does not limit the scope of protection of the present invention. The scope of protection includes all alternative technical features and implementation schemes adopted by those skilled in the art without inventive effort. Specifically, any implementation scheme obtained by replacing any technical feature in the present invention or combining any two or more technical features provided by the present invention should be within the scope of protection of the present invention. Where specific techniques and conditions are not specified in the embodiments, they are performed according to the techniques and conditions described in the literature in the field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0024] Example Example 1 This embodiment 1 provides a composite hydrogen storage material, which is composed of AB2 type Laves phase alloy (Zr 0.8 Ti 0.2 MnCr) powder and BCC structure vanadium-based solid solution alloy (V 0.75 Ti 0.11 Cr 0.12Fe 0.02 It is composed of powders, with a mass ratio of 20:80.

[0025] This embodiment 1 also provides a method for preparing a composite hydrogen storage material, including the following steps: Step (1), preparation and annealing of single-phase alloys: AB2 type Laves phase alloy (Zr 0.8 Ti 0.2 Preparation of MnCr: Zirconium (Zr), titanium sponge (Ti), manganese (Mn), and chromium (Cr) with purities all greater than 99.9% were selected as raw materials. The raw materials were accurately weighed according to the molar ratio of the chemical formula Zr0.8Ti0.2MnCr. The weighed raw material blocks were placed in a water-cooled copper crucible in a non-consumable vacuum arc melting furnace, and the furnace cavity was evacuated to 1.0 × 10⁻⁶. -3 After the pressure drops below Pa, high-purity argon is introduced as a protective atmosphere. An electric arc is then started for melting. To ensure uniform composition, the alloy ingot is repeatedly turned and melted at least four times. After melting, the resulting alloy ingot is placed in a vacuum annealing furnace and annealed at 1000°C for 24 hours, then cooled to room temperature in the furnace.

[0026] BCC structure vanadium-based solid solution alloy (V 0.75 Ti 0.11 Cr 0.12 Fe 0.02 Preparation of vanadium (V), titanium sponge (Ti), chromium (Cr), and pure iron (Fe) with purities all greater than 99.9% were selected as raw materials. According to the chemical formula V... 0.75 Ti 0.11 Cr 0.12 Fe 0.02 The molar ratios were precisely weighed. The alloy ingot was prepared using the same vacuum arc melting process as the AB2 type alloy described above. Subsequently, the alloy ingot was placed in a vacuum annealing furnace and annealed at 1400°C for 12 hours, then cooled to room temperature in the furnace.

[0027] Step (2), mechanical ball milling: The annealed AB2-type Laves phase alloy and BCC-structured vanadium-based solid solution alloy blocks from step (1) were placed in the grinding jars of a planetary ball mill and mechanically ball-milled under an argon atmosphere. The ball milling speed was set to 400 rpm and the grinding time to 6 hours. After ball milling, the powder was sieved through a 200-mesh standard sieve, and AB2-type Laves phase alloy powder and BCC-structured vanadium-based solid solution alloy powder with a particle size ≤75 μm were collected and obtained respectively.

[0028] Step (3), mechanical mixing: Accurately weigh the AB2 type Laves phase alloy powder and the BCC structure vanadium-based solid solution alloy powder obtained in step (2), ensuring a mass ratio of 20:80. Place both powders together in a ball mill jar and ball mill them under an inert atmosphere (such as argon). Set the ball-to-powder ratio to 10:1, the ball mill speed to 150 rpm, and the mixing time to 1.5 hours. Use the water-cooling jacket provided with the equipment to ensure that the temperature during the mixing process is ≤40℃ to prevent unnecessary diffusion reactions or phase transitions. After mixing, the resulting powder is the composite hydrogen storage material of Example 1.

[0029] Example 2 This embodiment 2 provides a composite hydrogen storage material, which is composed of AB2 type Laves phase alloy (Zr 0.7 Ti 0.3 MnCr) powder and BCC structure vanadium-based solid solution alloy (V 0.6 Ti 0.15 Cr 0.1 Fe 0.15 It is composed of powders in a mass ratio of 40:60.

[0030] This embodiment 2 provides a method for preparing a composite hydrogen storage material, including the following steps: Step (1), preparation and annealing of single-phase alloys: AB2 type Laves phase alloy (Zr 0.7 Ti 0.3 Preparation of ZnCr: Zirconium metal, titanium sponge, manganese metal, and chromium metal with a purity greater than 99.9% were selected as raw materials, and the ZnCr was prepared according to the chemical formula ZnCr. 0.7 Ti 0.3 The molar ratio of MnCr was weighed. An alloy ingot was prepared using the same vacuum arc melting process as in Example 1. Subsequently, the alloy ingot was vacuum annealed at 900°C for 24 hours, and then cooled in the furnace.

[0031] BCC structure vanadium-based solid solution alloy (V 0.6 Ti 0.15 Cr 0.1 Fe 0.15 Preparation of vanadium metal, titanium sponge, chromium metal, and pure iron, all with a purity greater than 99.9%, were selected as raw materials and prepared according to the chemical formula V. 0.6 Ti 0.15 Cr 0.1 Fe 0.15 The molar ratio was weighed. An alloy ingot was prepared using the same vacuum arc melting process as in Example 1. Subsequently, the alloy ingot was vacuum annealed at 1400°C for 12 hours, and then cooled in the furnace.

[0032] Step (2), mechanical ball milling: The two alloy blocks annealed in step (1) were placed in a planetary ball mill and mechanically ball-milled under an argon atmosphere. The ball milling speed was set to 300 rpm and the ball milling time was 8 hours. After ball milling, the powder was sieved through a 200-mesh standard sieve, and alloy powder with a particle size ≤75μm was collected.

[0033] Step (3), mechanical mixing: Accurately weigh the two alloy powders obtained in step (2) to ensure a mass ratio of 40:60. Place the powders together in a ball mill jar and ball mill them under an inert atmosphere. Set the ball-to-powder ratio to 8:1, the rotation speed to 150 rpm, the mixing time to 2 hours, and control the mixing temperature to ≤40℃. After mixing, the composite hydrogen storage material of Example 2 is obtained.

[0034] Results analysis: The composite hydrogen storage material prepared in Example 2 was subjected to the same activation and performance tests as in Example 1 (performance test section).

[0035] Test results show that the composite hydrogen storage material provided in Example 2 has an effective hydrogen release capacity of approximately 1.0 wt% at a low temperature of 5°C, significantly better than Comparative Example 2 (BCC alloy), which releases almost no hydrogen. At a high temperature of 70°C, the effective hydrogen release capacity reaches 1.6 wt%, significantly higher than the 1.2 wt% of Comparative Example 1 (AB2 alloy). In the hydrogen absorption kinetics test at 20°C, the material completes hydrogen absorption in approximately 8 minutes, with a saturated hydrogen absorption capacity of 2.0 wt%, higher than the 1.7 wt% of Comparative Example 1. In the cycle stability test, after 10 cycles, its capacity retention rate is as high as 97.0%. Example 3 This embodiment 3 provides a composite hydrogen storage material, which is composed of AB2 type Laves phase alloy (ZrMnCr, x=0) powder and BCC structure vanadium-based solid solution alloy (V 0.5 Ti 0.2 Cr 0.2 Fe 0.1 It is composed of powders in a mass ratio of 30:70.

[0036] This embodiment 3 provides a method for preparing a composite hydrogen storage material, including the following steps: Step (1), preparation and annealing of single-phase alloys: Preparation of AB2 type Laves phase alloy (ZrMnCr): Zirconium, manganese, and chromium with purities all greater than 99.9% were selected as raw materials and weighed according to the molar ratio of the chemical formula ZrMnCr. Alloy ingots were prepared using the same process as in Example 1. Subsequently, the alloy ingots were vacuum annealed at 1200°C for 24 hours.

[0037] BCC structure vanadium-based solid solution alloy (V 0.5 Ti 0.2 Cr 0.2 Fe 0.1 Preparation of vanadium metal, titanium sponge, chromium metal, and pure iron, all with a purity greater than 99.9%, were selected as raw materials and prepared according to the chemical formula V. 0.5 Ti 0.2 Cr 0.2 Fe 0.1 The molar ratio was weighed. An alloy ingot was prepared using the exact same process as in Example 1. Subsequently, the alloy ingot was vacuum annealed at 1300°C for 12 hours.

[0038] Step (2), mechanical ball milling: The two alloy blocks annealed in step (1) were subjected to mechanical ball milling. The ball milling speed was set to 500 rpm and the ball milling time was 4 hours. After ball milling, alloy powder with a particle size ≤75μm was collected by sieving.

[0039] Step (3), mechanical mixing: Accurately weigh the two alloy powders obtained in step (2) to ensure a mass ratio of 30:70. Place the powders together in a ball mill jar and ball mill them under an inert atmosphere. Set the ball-to-powder ratio to 12:1, the rotation speed to 150 rpm, the mixing time to 1 hour, and control the mixing temperature to ≤40℃.

[0040] Results analysis: The performance of the composite hydrogen storage material prepared in Example 3 was tested. The test results showed that the effective hydrogen release capacity of the composite hydrogen storage material provided in Example 3 was approximately 0.6 wt% at 5°C, achieving a breakthrough that Comparative Example 2 (BCC alloy) could not be applied at this temperature; the effective hydrogen release capacity at 70°C reached 1.9 wt%, higher than Comparative Example 1 (AB2 alloy). In the hydrogen absorption kinetics test at 20°C, the material completed hydrogen absorption in approximately 12 minutes, and its saturated hydrogen absorption capacity was 1.9 wt%, significantly higher than Comparative Example 1. In the cycle stability test, after 10 cycles, its capacity retention rate was 95.5%.

[0041] Example 4 This embodiment 4 provides a composite hydrogen storage material, which is composed of an AB2 type Laves phase alloy (Zr). 0.5 Ti 0.5 MnCr, x=0.5) powder and BCC structure vanadium-based solid solution alloy (V 0.8 Ti 0.1 Cr 0.1 It is composed of powders in a mass ratio of 30:70.

[0042] This embodiment 4 provides a method for preparing a composite hydrogen storage material, including the following steps: Step (1), preparation and annealing of single-phase alloys: AB2 type Laves phase alloy (Zr 0.5 Ti 0.5 Preparation of ZnCr: Zirconium metal, titanium sponge, manganese metal, and chromium metal with a purity greater than 99.9% were selected as raw materials, and the ZnCr was prepared according to the chemical formula ZnCr. 0.5 Ti 0.5 The molar ratio of MnCr was weighed. An alloy ingot was prepared using the exact same process as in Example 1. Subsequently, the alloy ingot was vacuum annealed at 1050°C for 24 hours.

[0043] BCC structure vanadium-based solid solution alloy (V 0.8 Ti 0.1 Cr 0.1 Preparation of vanadium metal, sponge titanium, and chromium metal, all with a purity greater than 99.9%, were selected as raw materials and prepared according to the chemical formula V. 0.8 Ti 0.1 Cr 0.1 The molar ratio was weighed. An alloy ingot was prepared using the exact same process as in Example 1. Subsequently, the alloy ingot was vacuum annealed at 1500°C for 12 hours.

[0044] Step (2), mechanical ball milling: The two alloy blocks annealed in step (1) were subjected to mechanical ball milling. The ball milling speed was set to 450 rpm and the ball milling time was 5 hours. After ball milling, alloy powder with a particle size ≤75 μm was collected by sieving.

[0045] Step (3), mechanical mixing: Accurately weigh the two alloy powders obtained in step (2) to ensure a mass ratio of 30:70. Place the powders together in a ball mill jar and ball mill them under an inert atmosphere. Set the ball-to-powder ratio to 10:1, the rotation speed to 150 rpm, the mixing time to 1.5 hours, and control the mixing temperature to ≤40℃.

[0046] Results analysis: The performance of the composite hydrogen storage material prepared in Example 4 was tested.

[0047] Test results show that the composite hydrogen storage material provided in Example 4 has an effective hydrogen release capacity of approximately 0.7 wt% at 5°C, thus solving the low-temperature performance problem of Comparative Example 2. At 70°C, the effective hydrogen release capacity reaches 1.85 wt%, higher than Comparative Example 1. In the hydrogen absorption kinetics test at 20°C, the material's hydrogen absorption saturation time is approximately 11 minutes, and its saturated hydrogen absorption capacity reaches 2.0 wt%, twice the capacity of Comparative Example 1. In the cycle stability test, after 10 cycles, its capacity retention rate is 96.0%, indicating good stability.

[0048] Example 5 This embodiment 5 provides a composite hydrogen storage material, the material being composed of AB2 phase (Zr). 0.75 Ti 0.25 MnCr) and BCC phase (V 0.65 Ti 0.15 Cr 0.1 Fe 0.1 It is composed of 30:70 components.

[0049] This embodiment 5 provides a method for preparing a composite hydrogen storage material, including the following steps: Step (1), preparation and annealing of single-phase alloys: AB2 type Laves phase alloy (Zr 0.75 Ti 0.25 Preparation of MnCr: According to the chemical formula Zr 0.75 Ti 0.25 The MnCr raw materials were weighed and alloy ingots were prepared using the same process as in Example 1. Subsequently, they were vacuum annealed at 1050°C for 24 hours.

[0050] BCC structure vanadium-based solid solution alloy (V 0.65 Ti 0.15 Cr 0.1 Fe 0.1 Preparation of V: ​​according to chemical formula V 0.65 Ti 0.15 Cr 0.1 Fe 0.1 The raw materials were weighed and alloy ingots were prepared using the same process as in Example 1. Subsequently, they were vacuum annealed at 1400°C for 12 hours.

[0051] Step (2), mechanical ball milling: The two annealed alloy blocks were subjected to mechanical ball milling. The ball milling speed was set to 400 rpm, and the milling time was 6 hours. Alloy powder with a particle size ≤75 μm was collected by sieving.

[0052] Step (3), mechanical mixing: Accurately weigh the two alloy powders to ensure a mass ratio of 30:70. Mix them in a ball mill jar, setting the ball-to-powder ratio to 10:1, the rotation speed to 150 rpm, the mixing time to 1.5 hours, and controlling the mixing temperature to ≤40℃.

[0053] Results analysis: The performance of the composite hydrogen storage material prepared in Example 5 was tested.

[0054] Test results show that the composite hydrogen storage material provided in Example 5 has an effective hydrogen release capacity of approximately 1.2 wt% at 5°C, exhibiting excellent low-temperature performance; the effective hydrogen release capacity reaches 1.95 wt% at 70°C. In the hydrogen absorption kinetics test at 20°C, the material completes hydrogen absorption within 9 minutes, with a saturated hydrogen absorption capacity of 2.1 wt%. In the cycle stability test, after 10 cycles, its capacity retention rate is as high as 96.8%.

[0055] Example 6 This embodiment 6 provides a composite hydrogen storage material, which uses a preferred alloy composition (the composition in embodiment 1) with a mass ratio of 20:80.

[0056] This embodiment 6 provides a method for preparing a composite hydrogen storage material, including the following steps: Step (1), preparation and annealing of single-phase alloys: AB2 type Laves phase alloy (Zr 0.8 Ti 0.2 Preparation of MnCr: Alloy ingots were prepared using the same process as in Example 1. Subsequently, they were vacuum annealed at 900°C for 24 hours.

[0057] BCC structure vanadium-based solid solution alloy (V 0.75 Ti 0.11 Cr 0.12 Fe 0.02 Preparation of the alloy ingot: The alloy ingot was prepared using the same process as in Example 1. Subsequently, it was vacuum annealed at 1500°C for 12 hours.

[0058] Step (2), mechanical ball milling: The two annealed alloy blocks were subjected to mechanical ball milling. The ball milling speed was set to 300 rpm, and the milling time was 4 hours. Alloy powder with a particle size ≤75 μm was collected by sieving.

[0059] Step (3), mechanical mixing: Accurately weigh the two alloy powders to ensure a mass ratio of 20:80. Mix them in a ball mill jar, setting the ball-to-powder ratio to 12:1, the rotation speed to 150 rpm, the mixing time to 1 hour, and controlling the mixing temperature to ≤40℃.

[0060] Results analysis: The performance of the composite hydrogen storage material prepared in Example 6 was tested.

[0061] Test results show that the composite hydrogen storage material provided in Example 6 has an effective hydrogen release capacity greater than 0.6 wt% at 5°C and an effective hydrogen release capacity of 1.9 wt% at 70°C. In the hydrogen absorption kinetics test at 20°C, the material's hydrogen absorption saturation time is approximately 10 minutes, and its saturated hydrogen absorption capacity is 2.15 wt%. In the cycle stability test, after 10 cycles, its capacity retention rate is 96.0%.

[0062] Comparative Example Comparative Example 1 Comparative Example 1 provides an AB2 type single-phase hydrogen storage alloy with the chemical formula Zr. 0.8 Ti 0.2 MnCr.

[0063] Comparative Example 1 provides a method for preparing AB2 type single-phase hydrogen storage alloy powder, including the following steps: Alloy smelting and annealing: Zirconium (Zr), titanium sponge (Ti), manganese (Mn), and chromium (Cr) with purities all greater than 99.9% were selected as raw materials, and annealing was carried out according to Zr... 0.8 Ti 0.2 The molar ratio of MnCr was weighed. An alloy ingot was prepared using the same vacuum arc melting process as step (1) in Example 1. Subsequently, the alloy ingot was vacuum annealed at 1000°C for 24 hours, and then cooled in the furnace.

[0064] Mechanical ball milling: The annealed alloy block was subjected to the same ball milling process and parameters as step (2) in Example 1 (400 rpm, 6 h) to crush and sieve, finally obtaining Zr with a particle size ≤75 μm. 0.8 Ti 0.2 MnCr alloy powder.

[0065] Comparative Example 2 Comparative Example 2 provides a BCC-type single-phase hydrogen storage alloy with the chemical formula V. 0.75 Ti 0.11 Cr 0.12 Fe 0.02 .

[0066] Comparative Example 2 provides a method for preparing BCC-type single-phase hydrogen storage alloy powder, including the following steps: Alloy smelting and annealing: Vanadium (V), titanium sponge (Ti), chromium (Cr), and pure iron (Fe) with purities all greater than 99.9% were selected as raw materials, and smelting was carried out according to V... 0.75 Ti 0.11 Cr0.12 Fe 0.02 The molar ratio was weighed. The alloy ingot was prepared using the same vacuum arc melting process as step (1) in Example 1. Subsequently, the alloy ingot was vacuum annealed at 1400°C for 12 hours and then cooled in the furnace.

[0067] Mechanical ball milling: The annealed alloy block was subjected to the same ball milling process and parameters as step (2) in Example 1 (400 rpm, 6 h) to crush and sieve, finally obtaining V with a particle size ≤75 μm. 0.75 Ti 0.11 Cr 0.12 Fe 0.02 alloy powder.

[0068] Performance Testing and Comparative Analysis To verify the technical effect of the composite hydrogen storage material of the present invention, the composite hydrogen storage material prepared in Example 1, the AB2 type single-phase hydrogen storage alloy prepared in Comparative Example 1, and the BCC type single-phase hydrogen storage alloy prepared in Comparative Example 2 were tested for hydrogen storage performance under the same conditions.

[0069] 1. Activation treatment: Approximately 2g of each sample powder was placed into a stainless steel reaction vessel of a Sieverts PCT testing apparatus and subjected to vacuum degassing at 300°C for 3 hours to remove surface-adsorbed gases and some oxides. After treatment, the reaction vessel was cooled to room temperature, then purged with 2.0 MPa of high-purity hydrogen, and heated to 50°C and maintained for 1 hour to absorb hydrogen. Afterward, the reaction vessel was evacuated to release hydrogen. This hydrogen absorption and release process was repeated three times to complete the activation of the material.

[0070] 2. Performance Test Results and Comparative Analysis: The composite hydrogen storage material provided in Example 1 of this invention: Test results are as follows Figure 1 , Figure 2 and Figure 3 As shown. By Figure 1 It can be seen that at a low temperature of 5℃, the effective hydrogen release capacity of the material is greater than 0.5 wt%; while at a high temperature of 70℃, the effective hydrogen release capacity reaches as high as 2.0 wt%, with a flat hydrogen release plateau and moderate pressure, exhibiting excellent wide-temperature-range operating characteristics. Figure 2 It can be seen that the material exhibits excellent hydrogen absorption kinetics at 20℃, completing the hydrogen absorption process essentially within 10 minutes, with a saturated hydrogen absorption capacity of no less than 2.2 wt%. Figure 3 It can be seen that the material has excellent cycle stability. After 10 hydrogen absorption and desorption cycles at 25°C, its capacity retention rate is as high as 96.5%.

[0071] The AB2 type single-phase alloy provided in Comparative Example 1: Test results are as follows Figure 4 and Figure 5 As shown. By Figure 4 It can be seen that the hydrogen release capacity of this alloy is less than 1.8 wt% at 5℃, and decreases to 1.4 wt% at 70℃, indicating that although it has a certain low-temperature hydrogen release capacity, its overall hydrogen storage capacity is limited. Figure 5 It can be seen that its hydrogen absorption time at 20°C is about 10 minutes, but its saturated hydrogen absorption capacity is only 1.7 wt%, which is far lower than that of the composite hydrogen storage material in Example 1 of this invention.

[0072] Comparative Example 2 provides a BCC-type single-phase alloy: Test results are as follows Figure 6 As shown, this alloy exhibits a reversible hydrogen release capacity of up to 2.5 wt% at 70 °C, demonstrating great potential. However, at a low temperature of 5 °C, its hydrogen release plateau pressure is below 0.01 MPa, making it almost impossible for hydrogen to be released from the material at this temperature, thus losing its value for cryogenic applications.

[0073] Conclusion: The above comparison clearly shows that the composite hydrogen storage material provided by this invention is not a simple superposition of the properties of the two components, but rather produces a significant synergistic gain effect. It successfully utilizes the structural characteristics of the AB2 phase to overcome the fatal flaw of the BCC phase, which has poor low-temperature performance and cannot be applied; at the same time, it leverages the high capacity characteristics of the BCC phase to break through the bottleneck of insufficient hydrogen storage capacity of the AB2 phase, ultimately obtaining a novel hydrogen storage material that combines high capacity, fast kinetics, and long cycle life over a wide temperature range.

[0074] For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations, but obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this invention.

Claims

1. A composite hydrogen storage material, characterized in that, It is composed of an AB2-type Laves phase alloy and a BCC-structured vanadium-based solid solution alloy; wherein the AB2-type Laves phase alloy and the BCC-structured vanadium-based solid solution alloy are structurally independent. The AB2 type Laves phase alloy is a Zr-Ti-Mn-Cr intermetallic compound with the general formula Zr. 1-x Ti x MnCr, where 0 ≤ x ≤ 0.5; The BCC structure vanadium-based solid solution alloy is a V-Ti-Cr-Fe quaternary solid solution alloy with the general formula V. y Ti z Cr m Fe n Where 0.5 ≤ y ≤ 0.8, 0.1 ≤ z ≤ 0.2, 0 < m ≤ 0.2, and n is the margin.

2. The composite hydrogen storage material according to claim 1, characterized in that, The chemical formula of the AB2 type Laves phase alloy is Zr. 0.8 Ti 0.2 MnCr.

3. The composite hydrogen storage material according to claim 1, characterized in that, The chemical formula of the BCC structure vanadium-based solid solution alloy is V 0.75 Ti 0.11 Cr 0.12 Fe 0.02 .

4. The composite hydrogen storage material according to claim 1, characterized in that, The mass ratio of the AB2 type Laves phase alloy to the BCC structure vanadium-based solid solution alloy is 20:80 to 40:

60.

5. The composite hydrogen storage material according to claim 4, characterized in that, The mass ratio of the AB2 type Laves phase alloy to the BCC structure vanadium-based solid solution alloy is 20:

80.

6. A method for preparing a composite hydrogen storage material as described in any one of claims 1-5, characterized in that, Includes the following steps: Step (1): AB2 type Laves phase alloy and BCC structure vanadium-based solid solution alloy were prepared by electric arc melting, and annealed after melting. Step (2): The annealed AB2 type Laves phase alloy and BCC structure vanadium-based solid solution alloy were mechanically ball-milled to obtain AB2 type Laves phase alloy powder and BCC structure vanadium-based solid solution alloy powder, respectively. Step (3) involves mechanically mixing the AB2 type Laves phase alloy powder and the BCC structure vanadium-based solid solution alloy powder obtained in step (2) under an inert atmosphere to obtain the composite hydrogen storage material.

7. The method for preparing the composite hydrogen storage material according to claim 6, characterized in that, In step (1), the AB2 type Laves phase alloy is annealed at a temperature of 900℃~1200℃ after melting; the BCC structure vanadium-based solid solution alloy is annealed at a temperature of 1300℃~1500℃ after melting.

8. The method for preparing the composite hydrogen storage material according to claim 6, characterized in that, In step (2), the ball milling speed is 300 rpm to 500 rpm, the ball milling time is 4 h to 8 h, and the particle size of AB2 type Laves phase alloy powder and BCC structure vanadium-based solid solution alloy powder is ≤75 μm.

9. The method for preparing the composite hydrogen storage material according to claim 6, characterized in that, In step (3), the mechanical mixing is ball milling, the ball-to-material ratio is 8~12:1, and the mixing temperature is ≤40℃.

10. An application of the composite hydrogen storage material as described in any one of claims 1-5, characterized in that, The composite hydrogen storage material is applied to a hydrogen energy system that performs reversible hydrogen storage and release operations within a wide temperature range of 5℃ to 70℃, wherein the hydrogen energy system is a fuel cell vehicle hydrogen storage system or a solar-coupled hydrogen storage system.

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