AB2 type Ti-Mn-based hydrogen storage alloy and preparation method thereof

Abstract

The invention discloses an AB2 type Ti-Mn-based hydrogen storage alloy and a preparation method thereof, and belongs to the technical field of hydrogen storage materials and preparation thereof. The problems that an existing AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy is difficult to activate, and the hydrogen absorption and desorption lag is large are solved. According to the AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy with the structural formula being TixZr1-xCryMn2-y, the AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy which is adjustable in plateau pressure, easy to activate and high in hydrogen storage capacity is obtained by regulating and controlling the content of elements on the side A and the side B, part of the alloy can absorb hydrogen at the room temperature without activation, the hydrogen absorption rate is high, 90% or above of hydrogen can be absorbed within 5 min, and the hydrogen storage capacity is high. The maximum hydrogen absorption capacity at room temperature can reach 2.06 wt.%, and the maximum hydrogen desorption capacity is 1.88 wt.%.

Description

Technical Field

[0001] This invention relates to an AB2 type Ti-Mn based hydrogen storage alloy and its preparation method, belonging to the technical field of hydrogen storage materials and their preparation. Background Technology

[0002] Hydrogen possesses high energy density, high calorific value, abundant reserves, and wide applications, indicating a promising future. Currently, the hydrogen energy industry chain faces numerous technological challenges in hydrogen production, storage, and application. The construction of hydrogen energy systems is still immature. Hydrogen storage and transportation technologies are relatively weak links in hydrogen energy development and are one of the key issues for the practical, large-scale, and industrialized application of hydrogen energy. The development of high-performance hydrogen storage materials is fundamental to the development of hydrogen storage technology. Compared to high-pressure gaseous hydrogen storage and cryogenic liquid hydrogen storage, solid-state hydrogen storage technology stores hydrogen in an atomic state within metal hydrides. It eliminates the need for high-pressure and insulated containers, offers better safety, and provides a high volumetric hydrogen storage density, offering a promising solution for the efficient and large-scale storage of hydrogen energy in the future.

[0003] AB2 type hydrogen storage alloy has high hydrogen storage capacity (volume hydrogen storage capacity 100g L). -1 The above-mentioned hydrogen storage capacity (approximately 2.0 wt.%), good platform characteristics, abundant raw materials, and mature preparation technology give it broad application prospects in the field of solid-state hydrogen storage. However, difficulties in activation and lag in hydrogen absorption / desorption curves remain major bottlenecks limiting its large-scale development and application. When AB2-type hydrogen storage alloys are exposed to air, they are prone to oxidation, leading to the formation of an oxide layer on the surface, resulting in poor performance during the initial hydrogen absorption process. Therefore, continuous activation treatment at high temperatures (above 200℃) and high hydrogen atmospheric pressure (5–6 MPa) is necessary to decompose the oxide layer and pave the way for hydrogen atoms to penetrate into the bulk.

[0004] To overcome the aforementioned technical barriers, researchers have conducted extensive research. Chinese patent CN116411214A provides an AB2 type Ti... a Cr b M c Ca d An alloy (where a = 0.8–1.2, b = 0.5–1.5, c = 0.5–1.5, d = 0.01–0.05) exhibits improved activation properties and reduced hydrogen absorption / desorption plateau slope by introducing specific Ca elements. While this method allows for activation at room temperature, it requires the prior preparation of an intermediate alloy, the introduction of a Ca source, and secondary heat treatment, resulting in a complex and energy-intensive process. Chinese patent CN115377433 A prepared AB2-type Ti. 1～1.2 Cr 0.8～ 1Mn 1～1.2A novel AB2-type hydrogen storage alloy, capable of room-temperature activation and exhibiting rapid hydrogen absorption / desorption rates and a high heat transfer coefficient, requires complex preparation techniques after melting and casting, including rapid quenching via strip spinning and high-energy ball milling with graphene, hindering large-scale production. Therefore, there is an urgent need to develop a novel AB2-type hydrogen storage alloy with a simple preparation process, good activation performance, high hydrogen storage capacity, and low cost. Summary of the Invention

[0005] To address the problems of difficult activation and large hydrogen absorption / desorption hysteresis in existing AB2-type Ti-Zr-Cr-Mn hydrogen storage alloys, this invention provides an AB2-type Ti-Mn-based hydrogen storage alloy and its preparation method.

[0006] The technical solution of this invention:

[0007] One objective of this invention is to provide an AB2-type Ti-Mn-based hydrogen storage alloy, the structural formula of which is Ti x Zr 1-x Cr y Mn 2-y , where x is 0.1-0.9 and y is 0.5-1.75.

[0008] Further specifying, the structural formula is Ti 0.8 Zr 0.2 Cr 1.5 Mn 0.5 .

[0009] Further specifying, the structural formula is Ti 0.6 Zr 0.4 Cr 1.0 Mn 1.0 .

[0010] Further specifying, the structural formula is Ti 0.5 Zr 0.5 Cr 1.75 Mn 0.25 .

[0011] Further specifying, the structural formula is Ti 0.4 Zr 0.6 Cr 0.5 Mn 1.5 .

[0012] Further specifying, the structural formula is Ti 0.3 Zr 0.7 Cr 1.25 Mn 0.75 .

[0013] The second objective of this invention is to provide a method for preparing the above-mentioned AB2 type Ti-Mn based hydrogen storage alloy, the method comprising the following steps:

[0014] (1) Weigh the mass of the metallic elements Ti, Zr, Cr and Mn according to their structural formulas;

[0015] (2) Place the metal element weighed in step (1) into the crucible of the vacuum non-consumable arc melting furnace, evacuate the furnace, and melt it under the protection of argon gas. Repeat the melting and casting to ensure that the alloy composition is uniform. Cool to obtain AB2 type Ti-Mn based hydrogen storage alloy.

[0016] Further specified, (1) the mass of Mn element in metallic elemental form is 5% excess.

[0017] Further specified, the smelting current in (2) is 90-130A.

[0018] Further restrictions apply, in (2) the material is repeatedly smelted more than 4 times.

[0019] Further specifying, in (2), the vacuum is evacuated to 2×10 -3 Below Pa.

[0020] Beneficial effects of this invention:

[0021] This invention provides a structure with the formula Ti x Zr 1-x Cr y Mn 2-y An AB2-type Ti-Zr-Cr-Mn hydrogen storage alloy was developed. By controlling the elemental content on the A and B sides, an AB2-type Ti-Zr-Cr-Mn hydrogen storage alloy with adjustable plateau pressure, easy activation, and high hydrogen storage capacity was obtained. Furthermore, some alloys can absorb hydrogen at room temperature without activation, exhibiting a fast hydrogen absorption rate, capable of absorbing over 90% of hydrogen within 5 minutes. The maximum hydrogen absorption capacity at room temperature reaches 2.06 wt.%, and the maximum hydrogen release capacity is 1.88 wt.%. Compared with existing technologies, it has the following advantages:

[0022] (1) Ti prepared in this invention x Zr 1-x Cr y Mn 2-y The hydrogen absorption plateau of the hydrogen storage alloy is adjustable. By controlling the alloy composition and the hydrogen absorption and desorption temperatures, the hydrogen absorption plateau pressure of the Ti-Zr-Cr-Mn hydrogen storage alloy (the pressure value when H / M = 0.5 is taken as the plateau pressure value) can reach a maximum of 1.61 MPa and a minimum of 0.0035 MPa, which can meet different application scenarios.

[0023] (2) Ti prepared by the present invention x Zr 1-x Cr y Mn 2-yThe hysteresis coefficient of the hydrogen storage alloy is adjustable. By controlling the alloy composition and the hydrogen absorption and desorption temperature, the hysteresis coefficient of the Ti-Zr-Cr-Mn hydrogen storage alloy ranges from a minimum of 0.02 to a maximum of 0.89, which can meet different hydrogen absorption and desorption applications.

[0024] (3) Preparation of Ti by the present invention x Zr 1-x Cr y Mn 2-y Hydrogen storage alloys have a simple and mature process, and the raw materials are abundant, inexpensive and readily available, making them suitable for large-scale industrial production. They can absorb hydrogen at room temperature without activation, and have broad application prospects. Attached Figure Description

[0025] Figure 1 The activation curves of the hydrogen storage alloys prepared in Examples 1-5 are shown at 25°C and a hydrogen pressure of 5.5 ± 0.4 MPa.

[0026] Figure 2 The activation curve of the hydrogen storage alloy prepared in Example 5 is shown at 150°C and a hydrogen pressure of 5.5 ± 0.4 MPa.

[0027] Figure 3 The hydrogen absorption kinetics curves of the hydrogen storage alloys prepared in Examples 1-5 at 25°C and a hydrogen pressure of 5.5 ± 0.4 MPa are shown.

[0028] Figure 4 The hydrogen absorption kinetics curves of the hydrogen storage alloys prepared in Examples 1-5 at 50°C and a hydrogen pressure of 5.5 ± 0.4 MPa are shown.

[0029] Figure 5 The hydrogen absorption kinetics curves of the hydrogen storage alloys prepared in Examples 1-5 at 75°C and a hydrogen pressure of 5.5 ± 0.4 MPa are shown.

[0030] Figure 6 The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 1 at 25℃, 50℃ and 75℃, and hydrogen pressure of 5.5±0.4MPa are shown.

[0031] Figure 7 The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 2 are shown at 25°C, 50°C and 75°C, and a hydrogen pressure of 5.5 ± 0.4 MPa.

[0032] Figure 8 The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 3 are shown at 25°C, 50°C and 75°C, and hydrogen pressure of 5.5±0.4MPa.

[0033] Figure 9The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 4 are shown at 25°C, 50°C and 75°C, and hydrogen pressure of 5.5±0.4MPa.

[0034] Figure 10 The hydrogen absorption / desorption PCT curves of the hydrogen storage alloy prepared in Example 5 are shown at 25°C, 50°C and 75°C, and hydrogen pressure of 5.5 ± 0.4 MPa.

[0035] Figure 11 The cycling performance curves of the hydrogen storage alloys prepared in Examples 1 and 2 at 50°C and a hydrogen pressure of 5.5 ± 0.4 MPa are shown. Detailed Implementation

[0036] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0037] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0038] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0040] Example 1

[0041] The structural formula of the AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy provided in this embodiment is Ti. 0.8 Zr 0.2 Cr 1.5 Mn 0.5 .

[0042] The above structural formula is Ti 0.8 Zr 0.2 Cr 1.5 Mn 0.5 The method for preparing the hydrogen storage alloy includes the following steps:

[0043] First, the mass of each metal element is calculated according to the atomic ratio of each metal element. Ti, Zr, Cr and Mn metal elements with a purity of 99.9% are selected. Since manganese has a high vapor pressure, it is easy to burn off during the smelting process. Therefore, the mass of Mn element is 5% excess during weighing to make up for the burn-off.

[0044] The specific weighing mass of Ti is 3.546g, Zr is 1.689g, Cr is 7.221g, and Mn is 2.670g.

[0045] Then, after the elemental metals are mixed evenly, they are placed in the crucible of a vacuum non-consumable arc melting furnace, and a vacuum of 2×10⁻⁶ is drawn. -3 Below Pa, argon gas is introduced as a protective gas, and the furnace is repeatedly purged with argon gas three times to ensure an oxygen-free environment. The alloy is melted and cooled to room temperature at a melting current of 90-130A to form an alloy ingot. The alloy is then flipped and melted again, repeating the melting process at least four times to ensure uniform alloy composition. After cooling, Ti is obtained. 0.8 Zr 0.2 Cr 1.5 Mn 0.5 Hydrogen storage alloy ingot.

[0046] The Ti prepared above 0.8 Zr 0.2 Cr 1.5 Mn 0.5 Performance testing of hydrogen storage alloy:

[0047] (1) Hydrogen storage performance test

[0048] Ti 0.8 Zr 0.2 Cr 1.5 Mn 0.5 The surface of the hydrogen storage alloy ingot was sanded to remove the oxide layer, and then the alloy was mechanically crushed to obtain 100-400 mesh alloy powder for later use. Approximately 1.5g of the prepared hydrogen storage alloy powder was weighed and placed into the reactor of a Sievert's PCT tester, and a vacuum of 1×10⁻⁶ was applied. -4 Below MPa, approximately 5.5 MPa of 99.99% pure hydrogen gas is introduced for initial activation at room temperature (25°C) (activation curve shown in Figure 1). Figure 1 (As shown in the image) After activation, the hydrogen gas was exhausted, and the temperature was lowered to 25°C. The hydrogen absorption kinetics at 25°C, 50°C, and 75°C were tested, and the results are as follows: Figures 3-5 As shown in the figure. The hydrogen absorption / desorption PCT curves of the alloy were tested under the following conditions: 25℃ with a hydrogen pressure of 5.5±0.4 MPa, 50℃ with a hydrogen pressure of 5.5±0.4 MPa, and 75℃ with a hydrogen pressure of 5.5±0.4 MPa. The results are shown in the figure. Figure 6 As shown.

[0049] analyze Figure 1 and Figures 3-6 It can be seen that the Ti prepared in Example 1 0.8 Zr 0.2 Cr 1.5 Mn 0.5 The hydrogen storage alloy can absorb hydrogen upon initial activation at 25℃. The maximum hydrogen absorption capacity at 25℃ is 1.90 wt.%, and the reversible hydrogen storage capacity is 1.71 wt.%. At 50℃, the maximum hydrogen absorption capacity is 1.84 wt.%, and the reversible hydrogen storage capacity is 1.67 wt.%. At 75℃, the maximum hydrogen absorption capacity is 1.66 wt.%, and the reversible hydrogen storage capacity is 1.54 wt.%. The hydrogen absorption plateau pressures of the alloy at 25℃, 50℃, and 75℃ are 0.34 MPa, 0.76 MPa, and 1.61 MPa, respectively (the pressure value at H / M = 0.5 is taken as the plateau pressure value). The hydrogen absorption curve and the hydrogen release curve basically overlap, with hysteresis coefficients of 0.03, 0.02, and 0.14, respectively.

[0050] (2) Cyclic performance test

[0051] The activated hydrogen storage alloy powder was subjected to cycle performance testing. The specific testing steps are as follows:

[0052] (a) The initial hydrogen storage capacity of the hydrogen storage alloy powder was tested after hydrogenation at 323 K and 5.5 ± 0.4 MPa for 30 min, followed by vacuuming to 1.0 × 10⁻⁶ MPa. -3 Below MPa.

[0053] (b) The initial hydrogen pressure is above 4 MPa, the hydrogenation reaction time is above 5 min, followed by dehydrogenation and evacuation to a vacuum of 1.0 × 10⁻⁶ MPa. -3 After passing through MPa, hydrogenation is carried out under the same conditions.

[0054] (c) Repeat the test 9 times in step (b). After the 9th cycle, raise the temperature to 473K to completely dehydrogenate for 60 minutes, then cool to 323K and perform the 10th cycle performance test in step (a). The hydrogen absorption capacity was calibrated and recorded.

[0055] (d) Repeat steps (a)-(c) to record the hydrogen storage capacity after the 20th and 30th cycles.

[0056] Test results are as follows Figure 11 As shown, the hydrogen absorption capacity in the first cycle was 1.77 wt.%, and the hydrogen absorption capacity after 30 cycles was 1.72 wt.%, with a capacity retention rate of 97.18%.

[0057] Example 2

[0058] The structural formula of the AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy provided in this embodiment is Ti. 0.6 Zr0.4 Cr 1.0 Mn 1.0 .

[0059] The above structural formula is Ti 0.6 Zr 0.4 Cr 1.0 Mn 1.0 The method for preparing the hydrogen storage alloy includes the following steps:

[0060] First, the mass of each metal element is calculated according to the atomic ratio of each metal element. Ti, Zr, Cr and Mn metal elements with a purity of 99.9% are selected. Since manganese has a high vapor pressure, it is easy to burn off during the smelting process. Therefore, the mass of Mn element is 5% excess during weighing to make up for the burn-off.

[0061] The specific weighing mass of Ti is 2.503g, Zr is 3.179g, Cr is 4.531g, and Mn is 5.026g.

[0062] Then, after the elemental metals are mixed evenly, they are placed in the crucible of a vacuum non-consumable arc melting furnace, and a vacuum of 2×10⁻⁶ is drawn. -3 Below Pa, argon gas is introduced as a protective gas, and the furnace is repeatedly purged with argon gas three times to ensure an oxygen-free environment. The melting current is in the range of 90-130A, and the alloy is melted and then cooled to room temperature to form an alloy ingot. Subsequently, the alloy is turned over and melted again, and the melting process is repeated more than four times to ensure that the alloy composition is uniform.

[0063] The Ti prepared above 0.6 Zr 0.4 Cr 1.0 Mn 1.0 Performance testing of hydrogen storage alloy:

[0064] (1) Hydrogen storage performance test

[0065] Ti 0.6 Zr 0.4 Cr 1.0 Mn 1.0 The surface of the hydrogen storage alloy ingot was sanded to remove the oxide layer, and then the alloy was mechanically crushed to obtain 100-400 mesh alloy powder for later use. Approximately 1.5g of the prepared hydrogen storage alloy powder was weighed and placed into the reactor of a Sievert's PCT tester, and a vacuum of 1×10⁻⁶ was applied. -4 Below MPa, approximately 5.5 MPa of 99.99% pure hydrogen gas is introduced for initial activation at room temperature (25°C) (activation curve shown in Figure 1). Figure 1 (As shown in the image) After activation, the hydrogen gas was exhausted, and the temperature was lowered to 25°C. The hydrogen absorption kinetics at 25°C, 50°C, and 75°C were tested, and the results are as follows: Figures 3-5As shown in the figure. The hydrogen absorption / desorption PCT curves of the alloy were tested under the following conditions: 25℃ with a hydrogen pressure of 5.5±0.4 MPa, 50℃ with a hydrogen pressure of 5.5±0.4 MPa, and 75℃ with a hydrogen pressure of 5.5±0.4 MPa. The results are shown in the figure. Figure 7 As shown.

[0066] analyze Figure 1 and Figures 3-5 as well as Figure 7 It can be seen that the Ti prepared in Example 2 0.6 Zr 0.4 Cr 1.0 Mn 1.0 The hydrogen storage alloy can absorb hydrogen upon initial activation at 25℃. The maximum hydrogen absorption capacity at 25℃ is 2.03 wt.%, and the reversible hydrogen storage capacity is 1.88 wt.%. At 50℃, the maximum hydrogen absorption capacity is 1.99 wt.%, and the reversible hydrogen storage capacity is 1.87 wt.%. At 75℃, the maximum hydrogen absorption capacity is 1.94 wt.%, and the reversible hydrogen storage capacity is 1.82 wt.%. The hydrogen absorption plateau pressures of the alloy at 25℃, 50℃, and 75℃ are 0.08 MPa, 0.18 MPa, and 0.39 MPa, respectively (the pressure value at H / M = 0.5 is taken as the plateau pressure value), and the hydrogen absorption / desorption hysteresis coefficients are 0.38, 0.32, and 0.18, respectively.

[0067] (2) Cyclic performance test

[0068] The activated hydrogen storage alloy powder was subjected to cycle performance testing. The specific testing steps are as follows:

[0069] (a) The initial hydrogen storage capacity of the hydrogen storage alloy powder was tested after hydrogenation at 323 K and 5.5 ± 0.4 MPa for 30 min, followed by vacuuming to 1.0 × 10⁻⁶ MPa. -3 Below MPa.

[0070] (b) The initial hydrogen pressure is above 4 MPa, the hydrogenation reaction time is above 5 min, followed by dehydrogenation and evacuation to a vacuum of 1.0 × 10⁻⁶ MPa. -3 After passing through MPa, hydrogenation is carried out under the same conditions.

[0071] (c) Repeat the test 9 times in step (b). After the 9th cycle, raise the temperature to 473K to completely dehydrogenate for 60 minutes, then cool to 323K and perform the 10th cycle performance test in step (a). The hydrogen absorption capacity was calibrated and recorded.

[0072] (d) Repeat steps (a)-(c) to record the hydrogen storage capacity after the 20th and 30th cycles.

[0073] Test results are as follows Figure 11As shown, the hydrogen absorption capacity was 1.92 wt.% in the first cycle and 1.93 wt.% after 30 cycles. The increase in hydrogen absorption capacity may be due to the alloy undergoing a certain degree of crushing during the hydrogen absorption and desorption process, which makes the alloy particles smaller and easier to contact with hydrogen, thus slightly increasing the amount of hydrogen absorbed.

[0074] Example 3

[0075] The structural formula of the AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy provided in this embodiment is Ti. 0.5 Zr 0.5 Cr 1.75 Mn 0.25 .

[0076] The above structural formula is Ti 0.5 Zr 0.5 Cr 1.75 Mn 0.25 The method for preparing the hydrogen storage alloy includes the following steps:

[0077] First, the mass of each metal element is calculated according to the atomic ratio of each metal element. Ti, Zr, Cr and Mn metal elements with a purity of 99.9% are selected. Since manganese has a high vapor pressure, it is easy to burn off during the smelting process. Therefore, the mass of Mn element is 5% excess during weighing to make up for the burn-off.

[0078] The specific weighing mass of Ti is 2.060g, Zr is 3.926g, Cr is 7.832g, and Mn is 1.241g.

[0079] Then, after the elemental metals are mixed evenly, they are placed in the crucible of a vacuum non-consumable arc melting furnace, and a vacuum of 2×10⁻⁶ is drawn. -3 Below Pa, argon gas is introduced as a protective gas, and the furnace is repeatedly purged with argon gas three times to ensure an oxygen-free environment. The melting current is in the range of 90-130A, and the alloy is melted and then cooled to room temperature to form an alloy ingot. Subsequently, the alloy is turned over and melted again, and the melting process is repeated more than four times to ensure that the alloy composition is uniform.

[0080] The Ti prepared above 0.5 Zr 0.5 Cr 1.75 Mn 0.25 Performance testing of hydrogen storage alloy:

[0081] Ti 0.5 Zr 0.5 Cr 1.75 Mn 0.25The surface of the hydrogen storage alloy ingot was sanded to remove the oxide layer, and then the alloy was mechanically crushed to obtain 100-400 mesh alloy powder for later use. Approximately 1.5g of the prepared hydrogen storage alloy powder was weighed and placed into the reactor of a Sievert's PCT tester, and a vacuum of 1×10⁻⁶ was applied. -4 Below MPa, approximately 5.5 MPa of 99.99% pure hydrogen gas is introduced for initial activation at room temperature (25°C) (activation curve shown in Figure 1). Figure 1 (As shown in the image) After activation, the hydrogen gas was exhausted, and the temperature was lowered to 25°C. The hydrogen absorption kinetics at 25°C, 50°C, and 75°C were tested, and the results are as follows: Figures 3-5 As shown in the figure. The hydrogen absorption / desorption PCT curves of the alloy were tested under the following conditions: 25℃ with a hydrogen pressure of 5.5±0.4 MPa, 50℃ with a hydrogen pressure of 5.5±0.4 MPa, and 75℃ with a hydrogen pressure of 5.5±0.4 MPa. The results are shown in the figure. Figure 8 As shown.

[0082] analyze Figure 1 and Figures 3-5 as well as Figure 8 It can be seen that the Ti prepared in Example 3 0.5 Zr 0.5 Cr 1.75 Mn 0.25 The hydrogen storage alloy can absorb hydrogen upon initial activation at 25℃. The maximum hydrogen absorption capacity at 25℃ is 1.98 wt.%, and the reversible hydrogen storage capacity is 1.32 wt.%. At 50℃, the maximum hydrogen absorption capacity is 1.94 wt.%, and the reversible hydrogen storage capacity is 1.54 wt.%. At 75℃, the maximum hydrogen absorption capacity is 1.86 wt.%, and the reversible hydrogen storage capacity is 1.55 wt.%. The hydrogen absorption plateau pressures of the alloy at 25℃, 50℃, and 75℃ are 0.02 MPa, 0.06 MPa, and 0.12 MPa, respectively (the pressure value at H / M = 0.5 is taken as the plateau pressure value), and the hydrogen absorption / desorption hysteresis coefficients are 0.83, 0.57, and 0.54, respectively.

[0083] Example 4

[0084] The structural formula of the AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy provided in this embodiment is Ti. 0.4 Zr 0.6 Cr 0.5 Mn 1.5 .

[0085] The above structural formula is Ti 0.4 Zr 0.6 Cr 0.5 Mn 1.5 The method for preparing the hydrogen storage alloy includes the following steps:

[0086] First, the mass of each metal element is calculated according to the atomic ratio of each metal element. Ti, Zr, Cr and Mn metal elements with a purity of 99.9% are selected. Since manganese has a high vapor pressure, it is easy to burn off during the smelting process. Therefore, the mass of Mn element is 5% excess during weighing to make up for the burn-off.

[0087] The specific weighing mass of Ti is 1.576g, Zr is 4.504g, Cr is 2.139g, and Mn is 7.120g.

[0088] Then, after the elemental metals are mixed evenly, they are placed in the crucible of a vacuum non-consumable arc melting furnace, and a vacuum of 2×10⁻⁶ is drawn. -3 Below Pa, argon gas is introduced as a protective gas, and the furnace is repeatedly purged with argon gas three times to ensure an oxygen-free environment. The melting current is in the range of 90-130A, and the alloy is melted and then cooled to room temperature to form an alloy ingot. Subsequently, the alloy is turned over and melted again, and the melting process is repeated more than four times to ensure that the alloy composition is uniform.

[0089] The Ti prepared above 0.4 Zr 0.6 Cr 0.5 Mn 1.5 Performance testing of hydrogen storage alloy:

[0090] Ti 0.4 Zr 0.6 Cr 0.5 Mn 1.5 The surface of the hydrogen storage alloy ingot was sanded to remove the oxide layer, and then the alloy was mechanically crushed to obtain 100-400 mesh alloy powder for later use. Approximately 1.5g of the prepared hydrogen storage alloy powder was weighed and placed into the reactor of a Sievert's PCT tester, and a vacuum of 1×10⁻⁶ was applied. -4 Below MPa, approximately 5.5 MPa of 99.99% pure hydrogen gas is introduced for initial activation at room temperature (25°C) (activation curve shown in Figure 1). Figure 1 (As shown in the image) After activation, the hydrogen gas was exhausted, and the temperature was lowered to 25°C. The hydrogen absorption kinetics at 25°C, 50°C, and 75°C were tested, and the results are as follows: Figures 3-5 As shown in the figure. The hydrogen absorption / desorption PCT curves of the alloy were tested under the following conditions: 25℃ with a hydrogen pressure of 5.5±0.4 MPa, 50℃ with a hydrogen pressure of 5.5±0.4 MPa, and 75℃ with a hydrogen pressure of 5.5±0.4 MPa. The results are shown in the figure. Figure 9 As shown.

[0091] analyze Figure 1 and Figures 3-5 as well as Figure 9 It can be seen that the Ti prepared in Example 4 0.4 Zr 0.6 Cr 0.5 Mn1.5 The hydrogen storage alloy can absorb hydrogen upon initial activation at 25℃. The maximum hydrogen absorption capacity at 25℃ is 2.01 wt.%, and the reversible hydrogen storage capacity is 1.14 wt.%. At 50℃, the maximum hydrogen absorption capacity is 1.99 wt.%, and the reversible hydrogen storage capacity is 1.82 wt.%. At 75℃, the maximum hydrogen absorption capacity is 1.96 wt.%, and the reversible hydrogen storage capacity is 1.89 wt.%. The hydrogen absorption plateau pressures of the alloy at 25℃, 50℃, and 75℃ are 0.01 MPa, 0.04 MPa, and 0.10 MPa, respectively (the pressure value at H / M = 0.5 is taken as the plateau pressure value), and the hydrogen absorption / desorption hysteresis coefficients are 0.89, 0.68, and 0.52, respectively.

[0092] Example 5

[0093] The structural formula of the AB2 type Ti-Zr-Cr-Mn hydrogen storage alloy provided in this embodiment is Ti. 0.3 Zr 0.7 Cr 1.25 Mn 0.75 .

[0094] The above structural formula is Ti 0.3 Zr 0.7 Cr 1.25 Mn 0.75 The method for preparing the hydrogen storage alloy includes the following steps:

[0095] First, the mass of each metal element is calculated according to the atomic ratio of each metal element. Ti, Zr, Cr and Mn metal elements with a purity of 99.9% are selected. Since manganese has a high vapor pressure, it is easy to burn off during the smelting process. Therefore, the mass of Mn element is 5% excess during weighing to make up for the burn-off.

[0096] The specific weighing mass of Ti is 1.168g, Zr is 5.194g, Cr is 5.286g, and Mn is 3.518g.

[0097] Then, after the elemental metals are mixed evenly, they are placed in the crucible of a vacuum non-consumable arc melting furnace, and a vacuum of 2×10⁻⁶ is drawn. -3 Below Pa, argon gas is introduced as a protective gas, and the furnace is repeatedly purged with argon gas three times to ensure an oxygen-free environment. The melting current is in the range of 90-130A, and the alloy is melted and then cooled to room temperature to form an alloy ingot. Subsequently, the alloy is turned over and melted again, and the melting process is repeated more than four times to ensure that the alloy composition is uniform.

[0098] The Ti prepared above 0.3 Zr 0.7 Cr 1.25 Mn 0.75 Performance testing of hydrogen storage alloy:

[0099] Ti 0.3 Zr 0.7 Cr 1.25 Mn 0.75 The surface of the hydrogen storage alloy ingot was sanded to remove the oxide layer, and then the alloy was mechanically crushed to obtain 100-400 mesh alloy powder for later use. Approximately 1.5g of the prepared hydrogen storage alloy powder was weighed and placed into the reactor of a Sievert's PCT tester, and a vacuum of 1×10⁻⁶ was applied. -4 Below MPa, approximately 5.5 MPa of 99.99% pure hydrogen gas is introduced for initial activation at room temperature (25°C) (activation curve shown in Figure 1). Figure 1 (As shown), purge the hydrogen gas, raise the temperature to 150°C, and introduce approximately 5.5 MPa of 99.99% pure hydrogen gas for high-temperature activation (activation curve shown). Figure 2 (As shown in the image) After activation, the hydrogen gas was exhausted, and the temperature was lowered to 25°C. The hydrogen absorption kinetics at 25°C, 50°C, and 75°C were tested, and the results are as follows: Figures 3-5 As shown in the figure. The hydrogen absorption / desorption PCT curves of the alloy were tested under the following conditions: 25℃ with a hydrogen pressure of 5.5±0.4 MPa, 50℃ with a hydrogen pressure of 5.5±0.4 MPa, and 75℃ with a hydrogen pressure of 5.5±0.4 MPa. The results are shown in the figure. Figure 10 As shown.

[0100] analyze Figures 1-5 as well as Figure 10 It can be seen that the Ti prepared in Example 5 0.3 Zr 0.7 Cr 1.25 Mn 0.75 The hydrogen storage alloy can absorb hydrogen after one activation at 150℃. The maximum hydrogen absorption capacity is 2.06 wt.% at 25℃, with a reversible hydrogen storage capacity of 1.03 wt.%. At 50℃, the maximum hydrogen absorption capacity is 2.06 wt.%, with a reversible hydrogen storage capacity of 1.49 wt.%. At 75℃, the maximum hydrogen absorption capacity is 1.98 wt.%, with a reversible hydrogen storage capacity of 1.86 wt.%. The hydrogen absorption plateau pressures of the alloy at 25℃, 50℃, and 75℃ are 0.003 MPa, 0.01 MPa, and 0.03 MPa, respectively (the pressure value is taken as H / M = 0.5), and the hydrogen absorption / desorption hysteresis coefficients are 0.15, 0.14, and 0.09, respectively.

[0101] In summary, the AB2-type Ti-Zr-Cr-Mn hydrogen storage alloy provided by this invention features adjustable plateau pressure, easy activation, and high hydrogen storage capacity. Some alloys can absorb hydrogen at room temperature without activation, exhibiting a rapid absorption rate, capable of absorbing over 90% of hydrogen within 5 minutes. The maximum hydrogen absorption capacity at 25°C reaches 2.06 wt.%, and the maximum hydrogen release capacity is 1.88 wt.%. This invention solves the problem of difficult activation of AB2-type hydrogen storage alloys, improving their hydrogen storage capacity. The hydrogen storage performance of the alloy can be adjusted by modifying the ratio of Ti, Zr, Cr, and Mn metal elements to meet different application scenarios.

[0102] The above description is only a preferred embodiment of the present invention. Given that those skilled in the art can make appropriate changes and modifications to the above embodiments, the present invention is not limited to the specific embodiments described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention.

Claims

1. An AB2-type Ti-Mn-based hydrogen storage alloy, characterized in that, The structural formula is Ti x Zr 1-x Cr y Mn 2-y , where x is 0.1-0.9 and y is 0.5-1.

75.

2. The hydrogen storage alloy according to claim 1, characterized in that, The structural formula is Ti 0.8 Zr 0.2 Cr 1.5 Mn 0.5 .

3. The hydrogen storage alloy according to claim 1, characterized in that, The structural formula is Ti 0.6 Zr 0.4 Cr 1.0 Mn 1.0 .

4. The hydrogen storage alloy according to claim 1, characterized in that, The structural formula is Ti 0.5 Zr 0.5 Cr 1.75 Mn 0.25 .

5. The hydrogen storage alloy according to claim 1, characterized in that, The structural formula is Ti 0.4 Zr 0.6 Cr 0.5 Mn 1.5 .

6. The hydrogen storage alloy according to claim 1, characterized in that, The structural formula is Ti 0.3 Zr 0.7 Cr 1.25 Mn 0.75 .

7. A method for preparing the AB2 type Ti-Mn based hydrogen storage alloy according to any one of claims 1 to 6, characterized in that, include: (1) Weigh the mass of the metallic elements Ti, Zr, Cr and Mn according to their structural formulas; (2) Place the weighed metal element from step (1) into the crucible of a vacuum non-consumable arc melting furnace, evacuate the furnace, and melt it under the protection of argon gas. Repeat the melting process to ensure that the alloy composition is uniform. Cool the alloy to obtain AB2 type Ti-Mn based hydrogen storage alloy.

8. The preparation method according to claim 7, characterized in that, (1) The mass of Mn element in the metal is in excess by 5%.

9. The preparation method according to claim 7, characterized in that, (2) The smelting current is 90-130A.

10. The preparation method according to claim 7, characterized in that, (2) It is repeatedly smelted more than 4 times.

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