A high-volume-capacity and easy-activation Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy and a preparation method thereof

Abstract

This invention belongs to the field of solid-state hydrogen storage technology, specifically relating to a high-volume-capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy and its preparation method. The specific composition of the hydrogen storage alloy is Ti1Fe. 0.9 Mn 0.1 Ce x Zr y x is any value among 0.02, 0.04, and 0.06, and y is any value among 0.02 and 0.06. This invention optimizes the alloy composition by adding transition elements Mn and Zr, and rare earth element Ce, to the AB-type hydrogen storage alloy TiFe. The rare earth element Ce exists as an independent phase, while the transition elements Zr and Mn partially replace the elements on the A and B sides, respectively. This results in the appearance of second phases Ce, CeO, and ZrMn2 in the TiFe matrix, significantly improving the activation performance of the Ti-Fe based alloy.

Description

Technical Field

[0001] This invention belongs to the field of solid-state hydrogen storage technology, specifically relating to a high-volume-capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy and its preparation method. Background Technology

[0002] Hydrogen energy, as a revolutionary energy source, boasts numerous advantages. However, the difficulty in storing and transporting hydrogen makes hydrogen storage technology a major constraint on its application. Ti-Fe-based hydrogen storage alloys offer advantages such as low cost, high volumetric hydrogen storage density, and reversible room-temperature hydrogen storage capability, making them an ideal choice for stationary hydrogen storage systems and demonstrating promising application prospects.

[0003] Pure TiFe alloys require multiple hydrogenation cycles for activation at 673 K and 6.5 MPa hydrogen atmosphere. The academic community believes this is mainly because oxygen passivates the surface of TiFe alloys, inhibiting the decomposition of hydrogen molecules into hydrogen atoms. Since the dissociation of hydrogen is a key step in hydrogenation, the activation problem has limited the development of Ti-Fe based alloys.

[0004] Currently, the main methods to improve the activation performance of Ti-Fe based alloys are optimizing the alloy composition and optimizing the preparation process. However, optimizing the alloy composition introduces a second phase, which, while improving activation performance, reduces the content of the hydrogen-absorbing phase, thus lowering hydrogen storage performance. Optimizing the preparation process, such as adding ball milling and rapid quenching, aims to increase the diffusion channels of hydrogen atoms by introducing fine grains and amorphous materials. However, since fine grains and amorphous materials cannot store hydrogen atoms, they reduce the hydrogen storage performance of the material and also have problems such as high production costs and high loss rates. In addition, hydrogen storage alloys have poor heat dissipation performance in practical applications, which can easily affect their hydrogen absorption performance. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a high volumetric capacity and easily activated Ti-Fe-Mn-Ce-Zr based hydrogen storage alloy and its preparation method. The present invention significantly improves the activation performance and heat dissipation capacity of the hydrogen storage alloy by optimizing the composition and preparation process. Furthermore, the preparation process of the hydrogen storage alloy of the present invention is simple, has good industrial feasibility, and has the potential for large-scale promotion and application.

[0006] The technical solution adopted by the present invention to solve the above problems is as follows:

[0007] A high-volume-capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy, wherein the specific composition of the hydrogen storage alloy is Ti1Fe 0.9 Mn 0.1 Ce x Zr yx is any value among 0.02, 0.04, and 0.06, and y is any value among 0.02 and 0.06.

[0008] Furthermore, the hydrogen storage alloy comprises a multiphase structure, which includes a main phase TiFe phase and a second phase Ce, CeO, and ZrMn2.

[0009] Furthermore, the Ce element in the hydrogen storage alloy is independent of the matrix of the hydrogen storage alloy and the Ce element is enriched at the sites, while the Zr and Mn elements in the hydrogen storage alloy are uniformly distributed in the matrix of the hydrogen storage alloy.

[0010] Through the above technical solution, the alloy of this invention still belongs to the Ti-Fe based alloy category, with TiFe as the main phase. Hydrogen atoms are stored in the tetrahedral and octahedral interstices of the TiFe unit cell. Since the second phase contains both hydrogenatable and non-hydrogenatable phases, increasing the proportion of the TiFe phase can increase the hydrogen storage capacity while ensuring activation performance. The hydrogen storage alloy of this invention belongs to the AB type hydrogen storage alloy, in which the transition element Mn is used to partially replace the B-side element Fe. Since the Mn phase is more active than Fe, in an environment with low oxygen content, Mn will preferentially oxidize and protect Fe, allowing iron to catalyze the decomposition of hydrogen molecules into hydrogen atoms. When the oxygen content is high, due to the large difference in lattice constants between the oxides of Ti and Mn, microcracks will be generated between the oxides of Ti and Mn, accelerating hydrogen dissociation and permeation. However, excessive Mn will lead to a large amount of TiMn. 1.5 The formation of rare earth elements (Zr) and their high volume expansion rate will lead to alloy pulverization, which is detrimental to the application of the alloy. Due to the difference in electron volume and electronegativity, Ce does not melt into the alloy matrix and exists independently. During smelting, Ce can absorb residual oxygen, improve the purity of the alloy, and help reduce the activation conditions of Ti-Fe based alloys. However, rare earth hydrides can only decompose at high temperatures, so excessive doping of rare earth elements is not conducive to the hydrogen storage performance of the alloy. The transition metal element Zr is used to partially replace the A-side element Ti. Zr can have a synergistic effect with Mn, and the resulting second phase ZrMn2 provides a channel for hydrogen atoms to enter the interior of the alloy, which is beneficial to the activation of the alloy. In addition, the high-density and chemically stable ZrO2 film formed during the oxidation of Zr can protect the active sites and improve the alloy's resistance to poisoning. However, the atomic volume of Zr is larger than that of Ti. After replacing Ti, it will lead to an increase in the unit cell volume. Excessive Zr will reduce the number of unit cells in the same volume, thus reducing the hydrogen storage performance of the alloy. This invention forms a moderately abundant and uniformly distributed second phase by doping with a small amount of rare earth element Ce and transition metal elements Mn and Zr, which allows hydrogen atoms to diffuse rapidly from the surface into the interior of the material, significantly improving the activation performance of TiFe alloy.

[0011] This invention provides a method for preparing a high-volume-capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy, comprising the following steps:

[0012] S1. Calculate the dosage based on the chemical formula composition and mix the ingredients. When calculating, add a certain amount of loss due to burn for Mn, Ce, and Zr.

[0013] S2. Place the weighed raw materials into a copper crucible in sequence, evacuate the vacuum, and then fill it with inert gas for washing. Repeat the washing process several times. After washing, smelt the raw materials. After the raw materials melt, turn on the electromagnetic stirring. After the electromagnetic stirring, wait for the material to solidify. After solidification, turn the material over and remelt it. Repeat this process several times to obtain an alloy ingot.

[0014] S3. Grind the surface of the alloy ingot, mechanically crush the alloy ingot and sieve it to obtain alloy powder;

[0015] S4. Add the alloy powder to the mold and press it into a block to obtain the hydrogen storage alloy.

[0016] Porosity is related to effective thermal conductivity. The higher the porosity, the lower the effective thermal conductivity. The empirical formula is: Effective thermal conductivity = Thermal conductivity of metal × (1 - Porosity) 2 Clearly, as porosity increases, the effective thermal conductivity decreases approximately exponentially. Metal powders have high porosity and low effective thermal conductivity. Furthermore, because the metal powders are in point contact, heat transfer relies on limited phonons, while air, with a thermal conductivity of only 0.024 W / (mK), is a poor conductor of heat; therefore, the metal powders have poor heat dissipation. Through the above technical solution, the pressing process can reduce the porosity of the sample, significantly improving the effective thermal conductivity. Simultaneously, the pressing process increases the contact area between the metal powders, and the pore type changes from interconnected pores that severely affect thermal conductivity to isolated pores with less impact on thermal conductivity, thereby improving the heat dissipation capacity of the hydrogen storage alloy of this invention.

[0017] Furthermore, in step S1, the amount of Mn, Ce, and Zr lost during burning is 3 to 8% of the mass of each element added.

[0018] Furthermore, in step S2, the inert gas is argon.

[0019] Further, in step S2, after the raw materials are placed in the copper crucible, they are divided into a bottom layer, a middle layer and a top layer. The bottom layer consists of Fe blocks and Zr blocks, the middle layer consists of Ti blocks, and the top layer consists of Mn particles and Ce particles compressed by the Ti blocks.

[0020] The above technical solution involves placing raw materials with higher melting points at the bottom layer to ensure that the raw materials are fully melted; the raw materials in the middle layer can protect the raw materials in the lower layer from direct impact of the electric arc and support the raw materials in the upper layer; the raw materials in the upper layer are volatile raw materials, and pressing them with Ti blocks can reduce the volatilization of the raw materials.

[0021] Furthermore, in step S2, the vacuum level of the vacuum pump is ≤5*10-3 Pa, inert gas is introduced to atmospheric pressure.

[0022] Through the above technical solution, Mn, Ce and Zr in the raw materials are easily oxidized. Washing gas can prevent the oxidation of the raw materials from reducing their effective content and increase the hydrogen storage capacity of the hydrogen storage alloy.

[0023] Furthermore, in step S2, the melting is carried out in a vacuum arc melting furnace, and the arc current of the melting is 140-150A.

[0024] Through the above technical solution, this current can maintain a suitable temperature in the molten pool and reduce the volatilization of raw materials.

[0025] Furthermore, in step S3, the grinding is performed using a belt sander with a mesh size of 50.

[0026] Furthermore, in step S3, the mesh size of the sieve is 200 mesh.

[0027] Furthermore, in step S4, the pressing is performed using a press machine with a pressure of 200-400 kN.

[0028] With the above technical solution, this pressure is the preferred value. If the pressure is too low, the block will be brittle, and the porosity is close to the limit under a certain pressure. If the pressure is too high, it will not affect the porosity and may even crush the block.

[0029] The present invention has the following beneficial effects:

[0030] 1. This invention optimizes the alloy composition by adding transition elements Mn, Zr, and rare earth element Ce to the AB-type hydrogen storage alloy TiFe. The rare earth element Ce exists as an independent phase, while the transition elements Zr and Mn partially replace the elements on the A and B sides, respectively. This results in the appearance of second phases Ce, CeO, and ZrMn2 in the TiFe matrix. More second phases provide more channels for hydrogen atoms to diffuse into the interior. Since different elements have different expansion coefficients during oxidation, microcracks will form between the oxide films of different elements, exposing fresh surfaces. This significantly improves the activation performance of Ti-Fe based alloys.

[0031] 2. This invention improves the poisoning resistance of Ti-Fe based alloys by adding the transition element Zr. Because Zr forms a ZrO2 film during oxidation, which has a much higher density and chemical stability than TiO2, this film can cover the active sites of Ti and Fe, preventing the dissociation and permeation of poisoning gases.

[0032] 3. This invention also introduces a pressing process to balance activation performance and hydrogen storage performance. Compared with powder samples, the pressed block, under the same volume, maintains easy activation while increasing the total hydrogen storage capacity. Furthermore, powder has a higher porosity under the same volume, and air is a poor conductor of heat. The pressing technology can significantly reduce porosity, thereby improving thermal conductivity and thus enhancing the heat dissipation capacity of the hydrogen storage material.

[0033] 4. The Ti-Fe based alloy provided by the present invention can be activated in just half an hour at 80°C and 4 MPa hydrogen pressure, wherein the hydrogen storage capacity of the powder is ≥1.69 wt.% and the hydrogen storage capacity of the bulk is ≥1.67 wt.%.

[0034] 5. The Ti-Fe based alloy raw materials provided by this invention are inexpensive and have a stable supply. The preparation process is simple and has good industrial feasibility, and has the potential for large-scale promotion and application. Attached Figure Description

[0035] Figure 1 These are SEM and EDS images of Example 2 and Comparative Example 1 of the hydrogen storage alloy of the present invention.

[0036] Figure 2 The image shows the XRD diffraction patterns of the hydrogen storage alloy of the present invention, before and after hydrogen absorption and desorption, in Comparative Example 1.

[0037] Figure 3 The XRD diffraction patterns of Example 2 of the hydrogen storage alloy of the present invention before and after hydrogen absorption and desorption are shown.

[0038] Figure 4 The first activation curves are for Example 2 and Comparative Example 1 of the hydrogen storage alloy of the present invention.

[0039] Figure 5 The hydrogen absorption kinetics curves of Example 2 and Comparative Example 1 of the hydrogen storage alloy of the present invention at 303 K are shown.

[0040] Figure 6 The PCT curves of hydrogen absorption and desorption at 303 K are for Example 2 and Comparative Example 1 of the hydrogen storage alloy of the present invention. Detailed Implementation

[0041] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to specific examples. However, the scope of protection of this invention is not limited to the following specific embodiments. The described embodiments are merely some, not all, of the embodiments of this invention, and are not intended to limit the invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0042] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0043] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0044] In the quantitative experiments in the following examples, three replicate experiments were set up, and the data are the average of the three replicate experiments or the average ± standard deviation. Example 1

[0045] The specific composition of the hydrogen storage alloy is Ti1Fe 0.9 Mn 0.1 Ce 0.02 Zr 0.02 The preparation method of the hydrogen storage alloy includes the following steps:

[0046] S1. The dosage is calculated based on the chemical formula composition, and the purity of the raw materials is ≥99.99%. When weighing Mn, Ce, and Zr, an additional 3-8% of the mass of each element is added as loss on ignition.

[0047] S2. Place the weighed raw materials into a copper crucible in the following order: bottom layer of Fe blocks and Zr blocks, middle layer of Ti blocks, and top layer of Mn particles and Ce particles compressed by Ti blocks. Evacuate the crucible to ≤5*10⁻⁶. -3 After Pa, argon gas is introduced to atmospheric pressure for gas washing. The gas washing is repeated 2 to 3 times. After gas washing, the material is smelted in a vacuum arc melting furnace with an arc current of 140 to 150 A. After the raw material melts, electromagnetic stirring is turned on for 10 to 30 minutes. After electromagnetic stirring, the material is allowed to solidify. After solidification, the material is turned over and remelted. This process is repeated 2 to 3 times to obtain an alloy ingot.

[0048] S3. Grind the surface of the alloy ingot with a 50-mesh belt abrasive, crush the alloy ingot mechanically with a stainless steel mortar and pass it through a 200-mesh sieve to obtain alloy powder;

[0049] S4. Add the alloy powder into a cylindrical mold with an inner diameter of 2cm, an outer diameter of 5cm, and a height of 10cm. Press the mold into a block using a press with a pressure of 300kN and hold the pressure for 3min to obtain the hydrogen storage alloy. Example 2

[0050] The difference between Example 2 and Example 1 lies in the composition of the hydrogen storage alloy. The specific composition of the hydrogen storage alloy in Example 2 is Ti1Fe. 0.9 Mn 0.1 Ce 0.04 Zr 0.02. Example 3

[0051] The difference between Example 3 and Example 1 lies in the composition of the hydrogen storage alloy. The specific composition of the hydrogen storage alloy in Example 3 is Ti1Fe. 0.9 Mn 0.1 Ce 0.06 Zr 0.02 . Example 4

[0052] The difference between Example 4 and Example 1 lies in the composition of the hydrogen storage alloy. The specific composition of the hydrogen storage alloy in Example 4 is Ti1Fe. 0.9 Mn 0.1 Ce 0.02 Zr 0.06 .

[0053] Comparative Example 1

[0054] The difference between Comparative Example 1 and Example 2 lies in the preparation method of the hydrogen storage alloy. The preparation method of Comparative Example 1 is as follows:

[0055] S1. Calculate the dosage based on the chemical formula composition and mix the ingredients. When weighing Mn, Ce, and Zr, add 3-8% of the mass of each element as loss on ignition.

[0056] S2. Place the weighed raw materials into a copper crucible in the following order: bottom layer of Fe blocks and Zr blocks, middle layer of Ti blocks, and top layer of Mn particles and Ce particles compressed by Ti blocks. Evacuate the crucible to ≤5*10⁻⁶. -3 After Pa, argon gas is introduced to atmospheric pressure for gas washing. The gas washing is repeated 2 to 3 times. After gas washing, the material is smelted in a vacuum arc melting furnace with an arc current of 140 to 150 A. After the raw material melts, electromagnetic stirring is turned on for 10 to 30 minutes. After electromagnetic stirring, the material is allowed to solidify. After solidification, the material is turned over and remelted. This process is repeated 2 to 3 times to obtain an alloy ingot.

[0057] S3. Grind the surface of the alloy ingot with a 50-mesh belt abrasive, then mechanically crush the alloy ingot with a stainless steel mortar and pass it through a 200-mesh sieve to obtain alloy powder.

[0058] Comparative Example 2

[0059] The difference between Comparative Example 2 and Example 2 is that the composition of the hydrogen storage alloy is different; the hydrogen storage alloy in Comparative Example 2 has a composition of Ti1Fe. 0.9 Mn 0.1 Ce 0.04 .

[0060] Experimental test:

[0061] 1. The phase structure of the examples and comparative examples before and after hydrogen absorption and desorption was tested by XRD, and the microstructure and elemental distribution of the powder and bulk were observed by SEM and EDS.

[0062] 2. The activation condition for the hydrogen storage alloy is to maintain it under vacuum at 353K for 0.5h.

[0063] 3. In Examples 1-4 and Comparative Example 2, a portion of the prepared powder was tested for hydrogen storage capacity, and the other portion was pressed into blocks for testing, ensuring that the quality of the examples and comparative examples was the same. Activation curves, kinetic curves, and PCT curves of the powder and blocks were tested using a fully automated Sieverts system. The hydrogen absorption temperature was 303 K, and the initial hydrogen pressure was 4 MPa; the hydrogen release temperature was 303 K, and hydrogen release was performed after vacuuming. Resistance to powdering can be observed from the hydrogen absorption and release kinetic curves of the powder and blocks in the first ten tests, and the specific results are shown in Table 1.

[0064] 4. Porosity Testing Method: Porosity is measured using the volumetric method. The specific procedure for calculating the porosity of a block is as follows: first, determine the total volume of the block using vernier calipers; then, break the sample and immerse it in a graduated cylinder filled with water to determine its skeleton volume. The water volume should be at least twice the sample volume. Subtracting the skeleton volume from the total volume gives the porosity. The specific procedure for calculating the porosity of a powder is as follows: first, obtain the total volume using the scale of the sample tube; then, immerse the powder in a graduated cylinder filled with water to determine its skeleton volume. The water volume should be at least twice the sample volume. Subtracting the skeleton volume from the total volume gives the porosity.

[0065] 5. The empirical formula for thermal conductivity is: Effective thermal conductivity = Thermal conductivity of metal × (1 - Porosity) 2 Thus, the heat dissipation capacity can be derived.

[0066] Specific test results are shown in Table 1 and... Figures 1-6 As shown.

[0067] Table 1

[0068]

[0069] Depend on Figure 1 It can be seen that the elements are evenly distributed and Ce exists as an independent phase. Figure 1 The upper half shows the SEM and EDS images of Comparative Example 1, and the lower half shows the SEM and EDS images of Example 2.

[0070] Depend on Figure 2 It can be seen that the main phase in the sample is TiFeH. 0.06 This indicates that the hydrogen storage alloy powder sample can absorb hydrogen even when it is not activated.

[0071] Depend on Figure 3It can be seen that the main phase of the hydrogen storage alloy block sample before hydrogen absorption and desorption cycles is TiFe phase. This may be because the specific surface area is reduced after pressing and molding, which is not conducive to gas entering the interior of the alloy.

[0072] Depend on Figure 4 As can be seen from the number of activations in Table 1, the hydrogen storage alloy powder or bulk of the present invention can absorb hydrogen without an incubation period, and the hydrogen absorption rate is fast. The hydrogen storage alloy of the present invention is easy to activate.

[0073] Depend on Figure 5 It can be seen that the pressing process has a negligible impact on the total hydrogen absorption and the hydrogen absorption rate.

[0074] Depend on Figure 6 It can be seen that the kinetic properties of the hydrogen storage alloy block and powder of the present invention change significantly. Combined with the anti-pulverization properties in Table 1, it shows that the hydrogen storage alloy of the present invention has good anti-pulverization properties.

[0075] The test results of Examples 1-4 show that the hydrogen storage alloy of the present invention has excellent activation performance, good resistance to poisoning, good activation performance and high hydrogen storage capacity for the same volume, and excellent heat dissipation capacity. Although the hydrogen storage capacity of Example 1 is slightly higher than that of Example 2, the increase is very small. In addition, the activation performance of Example 1 is not as good as that of Example 2. Therefore, the overall performance of Example 2 is better.

[0076] Referring to Table 1, a comparison of the test results of Example 2 and Comparative Example 1 shows that pressing hydrogen storage alloy powder into hydrogen storage alloys, while maintaining excellent activation performance, can improve the anti-pulverization properties, reduce porosity, and enhance the heat dissipation capacity of the hydrogen storage alloy. Furthermore, due to the reduced specific surface area after pressing, the hydrogen storage capacity decreases slightly for the same mass, but the decrease is very small. Since the mass of the bulk sample is significantly greater than that of the powder sample for the same volume, the total hydrogen storage capacity of the bulk sample is still greater than that of the powder sample for the same volume. Therefore, under the same volume conditions, the total hydrogen storage capacity of the bulk sample is significantly improved compared to the total hydrogen storage capacity of the powder sample.

[0077] A comparison of the test results of Example 2 and Comparative Example 2 shows that adding Zr can improve the activation performance and anti-poisoning ability of the hydrogen storage alloy of the present invention.

[0078] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0079] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0080] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A high-volume-capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy, characterized in that, The hydrogen storage alloy has a specific composition of Ti1Fe. 0.9 Mn 0.1 Ce x Zr y x is any value among 0.02, 0.04, and 0.06, and y is any value among 0.02 and 0.

06.

2. The high volumetric capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy according to claim 1, characterized in that, The hydrogen storage alloy comprises a multiphase structure, which includes a main phase TiFe phase and a second phase Ce, CeO, and ZrMn2.

3. The high volumetric capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy according to claim 2, characterized in that, The Ce element in the hydrogen storage alloy is independent of the hydrogen storage alloy matrix and the Ce element is enriched at the sites. The Zr and Mn elements in the hydrogen storage alloy are uniformly distributed in the hydrogen storage alloy matrix.

4. A method for preparing a high-volume-capacity and easily activated Ti-Fe-Mn-Ce-Zr-based hydrogen storage alloy as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. Calculate the dosage based on the chemical formula composition and mix the ingredients. When calculating, add a certain amount of loss due to burn for Mn, Ce, and Zr. S2. Place the weighed raw materials into a copper crucible, evacuate the vacuum, and then fill it with inert gas for washing. Repeat the washing process several times. After washing, melt the raw materials and turn on the electromagnetic stirring. After the electromagnetic stirring is completed, wait for the material to solidify. After solidification, turn the material over and remelt it. Repeat this process several times to obtain an alloy ingot. S3. Grind the surface of the alloy ingot, mechanically crush the alloy ingot and sieve it to obtain alloy powder; S4. Add the alloy powder to the mold and press it into a block to obtain the hydrogen storage alloy.

5. The preparation method according to claim 4, characterized in that, In step S1, the loss of Mn, Ce, and Zr is 3 to 8% of the mass of each element added.

6. The preparation method according to claim 4, characterized in that, In step S2, the raw materials are placed in a copper crucible and then divided into a bottom layer, a middle layer, and a top layer. The bottom layer consists of Fe blocks and Zr blocks, the middle layer consists of Ti blocks, and the top layer consists of Mn particles and Ce particles that are compressed by the Ti blocks.

7. The preparation method according to claim 4, characterized in that, The vacuum level evacuated in step S2 is ≤5*10. -3 Pa, inert gas is introduced to atmospheric pressure.

8. The preparation method according to claim 4, characterized in that, In step S3, the grinding is performed using a belt sander with a mesh size of 50.

9. The preparation method according to claim 4, characterized in that, The mesh size of the sieve in S3 is 200 mesh.

10. The preparation method according to claim 4, characterized in that, The pressing pressure in step S4 is 200-400 kN.

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