AB2 type hydrogen storage alloy as well as preparation method and application thereof

Abstract

The invention relates to an AB2 type hydrogen storage alloy and a preparation method and application thereof, the AB2 type hydrogen storage alloy comprises a matrix metal and a second metal, and the composition general formula of the matrix metal is Ti Zr Cr < c > Mn < d >; wherein 0.76 < = a < = 0.9, 0.16 < = b < = 0.24, 0.76 < = c < = 0.84, 1.05 < = d < = 1.2, and a + b + c + d = 3; and the second metal is metal except Ti, Zr, Cr and Mn. The composition of the matrix metal in the AB2 type hydrogen storage alloy is limited, the number of atoms of all elements is limited, meanwhile, the second metal is added, the prepared AB2 type hydrogen storage alloy is high in effective hydrogen storage capacity and small in hydrogen absorption and desorption platform hysteresis, and the high hydrogen storage capacity can still be kept after 3000 times of hydrogen absorption and desorption circulation.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage alloys, and particularly relates to an AB2 type hydrogen storage alloy, a preparation method thereof, and an application thereof. Background Art

[0002] Hydrogen energy is a perfect green energy source because it does not produce greenhouse gases such as carbon dioxide during use, and it can be perfectly matched with the electric energy generated by solar energy and wind energy with rich resources (converting electric energy into hydrogen) to achieve efficient utilization of energy. However, due to the flammable and explosive characteristics of hydrogen and its mainly gaseous form, collecting and utilizing it, that is, storing and transporting it, is a crucial link in the utilization of hydrogen energy. The existing hydrogen storage methods can be divided into three types: gaseous high-pressure hydrogen storage, liquid cryogenic hydrogen storage, and solid hydrogen storage. Among them, the gas pressure of gaseous high-pressure hydrogen storage is at least 70 times that of atmospheric pressure, and the volume of the hydrogen storage tank is relatively large; liquid cryogenic hydrogen storage requires a relatively low temperature, the liquefaction process consumes a large amount of energy and has a relatively high safety risk; solid hydrogen storage has significant advantages over the former two. The volumetric energy density of solid hydrogen storage is at least 1000 times higher than that of traditional gaseous high-pressure hydrogen storage, and the hydrogen storage conditions are broad and the safety is high. It is currently the most ideal hydrogen storage method. In recent years, extensive research has been carried out on using alloy materials as hydrogen storage materials. The main types of hydrogen storage alloys are as follows: AB type, AB2 type, AB5 type, A2B type, BCC type, etc. The AB5 type is mainly the LaNi5 alloy, and its maximum theoretical capacity is 1.4 wt%. The AB type is mainly the TiFe alloy, which has a CsCl structure, a high hydrogen storage capacity, and a theoretical hydrogen storage capacity of 1.86 wt%, which is greater than that of the AB5 type hydrogen storage alloy. However, its retention rate decreases rapidly after multiple cycles. The theoretical capacity of the AB2 type Ti-based alloy after composition optimization is 2.0 wt%, which is higher than that of the AB5 type hydrogen storage alloy, and it has a low price and good activation performance. Therefore, the AB2 type hydrogen storage alloy is more suitable for practical engineering applications.

[0003] CN118207463A discloses a rare earth AB2 type hydrogen storage alloy and a preparation method thereof. The general composition formula of the rare earth AB2 type hydrogen storage alloy is: Y 1-a-b RE a Zr b Fe 2-c M c, where \(0 < a \leq 0.05\), \(0.2 \leq b \leq 0.4\), \(0 < c \leq 0.5\); RE includes any one of La, Ce, Pr, or Sm; M includes any one of Mn, Al, Co, or Cu. The preparation method of the rare earth AB2 type hydrogen storage alloy comprises the following steps: (1) Mix metals according to the element ratio of the general composition formula of the rare earth AB2 type hydrogen storage alloy, and then carry out arc melting to obtain a cast alloy; the arc melting includes a first melting and a second melting carried out in sequence; (2) Heat-treat the cast alloy obtained in step (1), and obtain the rare earth AB2 type hydrogen storage alloy after furnace cooling, but the maximum hydrogen absorption amount of the rare earth AB2 type hydrogen storage alloy is only 1.86 wt%, and at the same time, its hydrogen absorption amount gradually decreases with the extension of the storage time.

[0004] In summary, it is necessary to prepare an AB2 type hydrogen storage alloy to increase its hydrogen absorption amount, and at the same time, ensure that its hydrogen absorption amount does not change after long-term storage. Summary of the Invention

[0005] To solve the above technical problems, the present invention limits the metal element composition in the AB2 type hydrogen storage alloy and adds a second metal thereto. The prepared AB2 type hydrogen storage alloy has a high effective hydrogen storage capacity and a small hysteresis, and at the same time, can still maintain a high hydrogen storage capacity after hydrogen absorption and desorption cycles.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides an AB2 type hydrogen storage alloy, the AB2 type hydrogen storage alloy includes a matrix metal and a second metal, and the general composition formula of the matrix metal is Ti a Zr b Cr c Mn d ; where \(0.76 \leq a \leq 0.9\), \(0.16 \leq b \leq 0.24\), \(0.76 \leq c \leq 0.84\), \(1.05 \leq d \leq 1.2\), and \(a + b + c + d = 3\);

[0008] The second metal is a metal other than Ti, Zr, Cr, and Mn.

[0009] In the AB2-type hydrogen storage alloy, the atomic number of Ti is 0.76 ≤ a ≤ 0.9, for example, it can be 0.76, 0.8, 0.84, 0.88 or 0.9. The atomic number of Zr in the AB2-type hydrogen storage alloy is 0.16 ≤ b ≤ 0.24, for example, it can be 0.16, 0.18, 0.2, 0.22 or 0.24. The atomic number of Cr in the AB2-type hydrogen storage alloy is 0.76 ≤ c ≤ 0.84, for example, it can be 0.76, 0.78, 0.8, 0.82 or 0.84. The atomic number of Mn in the AB2-type hydrogen storage alloy is 1.05 ≤ d ≤ 1.2, for example, it can be 1.05, 1.07, 1.1, 1.13, 1.15, 1.17 or 1.2. However, it is not limited to the listed values, and other unlisted values within the above numerical range are equally applicable.

[0010] The present invention defines that the matrix metal of the AB2-type hydrogen storage alloy contains Ti, Zr, Cr and Mn. Among them, Ti and Zr, as A-side elements, can form stable intermetallic compounds and provide a good hydrogen storage framework. The alloying of Ti and Zr helps to form the Laves phase structure, and this structure has a positive impact on the hydrogen storage performance. Cr and Mn, as B-side elements, can change the crystal structure and electron arrangement of the alloy. The addition of Cr and Mn helps to improve the hydrogen storage capacity and cycle stability of the alloy. Further, the present invention defines the atomic numbers of Ti, Zr, Cr and Mn so that the atomic numbers of Ti, Zr, Cr and Mn are within a specific range, which helps to form a stable C14 Laves phase and avoid the formation of other impurity phases in the alloy, thereby ensuring the hydrogen storage performance of the alloy. At the same time, the present invention adds a second metal to the AB2-type hydrogen storage alloy. The second metal can replace Ti or Zr in the AB2-type hydrogen storage alloy, improve the cycle performance, hysteresis and activation performance of the alloy, and further improve the hydrogen storage performance.

[0011] As a preferred technical solution of the present invention, the atomic numbers in the AB2-type hydrogen storage alloy satisfy 1.8(a + b) = c + d.

[0012] The ideal stoichiometric ratio of the AB2-type hydrogen storage alloy is A:B = 1:2, that is, (a + b):(c + d) = 1:2. However, the hydrogen storage performance does not reach the optimal under this ideal stoichiometric ratio. The present invention defines that the atomic numbers in the AB2-type hydrogen storage alloy satisfy 1.8(a + b) = c + d, that is, the proportion of A-site elements in the AB2-type hydrogen storage alloy increases slightly, which can improve the stability of the crystal structure, reduce the formation of non-C14 Laves phase. At the same time, it increases the maximum hydrogen storage capacity of the hydrogen storage alloy and reduces the plateau pressure.

[0013] Preferably, the second metal includes any one or a combination of at least two of Al, Fe, Ni, or Co. Typical but non-limiting combinations include: a combination of Al and Fe, a combination of Fe and Ni, a combination of Ni and Co, a combination of Al and Ni, a combination of Al and Co, a combination of Fe and Co, a combination of Al, Fe, and Ni, a combination of Al, Fe, and Co, a combination of Al, Ni, and Co, a combination of Fe, Ni, and Co, and a combination of Al, Fe, Ni, and Co. Preferably, it is a combination of Al and Fe.

[0014] In the present invention, a second metal is added to Ti a Zr b Cr c Mn d for modification to improve the cycle performance, hysteresis, and activation performance of the hydrogen storage alloy and increase its effective hydrogen storage capacity. Further preferably, when the added second metal is a combination of Al and Fe and the atomic ratio of Fe to Al is (1 - 2):1, it has a better hydrogen storage effect compared to adding a single second metal or other combinations of second metals. This is because, compared to a single second metal or other combinations of second metals, Al and Fe have a synergistic effect. The combination of Al and Fe can simultaneously optimize the lattice interstitial, electronic structure, release plastic stress, and the hysteresis of the hydrogen absorption and desorption plateau, thereby increasing the effective hydrogen storage capacity. Further, an atomic ratio of Fe to Al of (1 - 2):1 can fully exert the synergistic effect of Fe and Al and avoid a decrease in performance caused by an excessive amount of a certain element. Adding a single second metal or other combinations of second metals can only partially improve the hydrogen storage performance of the alloy and cannot simultaneously optimize the lattice interstitial and the hysteresis of the hydrogen absorption and desorption plateau.

[0015] Preferably, the atomic number of the second metal and the total atomic number of Ti a Zr b Cr c Mn d is in a ratio of (0.005 - 0.06):1. For example, it can be 0.005:1, 0.015:1, 0.03:1, 0.045:1, or 0.06:1, but is not limited to the listed values. Other unlisted values within the above numerical range are equally applicable.

[0016] As a preferred technical solution of the present invention, the AB2 type hydrogen storage alloy is a single-phase structure.

[0017] Preferably, the single-phase structure of the AB2 type hydrogen storage alloy is a C14 Laves phase.

[0018] The C14 Laves phase has a hexagonal close-packed structure. There are a large number of tetrahedral and octahedral interstitial sites in its crystal lattice. These interstitial sites can accommodate a large number of hydrogen atoms. At the same time, the sizes of the interstitial sites in the C14 Laves phase are moderate, which can effectively adsorb and release hydrogen atoms, thereby increasing the effective hydrogen storage capacity of the hydrogen storage alloy. Further, due to the structural stability of the C14 Laves phase, the hydrogen storage alloy can still maintain a high hydrogen storage capacity and performance after multiple hydrogen absorption and desorption cycles. The CsCl structure is a cubic structure. There are fewer interstitial sites in its crystal lattice and the sizes are smaller, making it difficult to accommodate a large number of hydrogen atoms, resulting in a lower hydrogen storage capacity. Further, the CsCl structure is prone to volume expansion and contraction during the hydrogen absorption and desorption cycles, leading to alloy pulverization and reducing the cycle life.

[0019] In a second aspect, the present invention provides a method for preparing an AB2 type hydrogen storage alloy according to the first aspect. The preparation method includes the following steps:

[0020] (1) Mix the matrix metal and the second metal according to the proportion of each element to obtain a mixed metal material. Perform melting treatment and refining treatment on the mixed metal material in sequence to obtain a cast alloy.

[0021] (2) Perform crushing treatment on the cast alloy to obtain granular cast alloy.

[0022] (3) Perform encapsulation treatment on the granular cast alloy to obtain an AB2 type hydrogen storage alloy.

[0023] The present invention first mixes the matrix metal and the second metal, and then performs melting treatment and refining treatment on them to obtain a cast alloy. Among them, the main purpose of the melting treatment is to melt and mix the mixed matrix metal and the second metal uniformly at high temperature to form an alloy with a C14 Laves phase structure and ensure the uniform distribution of various elements in the alloy, thereby ensuring the uniformity of the alloy performance to increase its hydrogen storage capacity. The main purpose of the refining treatment is to eliminate the performance fluctuations caused by raw material differences or uncertain factors during the melting process and ensure the quality stability of each batch of alloys. Then, perform crushing treatment on the cast alloy to obtain granular cast alloy with a larger specific surface area, which helps to improve the hydrogen absorption / desorption rate of the alloy. Finally, perform encapsulation treatment on the granular cast alloy to reduce the performance fluctuations caused by external environmental changes and ensure that the AB2 type hydrogen storage alloy still has the best performance when in use after long-term storage and transportation.

[0024] As a preferred technical solution of the present invention, the mixing in step (1) includes mixing Ti single substance, Zr single substance, Cr single substance, Mn single substance and the second metal.

[0025] All the raw materials required for the present invention are mixed at one time and then melted only once, which can not only significantly simplify the preparation process, reduce the operation steps and time, improve the production efficiency, but also reduce the burning loss coefficient of each raw material to save the consumption of raw materials and reduce the cost.

[0026] Preferably, the smelting treatment includes any one or a combination of at least two of induction smelting, arc smelting or levitation smelting. Typical but non-limiting combinations include: the combination of induction smelting and arc smelting, the combination of induction smelting and levitation smelting, the combination of arc smelting and levitation smelting, and the combination of induction smelting, arc smelting and levitation smelting. Preferably, it is induction smelting.

[0027] The present invention uses a 50 kg vacuum induction melting furnace for induction smelting, a 200 g-level arc melting furnace for arc smelting, and a 200 g-level levitation melting furnace for levitation smelting, which helps to evenly distribute the alloy components to improve the effective hydrogen storage capacity of the AB2 type hydrogen storage alloy. Preferably, a 50 kg vacuum induction melting furnace is used for induction smelting.

[0028] Preferably, the smelting treatment is carried out in a first inert gas.

[0029] Preferably, the first inert gas includes any one or a combination of at least two of argon, helium or neon. Typical but non-limiting combinations include: the combination of argon and helium, the combination of argon and neon, the combination of helium and neon, and the combination of argon, helium and neon.

[0030] Preferably, the pressure of the smelting treatment is 4×10 4 -8×10 4 Pa, for example, it can be 4×10 4 Pa, 5×10 4 Pa, 6×10 4 Pa, 7×10 4 Pa or 8×10 4 Pa, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0031] Preferably, the temperature of the smelting treatment is 1100 - 1450 °C, for example, it can be 1100 °C, 1200 °C, 1300 °C, 1400 °C or 1450 °C, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0032] Preferably, the time of the smelting treatment is 10 - 30 min, for example, it can be 10 min, 15 min, 20 min, 25 min or 30 min, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0033] As a preferred technical solution of the present invention, preheating treatment is also included before the smelting treatment.

[0034] Preferably, the vacuum degree of the preheating treatment is ≤ 3×10 -3 Pa, and for example, it can be 1×10 -3 Pa, 1.5×10 -3 Pa, 2×10 -3 Pa, 2.5×10 -3 Pa or 3×10 -3 Pa, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0035] Preferably, the temperature of the preheating treatment is 800 - 1000 °C, and for example, it can be 800 °C, 850 °C, 900 °C, 950 °C or 1000 °C, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0036] Preferably, the time of the preheating treatment is 8 - 12 min, and for example, it can be 8 min, 9 min, 10 min, 11 min or 12 min, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0037] As a preferred technical solution of the present invention, the temperature of the refining treatment is 1500 - 1600 °C, and for example, it can be 1500 °C, 1520 °C, 1540 °C, 1560 °C, 1580 °C or 1600 °C, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0038] Preferably, the time of the refining treatment is 8 - 15 min, and for example, it can be 8 min, 10 min, 12 min, 14 min or 15 min, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0039] Preferably, casting is also included after the refining treatment.

[0040] Preferably, the shape of the as-cast alloy is any one or a combination of at least two of square, cylindrical or conical. Among them, typical but non-limiting combinations include: the combination of square and cylindrical, the combination of square and conical, the combination of cylindrical and conical, and the combination of square, cylindrical and conical.

[0041] As a preferred technical solution of the present invention, the particle size of the granular as-cast alloy is ≥ 1 mm, for example, it can be 1 mm, 2 mm, 10 mm, 20 mm, 30 mm or 40 mm, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0042] Preferably, the particle size of the granular as-cast alloy is 1 - 10 mm, for example, it can be 1 mm, 3 mm, 5 mm, 7 mm or 10 mm, but is not limited to the listed values, and other unlisted values within the above value range are equally applicable.

[0043] Preferably, the encapsulation treatment is carried out in a second inert gas.

[0044] Preferably, the second inert gas includes any one or a combination of at least two of argon, helium or neon. Typical but non-limiting combinations include: a combination of argon and helium, a combination of argon and neon, a combination of helium and neon, and a combination of argon, helium and neon.

[0045] As a preferred technical solution of the present invention, the preparation method includes the following steps:

[0046] (1) Mix Ti single substance, Zr single substance, Cr single substance, Mn single substance and a second metal according to the proportion of each element to obtain a mixed metal material. Then evacuate the melting furnace to a vacuum degree ≤ 3×10 -3 Pa, preheat the mixed metal material at 800 - 1000 °C for 8 - 12 min, and then introduce a first inert gas to a pressure of 4×10 4 -8×10 4 Pa, carry out melting treatment at 1100 - 1450 °C for 10 - 30 min. Wait until all the raw materials are melted, carry out refining treatment at 1500 - 1600 °C for 8 - 15 min, and pour to obtain an as-cast alloy;

[0047] (2) Carry out crushing treatment on the as-cast alloy, and screen the crushed as-cast alloy to obtain a granular as-cast alloy with a particle size ≥ 1 mm;

[0048] (3) Carry out encapsulation treatment on the granular as-cast alloy in a second inert gas atmosphere to obtain an AB2 type hydrogen storage alloy.

[0049] In a third aspect, the present invention provides an application of the AB2 type hydrogen storage alloy according to the first aspect in a hydrogen fuel cell hydrogen storage device, a fixed hydrogen storage device, a new energy vehicle or electric energy to hydrogen energy storage.

[0050] The AB2-type hydrogen storage alloy prepared by the present invention has a high effective hydrogen storage capacity, a large volumetric energy density, good reversibility, excellent application value, and is applicable to energy fields such as hydrogen storage devices for hydrogen fuel cells, fixed hydrogen storage devices, new energy vehicles, and power-to-hydrogen energy storage.

[0051] Compared with the prior art, the present invention has at least the following beneficial effects:

[0052] (1) By limiting the composition of the matrix metal in the AB2-type hydrogen storage alloy and the atomic numbers of each element, and adding a second metal to the AB2-type hydrogen storage alloy, the effective hydrogen storage capacity of the AB2-type hydrogen storage alloy can reach more than 1.75 wt%, and after 3000 hydrogen absorption and desorption cycles, the effective hydrogen storage retention can be maintained at more than 93.6%.

[0053] (2) The preparation method of the AB2-type hydrogen storage alloy provided by the present invention has the advantages of simple preparation method, low cost, similar performance of the hydrogen storage alloy obtained in each batch, good uniformity, and suitability for large-scale preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 is the pressure-composition-temperature (PCT) curve of Example 1 and Example 4 of the present invention.

[0055] Figure 2 is the pressure-composition-temperature (PCT) curve of Example 1 and Comparative Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0056] The technical solution of the present invention will be further described below with reference to the drawings and through specific embodiments. However, the following examples are only simple examples of the present invention and do not represent or limit the scope of the protection of the present invention. The scope of protection of the present invention is subject to the claims.

[0057] Example 1

[0058] This example provides an AB2-type hydrogen storage alloy, and the composition of the AB2-type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 Fe 0.1 Al 0.05 , and the structure of the AB2-type hydrogen storage alloy is the C14 Laves phase.

[0059] The present invention also provides a preparation method of the AB2-type hydrogen storage alloy, and the preparation method includes the following steps:

[0060] (1) Mix the base metals and the second metals of Ti, Zr, Cr, Mn, Fe, and Al in an atomic ratio of 0.85:0.22:0.8:1.13:0.1:0.05 in the product to obtain a mixed metal charge. Among them, considering the burn - loss coefficients of each element are Ti = 1, Zr = 1.12, Cr = 1, Mn = 1.02, Fe = 1, Al = 1 respectively. Then put the prepared mixed metal charge into a 50 kg - class induction melting furnace for induction melting. Evacuate to 2×10 -3 Pa, pre - heat at 900 °C for 10 min first, then introduce argon until the pressure is 6×10 4 Pa, then melt at 1200 °C for 20 min. After all the raw materials are melted, refine at 1550 °C for 10 min. Pour the refined mixed metal into a square water - cooled mold to obtain a square as - cast alloy;

[0061] (2) Use a jaw crusher to crush the as - cast alloy under argon protection, and use a 10 - mesh sieve to screen it to obtain granular as - cast alloy with a particle size of 5 - 8 mm;

[0062] (3) Collect the granular as - cast alloy with a polyethylene (PE) flat bag, introduce argon in a packaging machine and then package it to obtain an AB2 - type hydrogen storage alloy.

[0063] Example 2

[0064] This example provides an AB2 - type hydrogen storage alloy, and the composition of the AB2 - type hydrogen storage alloy is Ti 0.9 Zr 0.17 Cr 0.84 Mn 1.09 Fe 0.008 Al 0.008 , and the structure of the AB2 - type hydrogen storage alloy is the C14 Laves phase.

[0065] The present invention also provides a preparation method of the AB2 - type hydrogen storage alloy, and the preparation method includes the following steps:

[0066] (1) Mix the base metals and the second metals of Ti, Zr, Cr, Mn, Fe, and Al in an atomic ratio of 0.9:0.17:0.84:1.09:0.008:0.008 in the product to obtain a mixed metal charge. Among them, considering the burn - loss coefficients of each element are Ti = 1, Zr = 1.13, Cr = 1, Mn = 1.05, Fe = 1, Al = 1 respectively. Then put the prepared mixed metal charge into a 200 g - class arc melting furnace for arc melting. Evacuate to 3×10 -3Pa. First, perform a preheating treatment at 800 °C for 12 min, then introduce helium until the pressure reaches 4×10 4 Pa. Then, perform a melting treatment at 1450 °C for 10 min. After all the raw materials are melted, perform a refining treatment at 1600 °C for 8 min. Pour the refined mixed metal into a cylindrical water-cooled mold to obtain a cylindrical as-cast alloy;

[0067] (2) Use a jaw crusher to crush the as-cast alloy under argon protection, and use a 10-mesh sieve to screen it to obtain granular as-cast alloy with a particle size of 5 - 8 mm;

[0068] (3) Collect the granular as-cast alloy with a PE flat pocket, introduce helium in a packaging machine and then perform packaging to obtain an AB2-type hydrogen storage alloy.

[0069] Example 3

[0070] This example provides an AB2-type hydrogen storage alloy, and the composition of the AB2-type hydrogen storage alloy is Ti 0.83 Zr 0.24 Cr 0.76 Mn 1.17 Fe 0.18 , and the structure of the AB2-type hydrogen storage alloy is the C14 Laves phase.

[0071] The present invention also provides a preparation method of the AB2-type hydrogen storage alloy, and the preparation method includes the following steps:

[0072] (1) Mix the base metal and the second metal of Ti, Zr, Cr, Mn, and Fe single elements according to the atomic ratio of 0.83:0.24:0.76:1.17:0.18 in the product. Considering the burn-off coefficients of each element are Ti = 1, Zr = 1.1, Cr = 1, Mn = 1.03, Fe = 1 respectively, then put the prepared mixed metal material into a 200g-class levitation melting furnace for levitation melting, evacuate to 1×10 -3 Pa. First, perform a preheating treatment at 1000 °C for 8 min, then introduce neon until the pressure reaches 8×10 4 Pa. Then, perform a melting treatment at 1100 °C for 30 min. After all the raw materials are melted, perform a refining treatment at 1500 °C for 15 min. Pour the refined mixed metal into a conical water-cooled mold to obtain a conical as-cast alloy;

[0073] (2) Use a jaw crusher to crush the as-cast alloy under argon protection, and use a 10-mesh sieve to screen it to obtain granular as-cast alloy with a particle size of 5 - 8 mm;

[0074] (3) Collect the granular as-cast alloy with a PE flat pocket, introduce neon gas in a packaging machine and then package it to obtain the AB2 type hydrogen storage alloy.

[0075] Example 4

[0076] This example provides an AB2 type hydrogen storage alloy. The difference from Example 1 is only that, except for adjusting the atomic ratio of the second metals Fe and Al to 4:1, the composition of the AB2 type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 Fe 0.12 Al 0.03 , that is, in step (1) of the preparation method, the Ti single substance, Zr single substance, Cr single substance, Mn single substance, Fe single substance and Al single substance are mixed according to the atomic ratio of 0.85:0.22:0.8:1.13:0.12:0.03 in the product to obtain the mixed metal material. Among them, the burn-off coefficients of each element are Ti = 1, Zr = 1.11, Cr = 1, Mn = 1.02, Fe = 1, Al = 1 respectively. Except for this, the rest are the same as in Example 1.

[0077] Example 5

[0078] This example provides an AB2 type hydrogen storage alloy. The difference from Example 1 is only that, except for adjusting the atomic ratio of the second metals Fe and Al to 0.5:1, the composition of the AB2 type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 Fe 0.05 Al0 .1 , that is, in step (1) of the preparation method, the Ti single substance, Zr single substance, Cr single substance, Mn single substance, Fe single substance and Al single substance are mixed according to the atomic ratio of 0.85:0.22:0.8:1.13:0.05:0.1 in the product to obtain the mixed metal material. Among them, the burn-off coefficients of each element are Ti = 1, Zr = 1.08, Cr = 1, Mn = 1.04, Fe = 1, Al = 1.01 respectively. Except for this, the rest are the same as in Example 1.

[0079] Example 6

[0080] This example provides an AB2 type hydrogen storage alloy. The difference from Example 1 is only that, except for replacing the second metals Fe and Al with the same number of atoms of Al, the composition of the AB2 type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 Al 0.15, that is, in step (1) of the preparation method, the matrix metal and the second metal are mixed with Ti, Zr, Cr, Mn, and Al in an atomic ratio of 0.85:0.22:0.8:1.13:0.15 to obtain a mixed metal material. Among them, considering the burn-off coefficients of each element are Ti = 1, Zr = 1.09, Cr = 1, Mn = 1.05, Al = 1, the rest are the same as in Example 1.

[0081] Example 7

[0082] This example provides an AB2-type hydrogen storage alloy. The difference from Example 1 is only that, in addition to the number of atoms in the AB2-type hydrogen storage alloy satisfying 2(a + b) = c + d and keeping the number of Cr atoms unchanged, the composition of the AB2-type hydrogen storage alloy is Ti 0.8 Zr 0.2 Cr 0.8 Mn 1.2 Fe 0.1 Al 0.05 , that is, in step (1) of the preparation method, the matrix metal and the second metal are mixed with Ti, Zr, Cr, Mn, Fe, and Al in an atomic ratio of 0.8:0.2:0.8:1.2:0.1:0.05 in the product to obtain a mixed metal material. Among them, the burn-off coefficients of each element are Ti = 1, Zr = 1.11, Cr = 1.01, Mn = 1.03, Fe = 1, Al = 1, and the rest are the same as in Example 1.

[0083] Example 8

[0084] This example provides an AB2-type hydrogen storage alloy. The difference from Example 1 is only that, in addition to the ratio of the number of atoms of the second metal to the total number of atoms in Ti a Zr b Cr c Mn d is 0.002:1, and at the same time, keeping the atomic ratio of Fe and Al as 2:1, that is, the composition of the AB2-type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 Fe 0.004 Al 0.002 , that is, in step (1) of the preparation method, the matrix metal and the second metal are mixed with Ti, Zr, Cr, Mn, Fe, and Al in an atomic ratio of 0.85:0.22:0.8:1.13:0.004:0.002 in the product to obtain a mixed metal material. Among them, the burn-off coefficients of each element are Ti = 1, Zr = 1.13, Cr = 1.01, Mn = 1.04, Fe = 1, Al = 1, and the rest are the same as in Example 1.

[0085] Example 9

[0086] This example provides an AB2-type hydrogen storage alloy, which is only different from Example 1 in that, except that the ratio of the number of atoms of the second metal to the total number of atoms in Ti a Zr b Cr c Mn d is 0.09:1, and at the same time, the atomic ratio of Fe and Al is maintained at 2:1, that is, the composition of the AB2-type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 Fe 0.18 Al 0.09 , that is, in step (1) of the preparation method, the Ti single substance, Zr single substance, Cr single substance, Mn single substance, Fe single substance and Al single substance are mixed according to the atomic ratio of 0.85:0.22:0.8:1.13:0.18:0.09 in the product to obtain a mixed metal material. Among them, the burn-off coefficients of each element are Ti = 1.1, Zr = 1.06, Cr = 1, Mn = 1.02, Fe = 1, Al = 1 respectively, and the rest are the same as in Example 1.

[0087] Example 10

[0088] This example provides an AB2-type hydrogen storage alloy, which is only different from Example 1 in that, except that in step (1), the Ti single substance, Cr single substance, Mn single substance, Fe single substance and Al single substance are first mixed according to the atomic ratio of 0.85:0.8:1.13:0.1:0.05 in the product, and the first melting is carried out for 10 min, and then Zr single substance with an atomic ratio of 0.22:0.85 to the Ti single substance is added, and the second melting is carried out for 10 min. Among them, the operating conditions of the first melting and the second melting are the same as those in the melting in Example 1, and the burn-off coefficients of each element are Ti = 1.1, Zr = 1.2, Cr = 1, Mn = 1.06, Fe = 1, Al = 1 respectively, and the rest are the same as in Example 1.

[0089] Example 11

[0090] This example provides an AB2-type hydrogen storage alloy, which is only different from Example 1 in that, except that the melting treatment in step (1) is replaced by arc melting using a 200 g-level arc melting furnace instead of induction melting using a 50 kg-level induction melting furnace, and the rest are the same as in Example 1.

[0091] Comparative Example 1

[0092] This comparative example provides an AB2-type hydrogen storage alloy, which is only different from Example 6 in that, except for not containing the second metal Al, that is, the composition of the AB2-type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 and the rest are the same as those in Example 6.

[0093] Comparative Example 2

[0094] This comparative example provides an AB2-type hydrogen storage alloy, which is only different from Example 6 in that, except that the Zr content is too high, the Ti content is adjusted accordingly to maintain the total of 3, that is, the composition of the AB2-type hydrogen storage alloy is Ti 0.67 Zr 0.4 Cr 0.8 Mn 1.13 Al 0.15 and the rest are the same as those in Example 6.

[0095] Comparative Example 3

[0096] This comparative example provides an AB2-type hydrogen storage alloy, which is only different from Example 6 in that, except that the Zr content is too low, the Ti content is adjusted accordingly to maintain the total of 3, that is, the composition of the AB2-type hydrogen storage alloy is Ti 1.05 Zr 0.02 Cr 0.8 Mn 1.13 Al 0.15 and the rest are the same as those in Example 6.

[0097] Comparative Example 4

[0098] This comparative example provides an AB2-type hydrogen storage alloy, which is only different from Example 6 in that, except that Zr is replaced by Y with the same number of atoms, that is, the composition of the AB2-type hydrogen storage alloy is Ti 0.85 Y 0.22 Cr 0.8 Mn 1.13 Al 0.15 and the rest are the same as those in Example 6.

[0099] Comparative Example 5

[0100] This comparative example provides an AB2-type hydrogen storage alloy, which is only different from Example 6 in that, except that Mn is replaced by Fe with the same number of atoms, that is, the composition of the AB2-type hydrogen storage alloy is Ti 0.85 Zr 0.22 Cr 0.8 Fe 1.13 Al 0.15 and the rest are the same as those in Example 6.

[0101] Comparative Example 6

[0102] This comparative example provides an AB2-type hydrogen storage alloy, which is different from Example 1 only in that, except that the composition of the AB2-type hydrogen storage alloy is Ti 0.5 Zr 0.57 Cr 0.6 Mn 1.33 Fe 0.1 Al 0.05 in addition, the rest are the same as in Example 1.

[0103] Comparative Example 7

[0104] This comparative example provides an AB2-type hydrogen storage alloy, which is different from Example 1 only in that, except that the composition of the AB2-type hydrogen storage alloy is Ti 0.95 Zr 0.12 Cr 1.1 Mn 0.83 Fe 0.1 Al 0.05 in addition, the rest are the same as in Example 1.

[0105] The hydrogen storage performances of the prepared AB2-type hydrogen storage alloys were tested respectively under the conditions of 3 MPa H2, 10 °C and 3 MPa H2, 70 °C, and the pressure-composition-temperature (P-C-T) curves were obtained. Among them, the effective hydrogen release amount (wt%) = the maximum hydrogen absorption amount (3 MPa, 10 °C, wt%) - the hydrogen release residual amount (1 MPa, 70 °C, wt%), and the hysteresis coefficient Hf = ln (hydrogen absorption plateau pressure / hydrogen release plateau pressure). The test results are shown in Table 1.

[0106] Table 1

[0107]

[0108]

[0109] It can be seen from the test results that:

[0110] (1) It can be seen from Examples 1 to 2 that in the present invention, by adding a second metal to Ti a Zr b Cr c Mn d wherein the second metal is a combination of Al and Fe, and at the same time, the atomic ratio of Fe and Al is (1-2):1, the effective hydrogen release amount of the obtained AB2-type hydrogen storage alloy can reach more than 1.75 wt%, the retention amount after 3000 cycles is more than 93.6%, the hysteresis of the hydrogen absorption and release plateau is small, and the hysteresis coefficient can be controlled within 0.51.

[0111] (2) It can be seen from Example 1 and Example 3 that the AB2-type hydrogen storage alloy in Example 1 includes a matrix metal and a second metal composed of a combination of Al and Fe. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained in Example 1 is 1.76 wt%, the retention amount after 3000 cycles is 93.6%, and the hysteresis coefficient is 0.51. While the AB2-type hydrogen storage alloy in Example 3 includes a matrix metal and a second metal Fe. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained in Example 3 is 1.74 wt%, the retention amount after 3000 cycles is 93.5%, and the hysteresis coefficient is 0.89. Thus, it shows that adding a second metal to Ti a Zr b Cr c Mn d for modification, when the added second metal is a combination of Al and Fe and the atomic ratio of Fe to Al is (1 - 2):1, it has a better hydrogen storage effect compared to adding a single second metal. Al and Fe have a synergistic effect. The combination of Al and Fe can simultaneously optimize the lattice interstitial, electronic structure, release plastic stress, and the hysteresis of the hydrogen absorption and desorption platform, thereby increasing the effective hydrogen storage amount.

[0112] (3) It can be seen from Example 1 and Examples 4 - 5 that the atomic ratio of Fe to Al in the AB2-type hydrogen storage alloy of Example 1 is 2:1. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained in Example 1 is 1.76 wt%, the retention amount after 3000 cycles is 93.6%, and the hysteresis coefficient is 0.51. While the atomic ratio of Fe to Al in the AB2-type hydrogen storage alloy of Example 4 is 4:1. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained in Example 4 is 1.75 wt%, the retention amount after 3000 cycles is 92.9%, and the hysteresis coefficient is 0.61. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained in Example 5 is 1.68 wt%, the retention amount after 3000 cycles is 93.3%, and the hysteresis coefficient is 0.57. Thus, it shows that adding a second metal to Ti a Zr b Cr c Mn d for modification, when the added second metal is a combination of Al and Fe and by limiting the atomic ratio of Al to Fe to 1:(1 - 2), it can simultaneously optimize the lattice interstitial, electronic structure, release plastic stress, and the hysteresis of the hydrogen absorption and desorption platform, thereby increasing the effective hydrogen storage amount.

[0113] (4) It can be seen from Example 1 and Example 6 that the AB2 type hydrogen storage alloy in Example 1 includes a matrix metal and a second metal composed of a combination of Al and Fe. The effective hydrogen release amount of the AB2 type hydrogen storage alloy obtained in Example 1 is 1.76 wt%, the retention amount after 3000 cycles is 93.6%, and the hysteresis coefficient is 0.51. While the AB2 type hydrogen storage alloy in Example 6 includes a matrix metal and a second metal Al. The effective hydrogen release amount of the AB2 type hydrogen storage alloy obtained in Example 6 is 1.72 wt%, the retention amount after 3000 cycles is 93.2%, and the hysteresis coefficient is 0.39. Thus, it is shown that when adding a second metal to Ti a Zr b Cr c Mn d for modification, when the added second metal is a combination of Al and Fe and the atomic ratio of Fe to Al is (1 - 2):1, it has a better hydrogen storage effect compared with adding a single second metal. Al and Fe have a synergistic effect. The combination of Al and Fe can optimize the lattice interstitial, electronic structure, release plastic stress, and the hysteresis of the hydrogen absorption and desorption plateau simultaneously, thereby increasing the effective hydrogen storage amount. While in Ti a Zr b Cr c Mn d adding a single second metal Al can only optimize the hysteresis of its hydrogen absorption and desorption plateau.

[0114] (5) It can be seen from Example 1 and Example 7 that the composition of the AB2 type hydrogen storage alloy in Example 1 is Ti 0.85 Zr 0.22 Cr 0.8 Mn 1.13 Fe 0.1 Al 0.05 , where the sum of the atomic numbers of Cr and Mn is 1.8 times the sum of the atomic numbers of Ti and Zr. The maximum hydrogen absorption amount of the AB2 type hydrogen storage alloy obtained in Example 1 can reach 2.01 wt% under the conditions of 3 MPa and 10 °C. The maximum hydrogen absorption amount of the AB2 type hydrogen storage alloy obtained in Example 7 is 1.89 wt% under the conditions of 3 MPa and 10 °C. Thus, it is shown that by limiting the atomic numbers in the matrix metal Ti a Zr b Cr c Mn d of the AB2 type hydrogen storage alloy to satisfy 1.8(a + b) = c + d, the stability of the crystal structure can be improved, the formation of non-C14 Laves phase can be reduced, and the maximum hydrogen storage amount of the hydrogen storage alloy can be increased.

[0115] (6) It can be seen from Example 1 and Examples 8-9 that in Example 1, the ratio of the number of atoms of the second metal to the total number of atoms of the base metal is 0.05:1, and the effective hydrogen release amount of the AB2 type hydrogen storage alloy obtained in Example 1 is 1.76wt%, the retention amount after 3000 cycles is 93.6%, and the hysteresis coefficient is 0.51; while in Example 8, the ratio of the number of atoms of the second metal to the total number of atoms of the base metal is 0.002:1, and the effective hydrogen release amount of the AB2 type hydrogen storage alloy obtained in Example 8 is 1.69wt%, the retention amount after 3000 cycles is 92.9%, and the hysteresis coefficient is 0.54; in Example 9, the ratio of the number of atoms of the second metal to the total number of atoms of the base metal is 0.09:1, and the effective hydrogen release amount of the AB2 type hydrogen storage alloy obtained in Example 9 is 1.69wt%, the retention amount after 3000 cycles is 92.7%, and the hysteresis coefficient is 0.62. This shows that the present invention, by limiting the number of atoms of the second metal to Ti a Zr b Cr c Mn d The ratio of the total number of atoms in the alloy is (0.005-0.06):1, which can improve the cycle performance, hysteresis and activation performance of the alloy and further improve the hydrogen storage performance.

[0116] (7) It can be seen from Examples 1 and 10 that in Example 1, Ti, Zr, Cr, Mn, Fe and Al are directly mixed according to the atomic number ratio in the product to obtain a mixed metal material, and then preheating, smelting and refining are performed in sequence. The element burn-out coefficients are Ti=1, Zr=1.12, Cr=1, Mn=1.02, Fe=1, and Al=1, respectively. At the same time, the effective hydrogen release amount of the AB2 type hydrogen storage alloy obtained is 1.76wt%, and the retention amount after 3000 cycles is 93.6%; while in Example 10, Ti, Cr, Mn, Fe and Al are first mixed according to the atomic number ratio in the product to obtain a mixed metal material, and then preheating, smelting and refining are performed in sequence. The invention discloses a method for preparing an AB2 hydrogen storage alloy having a first smelting treatment and a second smelting treatment, and then adding Zr single substance, and performing a second smelting, and then performing a refining treatment, wherein the element burn-up coefficients are Ti=1.1, Zr=1.2, Cr=1, Mn=1.06, Fe=1, and Al=1, respectively. At the same time, the effective hydrogen release amount of the AB2 hydrogen storage alloy obtained is 1.72wt%, and the retention amount after 3000 cycles is 92.1%. It is shown that the present invention can not only significantly simplify the preparation process, reduce the operation steps and time, and improve the production efficiency by mixing all the required raw materials at one time and then performing only one smelting, but also reduce the burn-up coefficient of each raw material, so as to save the amount of raw materials and reduce the cost. Furthermore, the effective hydrogen release amount and the circulation retention amount of the AB2 hydrogen storage alloy can be increased.

[0117] (8) It can be seen from Example 1 and Example 11 that in Example 1, a 50 kg-level induction melting furnace was used to conduct induction melting on the mixed metal materials. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained was 1.76 wt%, and the retention amount after 3000 cycles was 93.6%. While in Example 11, a 200 g-level arc melting furnace was used to conduct arc melting on the mixed metal materials. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained was 1.68 wt%, and the retention amount after 3000 cycles was 92.3%. This shows that using a 50 kg-level induction melting furnace to conduct induction melting on the mixed metal materials can not only increase the processing amount of the AB2-type hydrogen storage alloy, but also, due to the larger volume of the melting furnace, the AB2-type hydrogen storage alloy prepared is more uniform, and the hydrogen storage alloy performance of the AB2-type hydrogen storage alloy is more excellent.

[0118] (9) It can be seen from Example 6 and Comparative Example 1 that the AB2-type hydrogen storage alloy in Comparative Example 1 only contains the matrix metal and does not contain the second metal. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained was 1.66 wt%, and the retention amount after 3000 cycles was 92.6%. This shows that the AB2-type hydrogen storage alloy obtained by adding the second metal to the matrix metal Ti a Zr b Cr c Mn d in the present invention can increase the effective hydrogen release amount of the AB2-type hydrogen storage alloy and increase the retention amount of the AB2-type hydrogen storage alloy after 3000 cycles.

[0119] (10) It can be seen from Example 6 and Comparative Examples 2-3 that in the AB2-type hydrogen storage alloy of Comparative Example 2, the content of Zr is too high and the content of Ti is too low. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained was 1.65 wt%, and the retention amount after 3000 cycles was 92.8%. In the AB2-type hydrogen storage alloy of Comparative Example 3, the content of Zr is too low and the content of Ti is too high. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained was 1.63 wt%, and the retention amount after 3000 cycles was 91.3%. This shows that by limiting the atomic numbers of the respective elements in the matrix metal Ti a Zr b Cr c Mn d in the present invention to be within a specific range, the comprehensive performance of the alloy can be ensured to be good.

[0120] (11) It can be seen from Example 6 and Comparative Examples 4-5 that in Comparative Example 4, Zr was replaced with Y having the same number of atoms, and the effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained was 1.66 wt%, the retention amount after 3000 cycles was 92.9%, and the hysteresis coefficient was 0.50. In Comparative Example 5, Mn was replaced with Fe having the same number of atoms, and the effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained was 1.67 wt%, the retention amount after 3000 cycles was 93.1%, and the hysteresis coefficient was 0.52. Thus, it is shown that by defining the composition of the matrix metal elements in the AB2-type hydrogen storage alloy, the AB2-type hydrogen storage alloy prepared has a high effective hydrogen storage capacity, small hysteresis, and can still maintain a high hydrogen storage capacity after hydrogen absorption and release cycles, and the comprehensive performance of the alloy is good.

[0121] (12) It can be seen from Example 1 and Comparative Examples 6-7 that although a second metal was added to the AB2-type hydrogen storage alloys in Comparative Examples 6 and 7, and the second metal was a combination of Al and Fe, the atomic numbers of the respective elements in the matrix metal were adjusted. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained in Comparative Example 6 was 1.65 wt%, the retention amount after 3000 cycles was 93.3%, and the hysteresis coefficient was 0.65. The effective hydrogen release amount of the AB2-type hydrogen storage alloy obtained in Comparative Example 7 was 1.65 wt%, the retention amount after 3000 cycles was 92.8%, and the hysteresis coefficient was 0.63. Thus, it is shown that by limiting the atomic numbers of the matrix metal in the AB2-type hydrogen storage alloy within a specific range, the AB2-type hydrogen storage alloy prepared has a high effective hydrogen storage capacity, small hysteresis, and can still maintain a high hydrogen storage capacity after hydrogen absorption and release cycles, and the comprehensive performance of the alloy is good.

[0122] In summary, by defining the composition of the matrix metal in the AB2-type hydrogen storage alloy and limiting the atomic numbers of the respective elements, and at the same time adding a second metal thereto, the AB2-type hydrogen storage alloy prepared has a high effective hydrogen storage capacity and can still maintain a high hydrogen storage capacity after hydrogen absorption and release cycles. Further, the preparation method of the AB2-type hydrogen storage alloy provided by the present invention has the advantages of simple preparation method, low cost, similar performance of the hydrogen storage alloy obtained in each batch, good uniformity, and being suitable for large-scale preparation.

[0123] The applicant declares that the above description is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A hydrogen storage alloy of AB2 type, characterized in that, The AB2-type hydrogen storage alloy includes a matrix metal and a second metal. The general composition formula of the matrix metal is Ti a Zr b Cr c Mn d ; wherein, 0.76 ≤ a ≤ 0.9, 0.16 ≤ b ≤ 0.24, 0.76 ≤ c ≤ 0.84, 1.05 ≤ d ≤ 1.2, and a + b + c + d = 3; The second metal is a metal other than Ti, Zr, Cr, and Mn.

2. The AB2 type hydrogen storage alloy according to claim 1, characterized in that, In the AB2 type hydrogen storage alloy, the atomic numbers satisfy 1.8(a + b) = c + d; Preferably, the second metal includes any one or a combination of at least two of Al, Fe, Ni, or Co, and preferably a combination of Al and Fe; Preferably, the ratio of the number of atoms of the second metal to the total number of atoms in a Zr b Cr c Mn d is (0.005 - 0.06):

1.

3. The AB2 type hydrogen storage alloy according to claim 1 or 2, characterized in that, The AB2 type hydrogen storage alloy has a single-phase structure; Preferably, the single-phase structure of the AB2 type hydrogen storage alloy is a C14 Laves phase.

4. A method for preparing an AB2 type hydrogen storage alloy according to any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) Mix the matrix metal and the second metal according to the proportions of each element to obtain a mixed metal material, and successively perform melting treatment and refining treatment on the mixed metal material to obtain a cast alloy; (2) Perform crushing treatment on the cast alloy to obtain granular cast alloy; (3) Perform encapsulation treatment on the granular cast alloy to obtain an AB2 type hydrogen storage alloy.

5. The preparation method according to claim 4, characterized in that, The mixing in step (1) includes mixing Ti element, Zr element, Cr element, Mn element, and the second metal; Preferably, the melting treatment includes any one or a combination of at least two of induction melting, arc melting, or levitation melting; Preferably, the melting treatment is carried out in a first inert gas; Preferably, the first inert gas includes any one or a combination of at least two of argon, helium, or neon; Preferably, the pressure of the smelting treatment is 4×10 4 - 8×10 4 Pa; Preferably, the temperature of the melting treatment is 1100 - 1450 °C; Preferably, the time of the melting treatment is 10 - 30 min.

6. The preparation method according to claim 4 or 5, characterized in that Before the melting treatment, a preheating treatment is also included; Preferably, the vacuum degree of the preheating treatment is ≤ 3×10 -3 Pa; Preferably, the temperature of the preheating treatment is 800 - 1000 °C; Preferably, the time of the preheating treatment is 8 - 12 min.

7. The preparation method according to any one of claims 4-6, characterized in that, The temperature of the refining treatment is 1500 - 1600 °C; Preferably, the time of the refining treatment is 8 - 15 min; Preferably, casting is also included after the refining treatment; Preferably, the shape of the cast alloy is any one or a combination of at least two of square, cylindrical, or conical.

8. The preparation method according to any one of claims 4-7, characterized in that, The particle size of the granular cast alloy is ≥ 1 mm; Preferably, the particle size of the granular cast alloy is 1 - 10 mm; Preferably, the encapsulation treatment is carried out in a second inert gas; Preferably, the second inert gas includes any one or a combination of at least two of argon, helium, or neon.

9. The preparation method according to any one of claims 4-8, characterized in that, The preparation method includes the following steps: (1) Mix Ti, Zr, Cr, Mn and the second metal according to the proportion of each element to obtain a mixed metal material. Then, evacuate the melting furnace to a vacuum degree of ≤ 3×10 -3 Pa, preheat the mixed metal material at 800 - 1000 °C for 8 - 12 min, and then introduce the first inert gas until the pressure reaches 4×10 4 - 8×10 4 Pa, carry out melting treatment at 1100 - 1450 °C for 10 - 30 min. Wait until all the raw materials are melted, carry out refining treatment at 1500 - 1600 °C for 8 - 15 min, and pour to obtain a cast alloy; (2) Perform crushing treatment on the cast alloy and screen the crushed cast alloy to obtain a granular cast alloy with a particle size ≥ 1 mm; (3) Perform encapsulation treatment on the granular cast alloy in a second inert gas atmosphere to obtain an AB2 type hydrogen storage alloy.

10. Use of the AB2 type hydrogen storage alloy according to any one of claims 1-3, characterized in that, The AB2 type hydrogen storage alloy is used in a hydrogen fuel cell hydrogen storage device, a fixed hydrogen storage device, a new energy vehicle, or electric energy to hydrogen energy storage.

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