Double-rare-earth-doped magnesium-based hydrogen storage alloy and preparation method thereof

Abstract

The invention discloses a double-rare-earth-doped magnesium-based hydrogen storage alloy and a preparation method thereof, relates to the technical field of hydrogen storage alloys, and solves the problems that an existing magnesium-based hydrogen storage material is limited in hydrogen storage capacity and slow in hydrogen absorption and dehydrogenation rate. The alloy comprises 68.8-91 wt.% of Mg, 5-15 wt.% of Ni, 2-8 wt.% of Y, 2-8 wt.% of Eu, and the balance of Fe and unavoidable impurities. The material is composed of an alpha-Mg phase, an LPSO phase, a Mg2Ni phase and a Mg17Eu2 phase, wherein Mg2Ni, Mg17Eu2 and part of alpha-Mg form a ternary eutectic structure. The magnesium ingot, the magnesium-nickel alloy, the magnesium-yttrium alloy and the magnesium-europium alloy are placed in a smelting crucible, protective atmosphere is introduced, and the melt is heated to 700-750 DEG C and stirred to be melted; and cooling to 680-700 DEG C, casting to obtain an alloy ingot, and crushing to obtain alloy powder. The method can be used in hydrogen energy storage and transportation, fuel cells, new energy automobiles, distributed energy systems, aerospace and other hydrogen energy related fields needing efficient hydrogen storage.

Description

Technical Field

[0001] This invention relates to the field of hydrogen storage alloy materials technology, specifically to a magnesium-based hydrogen storage alloy doped with two rare earth elements and its preparation method. Background Technology

[0002] As hydrogen energy continues to play an increasingly important role in the energy mix, the development of safe, efficient, and reversible solid-state hydrogen storage materials has become a research hotspot in the field of hydrogen energy technology. Among them, magnesium-based hydrogen storage alloys are considered one of the most promising solid-state hydrogen storage systems due to their high theoretical hydrogen storage capacity, abundant resources, and low cost. However, traditional magnesium-based hydrogen storage materials generally suffer from slow hydrogen absorption reaction rates and complex activation processes in practical applications, making it difficult to achieve rapid and efficient hydrogen storage processes under medium and low temperature conditions, which severely limits their engineering application prospects.

[0003] To improve the hydrogen storage kinetics of magnesium-based materials, researchers have proposed various modification strategies, the most common of which is the introduction of catalysts or the construction of composite hydrogen storage systems, such as the addition of transition metals, metal oxides, or carbon-based materials. While these methods can accelerate the hydrogen absorption and desorption rates to some extent, they typically require additional preparation processes and result in complex system compositions. Therefore, improving the intrinsic hydrogen absorption kinetics of magnesium-based materials through alloy composition and microstructure design without relying on external catalysts remains a key challenge in this field.

[0004] In magnesium-based hydrogen storage alloy systems, the introduction of rare earth element Y into magnesium-nickel-yttrium (Mg-Ni-Y) alloys induces the formation of a long-period stacked-order (LPSO) structure, resulting in a multiphase microstructure where α-Mg, Mg2Ni, and LPSO phases coexist, thus endowing the alloy with better hydrogen storage performance. In this system, Mg2Ni and its reversible hydride Mg2NiH4 phase significantly reduce the thermodynamic energy barrier for hydrogen storage in Mg alloys. The LPSO phase can undergo in-situ evolution during hydrogen absorption, forming a nanoscale dispersed phase system composed of MgH2, Mg2NiH4, and YH3 / YH2, introducing lattice distortion and defect structures into the matrix, thereby creating a composite interface structure at the microscopic level that is conducive to hydrogen adsorption and diffusion. According to existing research, the maximum practical hydrogen storage capacity of Mg-Ni-Y alloys without catalyst assistance is difficult to exceed 5.5 wt%, especially under intermediate temperature conditions (~250 ℃) or during short-term hydrogen absorption, where the effective hydrogen storage capacity is even more limited. Therefore, there is still room for improvement in the hydrogen storage capacity and hydrogen absorption kinetics performance of Mg-Ni-Y alloys.

[0005] Studies have shown that in Mg-Ni-Y alloys, the eutectic region composed of α-Mg and Mg2Ni can significantly increase the number of phase interfaces, thereby providing more effective reaction interfaces for hydrogen adsorption and desorption processes, accelerating hydrogenation and dehydrogenation kinetics, and improving the overall hydrogen storage efficiency and capacity of the alloy. Based on this, further structural design of the eutectic structure to construct a more complex eutectic region with richer interfaces holds promise for continuously improving hydrogen storage performance. Given that europium (Eu) exhibits phase-forming characteristics in magnesium-based alloys different from conventional rare earth elements, Mg can be introduced into the α-Mg+Mg2Ni eutectic region. 17 Eu2 phase, thus constructing a structure composed of α-Mg, Mg2Ni and Mg 17 The ternary eutectic region composed of Eu2 further increases the phase boundary density and optimizes the synergistic effect of the microstructure. Based on this, a magnesium-nickel-yttrium-europium (Mg-Ni-Y-Eu) alloy system was developed, which has obvious necessity and practical application value for improving the capacity and hydrogen absorption / desorption rate of magnesium-based hydrogen storage alloys. Summary of the Invention

[0006] To address the issues of limited hydrogen storage capacity and slow hydrogen absorption / desorption rates in existing magnesium-based hydrogen storage materials, this invention proposes a high-capacity magnesium-based hydrogen storage alloy and its preparation method.

[0007] The technical solution of the present invention is as follows: A magnesium-based hydrogen storage alloy doped with two rare earth elements comprises the following components by mass percentage: 68.8~91 wt.% Mg, 5~15 wt.% Ni, 2~8 wt.% Y, 2~8 wt.% Eu; The magnesium-based hydrogen storage alloy consists of α-Mg phase, LPSO phase, Mg2Ni phase, and Mg. 17 It consists of the Eu2 phase, including Mg2Ni and Mg 17 Eu2 forms a ternary eutectic structure with some α-Mg.

[0008] Preferably, the dual rare earth-doped magnesium-based hydrogen storage alloy comprises the following components by mass percentage: 80 wt.% Mg, 10 wt.% Ni, 6 wt.% Y, 4 wt.% Eu.

[0009] The present invention also provides a method for preparing the above-mentioned dual rare earth doped magnesium-based hydrogen storage alloy, comprising the following steps: Magnesium ingots, magnesium-nickel alloys, magnesium-yttrium alloys, and magnesium-europium alloys were weighed and batched according to their alloy composition. Place all raw materials in a melting crucible, introduce a protective atmosphere, and heat the melt to 700~750℃, stirring thoroughly until melted; Clean the surface of the melt, cool the magnesium alloy melt to 680~700℃, and cast it to obtain a magnesium alloy ingot; Magnesium alloy powder for hydrogen storage is obtained by crushing magnesium alloy through mechanical grinding.

[0010] Preferably, the crushing process involves crushing the material into powder with a particle size of less than 100 μm.

[0011] This invention solves the core problems of traditional magnesium-based hydrogen storage alloys, such as limited hydrogen storage capacity, slow hydrogen absorption and desorption rates, and complex activation processes, through precise composition design, unique microstructure construction, and suitable preparation processes. Compared with existing Mg-Ni-Y alloys, it achieves improved hydrogen storage performance and has the advantages of simple process and no need for external catalysts for industrialization. The specific beneficial effects are as follows: 1. The alloy provided by this invention forms α-Mg phase, LPSO phase, Mg2Ni phase and Mg 17 The Eu2 phase has a multiphase structure, and Mg2Ni and Mg 17 Eu2 and some α-Mg form a micron-scale ternary eutectic region, which significantly increases the phase boundary density and effective reaction interface compared to the traditional binary eutectic region, providing more active sites and transport channels for the adsorption and diffusion of hydrogen atoms. At the same time, the lath-shaped LPSO phase is uniformly distributed in the matrix, and can evolve in situ to form a nanoscale dispersed phase when hydrogen is absorbed, introducing lattice distortion and defect structure, further reducing hydrogen diffusion resistance, and optimizing the hydrogen storage kinetics process from the microstructural level.

[0012] 2. This invention requires no external catalyst, and significantly improves the hydrogen storage capacity and hydrogen absorption and dehydrogenation rates of the alloy: at a hydrogen pressure of 3 MPa, the maximum hydrogen storage capacity reaches 5.8 wt.% at 250°C and 6.2 wt.% at 340°C, breaking through the limitation that the actual hydrogen storage capacity of traditional Mg-Ni-Y alloys without catalyst assistance is difficult to exceed 5.5 wt.%; the hydrogen absorption efficiency is excellent, reaching 5.3 wt.% at 250°C and 5.9 wt.% at 340°C after 5 minutes of hydrogen absorption under a hydrogen pressure of 3 MPa; the dehydrogenation rate is extremely fast, requiring only 1.5 minutes to dehydrogenate 5 wt.% under vacuum conditions at 340°C, greatly improving the practicality of hydrogen storage under medium and low temperature conditions.

[0013] 3. The components of this invention have complementary functions and synergistically regulate the alloy structure and properties: Ni is the core element for hydrogen storage, and the generated Mg2Ni phase absorbs hydrogen to form a reversible hydrogen storage hydride Mg2NiH4, which has a higher hydrogen diffusion rate than MgH2 and can also reduce the hydrogen desorption temperature of the alloy; Eu has unique phase formation characteristics, preferentially enriching Mg2Ni at the Mg2Ni phase boundary in the α-Mg+Mg2Ni eutectic region to form Mg 17The Eu2 phase constructs a ternary eutectic region, directly regulating the hydrogen storage reaction kinetics; Y can effectively suppress the formation of coarse blocky Mg2Eu phase by Eu alone, forcing Eu to participate more in the formation of a refined eutectic structure, avoiding the coarse second phase from destroying the uniformity of the structure and hindering hydrogen diffusion, thus ensuring the stability of the overall hydrogen storage performance of the alloy.

[0014] 4. The preparation process of this invention can be achieved through smelting, casting, and mechanical grinding only. There is no need to add additional catalysts or construct composite systems. The process steps are few and the operation is simple. Moreover, the process parameter range of smelting and grinding is clear, which can precisely control the alloy phase composition and powder particle size. The prepared alloy has good crystallinity, uniform phase distribution, and excellent structural stability. It avoids the problems of chaotic system composition and increased cost caused by complex processes, and is more suitable for large-scale production and engineering applications.

[0015] This invention can be widely applied in hydrogen energy-related fields that require safe and efficient solid-state hydrogen storage, such as hydrogen energy storage and transportation, fuel cells, new energy vehicles, distributed energy systems, and aerospace. Attached Figure Description

[0016] Figure 1 The XRD pattern of the alloy in Example 1; Figure 2 Example 1: SEM backscattered image of the alloy and high-resolution image of the ternary eutectic region; Figure 3 Example 1: TEM image of the alloy and its Mg content. 17 Electron diffraction images of the Eu2 phase; Figure 4 SEM backscattered image and high-resolution image of the binary eutectic region of alloy 1 (Comparative Example 1); Figure 5 SEM backscattered image of alloy 2 and high-resolution image of the ternary eutectic region. Detailed Implementation

[0017] To make the technical solutions of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the following embodiments are only used to better understand the technical solutions of the present invention and should not be construed as limiting the present invention.

[0018] Example 1. Mg-10Ni-6Y-4Eu alloy: Magnesium ingots, magnesium-nickel alloys, magnesium-yttrium alloys, and magnesium-europium alloys were weighed and batched according to their alloy composition (Mg: 80 wt.%, Ni: 10 wt.%, Y: 6 wt.%, Eu: 4 wt.%). All raw materials were placed in a melting crucible, a protective atmosphere was introduced, and the melt was heated to 730 °C and stirred thoroughly until melted. The surface of the melt was cleaned, and the magnesium alloy melt was cooled to 690 °C, allowed to stand, and then cast to obtain magnesium alloy ingots. The magnesium alloy was then mechanically ground into powder with a particle size of less than 100 μm to obtain hydrogen storage magnesium alloy powder.

[0019] The XRD results of the alloy are as follows: Figure 1 As shown in the figure, the α-Mg phase, LPSO phase, Mg2Ni phase, and Mg are clearly visible. 17 The characteristic diffraction peaks of the Eu2 phase, with moderate intensity and sharp peak shape for each phase, indicate good crystallinity and uniform phase distribution of the alloy. The absence of Mg2Eu impurity phase peaks proves that Y element effectively suppresses the individual enrichment of Eu, avoiding the negative impact of coarse, bulky Mg2Eu on hydrogen storage performance, and providing a structural basis for rapid hydrogen diffusion.

[0020] The SEM image of the microstructure of the alloy is as follows: Figure 2 As shown in (a), it includes a dark black ellipsoidal α-Mg phase, a gray lath-like LPSO phase, and a flocculent eutectic region with multi-colored contrast. A magnified SEM image of the eutectic region is shown below. Figure 2 As shown in (b), it consists of Mg2Ni and Mg 17 Eu2 is composed of a small amount of α-Mg. The lamellar LPSO phase is uniformly distributed in the α-Mg matrix and can evolve in situ to form a nanoscale dispersed phase during hydrogen absorption, introducing lattice distortion and defects, providing numerous active sites for hydrogen adsorption and diffusion. The flocculent ternary eutectic region has a micrometer-scale size and a high phase boundary density between phases, significantly increasing the hydrogen reaction interface and allowing hydrogen atoms to rapidly react in α-Mg, Mg2Ni, and Mg. 17 Eu2 interphase diffusion increases the hydrogen absorption rate.

[0021] Mg 17 The structure of the Eu2 phase was further determined by TEM and selected area electron diffraction, see [link to TEM]. Figure 3 As shown in the TEM image, Mg is visible. 17 The Eu2 phase exhibits a nanoscale lamellar structure, uniformly distributed within the ternary eutectic region. Mg 17 The nanoscale lamellar structure of the Eu2 phase further refines the microstructure of the ternary eutectic region, increases the phase boundary density, shortens the diffusion path of hydrogen atoms, and significantly improves the hydrogen adsorption and desorption kinetics; Mg 17The ordered crystal structure of the Eu2 phase has good hydrogen adsorption capacity and can serve as a hydrogen storage site to improve the overall hydrogen storage capacity of the alloy. At the same time, its lattice matching with Mg2Ni and α-Mg is good, which avoids the increase in hydrogen diffusion resistance caused by lattice mismatch.

[0022] Magnesium alloy powder was used for hydrogen storage tests. The hydrogen absorption rates after absorbing hydrogen for 5 minutes at 3 MPa hydrogen pressure were 5.3 wt.% (250 °C) and 5.9 wt.% (340 °C). The hydrogen release rate after dehydrogenation under vacuum conditions at 250 °C for 30 minutes was 2.9 wt.%. The time required for the alloy to dehydrogenate 5 wt.% under vacuum conditions at 340 °C was 1.5 minutes.

[0023] Example 2. Mg-10Ni-8Y-2Eu alloy: Magnesium ingots, magnesium-nickel alloy, magnesium-yttrium alloy, and magnesium-europium alloy were weighed and batched according to the alloy composition (Mg: 80 wt.%, Ni: 10 wt.%, Y: 8 wt.%, Eu: 2 wt.%). All raw materials were placed in a melting crucible, a protective atmosphere was introduced, and the melt was heated to 730 °C and stirred thoroughly until melted. The surface of the melt was cleaned, and the magnesium alloy melt was cooled to 690 °C, allowed to stand, and then cast to obtain a magnesium alloy ingot. The magnesium alloy was mechanically ground into powder with a particle size of less than 100 μm to obtain hydrogen storage magnesium alloy powder.

[0024] Magnesium alloy powder was used for hydrogen storage tests. The hydrogen absorption rates after absorbing hydrogen for 5 minutes at 3 MPa hydrogen pressure were 5.1 wt.% (250 °C) and 5.6 wt.% (340 °C). The hydrogen release rate after dehydrogenation under vacuum conditions at 250 °C for 30 minutes was 2.5 wt.%. The time required for dehydrogenation of 5 wt.% under vacuum conditions at 340 °C was 3.1 minutes.

[0025] Example 3. Mg-10Ni-4Y-6Eu alloy: Magnesium ingots, magnesium-nickel alloy, magnesium-yttrium alloy, and magnesium-europium alloy were weighed and batched according to the alloy composition (Mg: 80 wt.%, Ni: 10 wt.%, Y: 4 wt.%, Eu: 6 wt.%). All raw materials were placed in a melting crucible, a protective atmosphere was introduced, and the melt was heated to 730 °C and stirred thoroughly until melted. The surface of the melt was cleaned, and the magnesium alloy melt was cooled to 690 °C, allowed to stand, and then cast to obtain a magnesium alloy ingot. The magnesium alloy was mechanically ground into powder with a particle size of less than 100 μm to obtain hydrogen storage magnesium alloy powder.

[0026] Magnesium alloy powder was used for hydrogen storage tests. The hydrogen absorption rates after absorbing hydrogen for 5 minutes at 3 MPa hydrogen pressure were 4.9 wt.% (250 °C) and 5.7 wt.% (340 °C), respectively. The hydrogen release rate after dehydrogenation under vacuum conditions at 250 °C for 30 minutes was 2.6 wt.%. The time required for dehydrogenation of 5 wt.% under vacuum conditions at 340 °C was 2.7 minutes.

[0027] Example 4. Mg-15Ni-8Y-8Eu alloy: Magnesium ingots, magnesium-nickel alloy, magnesium-yttrium alloy, and magnesium-europium alloy were weighed and batched according to the alloy composition (Mg: 69 wt.%, Ni: 15 wt.%, Y: 8 wt.%, Eu: 8 wt.%). All raw materials were placed in a melting crucible, a protective atmosphere was introduced, and the melt was heated to 750 °C and stirred thoroughly until melted. The surface of the melt was cleaned, and the magnesium alloy melt was cooled to 700 °C, allowed to stand, and then cast to obtain a magnesium alloy ingot. The magnesium alloy was mechanically ground into powder with a particle size of less than 100 μm to obtain hydrogen storage magnesium alloy powder.

[0028] Magnesium alloy powder was used for hydrogen storage tests. The hydrogen absorption rates after 5 min of hydrogen absorption at 3 MPa hydrogen pressure were 3.7 wt.% (250 °C) and 4.1 wt.% (340 °C), respectively. The hydrogen release rate after dehydrogenation of the alloy at 250 °C under vacuum for 30 min was 2.3 wt.%. The time required for the alloy to dehydrogenate 5 wt.% under vacuum at 340 °C was 8.4 min.

[0029] Example 5. Mg-5Ni-2Y-2Eu alloy: Magnesium ingots, magnesium-nickel alloy, magnesium-yttrium alloy, and magnesium-europium alloy were weighed and batched according to the alloy composition (Mg: 91 wt.%, Ni: 5 wt.%, Y: 2 wt.%, Yb: 2 wt.%). All raw materials were placed in a melting crucible, a protective atmosphere was introduced, and the melt was heated to 700 °C and stirred thoroughly until melted. The surface of the melt was cleaned, and the magnesium alloy melt was cooled to 680 °C, allowed to stand, and then cast to obtain a magnesium alloy ingot. The magnesium alloy was mechanically ground into powder with a particle size of less than 100 μm to obtain hydrogen storage magnesium alloy powder.

[0030] Magnesium alloy powder was used for hydrogen storage tests. The hydrogen absorption rates after absorbing hydrogen for 5 minutes at 3 MPa hydrogen pressure were 4.2 wt.% (250 °C) and 4.7 wt.% (340 °C), respectively. The hydrogen release rate after dehydrogenation under vacuum conditions at 250 °C for 30 minutes was 0.9 wt.%. The time required for the alloy to dehydrogenate 5 wt.% under vacuum conditions at 340 °C was 15.6 minutes.

[0031] Comparative Example 1. Mg-10Ni-10Y alloy: Magnesium ingots, magnesium-nickel alloys, magnesium-yttrium alloys, and magnesium-europium alloys were weighed and batched according to their alloy compositions (Mg: 80 wt.%, Ni: 10 wt.%, Y: 10 wt.%). All raw materials were placed in a melting crucible, a protective atmosphere was introduced, and the melt was heated to 730 °C and stirred thoroughly until melted. The surface of the melt was cleaned, and the magnesium alloy melt was cooled to 690 °C, allowed to stand, and then cast to obtain magnesium alloy ingots. The magnesium alloy was mechanically ground into powder with a particle size of less than 100 μm to obtain hydrogen storage magnesium alloy powder.

[0032] The SEM image of the microstructure of the alloy is as follows: Figure 4 As shown in (a), α-Mg phase, LPSO phase and binary eutectic region are visible, with no Mg present. 17 Eu2 phase; magnified SEM image of the binary eutectic region as follows: Figure 4 As shown in (b), the binary eutectic region is composed of Mg₂Ni and a small amount of α-Mg. The absence of Eu prevents the formation of a ternary eutectic region, resulting in a significantly lower phase boundary density in the binary eutectic region compared to the ternary eutectic region in Example 1. This limits the reaction interface available for hydrogen atom diffusion, thus leading to a significantly lower hydrogen absorption rate than in Example 1. Furthermore, the Mg₂Ni phase in the binary eutectic region is more dispersed, exhibiting poor phase boundary bonding with the α-Mg matrix. This results in greater diffusion resistance between phases for hydrogen atoms, limiting the improvement in hydrogen storage capacity. This demonstrates that introducing Eu to construct the ternary eutectic region is crucial for enhancing hydrogen storage performance.

[0033] Magnesium alloy powder was used for hydrogen storage tests. The hydrogen absorption rates after 5 min of hydrogen absorption at 3 MPa hydrogen pressure were 3.5 wt.% (250 °C) and 4.6 wt.% (340 °C), respectively. The hydrogen release rate after dehydrogenation of the alloy at 250 °C under vacuum for 30 min was 2.8 wt.%. The time required for the alloy to dehydrogenate 5 wt.% under vacuum at 340 °C was 2.4 min.

[0034] Comparative Example 2. Mg-10Ni-10Eu alloy: Magnesium ingots, magnesium-nickel alloys, magnesium-yttrium alloys, and magnesium-europium alloys were weighed and batched according to their alloy compositions (Mg: 80 wt.%, Ni: 10 wt.%, Eu: 10 wt.%). All raw materials were placed in a melting crucible, a protective atmosphere was introduced, and the melt was heated to 730 °C and stirred thoroughly until melted. The surface of the melt was cleaned, and the magnesium alloy melt was cooled to 690 °C, allowed to stand, and then cast to obtain magnesium alloy ingots. The magnesium alloy was then mechanically ground into powder with a particle size of less than 100 μm to obtain hydrogen storage magnesium alloy powder.

[0035] The SEM image of the microstructure of the alloy is as follows: Figure 5 As shown in (a), the α-Mg phase, bright blocky Mg2Eu phase and flocculent ternary eutectic region are visible. The Mg2Eu phase is large in size and unevenly distributed. Figure 5 (b) shows that the ternary eutectic region is composed of Mg 17 The alloy consists of Eu2, Mg2Ni, and a small amount of α-Mg. The absence of Y element prevents Eu from effectively participating in the formation of the eutectic structure, resulting in the accumulation of large amounts of Eu to form a coarse, blocky Mg2Eu phase. This phase has no hydrogen storage capacity and is unevenly distributed, disrupting the alloy's microstructure homogeneity and increasing the diffusion resistance of hydrogen atoms. Consequently, its dehydrogenation rate at 250°C for 30 min is only 0.8 wt.%, exhibiting extremely poor dehydrogenation reversibility. Although this alloy possesses a ternary eutectic region, the coarse Mg2Eu phase occupies a large amount of space, reducing the proportion of the effective hydrogen storage phase. This leads to its hydrogen storage capacity and hydrogen absorption rate being lower than those of Example 1, demonstrating the necessity of Y element in regulating Eu phase formation and ensuring the alloy's hydrogen storage performance.

[0036] Magnesium alloy powder was used for hydrogen storage tests. The hydrogen absorption rates after absorbing hydrogen for 5 minutes at 3 MPa hydrogen pressure were 3.9 wt.% (250 °C) and 5.5 wt.% (340 °C), respectively. The hydrogen release rate after dehydrogenation under vacuum conditions at 250 °C for 30 minutes was 0.8 wt.%. The time required for dehydrogenation of 5 wt.% under vacuum conditions at 340 °C was 2.8 minutes.

[0037] The hydrogen storage performance test results of each embodiment and comparative example are shown in Table 1.

[0038] Table 1

[0039] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A magnesium-based hydrogen storage alloy doped with two rare earth elements, characterized in that, It contains the following components by mass percentage: 68.8~91 wt.% Mg, 5~15 wt.% Ni, 2~8 wt.% Y, 2~8 wt.% Eu, 0~0.2 wt.% impurities; The magnesium-based hydrogen storage alloy consists of α-Mg phase, LPSO phase, Mg2Ni phase, and Mg. 17 It consists of the Eu2 phase, including Mg2Ni and Mg 17 Eu2 forms a ternary eutectic structure with some α-Mg.

2. The magnesium-based hydrogen storage alloy with dual rare earth doping according to claim 1, characterized in that, It contains the following components by mass percentage: 80 wt.% Mg, 10 wt.% Ni, 6 wt.% Y, 4 wt.% Eu.

3. A method for preparing a magnesium-based hydrogen storage alloy with dual rare earth doping as described in claim 1 or 2, characterized in that, Includes the following steps: Magnesium ingots, magnesium-nickel alloys, magnesium-yttrium alloys, and magnesium-europium alloys were weighed and batched according to their alloy composition. Place all raw materials in a melting crucible, introduce a protective atmosphere, and heat the melt to 700~750℃, stirring thoroughly until melted; Clean the surface of the melt, cool the magnesium alloy melt to 680~700℃, and cast it to obtain a magnesium alloy ingot; Magnesium alloy powder for hydrogen storage is obtained by crushing magnesium alloy through mechanical grinding.

4. The method for preparing the dual rare earth-doped magnesium-based hydrogen storage alloy according to claim 3, characterized in that, The crushing process involves crushing the material into powder with a particle size of less than 100 μm.

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