High entropy doped hydrogen storage alloy and preparation method thereof

Abstract

This application belongs to the field of hydrogen storage alloy technology, and particularly relates to a high-entropy doped hydrogen storage alloy and its preparation method. The general chemical formula of the high-entropy doped hydrogen storage alloy is: TiCr (1.2‑x) V y (HEA) x Where 0 < x ≤ 0.2, 0.5 ≤ y ≤ 0.8, and HEA (High-entropy alloy) is a high-entropy alloy. The high-entropy doped hydrogen storage alloy provided in this application is obtained by modifying a Ti-Cr-V based hydrogen storage alloy by doping it with a high-entropy alloy. Through the synergistic effect between the various metal elements in the high-entropy alloy, multiple factors such as the crystal structure, electronic structure, and bulk modulus of the high-entropy doped hydrogen storage alloy are altered, thereby improving the thermodynamic properties of the hydrogen absorption and desorption reactions, and increasing the hydrogen absorption and desorption plateau and effective dehydrogenation capacity.

Description

Technical Field

[0001] This application belongs to the field of hydrogen storage alloy technology, and particularly relates to a high-entropy doped hydrogen storage alloy and its preparation method. Background Technology

[0002] Hydrogen fuel boasts advantages such as high energy density, high abundance, and no pollution from byproducts, making it an ideal synthetic fuel that can replace fossil fuels, particularly suitable for transportation applications. However, hydrogen storage remains a bottleneck to be solved. Currently, high-pressure hydrogen storage is still the main method for hydrogen storage in hydrogen-powered vehicles, but it suffers from "one low and two highs"—low hydrogen volumetric storage density, high safety risks, and high hydrogen supply costs. In contrast, low-pressure solid-state hydrogen storage offers "one high and two lows"—high hydrogen volumetric storage density, low safety risks, and low hydrogen supply costs, making it a very promising technology. Ti-Cr-V based hydrogen storage alloys are representative of third-generation hydrogen storage alloys, belonging to Ti-V based BCC (the body-centered cubic) solid solution alloys. Compared to AB5, AB2, and AB-type hydrogen storage alloys, this type of alloy exhibits a higher hydrogen storage capacity (approximately 4 wt%) at room temperature. However, the large-scale practical application of this type of alloy is currently limited by problems such as high activation difficulty, low dehydrogenation capacity, poor pressure-composition-temperature (PCT) platform characteristics, and high cost.

[0003] Existing technologies have already improved the performance of Ti-Cr-V hydrogen storage alloys through simple mono- and binary doping. However, low-V (V below 30 at%) Ti-Cr-V hydrogen storage materials still face some challenges, such as low low-temperature dehydrogenation capacity and difficulty in activation. Therefore, it is urgent to improve the thermal / kinetic properties of Ti-Cr-V hydrogen storage alloys, enhance the hydrogen desorption platform and effective hydrogen desorption capacity, and simultaneously improve activation performance to promote their large-scale application. Summary of the Invention

[0004] The purpose of this application is to provide a high-entropy doped hydrogen storage alloy and its preparation method, aiming to solve the technical problems of low low-temperature dehydrogenation capacity and difficult activation of existing hydrogen storage alloys.

[0005] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0006] In a first aspect, this application provides a high-entropy-doped hydrogen storage alloy, the general chemical formula of which is:

[0007] TiCr (1.2-x) V y (HEA) x ;

[0008] Where 0 < x ≤ 0.2, 0.5 ≤ y ≤ 0.8, HEA (High-entropy alloy) is a high-entropy alloy.

[0009] Furthermore, the metallic elements in the high-entropy alloy include four or more of the following: Al, Nb, Mo, Mn, Fe, Co, and Ni.

[0010] Furthermore, the molar ratio of each metal element in the high-entropy alloy is 1.

[0011] Furthermore, the high-entropy alloy comprises: Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 .

[0012] Furthermore, the high-entropy alloy comprises: Al 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 .

[0013] Furthermore, the high-entropy alloy comprises: Fe 0.25 Co 0.25 Ni 0.25 Mn 0.25 .

[0014] Furthermore, the high-entropy doped hydrogen storage alloy includes, but is not limited to: TiCr 1.0 V 0.7 (HEA) 0.2 TiCr 1.1 V 0.6 (HEA) 0.1 TiCr 1.0 V 0.6 (HEA) 0.2 TiCr 1.0 V 0.5 (HEA) 0.2 and TiCr 1.0 V 0.8 (HEA) 0.2 .

[0015] Furthermore, the high-entropy doped hydrogen storage alloy is TiCr. 1.0 V 0.7 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.1 V 0.6(Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.1 TiCr 1.0 V 0.6 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.0 V 0.5 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.0 V 0.8 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.1 V 0.6 (Al 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 ) 0.1 or TiCr 1.0 V 0.7 (Fe 0.25 Co 0.25 Ni 0.25 Mn 0.25 ) 0.2 .

[0016] Secondly, this application provides a method for preparing a high-entropy doped hydrogen storage alloy, comprising the following steps:

[0017] After obtaining the various metal raw material components of the high-entropy doped hydrogen storage alloy, a melting process was carried out under an inert atmosphere to obtain the alloy with the general chemical formula TiCr. (1.2-x) V y (HEA) x The high-entropy doped hydrogen storage alloy, wherein 0 < x ≤ 0.2, 0.5 ≤ y ≤ 0.8, and HEA is a high-entropy alloy.

[0018] Furthermore, the smelting process includes:

[0019] A high-entropy alloy is prepared by smelting metal raw materials other than Ti, Cr, and V, and then the high-entropy alloy is mixed and smelted with Ti, Cr, and V.

[0020] or,

[0021] All the metal raw materials are mixed and smelted.

[0022] Furthermore, the preparation method also includes heat treatment of the high-entropy doped hydrogen storage alloy obtained by melting.

[0023] Furthermore, the heat treatment step includes: heating the high-entropy doped hydrogen storage alloy to above 1400°C at a heating rate of 10-15°C / min, holding it at that temperature for more than 1 hour in an inert atmosphere, and then quenching it in cold water.

[0024] The high-entropy doped hydrogen storage alloy provided in the first aspect of this application is obtained by modifying a Ti-Cr-V based hydrogen storage alloy by doping it with a high-entropy alloy. The synergistic effect between the various metal elements in the high-entropy alloy alters multiple factors such as the crystal structure, electronic structure, and bulk modulus of the high-entropy doped hydrogen storage alloy, improving the thermodynamic properties of the hydrogen absorption and desorption reactions, and increasing the hydrogen absorption and desorption plateau and effective dehydrogenation capacity. Furthermore, the high-entropy doped hydrogen storage alloy has a two-phase structure of BCC phase and C14 Laves phase (intermetallic compound), where the BCC phase ensures the hydrogen storage capacity of the high-entropy doped hydrogen storage alloy; and the cost of the high-entropy doped hydrogen storage alloy is reduced due to the reduction of the expensive vanadium content. The C14 Laves phase has a catalytic effect; its brittle fracture generates a large number of fresh surfaces, promoting hydrogen dissociation and acting as a rapid hydrogen atom diffusion channel, improving the kinetics and activation performance of the hydrogen absorption and desorption reactions.

[0025] The method for preparing high-entropy doped hydrogen storage alloys provided in the second aspect of this application is simple, low-cost, and easily industrialized. The synergistic effect among the various metal elements in the high-entropy doped hydrogen storage alloy alters multiple factors such as the crystal structure, electronic structure, and bulk modulus of the alloy, improving the thermodynamic properties of the hydrogen absorption and desorption reactions, and increasing the hydrogen absorption / desorption plateau and effective dehydrogenation capacity. Furthermore, the high-entropy doped hydrogen storage alloy possesses a two-phase structure of BCC and C14 Laves phases (intermetallic compounds). The BCC phase ensures the hydrogen storage capacity of the high-entropy doped hydrogen storage alloy; and the cost of the high-entropy doped hydrogen storage alloy is reduced due to the reduction of expensive vanadium content. The C14 Laves phase has a catalytic effect; its brittle fracture generates a large number of fresh surfaces, promoting hydrogen dissociation and acting as a rapid hydrogen atom diffusion channel, improving the kinetics and activation performance of the hydrogen absorption and desorption reactions. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1a The hydrogen storage alloys of Comparative Examples 1-5 and Example 1 of this application are shown as the initial hydrogen absorption kinetics curves at 25°C and 3MPa H2.

[0028] Figure 1b The dehydrogenation PCT curves of the hydrogen storage alloys of Comparative Examples 1-5 and Example 1 of this application at 70°C are shown.

[0029] Figure 2a The first hydrogen absorption kinetic curves of the high-entropy doped hydrogen storage alloys in Examples 1 and 2 of this application at 25°C and 3MPa are shown.

[0030] Figure 2b The PCT curves for the dehydrogenation of the high-entropy doped hydrogen storage alloys in Examples 1 and 2 of this application are shown at 70°C.

[0031] Figure 3 The images show the refined XRD patterns of hydrogen storage alloys in Comparative Example 6 and Examples 3 and 4 of this application.

[0032] Figure 4a The hydrogen storage alloys of Comparative Example 6 and Examples 3 and 4 of this application are shown as the first hydrogen absorption kinetic curves at 25°C and 3MPa H2.

[0033] Figure 4b The dehydrogenation PCT curves of the hydrogen storage alloys of Comparative Example 6 and Examples 3 and 4 of this application at 70°C are shown.

[0034] Figure 5 The images shown are the refined XRD patterns of the high-entropy doped hydrogen storage alloys in Examples 1, 4, 5, and 6 of this application.

[0035] Figure 6a The figures show the initial hydrogen absorption kinetics curves of the high-entropy doped hydrogen storage alloys in Examples 1, 4, 5, and 6 of this application at 25°C and 3 MPa H2.

[0036] Figure 6b The PCT curves for the dehydrogenation of the high-entropy doped hydrogen storage alloys in Examples 1, 4, 5, and 6 of this application are shown at 70°C.

[0037] Figure 7 The images show the XRD patterns of hydrogen storage alloys in Examples 7, 8 and Comparative Example 6 of this application.

[0038] Figure 8aThe hydrogen storage alloys of Examples 7, 8 and Comparative Example 6 of this application are shown as the first hydrogen absorption kinetic curves at 25°C and 3MPa H2.

[0039] Figure 8b The dehydrogenation PCT curves of hydrogen storage alloys in Examples 7, 8 and Comparative Example 6 of this application are shown at 70°C.

[0040] Figure 9 The images are XRD patterns of the high-entropy doped hydrogen storage alloys of Examples 1 and 9 of this application.

[0041] Figure 10a The first hydrogen absorption kinetic curves of the high-entropy doped hydrogen storage alloys in Examples 1 and 9 of this application at 25°C and 3MPa H2.

[0042] Figure 10b The dehydrogenation PCT curves of the high-entropy doped hydrogen storage alloys in Examples 1 and 9 of this application at 70°C.

[0043] Figure 11 These are the refined XRD patterns of the high-entropy doped hydrogen storage alloys in Examples 1 and 10 of this application before and after heat treatment.

[0044] Figure 12 This is a backscattered electron micrograph of the high-entropy doped hydrogen storage alloy of Example 10 of this application.

[0045] Figure 13a The PCT curves of dehydrogenation of the high-entropy doped hydrogen storage alloys at 70°C before and after heat treatment in Examples 1 and 10 of this application are shown.

[0046] Figure 13b The PCT curves of hydrogen absorption and desorption at different temperatures are shown for the high-entropy doped hydrogen storage alloy after heat treatment in Example 10 of this application.

[0047] Figure 14 The images show the XRD patterns of the alloy samples from Example 1 and Comparative Examples 1-5 of this application. Detailed Implementation

[0048] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0049] In this application, the term "and / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0050] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b or c", or "at least one of a, b and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0051] It should be understood that in the various embodiments of this application, the order of the above processes does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0052] The weights of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship between the weights of the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass in the embodiments of this application can be a well-known unit of mass in the chemical industry, such as μg, mg, g, or kg.

[0053] The terms "first" and "second" are used for descriptive purposes only, to distinguish objects, such as substances, from one another, and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. For example, without departing from the scope of the embodiments of this application, "first XX" may also be referred to as "second XX," and similarly, "second XX" may also be referred to as "first XX." Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0054] Hydrogen storage alloys require pressures below 1 atmosphere (0.1 MPa) to remove hydrogen, making them impractical for real-world applications. Therefore, in practical applications, the effective dehydrogenation capacity should be defined as the amount of hydrogen removed when dehydrogenation is stopped at 0.1 MPa.

[0055] The term "BCC phase" refers to a body-centered cubic structure phase, in which both the tetrahedral and octahedral interstices in the Ti-Cr-V based BCC solid solution can store hydrogen.

[0056] The term "C14 Laves phase" refers to the close-packed cubic C14 Laves phase, in which only the tetrahedral interstices of the TiCr2-based hydrogen storage alloy can be used for hydrogen storage.

[0057] The term "high-entropy alloy" is an emerging multi-metal alloy that consists of at least four metal alloys in almost equal quantities.

[0058] The term "incubation period" refers to the distance between the hydrogen absorption start line of the alloy and the vertical axis. The shorter the distance, the shorter the incubation period; conversely, the longer the incubation period.

[0059] The term "at%" is a unit of "atomic percentage" (at is an abbreviation for atom), used to describe the atomic content (percentage) of various elements in an inorganic substance.

[0060] Currently, Ti-Cr-V based hydrogen storage alloys represent the third generation of hydrogen storage alloys and belong to the Ti-V based BCC solid solution alloy category. These alloys exhibit higher hydrogen storage capacity (approximately 4 wt%) at room temperature. However, they currently suffer from drawbacks such as high activation difficulty, low dehydrogenation capacity, poor pressure-composition-temperature (PCT) plateau characteristics, and high cost.

[0061] To improve the thermal / kinetic properties of Ti-Cr-V based hydrogen storage alloys, enhance the hydrogen desorption plateau and effective hydrogen desorption capacity, and improve activation performance to promote their large-scale application, the applicant's research found that elemental doping not only effectively improves the overall hydrogen storage performance of Ti-Cr-V based hydrogen storage alloys but also reduces costs. Specifically, for low-vanadium Ti-Cr-V alloys with a V content of 15-30 at%, doping with heavy transition metals (M) such as Nb, Ta, and Mo promotes the formation of the BCC phase and increases hydrogen storage capacity. Furthermore, these elements can improve the compositional and structural uniformity of Ti-Cr-V alloys, making the PCT curve plateau flatter. Later-stage d-block transition metals in the periodic table, such as Fe, Co, and Ni, typically have more electrons; doping with these elements can reduce the stability of hydrides, thereby lowering the dehydrogenation temperature. Low-cost Fe or V-Fe alloys have been widely introduced into Ti-Cr-V based alloys. Compared to Ti, Cr, and V, Fe has a smaller atomic radius, increasing the plateau pressure; therefore, doping with iron can improve the alloy's dehydrogenation capability.

[0062] Therefore, although traditional simple mono- or binary doping can improve the performance of Ti-Cr-V hydrogen storage alloys to some extent, low-V Ti-Cr-V hydrogen storage materials still have some problems, such as a low hydrogen desorption plateau that makes hydrogen desorption difficult and activation difficulties.

[0063] Based on this, this application proposes a novel high-entropy doped hydrogen storage alloy.

[0064] The technical solution of this application is described in detail below with reference to the following embodiments.

[0065] The first aspect of this application provides a high-entropy-doped hydrogen storage alloy, the general chemical formula of which is:

[0066] TiCr(1.2-x) V y (HEA) x ;

[0067] Where 0 < x ≤ 0.2, 0.5 ≤ y ≤ 0.8, HEA (High-entropy alloy) is a high-entropy alloy.

[0068] The high-entropy doped hydrogen storage alloy provided in the first aspect of this application is a modification of a Ti-Cr-V based hydrogen storage alloy by doping it with a high-entropy alloy. The synergistic effect between the various metal elements in the high-entropy alloy, due to the differences in atomic radius, valence electron number, and bulk modulus of each metal element, can alter multiple factors such as the crystal structure, electronic structure, and bulk modulus of the hydrogen storage alloy after high-entropy doping, thereby improving the thermodynamic properties of the hydrogen absorption and desorption reactions, increasing the hydrogen absorption and desorption plateau, and enhancing the effective dehydrogenation capacity. Furthermore, the high-entropy doped hydrogen storage alloy possesses a two-phase structure of BCC phase and C14 Laves phase (intermetallic compound). The BCC phase ensures the hydrogen storage capacity of the high-entropy doped hydrogen storage alloy; the C14 Laves phase has a catalytic effect, and its easily fractured, abundant fresh surface promotes hydrogen dissociation and acts as a rapid diffusion channel for hydrogen atoms, improving the kinetics and activation performance of the hydrogen absorption and desorption reactions. Moreover, due to the different atomic radii of the various metals, the prepared high-entropy doped hydrogen storage alloy exhibits increased crystal structure defects, which is expected to improve the hydrogen absorption capacity. Moreover, since the vanadium content in high-entropy doped hydrogen storage alloys is less than 30 at%, it belongs to the low-vanadium Ti-Cr-V system hydrogen storage material. The reduction in vanadium content lowers the cost of high-entropy doped hydrogen storage alloys.

[0069] In some embodiments, the high-entropy alloy used for doping includes four or more of the following metallic elements: Al, Nb, Mo, Mn, Fe, Co, and Ni. These metallic elements are inexpensive. Among them, Mo and Nb are beneficial for the formation of a stable BCC phase in the high-entropy doped hydrogen storage alloy, ensuring the hydrogen absorption capacity of the high-entropy doped hydrogen storage alloy. Fe, Mn, Co, and Ni are beneficial for improving the plateau or enhancing the PCT plateau characteristics. In addition, Nb, Mo, Mn, Fe, Co, and Ni are cheaper transition metals compared to vanadium. Therefore, Al, Nb, Mo, Mn, Fe, Co, and Ni are suitable for low-V Ti-Cr-V system hydrogen storage alloys, and the resulting high-entropy doped hydrogen storage alloy has a lower cost.

[0070] In some embodiments, the molar ratio of each metal element in the high-entropy alloy is 1, which can be finely adjusted.

[0071] In some embodiments, the sum of the molar numbers of each metal element in the high-entropy alloy is 1. The high-entropy alloy doping replaces the content of V element in the original Ti-Cr-V hydrogen storage alloy, thereby reducing the vanadium content in the high-entropy doped hydrogen storage alloy and lowering production costs.

[0072] In some embodiments, high-entropy alloys include, but are not limited to: Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 Al 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 Fe 0.25 Co 0.25 Ni 0.25 Mn 0.25 At least one of the following. In the embodiments of this application, the synergistic effect between the various metal elements in the high-entropy alloy changes multiple factors such as the crystal structure, electronic structure, and bulk modulus of the high-entropy doped hydrogen storage alloy, thereby improving the thermodynamic properties of the hydrogen absorption and desorption reactions of the high-entropy doped hydrogen storage alloy and increasing the hydrogen absorption and desorption plateau and effective dehydrogenation capacity.

[0073] In some embodiments, the atomic percentage of vanadium in the high-entropy doped hydrogen storage alloy is less than 30 at, which reduces the cost of the high-entropy doped hydrogen storage alloy.

[0074] In some embodiments, the atomic percentage of vanadium in the high-entropy doped hydrogen storage alloy is 18.5% to 26.7 at%.

[0075] In some embodiments, high-entropy doped hydrogen storage alloys include, but are not limited to: TiCr 1.0 V 0.7 (HEA) 0.2 TiCr 1.1 V 0.6 (HEA) 0.1 TiCr 1.0 V 0.6 (HEA) 0.2 TiCr 1.0 V 0.5 (HEA) 0.2 and TiCr 1.0 V 0.8 (HEA) 0.2 High-entropy doped hydrogen storage alloys possess a dual-phase structure consisting of a BCC phase and a C14 Laves phase (intermetallic compound). The BCC phase ensures the hydrogen storage capacity of the high-entropy doped hydrogen storage alloy. Furthermore, the reduced vanadium content lowers the cost of the high-entropy doped hydrogen storage alloy. The C14 Laves phase exhibits catalytic activity; its brittle fracture generates a large amount of fresh surface, promoting hydrogen dissociation and acting as a rapid diffusion channel for hydrogen atoms, thus improving the kinetics and activation performance of hydrogen absorption and desorption reactions.

[0076] In some embodiments, the high-entropy doped hydrogen storage alloy is TiCr 1.0 V0.7 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 The alloy exhibits excellent activation properties with virtually no incubation period; at 70℃ and 0.1 MPa, the effective dehydrogenation capacity is 1.73 wt%; under H2 conditions at 25℃ and 3 MPa, TiCr... 1.0 V 0.7 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 The alloy has a maximum hydrogen absorption capacity of 3.37 wt%.

[0077] In some specific embodiments, the high-entropy doped hydrogen storage alloy is TiCr. 1.1 V 0.6 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.1 TiCr 1.0 V 0.6 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.0 V 0.5 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.0 V 0.8 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.1 V 0.6 (Al 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 ) 0.1 TiCr 1.1 V 0.6 (Al0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 ) 0.2 or TiCr 1.0 V 0.7 (Fe 0.25 Co 0.25 Ni 0.25 Mn 0.25 ) 0.2 .

[0078] The high-entropy doped hydrogen storage alloys described in the above embodiments of this application can be prepared by the method described in the following embodiments.

[0079] The second aspect of this application provides a method for preparing a high-entropy doped hydrogen storage alloy, comprising the following steps:

[0080] S10. After obtaining the various metal raw material components in the high-entropy doped hydrogen storage alloy, the alloy is smelted under an inert atmosphere to obtain the alloy with the general chemical formula TiCr. (1.2-x) V y (HEA) x A high-entropy doped hydrogen storage alloy, wherein 0 < x ≤ 0.2, 0.5 ≤ y ≤ 0.8, and HEA is a high-entropy alloy.

[0081] The method for preparing high-entropy doped hydrogen storage alloys provided in the second aspect of this application is simple, low-cost, and easily industrialized. The synergistic effect between the various metal elements in the high-entropy doped hydrogen storage alloy alters multiple factors such as the crystal structure, electronic structure, and bulk modulus of the alloy, improving the thermodynamic properties of the hydrogen absorption and desorption reactions, and increasing the hydrogen absorption / desorption plateau and effective dehydrogenation capacity. Furthermore, the high-entropy doped hydrogen storage alloy possesses a two-phase structure of BCC and C14 Laves phases (intermetallic compounds). The BCC phase ensures the hydrogen storage capacity of the high-entropy doped hydrogen storage alloy; and the cost of the high-entropy doped hydrogen storage alloy is reduced due to the reduction of expensive vanadium content. The C14 Laves phase has a catalytic effect; its brittle fracture generates a large number of fresh surfaces, promoting hydrogen dissociation and acting as a rapid hydrogen atom diffusion channel, improving the kinetics and activation performance of the hydrogen absorption and desorption reactions.

[0082] In some embodiments, the smelting process in step S10 includes: first smelting metal raw materials other than Ti, Cr, and V to obtain a high-entropy alloy, and then mixing and smelting the high-entropy alloy with Ti, Cr, and V. The resulting high-entropy doped hydrogen storage alloy has a shorter incubation period, which is beneficial for hydrogen absorption and improves activation performance.

[0083] In some embodiments, when melting the high-entropy alloy with Ti, Cr, and V, the titanium ingot is first melted to absorb oxygen; the high-entropy doped alloy is flipped and remelted at least four times to ensure compositional uniformity.

[0084] In some embodiments, the preparation of high-entropy alloys specifically includes:

[0085] (1) Metal raw materials other than Ti, Cr and V are subjected to electric arc melting to obtain ingots;

[0086] (2) Remove the oxide layer on the surface of the ingot to obtain a high-entropy alloy.

[0087] In some embodiments, the method for removing the oxide layer from the surface of the ingot includes polishing the surface of the ingot.

[0088] In other embodiments, the melting process in step S10 includes: melting all metal raw materials at once; that is, mixing and melting the various metal raw material components simultaneously. The melting process is simple, and the high-entropy doped hydrogen storage alloy prepared has a long incubation period and poor activation performance, but the effective dehydrogenation capacity is close.

[0089] In some embodiments, when preparing a high-entropy doped hydrogen storage alloy containing manganese, an excess of manganese of 5 wt% higher than the set content is used for smelting to compensate for the evaporation loss during the smelting process caused by the low boiling point of manganese.

[0090] In some specific embodiments, a method for preparing a high-entropy doped hydrogen storage alloy is provided. The method involves doping the high-entropy alloy into a low-V Ti-Cr-V based hydrogen storage material, including:

[0091] S11. Obtain the composition of each metal raw material in the high-entropy doped hydrogen storage alloy;

[0092] S21. Under inert atmosphere conditions, metal raw materials other than Ti, Cr, and V are subjected to electric arc melting to obtain high-entropy alloy ingots;

[0093] S31. The surface of the high-entropy alloy ingot is polished to remove the oxide layer, thus obtaining the high-entropy alloy;

[0094] S41. Under inert gas conditions, a high-entropy alloy is smelted with Ti, Cr, and V to obtain a high-entropy doped hydrogen storage alloy.

[0095] In some embodiments, in step S11 above, if a high-entropy doped hydrogen storage alloy containing manganese is prepared, an excess of manganese is used for smelting at a content 5 wt% higher than the set content, in order to compensate for the evaporation loss during the smelting process caused by the low boiling point of manganese.

[0096] In some embodiments, in step S21 above, arc melting utilizes electrical energy to generate an electric arc between the electrode and the material being melted, producing a high temperature of 2000 to 6000°C or higher, melting the raw material through arc radiation, temperature convection, and heat conduction; for most of the time during the melting of the raw material, the high-temperature heat source is surrounded by the furnace charge, and the heat loss caused by the high-temperature exhaust gas is relatively small, thus resulting in high thermal efficiency; the surface of the ingot is polished to remove the oxide layer, reducing metal oxide impurities in the high-entropy doped hydrogen storage alloy.

[0097] In some embodiments, in steps S21 and S41 above, a water-cooled copper crucible is used as the container for melting metal in a furnace cavity containing an inert atmosphere. The inert atmosphere in the furnace cavity is formed by sequentially using a mechanical pump and a molecular pump to evacuate to 3 × 10⁻⁶ m³ / s. -3 ~5×10 -3 Pa, and fill with inert gas (0.06MPa) to make the gas pressure in the furnace cavity lower than 1 standard atmosphere, so as to achieve negative pressure sealing in the furnace cavity; first, the furnace cavity is evacuated to a high vacuum to remove the air in the furnace cavity, and then inert gas is filled in for protection to prevent oxidation during smelting.

[0098] In some embodiments, the inert gas includes, but is not limited to, argon, helium, and neon.

[0099] In some embodiments, in steps S21 and S41 above, oxygen in the smelting environment is further removed by melting titanium ingots. The titanium ingots used for oxygen removal do not participate in the alloy smelting. Titanium readily reacts with oxygen; melting titanium ingots removes residual oxygen in the furnace cavity (smelting environment), further reducing metal oxidation during smelting and lowering the oxygen content in the high-entropy doped hydrogen storage alloy.

[0100] In this embodiment, when preparing the high-entropy alloy and the high-entropy doped hydrogen storage alloy, the high-entropy alloy ingot and the high-entropy doped hydrogen storage alloy ingot obtained by melting are flipped and remelted at least four times to ensure compositional uniformity.

[0101] In some embodiments, in step S41 above, the high-entropy alloy is melted with Ti, Cr, and V by means of electric arc melting.

[0102] In some specific embodiments, a method for preparing a high-entropy doped hydrogen storage alloy is provided, comprising the following steps:

[0103] S12. Obtain the composition of each metal raw material in the high-entropy doped hydrogen storage alloy;

[0104] S22. Under inert atmosphere conditions, high-entropy doped hydrogen storage alloys are obtained by arc melting of various metal raw materials.

[0105] In other specific embodiments, the high-entropy doped hydrogen storage alloy obtained by arc melting of various metal raw materials has a longer incubation period and poorer activation performance compared with the high-entropy doped hydrogen storage alloy obtained by the above preparation method (melting high-entropy alloy with Ti, Cr, and V to obtain high-entropy doped hydrogen storage alloy), but the effective dehydrogenation capacity is similar.

[0106] In other specific embodiments, a method for preparing a high-entropy doped hydrogen storage alloy is provided, comprising the following steps:

[0107] S13. Obtain the composition of each metal raw material in the high-entropy doped hydrogen storage alloy;

[0108] S23. Under inert atmosphere conditions, metal raw materials other than Ti, Cr, and V are subjected to electric arc melting to obtain ingots;

[0109] S33. Grind the surface of the ingot to remove the oxide layer and obtain a high-entropy alloy;

[0110] S43. Under inert atmosphere conditions, a high-entropy alloy is smelted with Ti, Cr, and V to obtain a high-entropy doped hydrogen storage alloy.

[0111] S53. The high-entropy doped hydrogen storage alloy obtained by melting is subjected to heat treatment to reduce the content of C14Laves phase in the high-entropy doped hydrogen storage alloy and improve the uniformity of the alloy's microstructure, reduce the slope of the dehydrogenation plateau, and thus improve the effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy.

[0112] In some specific embodiments, the heat treatment steps include: heating the high-entropy doped hydrogen storage alloy to above 1400°C in a heat treatment furnace at a heating rate of 10-15°C / min, holding it at that temperature for more than 1 hour in an inert atmosphere, and then quenching it in cold water; after homogenization by holding it at high temperature during heat treatment, the quenching and rapid cooling retain the uniform structure at high temperature, which can improve the uniformity of composition and structure, reduce the slope of the hydrogen absorption and desorption plateau, and thus improve the effective hydrogen storage capacity of the Ti-Cr-V hydrogen storage alloy.

[0113] For example, the heat preservation time can be 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, etc.

[0114] In some specific embodiments, the inert atmosphere used in the heat treatment includes helium, neon, or argon.

[0115] In some specific embodiments, high-entropy doped hydrogen storage alloy TiCr 1.0 V 0.7 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2Through heat treatment, the effective dehydrogenation capacity was further increased to 1.86 wt%. In addition, the alloy can obtain an even higher effective hydrogen storage capacity of 2.21 wt% by absorbing hydrogen at a low temperature of 25°C and releasing hydrogen at a high temperature of 70°C.

[0116] In some other specific embodiments, a method for preparing a high-entropy doped hydrogen storage alloy is provided, comprising the following steps:

[0117] S14. Obtain the composition of each metal raw material in the high-entropy doped hydrogen storage alloy;

[0118] S24. Under inert gas conditions, high-entropy doped hydrogen storage alloy is obtained by electric arc melting after mixing various metal raw materials.

[0119] S34. The high-entropy doped hydrogen storage alloy obtained by melting is subjected to heat treatment to reduce the content of C14Laves phase in the high-entropy doped hydrogen storage alloy and improve the uniformity of the alloy, reduce the slope of the dehydrogenation plateau, and thus improve the effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy.

[0120] To ensure that the above-described implementation details and operations of this application are clearly understood by those skilled in the art, and to illustrate the high-entropy doped hydrogen storage alloy and its preparation method in the embodiments of this application, the above technical solutions are explained below through multiple embodiments and comparative examples. Furthermore, the dehydrogenation PCT curves at 70°C are selected for comparison in the embodiments and comparative examples because the heat recovery temperature of fuel cell vehicles can be above 70°C. This is not a limiting temperature for high-entropy doped hydrogen storage alloys.

[0121] Example 1

[0122] A TiCr 1.0 V 0.7 (HEA1) 0.2 High-entropy doped hydrogen storage alloy (HEA1 is Nb) 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 The preparation method includes the following steps:

[0123] ① Take Nb, Fe, Co, Ni, and Mn according to the set content; among them, use an excess of manganese that is 5wt% higher than the set content for smelting to compensate for the evaporation loss during the smelting process caused by the low boiling point of manganese.

[0124] ② Nb, Fe, Co, Ni and Mn are loaded into a crucible. Under an argon protective gas of 0.06 MPa, the titanium ingot in one of the crucibles is melted first to further remove oxygen. Then the alloy is melted by electric arc. The resulting high-entropy alloy ingot is flipped and remelted at least four times to obtain a HEA1 high-entropy alloy ingot.

[0125] ③ Grind the HEA1 ingot to remove the oxide layer.

[0126] ④ Weigh HEA1, Ti, Cr, and V according to the set content, and perform arc melting under an argon protective gas of 0.06 MPa: further deoxygenate the titanium ingot in the melting crucible; then perform arc melting on the crucible containing HEA1, Ti, Cr, and V, and flip and remelt the obtained high-entropy doped alloy ingot four times to finally obtain TiCr 1.0 V 0.7 (HEA1) 0.2 High-entropy doped hydrogen storage alloy.

[0127] ⑤ TiCr 1.0 V 0.7 (HEA1) 0.2 The oxide layer on the surface of the high-entropy doped hydrogen storage alloy is polished off, and then (it can be pulverized in air) to obtain TiCr. 1.0 V 0.7 (HEA1) 0.2 High entropy doped hydrogen storage alloy powder (HEA1 is Nb) 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ).

[0128] Example 2

[0129] A TiCr 1.0 V 0.7 (HEA1) 0.2 The preparation method of a high-entropy doped hydrogen storage alloy includes the following steps:

[0130] ① Take Nb, Fe, Co, Ni, Mn, Ti, Cr and V according to the set content. Among them, use an excess of manganese that is 5wt% higher than the set content to smelt in order to compensate for the evaporation loss during the smelting process caused by the low boiling point of manganese.

[0131] ② Arc melting was carried out under an argon protective gas pressure of 0.06 MPa. First, the titanium ingot in one of the crucibles was melted to further remove oxygen. Then, Nb, Fe, Co, Ni, Mn, Ti, Cr and V were arc melted. The resulting ingot was flipped and remelted four times to finally obtain TiCr. 1.0 V 0.7 (HEA1) 0.2 High-entropy doped hydrogen storage alloy.

[0132] ③ TiCr 1.0 V 0.7 (HEA1) 0.2 The oxide layer on the surface of the high-entropy doped hydrogen storage alloy was polished off, and then pulverized in air to obtain TiCr. 1.0 V0.7 (HEA1) 0.2 High-entropy doped hydrogen storage alloy powder.

[0133] Example 3

[0134] A TiCr 1.1 V 0.6 (HEA1) 0.1 High-entropy doped hydrogen storage alloy (HEA1 is Nb) 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 The preparation method is basically the same as in Example 1, except that TiCr is prepared. 1.0 V 0.6 (HEA1) 0.2 A high-entropy doped hydrogen storage alloy, wherein the content of HEA1 is 0.1, the content of Cr is 1.1, and the content of V is 0.6.

[0135] Example 4

[0136] A TiCr 1.0 V 0.6 (HEA1) 0.2 The preparation method of the high-entropy doped hydrogen storage alloy is basically the same as that in Example 1, the only difference being that TiCr is used for preparation. 1.0 V 0.6 (HEA1) 0.2 A high-entropy doped hydrogen storage alloy, wherein the V content is 0.6%.

[0137] Example 5

[0138] A TiCr 1.0 V 0.5 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy is prepared using a method basically the same as in Example 1, except that: TiCr 1.0 V 0.5 (HEA1) 0.2 The V content in the high-entropy doped hydrogen storage alloy is 0.5%.

[0139] Example 6

[0140] A TiCr 1.0 V 0.8 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy is prepared using a method basically the same as in Example 1, except that: TiCr 1.0 V 0.8 (HEA1) 0.2 The V content in the high-entropy doped hydrogen storage alloy is 0.8%.

[0141] Example 7

[0142] A TiCr 1.1 V 0.6 (HEA2) 0.1 High entropy doped hydrogen storage alloy (HEA2 is Al) 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 The preparation method is basically the same as in Example 1, except that TiCr is prepared. 1.1 V 0.6 (HEA2) 0.1 High-entropy doped hydrogen storage alloy.

[0143] Example 8

[0144] A TiCr 1.0 V 0.6 (HEA2) 0.2 High entropy doped hydrogen storage alloy (HEA2 is Al) 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 The preparation method is basically the same as in Example 1, except that TiCr is prepared. 1.0 V 0.6 (HEA2) 0.2 High-entropy doped hydrogen storage alloy.

[0145] Example 9

[0146] A TiCr 1.0 V 0.7 (HEA3) 0.2 High entropy doped hydrogen storage alloy (HEA3 is Fe) 0.25 Co 0.25 Ni 0.25 Mn 0.25 The preparation method is basically the same as in Example 1, except that TiCr is prepared. 1.0 V 0.7 (HEA3) 0.2 High-entropy doped hydrogen storage alloy.

[0147] Example 10

[0148] The TiCr obtained in step ④ of the preparation method in Example 1 1.0 V 0.7 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy was heat-treated by heating at a rate of 10℃ / min, holding at 1400℃ for 2 hours in an argon atmosphere, and then quenching in cold water.

[0149] Comparative Example 1

[0150] According to TiCr 1.0 V 0.7 Nb 0.2 Composition design, calculation and weighing of Ti, Cr, V and Nb into a crucible, and obtaining TiCr by electric arc melting. 1.0 V 0.7 Nb 0.2 Hydrogen storage alloy.

[0151] Comparative Example 2

[0152] According to TiCr 1.0 V 0.7 Fe 0.2 Composition design, calculation and weighing of Ti, Cr, V and Fe into a crucible, and obtaining TiCr by electric arc melting. 1.0 V 0.7 Fe 0.2 Hydrogen storage alloy.

[0153] Comparative Example 3

[0154] According to TiCr 1.0 V 0.7 Co 0.2 Composition design, calculation and weighing of Ti, Cr, V and Co into a crucible, and obtaining TiCr by electric arc melting. 1.0 V 0.7 Co 0.2 Hydrogen storage alloy.

[0155] Comparative Example 4

[0156] According to TiCr 1.0 V 0.7 Ni 0.2 Composition design, calculation and weighing of Ti, Cr, V and Ni into a crucible, and obtaining TiCr by electric arc melting. 1.0 V 0.7 Ni 0.2 Hydrogen storage alloy.

[0157] Comparative Example 5

[0158] According to TiCr 1.0 V 0.7 Mn 0.2 Composition design, calculation and weighing of Ti, Cr, V and Mn into a crucible, and obtaining TiCr by electric arc melting. 1.0 V 0.7 Mn 0.2 Hydrogen storage alloy.

[0159] Comparative Example 6

[0160] According to TiCr 1.2V 0.6 Composition design, calculation, weighing of Ti, Cr, and V into a crucible, and obtaining TiCr through electric arc melting. 1.2 V 0.6 Hydrogen storage alloy.

[0161] To verify the progressiveness of the embodiments of this application, the samples prepared in Examples 1-10 and Comparative Examples 1-6 were subjected to the following performance tests, including:

[0162] A. The hydrogen absorption and desorption performance of the high-entropy doped hydrogen storage alloy was tested using Sievert's volumetric method with 100-200 mesh particles; 300 mesh particles were used for X-ray diffraction (XRD) analysis; among them, the high-entropy doped hydrogen storage alloy of Example 10 was also subjected to heat treatment. In addition to XRD and hydrogen absorption performance analysis, it was also subjected to backscattered electron microscopy analysis after mounting, grinding and polishing.

[0163] B. Approximately 2.5 g of sample was loaded into the reactor for performance testing. In the activation (initial hydrogen absorption kinetics) test, the temperature and initial hydrogen pressure were 25 °C and 3 MPa, respectively. After the initial activation test, hydrogen was released under vacuum at 25 °C until no more hydrogen was released. Then, the sample was re-hydrogenated at 25 °C and 5-6 MPa H₂ until equilibrium was reached. Afterward, the sample was evacuated under vacuum at 400 °C for at least 1.5 h; finally, a PCT test was performed to obtain the PCT curve.

[0164] The obtained phase and effective dehydrogenation capacity results are as follows: Figures 1a to 14 And as shown in Table 1 below:

[0165] Table 1. Crystal phases and effective dehydrogenation capacities of samples from Examples 1-10 and Comparative Examples 1-6

[0166]

[0167]

[0168] Depend on Figures 1a to 14 As shown in Table 1 above:

[0169] For Examples 1-10, the test results for incubation period, activation performance, and effective dehydrogenation capacity of the samples were good, indicating that high-entropy doping of Ti-Cr-V based hydrogen storage alloys can change multiple factors such as the crystal structure, electronic structure, and bulk modulus of high-entropy doped hydrogen storage alloys, thereby improving the thermodynamic properties of hydrogen absorption and desorption reactions, and increasing the hydrogen absorption and desorption plateau and effective dehydrogenation capacity. Specific test results are as follows:

[0170] In Example 1, by appendix Figure 5 From 3), we can see that TiCr 1.0 V 0.7 (HEA1)0.2 The hydrogen storage alloy exhibits a two-phase structure with BCC and C14Laves phases comprising 86.0% and 14.0%, respectively. TiCr 1.0 V 0.7 (HEA1) 0.2 High-entropy doped hydrogen storage alloy (with) Figure 1a Compared with Comparative Examples 1-5, TiCr 1.0 V 0.7 (HEA1) 0.2 The alloy exhibits the fastest hydrogen absorption rate and the best activation performance. TiCr at 70℃ 1.0 V 0.7 (HEA1) 0.2 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.73 wt% (see attached figure). Figure 1b The concentration of TiCr in Comparative Examples 1-5 was significantly higher than that in TiCr. 1.0 V 0.7 Nb 0.2 Alloy (0.10wt%), TiCr 1.0 V 0.7 Fe 0.2 Alloy (0.51 wt%), TiCr 1.0 V 0.7 Ni 0.2 Alloy (1.42 wt%) and TiCr 1.0 V 0.7 Mn 0.2 Alloy (1.02 wt%).

[0171] In Example 2, TiCr 1.0 V 0.7 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy has a longer incubation period than the high-entropy doped hydrogen storage alloy in Example 1 (see appendix). Figure 2a However, the effective dehydrogenation capacity at 70℃ is not significantly different (see appendix). Figure 2b ).

[0172] In Example 3, TiCr 1.1 V 0.6 (HEA1) 0.1 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 3 As shown in Figure 2), the initial hydrogen absorption kinetic curve is attached. Figure 4a As shown in the attached figure, the PCT curve is... Figure 4b As shown. (From the appendix) Figure 3 From 2), we can see that TiCr 1.1 V 0.6 (HEA1) 0.1 The high-entropy doped hydrogen storage alloy exhibits a two-phase structure consisting of BCC and C14Laves phases, accounting for 84.9% and 15.1%, respectively. (See attached...) Figure 4a It can be seen that, compared with Comparative Example 6, TiCr 1.1 V 0.6 (HEA1) 0.1 High-entropy doped hydrogen storage alloys exhibit faster hydrogen absorption rates and better activation performance. (From the attached...) Figure 4b As shown in Table 1, at 70℃, TiCr 1.1 V 0.6 (HEA1) 0.1 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.37 wt%, which is higher than that of TiCr. 1.2 V 0.6 1.21 wt% of the alloy (Comparative Example 6).

[0173] In Example 4, TiCr 1.0 V 0.6 (HEA1) 0.2 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 3 As shown in Figure 2), the initial hydrogen absorption kinetic curve is attached. Figure 4a As shown in the attached figure, the PCT curve is... Figure 4b As shown. (From the appendix) Figure 3 From 3), we can see that TiCr 1.0 V 0.6 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy exhibits a two-phase structure consisting of a BCC phase and a C14Laves phase, accounting for 75.4% and 24.6%, respectively. (See attached...) Figure 4a It can be seen that, compared with Comparative Example 6, TiCr 1.0 V 0.6 (HEA1) 0.2 High-entropy doped hydrogen storage alloys exhibit faster hydrogen absorption rates and superior activation performance. (From the attached...) Figure 4b It can be seen that at 70℃, TiCr 1.0 V 0.6 (HEA1) 0.2 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.54 wt%, which is higher than that of TiCr. 1.2 V 0.6 1.21 wt% of the alloy (Comparative Example 6).

[0174] In Example 5, TiCr 1.0 V 0.5 (HEA1) 0.2 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 5 As shown in Figure 1), the initial hydrogen absorption kinetic curve is attached. Figure 6a As shown in the attached figure, the PCT curve is... Figure 6b As shown. (From the appendix) Figure 5 From 1), we know that TiCr 1.0 V0.5 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy exhibits a two-phase structure consisting of a BCC phase and a C14Laves phase, accounting for 61.6% and 38.4% respectively. (See attached...) Figure 6a It can be seen that, compared with Comparative Example 6, TiCr 1.0 V 0.5 (HEA1) 0.2 High-entropy doped hydrogen storage alloys exhibit faster hydrogen absorption rates and superior activation performance. (From the attached...) Figure 6b It can be seen that at 70℃, TiCr 1.0 V 0.5 (HEA1) 0.2 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.22 wt%.

[0175] In Example 6, TiCr 1.0 V 0.8 (HEA1) 0.2 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 5 As shown in section 4), the initial hydrogen absorption kinetic curve is attached. Figure 6a As shown in the attached figure, the PCT curve is... Figure 6b As shown. (From the appendix) Figure 5 From 4), we can see that TiCr 1.0 V 0.8 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy is a single-phase BCC alloy. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 6a It can be seen that, compared with Comparative Example 6 below, TiCr 1.0 V 0.8 (HEA1) 0.1 High-entropy doped hydrogen storage alloys exhibit faster hydrogen absorption rates and superior activation performance. (From the attached...) Figure 6b It can be seen that at 70℃, TiCr 1.0 V 0.8 (HEA1) 0.1 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.48 wt%, which is higher than that of TiCr. 1.2 V 0.6 1.21 wt% of the alloy (Comparative Example 6).

[0176] This shows that, although TiCr 1.0 V 0.8 (HEA1) 0.1 High-entropy doped hydrogen storage alloys contain only a single BCC phase, but due to the high-entropy doping of multiple metal elements, the synergistic effect of each metal element results in higher activation performance and effective dehydrogenation capacity than undoped TiCr. 1.2 V 0.6 alloy.

[0177] In Example 7, TiCr 1.1 V 0.6 (HEA2) 0.1 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 7 As shown in Figure 3), the initial hydrogen absorption kinetic curve is attached. Figure 8a As shown in the attached figure, the PCT curve is... Figure 8b As shown. (From the appendix) Figure 7 From 3), we can see that TiCr 1.1 V 0.6 (HEA2) 0.1 The high-entropy doped hydrogen storage alloy is a single-phase BCC alloy. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 8a It can be seen that, compared with Comparative Example 6 below, TiCr 1.1 V 0.6 (HEA2) 0.1 High-entropy doped hydrogen storage alloys exhibit low hydrogen absorption rates and activation performance. (The last sentence appears to be incomplete and possibly refers to a separate topic.) Figure 8b It can be seen that at 70℃, TiCr 1.1 V 0.6 (HEA2) 0.1 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.39 wt%, which is higher than that of TiCr. 1.2 V 0.6 The alloy (Comparative Example 6) was 1.21 wt%. This shows that TiCr... 1.1 V 0.6 (HEA2) 0.1 Although the high-entropy doped hydrogen storage alloy has a lower hydrogen absorption rate and activation performance than the TiCr alloy in Comparative Example 6, 1.2 V 0.6 Although it is an alloy, its effective dehydrogenation capacity at 70℃ is still high.

[0178] In Example 8, TiCr 1.0 V 0.6 (HEA2) 0.2 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 7 As shown in Figure 2), the initial hydrogen absorption kinetic curve is attached. Figure 8a As shown in the attached figure, the PCT curve is... Figure 8b As shown. (From the appendix) Figure 7 From 2), we can see that TiCr 1.0 V 0.6 (HEA2) 0.2 The high-entropy doped hydrogen storage alloy is a single-phase BCC alloy. (The last sentence appears to be incomplete and possibly refers to a different topic.) Figure 8a It can be seen that, compared with Comparative Example 6 below, TiCr 1.0 V 0.6 (HEA2) 0.2 The hydrogen absorption rate and activation performance of the high-entropy doped hydrogen storage alloy are not high, but they are better than those of the TiCr alloy in Example 7. 1.1 V 0.6(HEA2) 0.1 High, indicating that increasing the HEA doping content can improve the hydrogen absorption rate and activation performance of high-entropy doped hydrogen storage alloys. (From the attached...) Figure 8b It can be seen that at 70℃, TiCr 1.0 V 0.6 (HEA2) 0.2 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.37 wt%, which is higher than that of TiCr. 1.2 V 0.6 The alloy (Comparative Example 6) was 1.21 wt%. This shows that TiCr... 1.0 V 0.6 (HEA2) 0.2 Although the high-entropy doped hydrogen storage alloy has a lower hydrogen absorption rate and activation performance than the TiCr alloy in Comparative Example 6, 1.2 V 0.6 It is an alloy, but it has a high effective dehydrogenation capacity at 70°C, and its hydrogen absorption rate and activation performance can be improved by increasing the doping content of HEA.

[0179] In Example 9, TiCr 1.0 V 0.7 (HEA3) 0.2 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 9 As shown in Figure 2), the initial hydrogen absorption kinetic curve is attached. Figure 10a As shown in the attached figure, the PCT curve is... Figure 10b As shown. (From the appendix) Figure 9 From 2), we can see that TiCr 1.0 V 0.7 (HEA3) 0.2 The high-entropy doped hydrogen storage alloy exhibits a two-phase structure consisting of a BCC phase and a C14Laves phase, with the BCC phase being the dominant phase. (The remaining text appears to be unrelated and possibly machine-generated.) Figure 10a It can be seen that, compared with Example 1, TiCr 1.0 V 0.7 (HEA3) 0.2 The hydrogen absorption rate and activation performance of high-entropy doped hydrogen storage alloys are not high. Therefore, it is evident that the high-entropy doped hydrogen storage alloy with Nb (Example 1) and the undoped TiCr alloy are... 1.0 V 0.7 (HEA3) 0.2 Compared to the high-entropy doped hydrogen storage alloy (in this embodiment), the Nb-doped high-entropy doped hydrogen storage alloy exhibits better activation performance. (See attached...) Figure 10b It can be seen that at 70℃, TiCr 1.0 V 0.7 (HEA3) 0.2 The effective dehydrogenation capacity of the high-entropy doped hydrogen storage alloy is 1.74 wt%, which is comparable to that of TiCr. 1.0 V 0.7 (HEA1)0.2 The 1.73 wt% of the high-entropy doped hydrogen storage alloy (Example 1) is close to, and much higher than, that of TiCr. 1.2 V 0.6 1.21 wt% of alloy (Comparative Example 6) and TiCr 1.0 V 0.6 (HEA2) 0.2 The 1.37 wt% concentration of the high-entropy doped hydrogen storage alloy (Example 8) further illustrates that the co-doping of Nb and other metallic elements synergistically improves hydrogen storage performance. This demonstrates that TiCr... 1.0 V 0.7 (HEA3) 0.2 Although the high-entropy doped hydrogen storage alloy has a low hydrogen absorption rate and activation performance, it has a high effective dehydrogenation capacity at 70°C, which is close to that of Example 1.

[0180] In Example 10, the heat-treated TiCr 1.0 V 0.7 (HEA1) 0.2 The XRD pattern of the high-entropy doped hydrogen storage alloy is attached. Figure 11 As shown in 2), the backscattered electron micrograph is as follows: Figure 12 As shown in the attached figure, the hydrogen absorption kinetics curve is... Figure 13a As shown in the attached figure, the PCT curve is... Figure 13b As shown.

[0181] Appendix Figure 11 2) shows that TiCr 1.0 V 0.7 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy contains only the BCC phase; the C14Laves phase cannot be detected, but according to the attached... Figure 12 It can be seen that a very small amount of C14Laves phase (light-colored part) still exists.

[0182] From the appendix Figure 13a It can be seen that the heat-treated TiCr 1.0 V 0.7 (HEA1) 0.2 The effective dehydrogenation capacity of the alloy at 70°C was further increased to 1.86 wt%.

[0183] From the appendix Figure 13b It can be seen that the heat-treated TiCr 1.0 V 0.7 (HEA1) 0.2 The high-entropy doped hydrogen storage alloy absorbs hydrogen at 25°C and dehydrogenates it to 1 atmosphere at 70°C, removing 2.21 wt% of hydrogen. This demonstrates that by employing a low-temperature hydrogen absorption method at 25°C and a high-temperature hydrogen release method at 70°C, the high-entropy doped hydrogen storage alloy can achieve a higher effective hydrogen storage capacity.

[0184] For Comparative Examples 1–6, the detection results for the incubation period, activation performance, and effective dehydrogenation capacity of the samples were unsatisfactory. The specific detection results are as follows:

[0185] In Comparative Example 1, the TiCr sample... 1.0 V 0.7 Nb 0.2 The analysis results are attached. Figure 1a and attached Figure 1b As shown. (From the appendix) Figure 1a It can be seen that TiCr 1.0 V 0.7 Nb 0.2 The alloy exhibits the longest hydrogen absorption incubation period and the worst activation performance. (From the attached...) Figure 1b It can be seen that at 70℃, TiCr 1.0 V 0.7 Nb 0.2 The dehydrogenation platform is the lowest, and the effective dehydrogenation amount is the smallest, at 0.10 wt%.

[0186] In Comparative Example 2, the TiCr sample... 1.0 V 0.7 Fe 0.2 The analysis results are attached. Figure 1a and attached Figure 1b As shown. (From the appendix) Figure 1a It can be seen that TiCr 1.0 V 0.7 Fe 0.2 Hydrogen storage alloys exhibit a short hydrogen absorption incubation period and good activation performance. (From the attached...) Figure 1b It can be seen that at 70℃, TiCr 1.0 V 0.7 Fe 0.2 The effective dehydrogenation capacity of the hydrogen storage alloy is only 0.51 wt%.

[0187] In Comparative Example 3, the TiCr sample... 1.0 V 0.7 Co 0.2 The analysis results are attached. Figure 1a and attached Figure 1b As shown. (From the appendix) Figure 1a It can be seen that TiCr 1.0 V 0.7 Co 0.2 Hydrogen storage alloys exhibit slow hydrogen absorption rates, poor hydrogen absorption kinetics, and poor activation performance. (From the attached...) Figure 1b It can be seen that at 70℃, although the effective dehydrogenation amount is 1.83wt%, TiCr 1.0 V 0.7 Co 0.2 The hydrogen storage alloy has an excessively high dehydrogenation platform.

[0188] In Comparative Example 4, the TiCr sample... 1.0 V0.7 Ni 0.2 The analysis results of Figure 1a and Figure 1b are shown as follows. From Figure 1a it can be seen that TiCr 1.0 V 0.7 Ni 0.2 hydrogen storage alloy has a relatively long hydrogen absorption incubation period and poor activation performance. From Figure 1b it can be seen that at 70 °C, TiCr 1.0 V 0.7 Ni 0.2 hydrogen storage alloy has an effective dehydrogenation amount of 1.42 wt%.

[0189] In Comparative Example 5, the analysis results of the sample TiCr 1.0 V 0.7 Mn 0.2 are shown as follows in Figure 1a and Figure 1b From Figure 1a it can be seen that TiCr 1.0 V 0.7 Mn 0.2 hydrogen storage alloy has a short hydrogen absorption incubation period and good activation performance. From Figure 1b it can be seen that at 70 °C, TiCr 1.0 V 0.7 Mn 0.2 hydrogen storage alloy has a very low dehydrogenation plateau and a small effective dehydrogenation amount, which is 1.02 wt%.

[0190] In Comparative Example 6, the analysis results of the sample TiCr 1.2 V 0.6 are shown as follows in 1) of Figure 3 , Figure 4a and Figure 4b From 1) of Figure 3 it can be seen that TiCr 1.2 V 0.6 hydrogen storage alloy has a pure BCC phase structure. From Figure 4a it can be seen that TiCr 1.2 V 0.6 hydrogen storage alloy has a relatively long hydrogen absorption incubation period and poor activation performance. From Figure 4b it can be seen that at 70 °C, TiCr 1.2 V 0.6 hydrogen storage alloy has an effective dehydrogenation amount of 1.21 wt%.

[0191] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high-entropy doped hydrogen storage alloy, characterized in that, The general chemical formula of the high-entropy doped hydrogen storage alloy is: TiCr (1.2-x) In y (HEA) x ; Wherein, 0 < x ≤ 0.2, 0.5 ≤ y ≤ 0.8, and HEA is a high-entropy alloy; the metal elements in the high-entropy alloy are four or more of Al, Nb, Mo, Mn, Fe, Co, and Ni; the molar ratio of each metal element in the high-entropy alloy used for doping is 1; and the sum of the molar numbers of each metal element in the high-entropy alloy is 1.

2. The high-entropy doped hydrogen storage alloy as described in claim 1, characterized in that, The high-entropy alloy comprises: No 0.2 Feb 0.2 Co 0.2 Ni 0.2 Mr 0.2 ; And / or, Al 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 ; And / or, Fe 0.25 Co 0.25 Ni 0.25 Mn 0.25 .

3. The high-entropy doped hydrogen storage alloy as described in claim 2, characterized in that, The high-entropy doped hydrogen storage alloy includes: TiCr 1.0 V 0.7 (HEA) 0.2 TiCr 1.1 V 0.6 (HEA) 0.1 TiCr 1.0 V 0.6 (HEA) 0.2 TiCr 1.0 V 0.5 (HEA) 0.2 and TiCr 1.0 V 0.8 (HEA) 0.2 .

4. The high-entropy doped hydrogen storage alloy as described in claim 3, characterized in that, The high-entropy doped hydrogen storage alloy is TiCr 1.0 V 0.7 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.1 V 0.6 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.1 TiCr 1.0 V 0.6 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.0 V 0.5 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.0 V 0.8 (Nb 0.2 Fe 0.2 Co 0.2 Ni 0.2 Mn 0.2 ) 0.2 TiCr 1.1 V 0.6 (Al 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 ) 0.1 TiCr 1.0 V 0.6 (Al 0.2 Nb 0.2 Fe 0.2 Co 0.2 Mn 0.2 ) 0.2 or TiCr 1.0 V 0.7 (Fe 0.25 Co 0.25 Ni 0.25 Mn 0.25 ) 0.2 .

5. A method for preparing a high-entropy doped hydrogen storage alloy as described in any one of claims 1 to 4, characterized in that, Includes the following steps: After obtaining the various metal raw material components of the high-entropy doped hydrogen storage alloy, a melting process was carried out under an inert atmosphere to obtain the alloy with the general chemical formula TiCr. (1.2-x) V y (HEA) x The high-entropy doped hydrogen storage alloy, wherein 0 < x ≤ 0.2, 0.5 ≤ y ≤ 0.8, and HEA is a high-entropy alloy.

6. The method for preparing the high-entropy doped hydrogen storage alloy as described in claim 5, characterized in that, The smelting process includes the following steps: The high-entropy alloy is prepared by smelting metal raw materials other than Ti, Cr, and V, and then the high-entropy alloy is mixed and smelted with Ti, Cr, and V. or, All the metal raw materials are mixed and smelted.

7. The method for preparing the high-entropy doped hydrogen storage alloy as described in claim 6, characterized in that, The preparation method further includes heat-treating the high-entropy doped hydrogen storage alloy.

8. The method for preparing the high-entropy doped hydrogen storage alloy as described in claim 7, characterized in that, The heat treatment steps include: heating the high-entropy doped hydrogen storage alloy to above 1400°C, holding it at that temperature for more than 1 hour in an inert atmosphere, and then quenching it in cold water.

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