Design method and system of magnesium-based hydrogen storage high-entropy alloy

Abstract

This invention belongs to the field of high-entropy alloy hydrogen storage technology in solid-state hydrogen storage. It discloses a method and system for designing magnesium-based high-entropy hydrogen storage alloys. First, a literature review identified high-entropy alloys with excellent hydrogen storage performance as the substrate material for the design. Then, first-principles calculations were used to screen stable geometric structure models of the high-entropy alloy and its hydride. Based on this, the interaction between metal atoms and hydrogen atoms in the high-entropy alloy was analyzed to determine the metal atoms that can be replaced by magnesium atoms. Next, first-principles calculations were used to achieve the substitution of the corresponding metal atoms with magnesium atoms, thereby designing the magnesium-based high-entropy alloy and its hydride. Finally, the lattice dynamic stability of the designed magnesium-based high-entropy alloy hydride structure was evaluated to verify the rationality of the design.

Description

Technical Field

[0001] This invention belongs to the field of high-entropy alloy hydrogen storage technology in solid-state hydrogen storage, and particularly relates to a new method for designing magnesium-based high-entropy hydrogen storage alloys. Background Technology

[0002] In recent years, high-entropy alloys have attracted much attention due to their excellent hydrogen storage performance. High-entropy alloys are a special type of multi-component alloy. Unlike traditional alloys, high-entropy alloys are typically single-phase solid solutions composed of main elements in equimolar ratios or with atomic concentrations ranging from 5 to 35 at.%. This unique chemical composition and structure endow high-entropy alloys with excellent hydrogen storage performance, including high hydrogen storage capacity, good hydrogen adsorption / desorption kinetics, and stable cycle life. Magnesium-based high-entropy alloys, as a special type of high-entropy alloy, have unique advantages in hydrogen storage. Adding magnesium can reduce the total molar mass ratio of the alloy, thereby achieving a higher mass hydrogen storage capacity. Furthermore, magnesium has extremely strong hydrogen adsorption capacity and a large atomic volume, providing more adsorption sites and further increasing the hydrogen storage capacity. Therefore, magnesium-based high-entropy alloys have great potential in the field of hydrogen storage. However, current research is limited, mainly because the selection space for the constituent elements of high-entropy alloys is very wide, and the influence of each metal element on the alloy performance varies, requiring control of the content of each element. This makes it difficult to screen for high-entropy alloys with high hydrogen storage performance.

[0003] Currently, researchers have employed various methods to identify the compositional regions where high-entropy alloys form single-phase alloys. For example, phase diagram calculations and semi-empirical parameter methods are the most commonly used methods for designing high-entropy alloys. Furthermore, determining the stoichiometry of high-entropy alloys based on the stoichiometry of existing AB2, A2B, and AB5 hydrogen storage alloys is also an effective method. However, experimentally, most high-entropy alloys designed using these methods exhibit low hydrogen storage capacities. Therefore, designing magnesium-based high-entropy alloys with high hydrogen storage capacity through first-principles calculations is particularly important. This method is efficient, simple, and easy to implement, and can provide a theoretical reference for related research.

[0004] Based on the above analysis, the existing technologies have the following problems and shortcomings: Hydrogen storage is a crucial link in hydrogen energy utilization, but traditional hydrogen storage methods suffer from low energy density and poor safety, making large-scale application difficult. Magnesium-based high-entropy alloys, due to their unique chemical composition and structure, possess the potential to become excellent hydrogen storage materials. However, current methods for designing magnesium-based high-entropy hydrogen storage alloys are not efficient. Therefore, the urgent task is to invent a method for designing magnesium-based high-entropy alloys with high hydrogen storage capacity. Summary of the Invention

[0005] This invention, combining first-principles calculations, provides a method for designing magnesium-based high-entropy alloys with high hydrogen storage capacity, addressing the problems existing in the prior art. By using this method, not only can experimental costs be effectively reduced, but the hydrogen storage capacity of high-entropy alloys can also be significantly increased.

[0006] This invention is achieved by selecting the optimal hydride model based on different hydrogen atom arrangements in high-entropy alloys and analyzing its lattice dynamics stability and hydrogen storage capacity, ultimately realizing the theoretical design of Mg-based high-entropy alloy hydrogen storage materials.

[0007] Furthermore, the method specifically includes:

[0008] Step 1: Select a high-entropy alloy with good hydrogen storage performance and construct a structural model of its different metal atom arrangements;

[0009] Step 2: Optimize the various high-entropy alloy geometric models obtained in Step 1, and select the configuration with the lowest energy as the final configuration.

[0010] Step 3: Add hydrogen atoms with a hydrogen metal atom ratio of 2 (H / M = 2) to the high-entropy alloy structure model with the lowest energy obtained in Step 2 to construct a high-entropy alloy hydride structure model;

[0011] Step four: Optimize the structure of the various high-entropy alloy hydride configurations obtained in step three, and select the configuration with the lowest energy as the final configuration;

[0012] Step 5: Perform lattice dynamics stability analysis on the hydride configuration with the lowest energy obtained in Step 4;

[0013] Step six: Analyze the interaction between the metal element and the hydrogen element in the hydride obtained in step five;

[0014] Step 7: Construct structural models of magnesium-based high-entropy alloys and their hydrides, and optimize the structures to obtain the configuration with the lowest energy.

[0015] Step 8: Perform lattice dynamics stability analysis on the magnesium-based high-entropy alloy hydride configuration obtained in Step 7.

[0016] Furthermore, the selection of high-entropy alloys with good hydrogen storage performance in step one, and the construction of geometrical models of their different metal atom arrangements, includes:

[0017] (1) Construct a BCC Ti unit cell structure model using modeling software;

[0018] (2) Expand the single-cell structure model in (1) to 5×2×3 using modeling software, and then replace the Ti atoms according to the atomic ratio Ti:V:Nb:Cr=4:3:1:2 to generate a POSCAR file.

[0019] (3) Design a program using Python to randomly arrange the coordinates of metal atoms in the POSCAR file in (2), and make the program run multiple times to generate 20 different BCC Ti24V18Nb6Cr12 high-entropy alloy configurations with different metal atom arrangements.

[0020] Furthermore, step two involves structural optimization of the various high-entropy alloy geometric models obtained in step one, selecting the configuration with the lowest energy as the final configuration, including:

[0021] Using VASP software, a series of single-point energy tests were performed on the lowest energy configuration of the BCC Ti24V18Nb6Cr12 high-entropy alloy in step one to obtain suitable calculation parameters K-point and cutoff energy ENCUT. Finally, K-point was determined to be 3×3×3 and ENCUT to be 450eV. In VASP software, the calculation parameters IBRION were set to 2 and PREC to Medium. Structural optimization was performed on all BCCTi24V18Nb6Cr12 configurations to obtain the ground state total energy of each configuration. The lowest energy configuration was selected as the structure of BCC Ti24V18Nb6Cr12.

[0022] Furthermore, in step three, hydrogen atoms with a hydrogen metal atom ratio of 2 (H / M = 2) are added to the high-entropy alloy structure model with the lowest energy obtained in step two to construct the geometric structure model of the high-entropy alloy hydride, including:

[0023] (1) Construct an FCC Ti single-cell structure model (containing 4 Ti atoms) using modeling software, expand the model to 5×1×3, and then replace the Ti atoms according to the atomic ratio Ti:V:Nb:Cr=4:3:1:2 to generate a POSCAR file.

[0024] (2) Using VESTA software, write the coordinates of the hydrogen atoms into the POSCAR file of (1);

[0025] (3) The metal atoms in the Ti24V18Nb6Cr12 hydride with H / M=2 were rearranged using a randomization method, resulting in a total of 20 configurations;

[0026] Furthermore, step four involves structural optimization of the various high-entropy alloy hydride configurations obtained in step three, selecting the configuration with the lowest energy as the final configuration. This includes:

[0027] In the VASP software, the calculation parameters IBRION were set to 2 and PREC was set to Medium. The structure of 20 different configurations of Ti24V18Nb6Cr12 was optimized to obtain the total ground state energy of each configuration. The configuration with the lowest energy was selected as the structure of the FCC Ti24V18Nb6Cr12 hydride with H / M=2.

[0028] Furthermore, step five involves performing a lattice dynamics stability analysis on the Ti24V18Nb6Cr12 hydride configuration obtained in step four, including:

[0029] Use the CONTCAR file obtained in step four as the POSCAR file for phonon spectrum calculation. In the INCAR file, set IBRION to -6 (using the finite difference method) to simulate the phonon spectrum of the material and evaluate the lattice dynamic stability of Ti24V18Nb6Cr12 hydride with H / M=2;

[0030] Furthermore, the interaction between the metal element and the hydrogen element in the Ti24V18Nb6Cr12 hydride obtained in step five of step six includes:

[0031] (1) Perform static self-consistent calculations for the lowest energy configuration, setting NSW=0 and ISYM=-1;

[0032] (2) Set the parameter “cohpGenerator from X1 to X2 type Mtype H” in the lobsterin file, where X1 and X2 refer to the metal-hydrogen atom distance range, M represents the metal atom, and H represents the hydrogen atom;

[0033] (3) Place the six output files obtained in (1): CONTCAR, IBZKPR, KPOINTS, OUTCAR, POTCAR, WAVECAR, and vasprun.xml and the lobsterin file in (3) in the same directory, and run the lobster program;

[0034] (4) Based on the output files COHPCAR.lobster and ICOHPLIST.lobster, analyze the interaction between the metal and hydrogen atoms. Determine that the metal atom with the weakest interaction with H atoms in the high-entropy alloy Ti24V18Nb6Cr12 is the Ti atom, and replace it with one Mg atom.

[0035] Furthermore, step seven, which involves constructing a structural model of a magnesium-based high-entropy alloy and its hydride, and optimizing the structure to obtain the configuration with the lowest energy, includes:

[0036] (1) Replace the Ti metal atom in Ti24V18Nb6Cr12 with 1 Mg atom. In order to avoid the boundary effect, only the position of Ti metal atom inside the supercell is considered as the substitution site of Mg. There are a total of 16 different Mg atom arrangements in the Mg1Ti23V18Nb6Cr12 magnesium-based high-entropy alloy structure.

[0037] (2) For the 16 different magnesium-based high-entropy alloy configurations obtained in (1), VASP software was used for structural optimization. The most stable structure was selected as the Mg1Ti23V18Nb6Cr12 magnesium-based high-entropy alloy structure.

[0038] (3) Using VESTA software, the coordinates of the hydrogen atoms were written into the POSCAR file in (2). The structure of the Mg1Ti23V18Nb6Cr12 hydride was optimized using VASP software.

[0039] Furthermore, step eight involves performing lattice dynamics stability analysis on the magnesium-based high-entropy alloy hydride configuration obtained in step seven, including:

[0040] Use the CONTCAR file obtained in step seven as the POSCAR file for phonon spectrum calculation. In the INCAR file, set IBRION to -6 (using the finite difference method) to simulate the phonon spectrum of the material and evaluate the lattice dynamic stability of Ti24V18Nb6Cr12 hydride with H / M=2.

[0041] Another object of the present invention is to provide a design system for magnesium-based high-entropy alloys, comprising:

[0042] 1) High-entropy alloy structure model construction module: Select high-entropy alloys with good hydrogen storage performance and construct structural models with different metal atom arrangements;

[0043] 2) High-entropy alloy structure optimization module: Optimizes the structure of various high-entropy alloy geometric models and selects the configuration with the lowest energy as the final configuration;

[0044] 3) High-entropy alloy hydride structure model construction module: Add hydrogen atoms with a hydrogen metal atom ratio of 2 (H / M=2) to the obtained high-entropy alloy structure model with the lowest energy to construct the high-entropy alloy hydride structure model;

[0045] 4) High-entropy alloy hydride structure optimization module: Optimize the structure of various high-entropy alloy hydride configurations obtained, and select the configuration with the lowest energy as the final configuration;

[0046] 5) Hydride lattice dynamics stability analysis module: Performs lattice dynamics stability analysis on the lowest energy hydride configuration obtained;

[0047] 6) Interaction Analysis Module: Analyzes the interactions between metal elements and hydrogen elements in the obtained hydrides;

[0048] 7) Magnesium-based high-entropy alloy structure model building module: Constructs structural models of magnesium-based high-entropy alloys and their hydrides, and performs structural optimization to obtain the configuration with the lowest energy.

[0049] 8) Magnesium-based high-entropy alloy hydride lattice dynamics stability analysis module: Perform lattice dynamics stability analysis on the obtained magnesium-based high-entropy alloy hydride configuration.

[0050] First, considering the above technical solutions and the technical problems they solve, the advantages of this technical solution and its positive effects are as follows:

[0051] (1) This invention proposes a technical solution for designing magnesium-based high-entropy alloys. This technical solution avoids many technical difficulties in preparing magnesium-based high-entropy hydrogen storage alloys, such as the optimization of alloy composition and structure design, the optimization of alloy preparation process, the method and quantification of hydrogen atom doping, and the evaluation of alloy performance and stability.

[0052] (2) This invention does not require specific experimental procedures. The results obtained from first-principles calculations can provide theoretical guidance for related experiments, and the relevant theories used are already very mature, so the reliability of the calculation results is high;

[0053] (3) This invention can successfully construct structural models of high-entropy alloys and their hydrides, which can shorten the experimental cycle, save human resources, and increase the repeatability and reliability of the research process, providing a theoretical basis for research in related fields.

[0054] (4) This invention determines the Mg substitution sites by analyzing the interactions between different metal atoms and hydrogen atoms;

[0055] (5) The present invention can evaluate the hydrogen storage performance and lattice dynamics stability of the designed magnesium-based high-entropy alloy, and the method is simple and easy to implement.

[0056] (6) This invention helps to reduce the use of fossil fuels, thereby effectively promoting sustainable development and ecological environmental protection.

[0057] Second, the significant technological advancements that may be achieved at each step are as follows:

[0058] Step 1: Constructing a BCC Ti unit cell structural model

[0059] Significant technological advancements:

[0060] Advanced modeling software and algorithms may be employed to achieve more accurate and efficient construction of BCC Ti unit cell structure models.

[0061] Optimize lattice constants and atomic positions to reduce errors in simulations and improve the accuracy and reliability of the model.

[0062] Step 2: Perform 5×2×3 cell expansion

[0063] Significant technological advancements:

[0064] Precise implementation of cell expansion operations ensures reasonable expansion of the cell size, maintaining the integrity and stability of the crystal lattice.

[0065] Efficient computational algorithms are employed to improve computational efficiency and shorten computation time.

[0066] Step 3: Replace metal atoms according to atomic ratio

[0067] Significant technological advancements:

[0068] Precise atomic ratio substitutions ensure accurate elemental proportions in the alloy.

[0069] Using advanced programming techniques, high-entropy alloy configurations can be generated quickly, improving computational efficiency and accuracy.

[0070] Step 4: Construct 20 high-entropy alloy configurations with different metal atom arrangements

[0071] Significant technological advancements:

[0072] By programming, the automated generation of various metal atom arrangements can be achieved, avoiding the tediousness and inefficiency of manual construction and saving time and manpower costs.

[0073] Obtaining diverse high-entropy alloy configurations using random arrangement methods helps to explore the structural space of alloys more comprehensively.

[0074] The aforementioned technological advancements primarily focus on the construction and optimization of high-entropy alloy structural models, encompassing advanced computational methods, efficient programming techniques, and automated construction processes. These advancements will provide more accurate, comprehensive, and efficient methods and tools for the theoretical design of high-entropy alloy hydrogen storage materials, contributing to the optimization of alloy structures, improvement of hydrogen storage performance, and the promotion of the application of high-entropy alloy materials in the field of hydrogen storage. Attached Figure Description

[0075] Figure 1 This is a flowchart of the design of magnesium-based hydrogen storage high-entropy alloy Mg1Ti23V18Nb6Cr12 provided in the embodiments of the present invention;

[0076] Figure 2These are geometric diagrams of (a) the optimized BCC phase Ti24V18Nb6Cr12 and (b) the FCC phase hydride with hydrogen concentration H / M=2 after hydrogenation, provided in the embodiments of the present invention.

[0077] Figure 3 This is a schematic diagram of the phonon spectrum of the FCC phase Ti24V18Nb6Cr12 hydride with a hydrogen concentration of H / M = 2 provided in an embodiment of the present invention;

[0078] Figure 4 This is a schematic diagram of the negative crystal orbital Hamiltonian population between metal atoms and hydrogen atoms in an FCC phase Ti24V18Nb6Cr12 hydride with a hydrogen concentration of H / M=2 provided in an embodiment of the present invention.

[0079] Figure 5 These are geometric diagrams of the optimized (a) BCC phase Mg1Ti23V18Nb6Cr12 and (b) FCC phase hydride with hydrogen concentration H / M=2 provided in the embodiments of the present invention.

[0080] Figure 6 This is a schematic diagram of the phonon spectrum of the FCC phase Mg1Ti23V18Nb6Cr12 hydride with a hydrogen concentration of H / M=2 provided in an embodiment of the present invention. Detailed Implementation

[0081] To make the objectives, technical solutions, and advantages of this invention clearer, a brief description is provided below with reference to examples. It should be noted that the specific examples described herein are merely illustrative and not limiting. Those skilled in the art can obtain other drawings based on these figures without any inventive effort.

[0082] like Figure 1 As shown in the embodiments of the present invention, the method for designing magnesium-based high-entropy alloy Mg1Ti23V18Nb6Cr12 based on first-principles calculations includes the following steps:

[0083] S101, construct the structural model of the quaternary high-entropy alloy BCC Ti24V18Nb6Cr12;

[0084] S102, construct the structural model of the quaternary high-entropy alloy FCC Ti24V18Nb6Cr12 hydride with hydrogen concentration H / M=2;

[0085] S103, Analyze the lattice dynamics stability of the FCC Ti24V18Nb6Cr12 hydride configuration obtained in S102;

[0086] S104, analyze the interaction results between metal elements and hydrogen elements in the Ti24V18Nb6Cr12 hydride obtained from S102, and determine the Mg substitution elements accordingly.

[0087] S105, construct the structural model of Mg1Ti23V18Nb6Cr12 magnesium-based high-entropy alloy after Mg substitution;

[0088] S106, construct the structural model of FCC Mg1Ti23V18Nb6Cr12 hydride with hydrogen concentration H / M=2;

[0089] S107, Analyze the lattice dynamic stability of the magnesium-based high-entropy alloy hydride configuration obtained in S106.

[0090] In S101 provided by this embodiment of the invention, the structural model of the quaternary high-entropy alloy BCC Ti24V18Nb6Cr12 is constructed, including the following steps:

[0091] Step 1.1: Select BCC Ti24V18Nb6Cr12 as the substrate;

[0092] Step 1.2: Construct a BCC Ti unit cell structure model using modeling software, which contains 2 Ti atoms;

[0093] Step 1.3: Expand the single-cell structure model from Step 1.2 to 5×2×3 using modeling software. The model contains 60 metal atoms. Then, replace the Ti atoms according to the atomic ratio Ti:V:Nb:Cr = 4:3:1:2 to generate a POSCAR file.

[0094] Step 1.4: Using a randomization method, the coordinates of metal atoms in the POSCAR file from Step 1.3 are randomly arranged to generate 20 different high-entropy alloy configurations.

[0095] Step 1.5: Use VASP software to optimize the structure of the 20 BCC Ti24V18Nb6Cr12 cascade configurations from Step 1.4, and select the configuration with the lowest energy as the final structure of BCC Ti24V18Nb6Cr12.

[0096] Step 1.6: Further structural optimization is performed on the lowest energy configuration: IBRION is set to 2, ISIF is set to 2, and structural optimization is performed once; then, keeping other parameters unchanged, ISIF is set to 7, and structural optimization is performed again. This process of changing the value of ISIF is repeated until the energy difference is less than 1 meV / atom. The result is as follows: Figure 2 As shown in (a), the lattice constant of BCCTi24V18Nb6Cr12 was calculated to be [value missing]. Compared with the experimental report The match is excellent, indicating that both the constructed structural model and the selected computational precision are reasonable.

[0097] In step S102 of this embodiment of the invention, obtaining the structural model of the quaternary high-entropy alloy FCCTi24V18Nb6Cr12 hydride with a hydrogen concentration of H / M = 2 includes the following steps:

[0098] Step 1.1: Using steps 1.1 to 1.6 of S101, construct the FCC Ti24V18Nb6Cr12 structural model;

[0099] Step 1.2: Use VESTA visualization software to write the coordinates of hydrogen atoms in the FCC interstitial space into the FCCTi24V18Nb6Cr12 obtained in Step 1.1 to construct the FCC Ti24V18Nb6Cr12 hydride structure model with H / M=2.

[0100] Step 1.3: The metal atoms in the Ti24V18Nb6Cr12 hydride with H / M = 2 are rearranged using a randomization method, resulting in a total of 20 configurations;

[0101] Step 1.4: Use VASP software to optimize the structure of the 20 Ti24V18Nb6Cr12 high-entropy alloy hydride structural models from Step 1.3, and select the configuration with the lowest energy as the structure of the FCC Ti24V18Nb6Cr12 hydride with hydrogen concentration H / M=2.

[0102] Step 1.5: Further structural optimization is performed on the lowest energy configuration: IBRION is set to 2, ISIF is set to 2, and structural optimization is performed once; then, keeping other parameters unchanged, ISIF is set to 7, and structural optimization is performed again. This process of changing the value of ISIF is repeated until the energy difference is less than 1 meV / atom. The result is as follows: Figure 2 As shown in (b).

[0103] In S103 provided in this embodiment of the invention, the lattice dynamic stability of the Ti24V18Nb6Cr12 hydride configuration obtained in S102 is analyzed, including the following steps:

[0104] Step 1.1: Use the CONTCAR file obtained in Step 1.5 of S102 as the POSCAR file for phonon spectrum calculation. In the INCAR file, set IBRION to -6 (using the finite difference method) to simulate the phonon spectrum of the material and evaluate the lattice dynamic stability of Ti24V18Nb6Cr12 hydride with H / M=2, such as... Figure 3 As shown.

[0105] In S104 provided in this embodiment of the invention, the interaction results between the metal element and the hydrogen element in the Ti24V18Nb6Cr12 hydride obtained in S102 are analyzed, and the substituent element of Mg is determined accordingly, including the following steps:

[0106] Step 1.1: Perform static self-consistent calculations for the lowest energy configuration, setting NSW = 0 and ISYM = -1;

[0107] Step 1.2: In the lobsterin file, set the parameter "cohpGenerator from 1.9 to 2.1type TitypeH", where 1.9 and 2.1 refer to the measured range of metal-hydrogen atom distances to analyze the interaction between Ti and H. The same method is used to analyze the interaction between vanadium (V), niobium (Nb), chromium (Cr), and hydrogen atom (H).

[0108] Step 1.3: Place the six generated files obtained in Step 1.1 (CONTCAR, IBZKPR, KPOINTS, OUTCAR, POTCAR, WAVECAR, and vasprun.xml) and the lobsterin file obtained in Step 1.2 in the same directory, and run the lobster program.

[0109] Step 1.4: Obtain the output file COHPCAR.lobster and import it into the plotting software to generate the crystal orbital Hamiltonian population map. Simultaneously, read the -ICOHP values ​​from the ICOHPLIST.lobster file, such as... Figure 4 As shown in the figure, the metal atom with the weakest interaction with H atoms in Ti24V18Nb6Cr12 is the Ti atom, so it is replaced by one Mg atom.

[0110] In S105 provided in this embodiment of the invention, the structural model of the Mg1Ti23V18Nb6Cr12 magnesium-based high-entropy alloy after Mg substitution is obtained, including the following steps:

[0111] Step 1.1: To avoid boundary effects, only the positions of Ti metal atoms inside the supercell are considered as substitution sites for Mg. From... Figure 2 (a) It can be seen that there are a total of 16 Ti atoms located inside the supercell in Ti24V18Nb6Cr12. Each of them is replaced by one Mg atom, resulting in 16 different Mg1Ti23V18Nb6Cr12 magnesium-based high-entropy alloy structures.

[0112] Step 1.2 involves structural optimization of the 16 different magnesium-based high-entropy alloy configurations obtained in Step 1.1. The structure with the lowest energy is selected as the final structure of Mg1Ti23V18Nb6Cr12, as shown in the figure. Figure 5 As shown in (a);

[0113] In S106 provided by this embodiment of the invention, obtaining the structural model of FCC Mg1Ti23V18Nb6Cr12 hydride with a hydrogen concentration of H / M = 2 includes the following steps:

[0114] Step 1.1: Using steps 1.1 to 1.6 of S101, construct the structural model of FCC Mg1Ti23V18Nb6Cr12;

[0115] Step 1.2: Use VESTA visualization software to write the coordinates of hydrogen atoms in the FCC interstitial space into the FCCCMg1Ti23V18Nb6Cr12 obtained in Step 1.1 to construct the FCC Mg1Ti23V18Nb6Cr12 hydride structure model with H / M=2.

[0116] Step 1.3: The metal atoms in the Mg1Ti23V18Nb6Cr12 hydride with H / M = 2 are rearranged using a randomization method, resulting in a total of 20 configurations;

[0117] Step 1.4: Use VASP software to optimize the structure of the 20 Mg1Ti23V18Nb6Cr12 high-entropy alloy hydride structure models from Step 1.3, and select the configuration with the lowest energy as the structure of the FCCCMg1Ti23V18Nb6Cr12 hydride with hydrogen concentration H / M=2.

[0118] Step 1.5: Further structural optimization is performed on the lowest energy configuration: IBRION is set to 2, ISIF is set to 2, and structural optimization is performed once; then, keeping other parameters unchanged, ISIF is set to 7, and structural optimization is performed again. This process of changing the value of ISIF is repeated until the energy difference is less than 1 meV / atom. The result is as follows: Figure 5 As shown in (b).

[0119] In S107 of this embodiment of the invention, the lattice dynamic stability of the magnesium-based high-entropy alloy hydride configuration obtained in S106 is analyzed, including the following steps:

[0120] Step 1.1: Use the CONTCAR file obtained in Step 1.5 of S106 as the POSCAR file for phonon spectrum calculation. In the INCAR file, set IBRION to -6 (using the finite difference method) to simulate the phonon spectrum of the material and evaluate the lattice dynamic stability of Mg1Ti23V18Nb6Cr12 hydride with a hydrogen concentration of H / M = 2. Figure 6 As shown.

[0121] Compared with the prior art, the technical solution of the present invention has the following technical advantages:

[0122] This invention designs magnesium-based high-entropy alloys with high hydrogen storage capacity using first-principles calculations, which helps reduce the manpower and financial resources required to test the hydrogen storage performance of materials. By analyzing the interactions between different metal atoms and hydrogen atoms, this invention determines the Mg substitution sites and evaluates the hydrogen storage performance and stability of the designed magnesium-based high-entropy alloys. The method is simple, easy to implement, and highly effective, with significant theoretical and experimental implications, contributing to the development of the field of alloy hydrogen storage.

[0123] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A design method for magnesium-based high-entropy alloys, characterized in that, Based on the different hydrogen atom arrangements in high-entropy alloys, the optimal hydride model was selected and its lattice dynamics stability and hydrogen storage capacity were analyzed, ultimately realizing the theoretical design of Mg-based high-entropy alloy hydrogen storage materials. Specifically, the following steps are included: Step 1: Select a high-entropy alloy with good hydrogen storage performance and construct a structural model of its different metal atom arrangements; Step 2: Optimize the various high-entropy alloy geometric models obtained in Step 1, and select the configuration with the lowest energy as the final configuration; Step 3: Add hydrogen atoms with a hydrogen metal atom ratio of 2 to the high-entropy alloy structure model with the lowest energy obtained in Step 2 to construct a high-entropy alloy hydride structure model. Step four: Optimize the structure of the various high-entropy alloy hydride configurations obtained in step three, and select the configuration with the lowest energy as the final configuration; Step 5: Perform lattice dynamics stability analysis on the hydride configuration with the lowest energy obtained in Step 4; Step six, analyze the interaction between metal elements and hydrogen elements in the hydride obtained in step five, Ti 24 V 18 Nb6Cr 12 The metal atom with the weakest interaction with H atoms is the Ti atom, so it is replaced with 1 Mg atom; Step 7: Construct structural models of magnesium-based high-entropy alloys and their hydrides, and optimize the structures to obtain the configuration with the lowest energy. Step 8: Perform lattice dynamics stability analysis on the magnesium-based high-entropy alloy hydride configuration obtained in Step 7. Step one includes: Step 1.1 Construct a BCCTi unit cell structure model using modeling software; Step 1.2 Use modeling software to expand the single-cell structure model in Step 1.1 to 5×2×3, and then replace the Ti atoms according to the atomic ratio Ti:V:Nb:Cr=4:3:1:2 to generate a POSCAR file; Step 1.

3. A program is designed using python language to realize the random arrangement of metal atom coordinates in the POSCAR file of step 1.2, and the program can be run multiple times to generate 20 different metal atom arrangements of BCCTi 24 V 18 Nb6Cr 12 high-entropy alloy configuration; Step three includes: Step 3.1 Construct a single-cell structure model of FCCTiH2 using modeling software, expand the model to 5×1×3, and then replace the Ti atoms according to the atomic ratio Ti:V:Nb:Cr=4:3:1:2 to generate a POSCAR file; Step 3.2 Design a Python program to randomly arrange the metal atom coordinates in the POSCAR file from Step 3.1, and enable the program to run multiple times to generate 20 different FCCTi coordinates of metal atom arrangements. 24 V 18 Nb6Cr 12 Hydride configuration; The interaction between the metal element and hydrogen element in the hydride obtained in step five of step six includes: Step 6.1 Use VASP software to process FCCTi with H / M = 2. 24 V 18 Nb6Cr 12 Perform static self-consistent calculations, setting NSW=0 and ISYM=-1; Step 6.2 Set the "cohpGeneratorfromX1toX2typeM typeH" parameter in the lobsterin file, where X1 and X2 refer to the measured range of metal-hydrogen atom distances; Step 6.3 Place the output files obtained in Step 6.1: CONTCAR, IBZKPR, KPOINTS, OUTCAR, POTCAR, WAVECAR, and vasprun.xml in the same directory as the lobsterin file in Step 6.2, and run the lobster program; Step 6.4 Analyze the interaction between the metal and hydrogen atoms based on the output files COHPCAR.lobster and ICOHPLIST.lobster.

2. The design method for magnesium-based high-entropy alloys as described in claim 1, characterized in that, Step five includes: In the INCAR file, setting IBRION to use the finite difference method to simulate the phonon spectrum of the material.

3. The design method for magnesium-based high-entropy alloys as described in claim 1, characterized in that, Step seven, which involves constructing a structural model of a magnesium-based high-entropy alloy and its hydride, and optimizing the structure to obtain the configuration with the lowest energy, includes: Step 7.1 Replace the Ti metal atom identified in Step 6 with one Mg atom. To avoid boundary effects, only the Ti metal atom positions inside the supercell are considered as Mg substitution sites. One Mg atom is used to replace each Ti atom, resulting in 16 different Mg1Ti atoms. 23 V 18 Nb6Cr 12 Magnesium-based high-entropy alloy configuration; Step 7.2 For the 16 different magnesium-based high-entropy alloy configurations obtained in Step 7.1, VASP software was used for structural optimization, and the configuration with the lowest energy was selected as Mg1Ti. 23 V 18 Nb6Cr 12 The final configuration of the magnesium-based high-entropy alloy.

4. A design system for magnesium-based high-entropy alloys that implements the design method for magnesium-based high-entropy alloys as described in any one of claims 1 to 3, characterized in that, include: 1) High-entropy alloy structure model construction module: Select high-entropy alloys with good hydrogen storage performance and construct structural models with different metal atom arrangements; 2) High-entropy alloy structure optimization module: Optimizes the structure of various high-entropy alloy geometric models and selects the configuration with the lowest energy as the final configuration; 3) High-entropy alloy hydride structure model construction module: Add hydrogen atoms with a hydrogen metal atom ratio of 2 to the obtained high-entropy alloy structure model with the lowest energy to construct the high-entropy alloy hydride structure model; 4) High-entropy alloy hydride structure optimization module: Optimize the structure of various high-entropy alloy hydride configurations obtained, and select the configuration with the lowest energy as the final configuration; 5) Hydride lattice dynamics stability analysis module: Performs lattice dynamics stability analysis on the lowest energy hydride configuration obtained; 6) Interaction Analysis Module: Analyzes the interactions between metal elements and hydrogen elements in the obtained hydrides; 7) Magnesium-based high-entropy alloy structure model building module: Constructs structural models of magnesium-based high-entropy alloys and their hydrides, and performs structural optimization to obtain the configuration with the lowest energy. 8) Magnesium-based high-entropy alloy hydride lattice dynamics stability analysis module: Perform lattice dynamics stability analysis on the obtained magnesium-based high-entropy alloy hydride configuration.

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