A method and system for calculating and evaluating hydrogen storage performance of a solid hydrogen storage material

Abstract

The application relates to the technical field of hydrogen storage performance calculation and evaluation, and discloses a solid hydrogen storage material hydrogen storage performance calculation and evaluation method and system, which comprises the following steps: using a functional density theory and a molecular dynamics method, constructing a material microcosmic model, and analyzing and designing the mechanical properties, electronic distribution, heat conduction performance and thermal stability of the material itself; calculating the adsorption state and adsorption energy of hydrogen molecules on the hydrogen storage material, and the hydrogen adsorption amount of the material under different pressures and temperatures, so as to calculate the hydrogen adsorption performance of the newly designed hydrogen storage material; and drawing a hydrogen adsorption kinetics curve of the solid hydrogen storage material, so as to calculate and evaluate the hydrogen storage kinetics performance of the material. The system comprises a performance analysis module, a performance calculation module and a performance evaluation module. The application can comprehensively improve the research and development efficiency and hydrogen storage performance of the solid hydrogen storage material in theory and actual application. Each step provides important theoretical support and data basis when solving different technical challenges.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hydrogen storage performance calculation and evaluation, and particularly relates to a solid hydrogen storage material hydrogen storage performance calculation and evaluation method and system. BACKGROUND

[0002] Hydrogen is a renewable energy with light mass, large energy density, water as oxide, and no harm to the environment, which is an ideal fossil energy substitute. At present, hydrogen has a very wide application in aerospace materials, industrial reducing gas, hydrogen fuel cells, new energy power plant energy storage, biological medicine and other social production and life, and is a very vigorous energy carrier. The main technical bottleneck restricting the development of hydrogen economy is hydrogen storage. There are three ways for hydrogen storage: high-pressure gaseous hydrogen storage, low-temperature liquid hydrogen storage and solid hydrogen storage. High-pressure gaseous hydrogen storage and low-temperature liquid hydrogen storage have the advantages of easy dehydrogenation and wide working conditions, but also have the disadvantages of easy hydrogen leakage, poor safety, large evaporation loss and the like, which makes a large amount of hydrogen wasted and increases the use cost of hydrogen. Solid hydrogen storage has the advantages of no evaporation loss, high safety, stable hydrogen storage performance, suitable for long-time and long-distance storage and the like, and has received extensive attention of researchers in recent years.

[0003] Prior art one, Chinese patent, application number 202210366610.8 discloses a membrane type hydrogen storage material, a preparation method and an application. The membrane type hydrogen storage material comprises a film forming fiber layer, and the film forming fiber layer is uniformly distributed with solid hydrogen storage materials. The solid hydrogen storage materials are combined with the film forming fiber materials to form a new type of membrane type solid hydrogen storage material which has the advantages of flexibility, scalability, ductility, high hydrogen storage density, convenient transportation and good safety performance. Although it can solve the problems of poor ductility, poor flexibility and inconvenience of wide application of conventional solid hydrogen storage materials, and realize the controllability of hydrogen release. However, there are problems of difficult material preparation and difficult hydrogen storage and release process.

[0004] Prior art two, Chinese patent, application number 202110191237.2 discloses a preparation method of ammonia metal solid hydrogen storage material and solid hydrogen storage material. The ammonia metal solid hydrogen storage material takes LiNH2 and MgH2 as main raw materials and is prepared by mechanical ball milling. The preparation method includes mass control process and activation method in the preparation process. The change of raw materials in the preparation process of the ammonia metal compound hydrogen storage material is determined to accurately monitor the preparation process and ensure the performance of the material after activation. In the activation process, the activation temperature and the control of the heating rate are determined. Although it can effectively avoid the performance decline of the material caused by overheating during activation and the safety hazards caused by overheating, it can prepare kilogram-level high-purity ammonia metal hydrogen storage material at one time, and is suitable for the large-scale production and application of this type of hydrogen storage material. However, the material preparation is difficult, the material hydrogen storage test measurement is complicated, the hydrogen storage and release process is slow, and the hydrogen release is not complete, which limits the application of solid hydrogen storage.

[0005] The prior art three, Chinese patent, application number 202210372866.X discloses an additive for improving the hydrogen storage performance of lithium magnesium nitrogen hydride and a preparation method and application thereof; the preparation method comprises the following steps: (1) adding vanadium pentoxide into a lithium carbonate solution, mixing uniformly, then adding hydrazine hydrate, and then obtaining a suspension liquid through ultrasonic oscillation; (2) transferring the suspension liquid obtained in the step (1) into a hydrothermal reaction kettle, and carrying out hydrothermal reaction at 100-120 DEG C for 18-24 hours; mixing the reaction liquid with ammonium metavanadate uniformly, and then evaporating the solution to collect the solid product; (3) heat-treating the solid product obtained in the step (2) at 500-550 DEG C for 5-12 hours in a nitrogen or argon-hydrogen mixed gas atmosphere to obtain the additive for improving the hydrogen storage performance of lithium magnesium nitrogen hydride; the additive for improving the hydrogen storage performance of lithium magnesium nitrogen hydride contains Li3VO4 and LiVO2, and the mass fraction of LiVO2 is 35%-50% based on the total mass of Li3VO4 and LiVO2. Although the hydrogen storage performance of lithium magnesium nitrogen hydride can be improved, the cost of the solid hydrogen storage material is increased, and the development cycle of the material is prolonged.

[0006] At present, the prior art one, the prior art two and the prior art three have the defects of low hydrogen storage capacity, difficult hydrogen storage and release process, slow hydrogen storage and release process dynamics and incomplete hydrogen release, which limits the application of solid hydrogen storage; therefore, in order to develop high-performance solid hydrogen storage materials, it is necessary to further improve the hydrogen adsorption performance of the materials while considering the kinetic characteristics of the materials during hydrogen storage and release; however, during the development of solid hydrogen storage materials, the preparation of the materials is difficult, the measurement of the hydrogen storage test of the materials is complicated, and the hydrogen storage performance of the prepared materials does not meet the expectation, which not only increases the research and development cost of the solid hydrogen storage materials, but also prolongs the development cycle of the materials; therefore, accurate evaluation of the hydrogen adsorption characteristics and kinetic characteristics of the target materials in the material selection stage in the early stage of material development can greatly reduce the subsequent experimental cost and test cycle, and provide theoretical support and direction guidance for subsequent experimental measurement. SUMMARY

[0007] The main purpose of the present application is to provide a solid hydrogen storage material hydrogen storage performance calculation and evaluation method and system to solve the problems of low hydrogen storage capacity, difficult hydrogen storage and release process, slow hydrogen storage and release process dynamics and incomplete hydrogen release in the prior art.

[0008] To achieve the above-mentioned purpose, the present application provides the following technical scheme:

[0009] A solid hydrogen storage material hydrogen storage performance calculation and evaluation method, the solid hydrogen storage material hydrogen storage performance calculation and evaluation method comprises:

[0010] By using the density functional theory (DFT) and molecular dynamics (MD), the mechanical properties, electronic distribution, thermal conductivity and thermal stability of the material are analyzed by constructing a microcosmic model of the material.

[0011] By calculating the adsorption state and adsorption energy of hydrogen molecules on the hydrogen storage material and the hydrogen adsorption amount of the material at different pressures and temperatures, the hydrogen adsorption performance of the newly designed hydrogen storage material is calculated.

[0012] The hydrogen adsorption kinetics curve of the solid-state hydrogen storage material is drawn to calculate and evaluate the hydrogen storage kinetics performance of the material.

[0013] As a further improvement of the present application, the material microcosmic model analysis process comprises:

[0014] The optimal lattice structure of the material is determined by using the geometric optimization of the application of the density functional theory, and the optimized structure of the material is calculated by selecting the exchange-correlation functional; the electronic density distribution of the optimized structure is obtained by calculation, and the electronic state, energy band structure and Fermi level information are extracted; the electrical conductivity of the material is analyzed, and the electrical conductivity and insulating properties are determined by the state density diagram and the energy band diagram; the charge transfer and localization phenomenon are evaluated by using Bader charge analysis, and the chemical properties and reaction behavior of the material are obtained; the interaction potential between materials is selected according to the characteristics of the materials and the nature of the interaction;

[0015] The optimal geometric structure obtained by using the density functional theory is used as the initial configuration of the molecular dynamics simulation; the temperature, pressure and time step parameters are set; the molecular dynamics simulation is run at different temperatures and pressures to obtain the thermal behavior, phase change process and mechanical response of the material; the adsorption and diffusion behavior of gas molecules on the surface of the material is tested to obtain the kinetic information; the stress-strain curve is generated by applying external stress, and the elastic modulus, yield strength and fracture behavior of the material are analyzed; the relative motion between atoms is analyzed, and the displacement field information is extracted to obtain the change of the mechanical properties of the material;

[0016] The thermal conductivity of the material at different temperatures is analyzed by using the non-equilibrium molecular dynamics method; the lattice vibration and phonon heat conduction are calculated to evaluate the influence of atomic-level thermal motion on macroscopic thermal conductivity; the stability and deformation of the material under high temperature environment are obtained by applying repeated thermal cycles in the molecular dynamics; after the material reaches thermal equilibrium state, the corresponding properties in the thermal excitation state are evaluated, and the potential phase transition or degradation mechanism is identified.

[0017] As a further improvement of the present application, the process of calculating the optimized structure of the material by using the exchange-correlation functional comprises:

[0018] Extract the initial structure of the material from the database, including atomic positions and symmetry; set the geometry optimization parameters in the calculation software, set the force and energy convergence criteria; start the calculation and run the geometry optimization;

[0019] Using the optimized crystal structure, perform a self-consistent field calculation to obtain the electron density distribution, view and analyze the electron density distribution in the file output; select a k-point grid to calculate the energy band along a specific high-symmetry direction; generate band diagrams and state density diagrams to analyze the filling state of each energy level; obtain the Fermi energy level position from the state density calculation and mark the Fermi energy level position in the band diagram;

[0020] Determine the properties of metals, semiconductors or insulators by the shape of the state density diagram; analyze the energy band gap width, calculate the conductivity and estimate the prediction model; use Bader charge analysis to calculate the charge value of each atom to ensure correct distribution of local charges, and present the charge distribution through visualization tools to analyze which atoms or compounds receive or lose electrons; combine the Bader results to analyze the degree of localization of electrons between different atoms to determine possible active sites.

[0021] As a further improvement of the present application, the process of calculating the hydrogen adsorption performance of the newly designed hydrogen storage material includes:

[0022] After obtaining the stable structure, perform molecular dynamics simulation and set the initial temperature and pressure; run MD simulation to obtain the kinetic stability and thermal stability data of the material, and obtain the selected structure of the material at different temperatures;

[0023] Add hydrogen molecules to the optimized hydrogen storage material model, calculate the energy of different adsorption sites on the surface, vacancies or three-dimensional channels, identify the optimal adsorption site, and evaluate the hydrogen adsorption energy of different sites by comparing the adsorption energy of different sites to select the adsorption site;

[0024] Perform thermodynamic calculations at different temperatures and pressures to evaluate the amount of hydrogen adsorbed in the material, use the adsorption isotherm to estimate the adsorption amount under different conditions, and quantify the hydrogen adsorption performance of the material.

[0025] As a further improvement of the present application, the process of obtaining the selected structure of the material at different temperatures includes:

[0026] Obtain the preliminary crystal structure of the hydrogen storage material and generate a three-dimensional model; perform geometry optimization on the initial structure, use the DFT method for calculation, optimize the coordinates of each atom, and obtain the lowest energy configuration; perform MD simulation for each target temperature;

[0027] The interatomic interaction of the material is described, and thermal equilibrium is performed under isobaric conditions at a set initial temperature; after reaching thermal equilibrium, the simulation is continued to obtain the motion and changes of atoms inside the material; the atomic coordinate data is extracted once, and the system configuration under the current temperature condition is recorded;

[0028] The collected structural data is analyzed, and the atomic displacement, square displacement, and average distance properties of the material at different temperatures are calculated; the coordination number and distribution between atoms and the energy minimization criterion are used to screen the most stable and representative structures at different temperatures; the selected stable structures at different temperatures are summarized, visualized, and a temperature spectrum is generated.

[0029] As a further improvement of the present application, the process of identifying the optimal adsorption site includes:

[0030] The surface and internal structure of the hydrogen storage material are geometrically described, and different possible hydrogen molecule adsorption sites are depicted using geometric features and spatial symmetry;

[0031] One or more hydrogen molecules are simultaneously introduced into the model of the hydrogen storage material, surrounding different labeled adsorption sites; dynamic simulation of hydrogen molecules at different adsorption sites is performed; under the set initial conditions, the motion of hydrogen molecules is observed, and the interaction between hydrogen molecules and the hydrogen storage material is recorded;

[0032] For each adsorption site, the interaction energy between the hydrogen molecule and the material is calculated using potential energy relationships; through an energy minimization program, the relative stability of the hydrogen molecule at each adsorption site is obtained; the calculated adsorption energy is compared, and the lowest energy site is identified as the optimal adsorption site.

[0033] As a further improvement of the present application, the process of quantifying the hydrogen adsorption performance of the material includes:

[0034] Using a gas adsorption isotherm determination device, hydrogen gas is introduced into the hydrogen storage material that has been pre-treated in a vacuum, and different hydrogen gas pressures are gradually applied; at each set pressure, the gas volume change, pressure change, and temperature change during the adsorption process are monitored in real time by a range instrument;

[0035] The amount of adsorbed hydrogen gas is compared with the mass of the material, and the hydrogen adsorption capacity per gram of material is calculated by calculating the change in the amount of substance of the gas at a specific pressure using the ideal gas state equation; under different temperature and pressure conditions, the corresponding gas adsorption experiment is performed; the adsorption isotherm model is applied for data fitting, and the thermodynamic parameters in the adsorption isotherm are extracted;

[0036] The maximum adsorption amount of hydrogen storage and the transfer and release characteristics of the gas in the material are obtained by calculating the adsorption isotherm and thermodynamic parameters; the adsorption efficiency under different conditions is recorded and analyzed, including the saturated adsorption amount, the kinetic adsorption rate and the desorption rate; and the test results are compared with the adsorption performance of the hydrogen storage material.

[0037] As a further improvement of the application, the process of calculating and evaluating the hydrogen storage kinetic performance of the material includes:

[0038] The pressure and flow changes of hydrogen at different time points are recorded in real time by the pressure sensor and the flow meter to form a dynamic monitoring data set; the data collected from the adsorption experiment is processed to calculate the hydrogen adsorption at different time points and record the hydrogen amount change at each time node;

[0039] According to the gas volume and pressure change, the amount of substance corresponding to the hydrogen adsorption is calculated by using the ideal gas state equation, and is compared with the material mass; using the obtained data, the adsorption rate of hydrogen is fitted by using a kinetic model to obtain the characteristics of the adsorption process;

[0040] The relationship curve between the hydrogen adsorption amount on the hydrogen storage material and the time is drawn on the coordinate ruler to show the time dependence of hydrogen adsorption; the key parameters are extracted from the drawn curve; the adsorption rate constant, diffusion coefficient and other important kinetic parameters of hydrogen are calculated to evaluate the hydrogen adsorption kinetic performance of the material.

[0041] As a further improvement of the application, the process of obtaining the characteristics of the adsorption process includes:

[0042] The obtained hydrogen adsorption amount and corresponding time data are used to establish a structured data table including time points, corresponding hydrogen pressure, flow, hydrogen adsorption amount information; the obtained data is preliminarily analyzed to draw the curve of hydrogen adsorption amount changing with time;

[0043] A fitting tool is selected, and a nonlinear least squares method is used to minimize the error between the estimated model and the experimental data; the experimental data is input and the model equation is selected;

[0044] The fitting curve is viewed to see the degree of agreement with the actual data, the key parameters of the fitting are output, the goodness of fit is calculated, and the value close to 1 indicates that the model predicts the adsorption behavior.

[0045] To achieve the above object, the application also provides the following technical scheme:

[0046] A solid hydrogen storage material hydrogen storage performance calculation and evaluation system is applied to the solid hydrogen storage material hydrogen storage performance calculation and evaluation method, and the solid hydrogen storage material hydrogen storage performance calculation and evaluation system includes:

[0047] The performance analysis module is used for analyzing the mechanical performance, electronic distribution, heat conduction performance and thermal stability of the designed material by constructing a microcosmic model of the material by using functional density theory and molecular dynamics;

[0048] The performance calculation module is used for calculating the hydrogen adsorption performance of the newly designed hydrogen storage material by calculating the adsorption state and adsorption energy of hydrogen molecules on the hydrogen storage material and the hydrogen adsorption amount of the material under different pressures and temperatures.

[0049] The performance evaluation module is used for drawing the hydrogen adsorption kinetics curve of the solid-state hydrogen storage material to calculate and evaluate the hydrogen storage kinetics performance of the material.

[0050] The micro model of the material is constructed and the performance analysis is performed through the DFT and MD methods, which allows the microstructure of the material to be optimized, and the most potential material system is identified; the mechanical properties, electronic distribution, thermal conductivity and thermal stability of the material can be in-depth analyzed, which provides necessary preliminary data for understanding the basic physical and chemical properties of the material; through calculation and simulation, the behavior of the new material in the hydrogen storage process can be estimated, and the advantages and disadvantages are identified, thereby providing guidance for subsequent experiments. Actual significance: the research and development period of the new material can be effectively shortened, blind experiments can be avoided through theoretical calculation, and the research efficiency is improved; the in-depth understanding of the physical and chemical properties of the material can provide important reference for subsequent hydrogen adsorption performance prediction and experiment, and the scientificity of design is enhanced. Hydrogen adsorption performance calculation: by calculating the adsorption state and adsorption energy of hydrogen molecules on the hydrogen storage material, the interaction strength between hydrogen molecules and the material can be obtained. This provides a quantitative index for evaluating the hydrogen storage potential of the material; the hydrogen adsorption amount under different pressures and temperatures can reflect the performance of the material under actual hydrogen storage conditions, and provides data support for understanding the behavior of the material under common hydrogen storage conditions such as room temperature and high pressure; through the evaluation of the hydrogen adsorption amount of different materials, the hydrogen storage material with excellent performance can be screened out, and a solid foundation is laid for subsequent experiments and practical applications. Actual significance: detailed calculation and evaluation of hydrogen adsorption performance can help to design materials according to specific application requirements, and screen out the most potential candidate materials; by optimizing the hydrogen adsorption performance of the material, more efficient hydrogen storage can be finally realized, and the practical application of renewable energy and hydrogen energy is promoted. Hydrogen adsorption kinetics performance evaluation: drawing the hydrogen adsorption kinetics curve can visually show the hydrogen adsorption and release process of the hydrogen storage material, including speed, stability and dynamic characteristics; through the analysis of the kinetics curve, the kinetic parameters in the hydrogen adsorption process can be obtained, such as adsorption rate constant and diffusion coefficient, which is crucial for understanding the migration behavior of hydrogen in the material; the overall evaluation of hydrogen storage performance in the macroscopic level is realized, which ensures that the screened material not only has advantages in quantitative adsorption performance, but also performs well in the kinetics of adsorption and desorption. Actual significance: the evaluation of hydrogen adsorption kinetics performance provides necessary dynamic characteristic analysis for the practical hydrogen storage application of the material, and increases the feasibility of the material in commercial application; through the kinetic analysis, the bottlenecks that may exist in the operation of the material can be identified, and further design and optimization are promoted. BRIEF DESCRIPTION OF DRAWINGS

[0051] Figure 1 The step flowchart schematic diagram of one embodiment of the solid hydrogen storage material hydrogen storage performance calculation and evaluation method of the application is shown in the figure.

[0052] Figure 2 The step flowchart schematic diagram of the material micro model analysis process of one embodiment of the solid hydrogen storage material hydrogen storage performance calculation and evaluation method of the application is shown in the figure.

[0053] Figure 3 A flow chart of a step of calculating hydrogen adsorption performance of a newly designed hydrogen storage material according to an embodiment of the hydrogen storage performance calculation and evaluation method of the solid hydrogen storage material;

[0054] Figure 4 A flow chart of a step of calculating and evaluating hydrogen storage kinetics performance of a material according to an embodiment of the hydrogen storage performance calculation and evaluation method of the solid hydrogen storage material;

[0055] Figure 5 A functional module diagram of an embodiment of the hydrogen storage performance calculation and evaluation system of the solid hydrogen storage material;

[0056] Figure 6 A structural diagram of an embodiment of the electronic device;

[0057] Figure 7 A structural diagram of an embodiment of the storage medium;

[0058] Figure 8 A structural diagram of a modified nitrogenated holey graphene cell model, (a), (b) and (c) are holey graphite, a single and two Na-modified holey graphene, respectively;

[0059] Figure 9 A diagram of the electronic energy band of the sodium-modified nitrogenated holey graphene, (a), (b) and (c) are holey graphite, a single and two Na-modified holey graphene energy band structure diagram, respectively;

[0060] Figure 10 A charge difference density diagram, (a) and (b) are charge difference density diagrams of a single and two Na-modified nitrogenated holey graphene, respectively;

[0061] Figure 11 A charge difference density diagram when hydrogen is adsorbed on the surface of the material, (a) and (b) are the result diagrams of a single and two Na-modified nitrogenated holey graphene, respectively;

[0062] Figure 12 A diagram of the electronic transport characteristics of the material, (a) is the electrical conductivity, and (b) is the power factor;

[0063] Figure 13 A diagram of the electronic thermal conductivity of the material;

[0064] Figure 14 A diagram of the phonon dispersion relationship of the material, (a), (b) and (c) are the result diagrams of holey graphite, a single and two Na-modified holey graphene, respectively;

[0065] Figure 15 Figure 2 is a schematic diagram of the phonon relaxation time and group velocity of the nitrogenated graphitic graphene of the present application;

[0066] Figure 16 Figure 4 is a schematic diagram of the phonon thermal conductivity of the material of the present application. DETAILED DESCRIPTION

[0067] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0068] The terms "first", "second", "third" in the present application are only for descriptive purpose, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second", "third" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "plurality" is at least two, for example, two, three, etc., unless otherwise explicitly and specifically limited. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device including a series of steps or units is not limited to the listed steps or units, but can optionally include steps or units not listed, or can optionally include other steps or units inherent to the process, method, product or device.

[0069] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that the embodiments described herein are merely examples from a much larger number of embodiments that can be claimed.

[0070] As Figure 1 shown, the present embodiment provides one embodiment of the solid hydrogen storage material hydrogen storage performance calculation and evaluation method, which specifically includes the following steps in the present embodiment:

[0071] Step S1: using functional density theory and molecular dynamics method, by constructing a microcosmic model of the material, analyzing the mechanical properties, electronic distribution, thermal conductivity and thermal stability of the material itself, etc.

[0072] Step S2: by calculating the adsorption state of hydrogen molecules on the hydrogen storage material, the adsorption energy and the hydrogen adsorption amount of the material at different pressures and temperatures, the hydrogen adsorption performance of the newly designed hydrogen storage material is calculated.

[0073] Step S3: draw the hydrogen adsorption kinetics curve of the solid-state hydrogen storage material, to calculate and evaluate the hydrogen storage kinetics performance of the material.

[0074] Preferably, the construction of the material micro-model in step S1 of the present embodiment and the performance analysis are carried out by DFT and MD methods, which can construct the micro-model of the material, allowing the optimization of the microstructure of the material and the identification of the most promising material system; can deeply analyze the mechanical properties, electronic distribution, thermal conductivity and thermal stability of the material, etc., to provide necessary preliminary data for understanding the basic physical and chemical properties of the material; through calculation and simulation, the behavior of new materials in the hydrogen storage process can be predicted, and its advantages and disadvantages can be identified, thereby providing guidance for subsequent experiments. Practical significance: It can effectively shorten the research and development cycle of new materials, avoid blind experiments through theoretical calculation, and improve research efficiency; in-depth understanding of the physical and chemical properties of the material can provide important reference for subsequent hydrogen adsorption performance prediction and experiment, and enhance the scientific nature of the design. Step S2 hydrogen adsorption performance calculation, by calculating the adsorption state and adsorption energy of hydrogen molecules on the hydrogen storage material, the interaction strength between hydrogen molecules and the material can be obtained. This provides a quantitative index for evaluating the hydrogen storage potential of the material; the calculation of hydrogen adsorption capacity under different pressures and temperatures can reflect the performance of the material under actual hydrogen storage conditions, and provide data support for understanding the behavior of the material under common hydrogen storage conditions such as room temperature and high pressure; by evaluating the hydrogen adsorption capacity of different materials, the best hydrogen storage material can be selected, laying a solid foundation for subsequent experiments and practical applications. Practical significance: Detailed calculation and evaluation of hydrogen adsorption performance can help to design materials according to specific application requirements and select the most promising candidate materials; by optimizing the hydrogen adsorption performance of the material, more efficient hydrogen storage can be achieved, promoting the practical application of renewable energy and hydrogen energy. Step S3 hydrogen adsorption kinetics performance evaluation, drawing the hydrogen adsorption kinetics curve can visually show the hydrogen adsorption and release process of the hydrogen storage material, including speed, stability and dynamic characteristics, etc.; through the analysis of the kinetic curve, the kinetic parameters in the hydrogen adsorption process can be obtained, such as adsorption rate constant and diffusion coefficient, etc., which is crucial for understanding the migration behavior of hydrogen in the material; the overall evaluation of hydrogen storage performance in the macroscopic level is realized, ensuring that the selected material not only has advantages in quantitative adsorption performance, but also performs well in the kinetics of adsorption and desorption. Practical significance: The evaluation of hydrogen adsorption kinetics performance provides necessary dynamic characteristic analysis for the practical hydrogen storage application of the material, increasing the feasibility of the material in commercial application; through kinetic analysis, the bottlenecks that may exist in the operation of the material can be identified, promoting further design and optimization.

[0075] In summary, the embodiment can comprehensively improve the research and development efficiency and hydrogen storage performance of solid hydrogen storage materials through systematic analysis and evaluation in three steps. Each step provides important theoretical support and data basis when solving different technical challenges. Not only can it accelerate the discovery and optimization of new materials and improve the efficiency of hydrogen storage, but also can make positive contributions to the future development of hydrogen energy utilization and renewable energy.

[0076] The embodiment can simplify the experimental exploration process, shorten the research and development cycle and cost of solid hydrogen storage materials, and provide theoretical support for experimental measurement by comprehensively and accurately calculating and evaluating the hydrogen storage performance of materials in the early stage of the design and development of high-performance solid hydrogen storage materials. The embodiment can calculate and evaluate the hydrogen storage performance of the selected target material in the early stage of the development of solid hydrogen storage materials, and provide theoretical guidance for experimental measurement, thereby saving experimental cost and reducing experimental cycle; based on first-principle calculation, the thermal stability, mechanical properties and electronic properties of solid hydrogen storage materials can be calculated to determine the characteristics and working properties of the materials themselves; based on first-principle calculation, the adsorption electron distribution characteristics of hydrogen molecules on the hydrogen storage material can be calculated to determine the adsorption state of hydrogen molecules on the material, thereby making a preliminary judgment of the hydrogen adsorption capacity of the hydrogen storage material; based on first-principle calculation, the adsorption energy of hydrogen molecules on the hydrogen storage material can be calculated to determine the maximum number of hydrogen molecules that can be stably adsorbed by the hydrogen storage material, calculate and evaluate the theoretical maximum hydrogen adsorption capacity of the material; using molecular dynamics method, the theoretical hydrogen adsorption capacity of the material under different temperatures and pressures can be calculated; the hydrogen storage performance of solid hydrogen storage materials under different working conditions is calculated and evaluated; using molecular dynamics method, the hydrogen adsorption kinetic curve of solid hydrogen storage materials under different pressures can be calculated to calculate and evaluate the kinetic characteristics in the hydrogen storage / release process of solid hydrogen storage materials, thereby estimating the hydrogen storage / release time.

[0077] In the embodiment, the hydrogen adsorption characteristics of the material are calculated by the DFT method, including the thermal stability of the material itself, the electronic distribution characteristics, the hydrogen adsorption characteristics at absolute zero, etc. The DFT method can calculate the electronic characteristics of the material, including the electronic band structure, the electronic state density, the electronic distribution, the Bader charge, the charge differential density, etc. by the VASP software package, so as to determine the basic electronic characteristics of the research material and analyze the mechanism of the hydrogen storage process. The first principle is a calculation method based on quantum mechanics, which can calculate the structure, energy, magnetism, optical characteristics, etc. of the material from the most basic principle, and has high accuracy and predictability. The DFT of the first principle is one of the most successful and popular methods in the field of solid physics and chemical calculation research at present. The theory solves the motion and interaction of atoms and molecules from the basic principle. The basic idea is to express all physical quantities of the system as a function of the electron density, i.e. the energy, electron spin, charge density, etc. of the system. This function is usually called the exchange-correlation function, which contains the exchange and correlation parts, which describe the exchange interaction between electrons and the interaction of electrons. The core idea of the functional density theory is to convert the many-body problem into a single-body problem, and to express the many-body wave function as a function of the electron density. According to the Hohenberg-Kohn theorem, the electron density uniquely determines the physical properties of the system, so the electron density can be solved by minimizing the total energy functional. The total energy functional can be expressed as:

[0078]

[0079] In the formula, T s [ρ] represents the kinetic energy of the electron freedom, υ ext (r) represents the external potential field, ρ(r) represents the electron density, E XC [ρ] represents the exchange energy caused by the interaction between electrons and the Pauli exclusion principle. The exchange correlation energy is the core of the density functional theory, which describes the influence of the interaction between electrons and the Pauli exclusion principle, and is the main difference between the functional density theory and other computational chemistry methods.

[0080] The physicochemical properties of the solid hydrogen storage material itself have an important influence on the hydrogen adsorption characteristics of the material, which can be calculated by combining VASP and VASPKIT software to analyze the energy band structure of the material. The energy band structure is one of the tools for qualitatively describing the characteristics of the motion of electrons in a crystal in solid physics. It describes the energy carried by forbidden or allowed electrons, which is caused by the diffraction of quantum dynamics electron waves in a periodic lattice. The energy band structure of the material determines a variety of properties, especially its electronic properties. The central task of energy band calculation is to solve the single-electron Schrödinger equation in the periodic potential field of the crystal:

[0081]

[0082] Its solution should have the form of Bloch function:

[0083] Ψ k (r) = e ikr u k (r)

[0084] u k (r) = u k (r + R n )

[0085] So when solving, first should find a reasonable approximation scheme to express u k (r) or give a solvable approximate expression of periodic potential field, solve the equation. From the band structure can determine whether the material is insulator, semiconductor or metal, so as to further analysis of electronic structure.

[0086] Through the band structure can qualitative understanding of the overall electronic properties of the material, and charge distribution and differential charge distribution can be analyzed in the material of the specific charge distribution. Similarly, this result can be combined with VASP and VASPKIT software, the electronic density of states, electronic distribution, Bader charge and charge differential density of the material are calculated and analyzed. The distribution of electrons in space is a cloud of electrons, and the charge analysis is to describe this chaotic and unclear electron cloud distribution in a simple way, as well as the number of charges around the atoms in the system. Charge distribution is widely used in research that needs to describe the charge state of the system. Using charge density analysis can analyze the bonding information between atoms, when the charge density analysis cannot show the bonding information, the differential charge density can be considered. The differential charge density is the difference between the charge density after the interaction of atoms and the atomic charge density at the corresponding point, which helps to understand the adsorption state between hydrogen molecules and solid-state hydrogen storage materials. Through the analysis of differential charge density, the charge movement and polarization direction in the process of bonding and bonding electron coupling can be clearly obtained. The formula for calculating the differential charge density is:

[0087] Δρ = ρ AB -ρ A -ρ B

[0088] Where ρ AB represents the structural charge density of the structure after the combination of materials A and B, ρ A and ρ B are the structural charge densities of materials A and B before combination. Subtracting them, the charge density change of material AB composed of materials A and B can be obtained, and the properties such as charge movement can be analyzed. From the charge movement characteristics, the interaction characteristics between the material and hydrogen molecules can be preliminarily determined.

[0089] The thermal conductivity has a great influence on the hydrogen storage kinetics of solid-state hydrogen storage materials. Materials with high thermal conductivity have faster response speed in temperature regulation during hydrogen storage and release, and thus have better hydrogen storage kinetics. The thermal conductivity of a material includes electronic thermal conductivity and phonon thermal conductivity. The carrier effective mass, elastic constant, electronic relaxation time, electronic thermal conductivity, power factor, and electronic thermal conductivity of a material can be calculated by using the DFT method, through the joint use of VASP, VASPKIT, and BoltzTraP2 software packages, so as to study the mechanical properties and electronic thermal conductivity of the material. The thermal carriers are electrons and phonons. In a material, free electrons with high temperature move faster, rapidly diffuse to the surrounding, and exchange energy with cold electrons (electrons with low temperature) through collision, and transfer heat. The electronic thermal conductivity (κ e ) of a material can be calculated by the Wiedemann-Franz law:

[0090] κ e = LσT

[0091] where T is the temperature, σ is the electrical conductivity, and L is the Lorentz constant. The formula for calculating the Lorentz constant is:

[0092]

[0093] where k B is the Boltzmann constant, e is the electron charge, r is the scattering radius of various scattering mechanisms, η is the Fermi energy, and F n (η) is the nth-order Fermi integral. The σ / τ and S of a material can be obtained by using the Boltztrap software. The electrical conductivity can be obtained according to the deformation potential theory. The electronic relaxation time (τ) can be obtained according to the following formula:

[0094]

[0095] where k B , m* and E1 are the Boltzmann constant, Planck constant, electron effective mass, and phase transition potential energy, respectively; and C is the elastic constant. The elastic constant describes the stiffness of the crystal in response to an applied strain, and the stress and strain of the system satisfy Hooke's law. Generally, the elastic constant is represented by a matrix, which can be used as a basis for judging the stability of a material. According to the Born stability criterion, if a material is stable, the following conditions must be met: the matrix C is positive definite; all eigenvalues of the matrix C are positive; all principal minors of the matrix C are positive; and any submatrix of the matrix C is positive.

[0096] Generally, phonons make the main contribution to the heat transfer process of solid-state hydrogen storage materials. By using the DFT method, the phonon properties of materials, including phonon dispersion relation, phonon relaxation time, phonon group velocity, lattice thermal conductivity, etc. can be calculated by combining VASP and Alamode software, and the thermal stability and phonon heat conduction characteristics of the materials can be studied. The solid lattice has a periodic structure, and atoms or ions vibrate around the equilibrium position, forming phonons. Phonons are the carriers of the lattice thermal conductivity of materials. According to the ideal gas model assumption, the lattice thermal conductivity of the material is:

[0097]

[0098] where C V is the constant volume heat capacity, v g is the phonon group velocity, l is the mean free path, and τ is the phonon relaxation time. C V is a material-specific parameter, which only changes with temperature when the material structure remains unchanged. v g can be obtained from the slope of the phonon branch in the phonon dispersion relation. In addition, the thermal stability of the material can also be determined from the phonon dispersion relation. If the phonon dispersion relation of the material at a certain temperature has imaginary frequencies (negative frequency phonons), it means that the material structure is unstable at this temperature. According to the Mie-Grüneisen rule, if there are multiple scattering mechanisms in the material, the relaxation time of the phonon can be written as follows:

[0099]

[0100] where τ U , τ B、 τ Str、 τ Res、 τ EP are the relaxation time components caused by U scattering, point defect scattering, grain boundary scattering, dislocation scattering, non-magnetic phonon resonance scattering, and electroacoustic scattering, respectively. Through the calculation, the thermal conductivity of solid-state hydrogen storage materials has been discussed completely. The above material properties are calculated by the first-principles method. Since the first-principles method can only calculate the relevant properties of materials at absolute zero, the hydrogen adsorption characteristics and dynamic characteristics of materials at working temperature cannot be evaluated by the first-principles method.

[0101] To solve the above problems, MD method is used to calculate and evaluate the hydrogen adsorption capacity and dynamic characteristics of the material at different temperatures and pressures by selecting appropriate force field using LAMMPS software. Molecular dynamics is a computational simulation method for studying the properties of a system by simulating the trajectories of atoms and molecules in the system. It is an important means of studying molecular systems. Based on Newtonian classical mechanics, the motion trajectories of molecules or atoms can be solved by giving the interaction between atoms and molecules in the molecular system. Then, the mechanical, thermodynamic and dynamic properties of the system can be calculated using certain statistical methods. In molecular dynamics, the intermolecular potential U(r) is usually used to represent the intermolecular interaction, and r is the intermolecular distance. Therefore, the intermolecular potential determines the structural and physicochemical properties of the material. Taking the most common intermolecular potential Lennard-Jones potential as an example, its mathematical expression is:

[0102]

[0103] where r = σ is the zero potential energy position of the system potential energy, and ε is the potential well depth. For different systems, appropriate potential functions should be selected to improve the accuracy of the calculation.

[0104] Molecular dynamics is a good complement to the first-principles method. Since the first-principles method can only calculate the electronic properties of the system at absolute zero temperature, and the computational resources are large, it can only calculate systems with a small number of atoms. Therefore, the first-principles method is only suitable for mechanism analysis of electronic and energy properties. Molecular dynamics can calculate larger systems and analyze energy and dynamic properties at different temperatures and pressures, but it cannot analyze the electronic properties of the system. Therefore, combining the first-principles method with molecular dynamics can take the advantages of both methods and complement each other, thereby making more comprehensive and accurate calculations and evaluations of the performance of hydrogen storage materials.

[0105] Further, as shown in Figure 2 The material microstructure analysis process in step S1 specifically includes the following steps:

[0106] Step S11: Use the application functional density theory to perform geometry optimization to determine the optimal lattice structure of the material, and select the exchange-correlation functional to calculate the optimized structure of the material; obtain the electronic density distribution of the optimized structure by calculation, and extract information such as electronic state, band structure and Fermi level;

[0107] The conductive properties of the material are analyzed, and the conductive performance and insulating characteristics are determined through the density of states diagram and the energy band diagram. The charge transfer and localization phenomena are evaluated by Bader charge analysis or other methods to obtain the chemical properties and reaction behavior of the material. For the interaction potential between materials, Lennard-Jones potential, EAM potential (embedded atom model), Tersoff potential, etc. are selected according to the characteristics of the material and the nature of the interaction.

[0108] Step S12: using the optimal geometry structure obtained by the application of functional density theory as the initial configuration of the molecular dynamics simulation;

[0109] The parameters such as temperature, pressure and time step are set. The molecular dynamics simulation is run at different temperatures and pressures to obtain the thermal behavior, phase transition process and mechanical response of the material. The adsorption and diffusion behavior of gas molecules (such as hydrogen, oxygen, etc.) on the material surface is tested to obtain the kinetic information.

[0110] An external stress is applied to generate a stress-strain curve, and the elastic modulus, yield strength and fracture behavior of the material are analyzed. The relative motion between atoms is analyzed to extract the displacement field information and obtain the mechanical property changes of the material.

[0111] Step S13: using non-equilibrium molecular dynamics method to analyze the thermal conductivity of the material at different temperatures; calculating the lattice vibration and phonon heat conduction to evaluate the influence of atomic level thermal motion on macroscopic thermal conductivity; applying repeated thermal cycles in molecular dynamics to obtain the stability and deformation of the material under high temperature environment;

[0112] After the material reaches thermal equilibrium state, the corresponding properties in the thermal excited state are evaluated, and the potential phase transition or degradation mechanism is identified.

[0113] Preferably, the geometry optimization and electronic structure analysis of step S11DFT of the present embodiment is to optimize the geometry of the material through DFT, ensure that the atomic arrangement reaches the lowest energy state, and obtain a stable lattice structure; calculate the electronic density distribution of the material, and analyze the electronic state, band structure and Fermi level on this basis to judge the conductivity and insulating properties of the material; use methods such as Bader charge analysis to evaluate charge localization and transfer phenomena, and obtain the chemical properties and reaction behavior of the material; select appropriate intermolecular potential (such as Lennard-Jones potential, EAM potential, etc.) according to the properties of the material to lay the foundation for subsequent molecular dynamics simulation. The significance achieved: providing accurate initial structure for subsequent molecular dynamics simulation ensures the reliability of the calculation results; through in-depth analysis of the electronic structure and charge distribution, helping to understand the chemical behavior, reactivity and potential applications of the material; identifying the electronic properties of the material provides an important theoretical basis for the improvement of materials and the design of new materials. Step S12 molecular dynamics simulation setting and analysis, using the crystal structure optimized by DFT as the initial configuration of molecular dynamics simulation; run molecular dynamics simulation under different temperature and pressure conditions to observe the thermal behavior, phase transition process and mechanical response of the material; test the adsorption and diffusion behavior of gas molecules (such as hydrogen, oxygen, etc.) on the surface of the material to obtain their kinetic characteristics; apply external stress to generate stress-strain curves to analyze the elastic modulus, yield strength and fracture behavior of the material. The significance achieved: dynamic data obtained through MD simulation enhances the understanding of the behavior of materials under actual application conditions; the generation and analysis of stress-strain curves can help identify the mechanical limits of materials, guide material optimization and application design; understanding the interaction of materials with gas molecules helps the development of applications in the fields of catalysis, hydrogen storage, etc. Step S13 thermal conductivity and thermal stability analysis, using non-equilibrium molecular dynamics method to analyze the thermal conductivity of the material at different temperatures to obtain the thermal conduction performance of the material; calculate the lattice vibration modes in the material to evaluate the influence of atomic-level thermal motion on macroscopic thermal conductivity through phonon scattering mechanism; apply thermal cycle conditions to observe the behavior of the material in high temperature environment and evaluate its thermal stability and potential structural changes; evaluate the thermal excitation state of the material after it reaches thermal equilibrium state to identify possible phase transition or degradation mechanism. The significance achieved: through thermal conductivity and thermal stability analysis, the reliability and performance of the material in high temperature applications can be evaluated; understanding the thermal conduction characteristics of the material can provide guidance for the design of thermal management materials, such as the development of thermal barrier materials or thermal conductive composites; identifying phase transition and degradation mechanisms at high temperatures helps to ensure the safety and stability of materials in various environments.

[0114] In summary, in the material micro-model analysis process of the embodiment, each step from DFT optimization, MD simulation to thermal performance analysis complements each other to form a complete research framework. Each step not only has an independent technical effect, but also jointly helps to understand and optimize the material performance, provides strong support for the combination of material science theory and material engineering practice. It is helpful to promote the development and application of new materials to meet the needs of future science and technology and industry.

[0115] Further, the process of selecting an exchange-correlation functional to calculate the optimized structure of the material in step S11 specifically includes the following steps:

[0116] Step S111: Extract the initial structure of the material from the database, including atomic positions, symmetry, etc.; set the geometry optimization parameters in the calculation software, set the force and energy convergence criteria; start the calculation and run the geometry optimization;

[0117] Step S112: Using the optimized crystal structure, perform self-consistent field calculation to obtain the electron density distribution, view and analyze the electron density distribution graph in the file output; select the k-point grid to calculate the energy band along a specific high-symmetry direction; generate the energy band diagram and the state density diagram to analyze the filling state of each energy level; obtain the Fermi energy level position from the state density calculation and mark the position of the Fermi energy level in the energy band diagram;

[0118] Step S113: Determine the properties of metal, semiconductor or insulator by the shape of the state density diagram; analyze the energy band gap width, calculate the conductivity and estimate the prediction model; calculate the charge value of each atom using Bader charge analysis to ensure the correct distribution of local charge, present the charge distribution through the visualization tool, and analyze which atoms or compounds receive or lose electrons; analyze the localization degree of electrons between different atoms in combination with the Bader results to determine the possible active sites.

[0119] Preferably, step S111 of the present embodiment performs geometry optimization, extracts the crystal structure of the material from a material database (such as Materials Project, AFLOW, ICSD, etc.), including atomic positions, atomic species, symmetry information, and lattice parameters; ensures the validity and reliability of the calculation results; sets the algorithm, convergence criteria (energy and force), and k-point grid related to geometry optimization in the calculation software, and the force convergence criterion ensures that numerical oscillation will not be triggered during optimization, while the energy convergence criterion ensures the accuracy of the results; after starting the calculation, the software iteratively adjusts the atomic positions according to the selected algorithm to reduce the system energy, and finally obtains a stable crystal structure. The significance achieved: with the optimized crystal structure as the basis for subsequent calculations and simulations, it is ensured that any further calculation results are based on a stable and reliable system state; through geometry optimization, it is ensured that the geometry of the material accurately reflects the true situation in its lowest energy state, laying the foundation for understanding the physical and chemical properties of the material. Step S112 electronic structure calculation, using the optimized crystal structure to perform self-consistent field calculation, obtaining the electronic density distribution of the material; making it possible to visualize the distribution of electrons in the material, thereby helping to understand the influence of different types of atoms on the electronic state; selecting an appropriate k-point grid, then calculating the band structure, generating the corresponding band diagram and density of states (DOS), and the clear graphics show the filling of the electronic state, indicating the conductivity or insulating property of the material; the Fermi level position is obtained through the density of states diagram, and is marked on the band diagram, the determination of the Fermi level is crucial for judging the electrical properties of the material and understanding the behavior of the electronic state. The significance achieved: provides a detailed theoretical basis for the electrical properties of the material, which can predict the conductivity of the material under different conditions, further supporting the design and application of new materials; the analysis of band diagram and density of states diagram helps researchers to judge the applicability of materials in a wide range of application scenarios, such as new energy, electronic devices, etc. Step S113 conductivity and charge analysis, by analyzing the density of states diagram and the band gap width, judging the conductivity characteristics of the material (such as metal, semiconductor or insulator), and predicting its performance in practical applications; through Bader charge analysis, calculating the charge value of each atom, and using visualization tools to present the charge distribution, providing information for understanding the charge transfer and localization phenomenon between atoms, especially identifying possible active sites. The significance achieved: through charge analysis, researchers can confirm the possible active sites of the material in the process of catalysis, sensing, etc., providing guidance for subsequent experimental research; by understanding the localization and transfer phenomenon of electrons, more forward-looking and targeted material improvement schemes are designed to meet the specific functional and performance requirements.

[0120] In summary, the whole process of the embodiment forms a systematic research framework from geometry optimization to electronic structure calculation, and then to conductivity and charge analysis. This systematic method can greatly improve the efficiency and accuracy of material development, and provide necessary support for the research and application of new materials.

[0121] Further, as shown in Figure 3 the process of calculating the hydrogen adsorption performance of the newly designed hydrogen storage material in step S2 specifically includes the following steps:

[0122] Step S21: After obtaining the stable structure, perform molecular dynamics simulation and set the initial temperature and pressure; run MD simulation to obtain the kinetic stability and thermal stability data of the material, and obtain the selected structure of the material at different temperatures;

[0123] Step S22: Add hydrogen molecules to the optimized hydrogen storage material model, calculate the energy of different adsorption sites such as surface, vacancy or three-dimensional channel, identify the optimal adsorption site, evaluate the hydrogen adsorption energy of different sites, and select the adsorption site by comparing the adsorption energy of different sites;

[0124] Step S23: Perform thermodynamic calculation under different temperatures and pressures to evaluate the hydrogen adsorption capacity in the material, use the adsorption isotherm to estimate the adsorption capacity under different conditions, and quantify the hydrogen adsorption performance of the material.

[0125] Preferably, step S21 of the present embodiment systematically analyzes the atomic motion and structural changes of the material under different initial temperature and pressure conditions through MD simulation, which helps to identify the stable state of the material under dynamic conditions; by observing and simulating the material's response over time, the thermal stability and thermal properties of the material, such as whether the material will undergo phase change, dissociation or loss of structural integrity under high temperature conditions, are evaluated; at different temperatures, a variety of structural state information of the material is collected, including lattice constant, atomic position, relative energy, etc. These data are crucial for subsequent adsorption performance analysis. Significance: By obtaining a dynamically stable structure, a basis for material optimization can be provided, ensuring that subsequent adsorption performance analysis is based on a stable foundation; the thermal stability of the material is a key factor in determining whether it can be used for a long time in actual hydrogen storage applications, improving the understanding of the application prospects of the material. Step S22 Energy calculation of hydrogen molecule adsorption sites: by adding hydrogen molecules to the optimized hydrogen storage material, energy calculations are performed on different adsorption sites (such as surface, vacancy or three-dimensional channel), which helps to evaluate the adsorption tendency and capacity of hydrogen; the site with the lowest adsorption energy is identified, providing the most favorable region for hydrogen adsorption, which provides a basis for achieving efficient hydrogen storage. Significance: Understanding the adsorption capacity of hydrogen molecules at different positions can guide how to optimize the microstructure of the hydrogen storage material, thereby improving the hydrogen storage capacity; by selecting the optimal adsorption site, the hydrogen adsorption capacity is improved, and the overall hydrogen adsorption performance of the hydrogen storage material is improved, which is the key to achieving efficient hydrogen storage. Step S23 Thermodynamic calculation and adsorption isotherm analysis: under different temperature and pressure conditions, the adsorption amount of hydrogen in the material is systematically evaluated through thermodynamic calculation, providing quantitative data for understanding how the material stores hydrogen in actual applications; using adsorption isotherms (such as Langmuir or BET model), the adsorption amount and adsorption characteristics of hydrogen are quantified by fitting different data points, providing standards for hydrogen storage behavior under different conditions. Significance: Based on the quantified adsorption performance, the new designed material can be compared with other known materials to evaluate its advantages and disadvantages relative to existing technology; through quantitative analysis, the design and optimization of hydrogen adsorption materials can be further improved in experiments and engineering applications to better meet specific hydrogen storage needs.

[0126] In summary, the present embodiment calculates the hydrogen adsorption performance of the newly designed hydrogen storage material through the above steps, which systematically evaluates the characteristics of the material in terms of kinetics and thermodynamics, not only providing guidance for the optimization and application of the material, but also playing an important role in promoting the application of clean energy technology (such as hydrogen energy) in practice. The achievements of each stage complement each other, providing a solid foundation for the development and innovation of materials science.

[0127] Further, the process of obtaining selected structures of the material at different temperatures in step S21 specifically includes the following steps:

[0128] Step S211: Obtain the preliminary crystal structure of the hydrogen storage material, generate a three-dimensional model; geometrically optimize the initial structure, calculate using the DFT method, optimize the coordinates of each atom, and obtain the lowest energy configuration; for each target temperature, perform MD simulation;

[0129] Step S212: Describe the interatomic interaction of the material, and perform thermal equilibrium under isobaric conditions at a set initial temperature; after reaching thermal equilibrium, continue running the simulation to obtain the motion and changes of atoms inside the material; atomic coordinate data is extracted every certain time (e.g. 0.1 nanoseconds) and the system configuration under the current temperature condition is recorded;

[0130] Step S213: Analyze the collected structure data, calculate the atomic displacement, square displacement, and average distance of the material at different temperatures, etc.; using the coordination number and distribution between atoms, and energy minimization and other criteria, screen out the most stable and representative structures at different temperatures; the selected stable structures at different temperatures are summarized, visualized, and a temperature spectrum is generated.

[0131] Preferably, step S211 of the present embodiment preliminary model construction and geometry optimization, by obtaining the preliminary crystal structure of the hydrogen storage material from literature or database, and generating a three-dimensional model, laying the foundation for subsequent calculation; using density functional theory (DFT) and other methods to optimize the initial structure, not only can minimize the total energy of the material, but also can identify and adjust the undesirable atomic position; through optimization, ensure that the coordinates of each atom obtain the best configuration, so that the material is in a stable state in thermodynamics. Meaning: geometric optimization ensures that the atomic arrangement is reasonable, and the material has better stability and reliability under operating conditions, providing a reliable starting structure for molecular dynamics simulation; the optimized structure has a key influence on the results of subsequent dynamic and thermodynamic calculations, and is directly related to the accurate evaluation of the hydrogen adsorption performance of the material. Step S212 molecular dynamics simulation and thermal equilibrium, in molecular dynamics simulation, a reasonable potential energy function or force field can accurately simulate the interaction between atomic groups, so as to better exhibit the dynamic characteristics of the material; by setting the initial temperature for thermal equilibrium, the structural changes of the material during the heating process can be observed, and the temperature and pressure of the system can be ensured to reach a stable state; by regularly extracting atomic coordinate data during simulation, the dynamic behavior and atomic distribution of the material at a specific temperature can be collected. Meaning: dynamic simulation after thermal equilibrium helps to understand the motion characteristics of the material under different temperature conditions, and to predict how the material responds to changes in external temperature and pressure, so as to make a reasonable assessment of its application prospects; subsequent analysis of the collected trajectory data is the basis for evaluating the performance of the material, and only with the support of a sufficient database, reliable energy calculation and property evaluation can be carried out. Step S213 structure data analysis and stable structure screening, analyze the collected structure data, calculate atomic displacement, square displacement, average distance of atoms, coordination number, etc., by comparing these physical characteristics, the stability and applicability of the material at different temperatures can be evaluated; using the atomic coordination number and energy minimization standard, the most stable and representative structure exhibited at different temperatures is identified, ensuring that the obtained model can truly reflect the state of the material in actual application; the generated temperature spectrum visualizes the structural changes and characterization of the material when affected by temperature, making the research results more intuitive and helping to better understand the material characteristics. Meaning: by quantitatively analyzing the characteristics of the selected structure at different temperatures, empirical support can be provided for hydrogen adsorption performance analysis, which is of great significance to scientific research and engineering application; the selected stable structure not only provides a basis for further optimization of hydrogen storage materials, but also provides a direction for the design and synthesis of new materials, promoting the development of hydrogen storage technology.

[0132] In summary, the selected structure of the hydrogen storage material at different temperatures is obtained through the above steps, which ensures that the final obtained structure can meet the diversified requirements in terms of function, performance and practicability, and helps to understand the behavior of the material in depth, and provides a solid foundation for future theoretical and applied research in the field of hydrogen storage.

[0133] Further, the process of identifying the optimal adsorption site in step S22 specifically includes the following steps:

[0134] Step S221: Geometrically describe the surface and internal structure of the hydrogen storage material, and use geometric features and spatial symmetry to depict different possible hydrogen molecule adsorption sites;

[0135] Among them, the marked sites should include: above the surface atoms ("top site"), in the middle ("bridge site") and vacancies inside the channel, etc.

[0136] Step S222: Introduce one or more hydrogen molecules into the model of the hydrogen storage material simultaneously around different marked adsorption sites; dynamically simulate the hydrogen molecules at different adsorption sites; under the set initial conditions, observe the motion of the hydrogen molecules and record the interaction with the hydrogen storage material;

[0137] Step S223: For each adsorption site, calculate the interaction energy between the hydrogen molecule and the material using the potential energy relationship; obtain the relative stability of the hydrogen molecule at each adsorption site through the energy minimization program; compare the calculated adsorption energy, and identify the site with the lowest energy as the optimal adsorption site.

[0138] Preferably, step S221 of the present embodiment describes geometry and defines adsorption sites. By analyzing the geometry and spatial symmetry of the hydrogen storage material, possible hydrogen molecule adsorption sites can be identified. The selection of sites is mainly based on the arrangement of surface atoms and their relationship with adjacent atoms. According to the structural characteristics of the hydrogen storage material, different types of adsorption sites (such as top sites, bridge sites, and vacancies in channels) are defined, providing a basis for subsequent computational simulation and analysis. Significance: This lays a solid foundation for subsequent adsorption simulation and energy calculation, ensuring that all possible hydrogen molecule adsorption sites are covered to the maximum extent, improving the comprehensiveness of the model; by accurately defining adsorption sites, experiments can be more effectively designed, unnecessary calculation and simulation time can be reduced, and research efficiency can be improved. Step S222: Dynamic simulation of hydrogen molecules, hydrogen molecules are introduced into the computational model of the hydrogen storage material simultaneously, and the dynamic behavior of hydrogen molecules in different adsorption sites is studied through MD simulation; under the given initial conditions (such as temperature and pressure), the motion trajectory of hydrogen molecules is observed, and relevant data of hydrogen molecule interaction with the material are collected. Significance: Through dynamic simulation, the motion law of hydrogen molecules in the hydrogen storage material and the influence on the material structure can be better understood, enhancing the understanding of the hydrogen adsorption behavior of the material; providing necessary dynamic information for subsequent energy calculation, making the calculation results more realistic, and improving the credibility of the simulation results. Step S223: Interaction energy calculation and optimal site identification, using force field and potential energy relationship, the interaction energy (adsorption energy) of hydrogen molecules in each adsorption site is calculated, providing quantitative data for evaluating adsorption capacity; through energy minimization program, the relative stability of hydrogen molecules in each adsorption site is evaluated to ensure that the optimal site selected has the lowest energy. Significance: Comparing the energy of each adsorption site can determine their respective adsorption capacity, and identifying the adsorption site with the lowest energy as the optimal adsorption site is the key to optimizing the performance of hydrogen storage materials; identifying the optimal adsorption site not only provides important data support for the application of hydrogen storage materials, but also provides a clear direction for the design and optimization of future materials.

[0139] In summary, the process of identifying the optimal hydrogen adsorption site in the present embodiment improves the accuracy and effectiveness of hydrogen adsorption performance research through refined steps. It provides a scientific basis for understanding and optimizing the hydrogen adsorption capacity of hydrogen storage materials. The research results not only enrich the understanding of hydrogen storage materials in theory, but also practically promote the future application and development.

[0140] Further, the process of quantifying the hydrogen adsorption performance of the material in step S23 specifically includes the following steps:

[0141] Step S231: using a gas adsorption isotherm measuring device, hydrogen is introduced into the hydrogen storage material pre-treated by vacuum, and different hydrogen pressures are gradually applied; at each set pressure, the gas volume change, pressure change and temperature change during the adsorption process are monitored in real time by a range instrument;

[0142] Step S232: calculate the change in the amount of substance of the gas at a specific pressure by the ideal gas state equation, compare the amount of adsorbed hydrogen with the mass of the material, and calculate the hydrogen adsorption amount per gram of material; under different temperature and pressure conditions, corresponding gas adsorption experiments are carried out; apply the adsorption isotherm model to fit the data and extract the thermodynamic parameters in the adsorption isotherm;

[0143] Step S233: through the calculation of the adsorption isotherm and the thermodynamic parameters, the maximum adsorption amount of the stored hydrogen and the transfer and release characteristics of the gas in the material are obtained; record and analyze the adsorption equivalent energy under different conditions, including the saturated adsorption amount, the kinetic adsorption rate and the desorption rate; compare the test results with the adsorption performance of the hydrogen storage material.

[0144] Preferably, the gas adsorption experiment of step S231 of the present embodiment is carried out using a gas adsorption isotherm measuring device, hydrogen gas is introduced into the hydrogen storage material treated in vacuum, and different hydrogen gas pressures are gradually applied. During this process, the changes in gas volume, pressure and temperature during the adsorption process are monitored in real time by a range instrument to ensure the accuracy and stability of the data acquisition; by real-time monitoring, a dynamic adsorption behavior model of the gas in the material can be generated, providing raw data support for subsequent data analysis. Significance: Ensure that the experiment is carried out under controlled conditions, so that oxidation, humidity or other external factors do not interfere with the adsorption process of hydrogen gas, thereby improving the credibility of the results; record the corresponding gas changes to provide a basis for subsequent quantitative analysis, ensuring that there is sufficient data support when evaluating the performance of the material. Step S232 calculates the amount of hydrogen adsorbed, calculates the amount of substance of the gas at a specific pressure by the ideal gas state equation (PV = nRT), thereby obtaining the amount of adsorbed hydrogen; compare the amount of adsorbed hydrogen with the mass of the hydrogen storage material to calculate the hydrogen adsorption capacity per gram of material, including corresponding data at different temperatures and pressures. Significance: Quantify the hydrogen adsorption capacity, so that the performance of the material can be described in quantifiable parameters (such as wt% or mol / kg), thereby providing a basis for evaluating its practical application potential; through data fitting and the application of adsorption isotherm models, thermodynamic parameters (such as adsorption energy, specific surface area, etc.) can be extracted, providing a deep foundation for understanding the internal mechanism of the material. Step S233 analyzes the characteristics and compares the results, obtains the maximum hydrogen adsorption capacity through the calculation of the adsorption isotherm and thermodynamic parameters, and analyzes the transfer and release characteristics of the gas inside the material, including the saturated adsorption capacity, adsorption and desorption rate, etc.; compare the test results obtained with the performance of the hydrogen storage materials in the existing literature to determine the advantages or disadvantages of the material studied in terms of hydrogen adsorption capacity. Significance: The analysis of maximum adsorption capacity and gas transfer characteristics provides a scientific basis for understanding the behavior of the material in hydrogen storage, helping to explain the internal mechanism of the material performance; by comparing with other hydrogen storage materials, the feasibility of the material in practical application can be quickly identified, promoting more effective material screening and optimization, and contributing to the development of hydrogen energy technology.

[0145] In summary, each step of the present embodiment plays an indispensable role in quantifying the hydrogen adsorption performance of the hydrogen storage material. Through systematic experiments, data analysis and performance comparison, not only the accuracy and reliability of the results are ensured, but also a clear direction for the optimization of hydrogen storage materials is provided. The in-depth understanding of the characteristics of the material improves the scientific basis and technical reference for future research and application development.

[0146] Further, as shown in Figure 4 , the process of calculating and evaluating the hydrogen storage kinetic performance of the material in step S3 specifically includes the following steps:

[0147] Step S31: Real-time record the pressure and flow changes of hydrogen at different time points through pressure sensor and flow meter, form dynamic monitoring data set; process the data collected from adsorption experiment, calculate the hydrogen adsorption at different time points, record the hydrogen amount change at each time node;

[0148] Step S32: Apply ideal gas state equation, calculate the amount of substance corresponding to hydrogen adsorption according to the change of gas volume and pressure, and compare with the mass of material; use the obtained data, apply kinetic model (such as Langmuir or BET model) to fit the adsorption rate of hydrogen, get the characteristics of adsorption process;

[0149] Step S33: Draw the relationship curve of hydrogen adsorption amount on hydrogen storage material (y axis) and time (x axis) on the coordinate ruler, show the time dependence of hydrogen adsorption; extract key parameters such as initial adsorption rate, equilibrium adsorption amount and dynamic equilibrium time from the drawn curve; calculate the important kinetic parameters such as adsorption rate constant and diffusion coefficient of hydrogen, evaluate the hydrogen adsorption kinetic performance of the material.

[0150] Preferably, step S31 of the present embodiment is real-time data recording and processing, which records the pressure and flow changes of hydrogen at different time points in real time through pressure sensors and flow meters, forms a comprehensive dynamic monitoring data set, and provides basic data; based on real-time data, the hydrogen adsorption amount at each time node is calculated, and the direct relationship between the hydrogen adsorption process and time is established. Significance: Real-time data extraction provides a complete view of the hydrogen adsorption process, ensuring the reliability and accuracy of the data; the cornerstone of further analysis and model fitting; understanding the different stages of the hydrogen adsorption process in the material makes subsequent analysis and results more detailed, especially in terms of dynamic and transient behavior analysis. Step S32 is the calculation of the amount of substance and the fitting of the kinetic model, which applies the ideal gas state equation to calculate the amount of substance of hydrogen according to the changes of gas volume and pressure, and provides a quantitative comparison between the hydrogen adsorption characteristics and the material quality; data fitting is performed using Langmuir or BET model, etc., the hydrogen adsorption rate of the material is determined by analyzing the adsorption isotherm, and the characteristics of the adsorption process are obtained. Significance: By calculating the amount of substance, the hydrogen adsorption capacity is quantified, making it possible to compare different materials and promoting the selection of hydrogen storage materials with superior performance; the application of kinetic models enables us to deeply understand the mechanism and characteristics of hydrogen adsorption, and to clearly understand the adsorption kinetics of the material, thereby guiding the optimization and design of the material. Step S33 is drawing analysis and key parameter extraction, which draws the relationship curve between the adsorption amount of hydrogen on the hydrogen storage material (y-axis) and time (x-axis), intuitively displays the time dependence of hydrogen adsorption, and facilitates the observation of the dynamic behavior of the adsorption process; key parameters such as initial adsorption rate, equilibrium adsorption amount and dynamic equilibrium time are extracted from the drawn curve, and important kinetic parameters such as adsorption rate constant and diffusion coefficient are calculated. Significance: The hydrogen adsorption kinetics curve provides a visual tool for evaluating and comparing the performance of hydrogen storage materials, making the hydrogen adsorption capacity of different materials more intuitive; by analyzing the key parameters, the adsorption rate and its influencing factors can be better understood, providing a theoretical basis for the design and development of new materials and promoting the further development of hydrogen storage technology.

[0151] In summary, the present embodiment systematically reveals the adsorption behavior and kinetic characteristics of hydrogen in hydrogen storage materials through real-time data recording, amount of substance calculation, kinetic model fitting and curve analysis, which provides a powerful support for material application and technological progress. Such methodology provides a comprehensive and systematic perspective for the research and application of hydrogen storage materials, enabling future hydrogen storage technology to develop towards higher efficiency and greater sustainability.

[0152] Further, the process of obtaining the characteristics of the adsorption process in step S32 specifically includes the following steps:

[0153] Step S321: Obtain the hydrogen adsorption amount and corresponding time data. Establish a structured data table including time points, corresponding hydrogen pressure, flow rate, hydrogen adsorption amount, etc. information; preliminarily analyze the obtained data, and draw the hydrogen adsorption amount-time curve;

[0154] Step S322: Select a fitting tool, use nonlinear least squares method to minimize the error between the estimated model and experimental data; input experimental data and select model equation;

[0155] Step S323: Check the fitting curve and the degree of agreement with the actual data, output the key parameters of the fitting, calculate the goodness of fit, and the value close to 1 indicates that the model predicts the adsorption behavior.

[0156] Preferably, the data structuring and preliminary analysis of step S321 of the embodiment, by establishing a structured data table, the hydrogen pressure, flow rate and adsorption amount of each time point in the hydrogen adsorption experiment are orderly arranged. This structured processing is helpful for subsequent data analysis and model fitting; preliminarily analyze the relationship between hydrogen adsorption amount and time, and draw the change curve, and the visualized graph is helpful to identify the trend and characteristics of the adsorption process. Significance: It provides a clear data basis for subsequent analysis, ensures the integrity and readability of the data, so that researchers can efficiently use these data for further analysis; through visualization, the hydrogen adsorption dynamics can be intuitively analyzed, and the initial stage, rapid adsorption, equilibrium state and other stages of adsorption can be quickly identified, which provides a basis for model selection, so that researchers can select the appropriate fitting model. Step S322 selects the fitting tool and data input, selects the appropriate fitting tool (such as Excel, Matlab, Python, etc.), and provides technical support for the fitting process through the nonlinear least squares method in the tool; input the structured data into the selected fitting software, select the corresponding model equation (such as Langmuir or BET model), which is convenient for parameter estimation. Significance: Various fitting tools have rich functions and flexibility, which makes the data processing process well standardized, and helps to improve efficiency and reliability of the results; accurate selection and input of model equation makes the fitting process targeted to the characteristics of experimental data, ensuring reasonable estimation of subsequent parameters, thereby improving the scientificity of the results. Step S323 analyzes and evaluates the fitting results, checks the fitting curve and the degree of agreement with the actual data, outputs the key parameters of the fitting (such as maximum adsorption amount, equilibrium constant), and calculates the goodness of fit (such as R 2 value); judge the fitness of the model to the experimental data according to the goodness of fit value, and R 2A value close to 1 means that the model can effectively predict the adsorption behavior. Meaning: by checking the matching degree of the fitted data and the actual experimental data, the effectiveness of the selected model can be verified, which provides a basis for the scientificity of the model; if the model cannot fit the data well, it may be necessary to re-evaluate the model or consider more complex adsorption mechanisms; the output of key parameters provides a quantitative basis for understanding the specific characteristics of the adsorption process, such as analyzing the adsorption capacity and kinetic characteristics of the material, thereby providing a direct basis for optimizing material properties and applications.

[0157] In summary, the embodiments collectively constitute a comprehensive analysis of the characteristics of the hydrogen adsorption process. The structuring and visualization of data make information processing and understanding more convenient, the selection of appropriate fitting tools and models ensures the reliability of the results, and through the evaluation of the fitting results, researchers can gain a deeper understanding of the hydrogen adsorption characteristics. The entire process not only improves the systematicness and rigor of the research, but also provides a new direction and foundation for future material optimization and application.

[0158] As shown in Figure 5 The embodiments also provide an embodiment of a solid hydrogen storage material hydrogen storage performance calculation and evaluation system, which is applied to the solid hydrogen storage material hydrogen storage performance calculation and evaluation method in the above embodiments. The solid hydrogen storage material hydrogen storage performance calculation and evaluation system includes a performance analysis module 1, a performance calculation module 2, and a performance evaluation module 3 connected in sequence.

[0159] The performance analysis module 1 is used to analyze the mechanical properties, electronic distribution, thermal conductivity, and thermal stability of the designed material itself by constructing a microcosmic model of the material using the functional density theory (DFT) and molecular dynamics (MD) methods. The performance calculation module 2 is used to calculate the hydrogen adsorption performance of the newly designed hydrogen storage material by calculating the adsorption state, adsorption energy of hydrogen molecules on the hydrogen storage material, and hydrogen adsorption amount of the material at different pressures and temperatures. The performance evaluation module 3 is used to draw the hydrogen adsorption kinetics curve of the solid hydrogen storage material to calculate and evaluate the hydrogen storage kinetic performance of the material.

[0160] Preferably, the performance analysis module 1 of the present embodiment utilizes DFT and MD methods, which can construct a microscopic model of the material, and the process of in-depth understanding of the structure and properties of the material is the basis of the design of hydrogen storage materials; by analyzing the mechanical properties, electron distribution, thermal conductivity and thermal stability of the material, not only the physical properties of the material under different environments can be obtained, but also the stability and applicability of the material can be evaluated; detailed quantitative data is provided for the subsequent module to support more accurate performance calculation. Detailed performance analysis is an important basis for determining the suitability of the material. Practical significance: by obtaining the basic physical and chemical properties of the material, this module can accelerate the screening and development process of new materials, reduce the need for blind experiments, and improve the overall R&D efficiency; in-depth understanding of the basic characteristics of the material helps to promote the optimized design of new materials and ensure their effectiveness and safety in hydrogen storage / application. The performance calculation module 2 obtains the interaction parameters between hydrogen and materials by calculating the adsorption state and adsorption energy of hydrogen molecules on the hydrogen storage material, and deeply understands the adsorption capacity of the material; the calculation of hydrogen adsorption amount under different pressures and temperatures can evaluate the hydrogen adsorption performance of the material under actual operating conditions, which is crucial for practical application; the data provided provides key parameters for the subsequent dynamic performance evaluation module to ensure a comprehensive understanding of hydrogen adsorption performance. Practical significance: providing quantitative standards for material screening helps researchers select the best hydrogen storage material according to specific conditions, which helps to improve the efficiency of hydrogen storage in practical applications; by systematically calculating the hydrogen adsorption performance, it promotes in-depth research on new hydrogen storage materials and promotes scientific progress. The performance evaluation module 3 draws the hydrogen adsorption kinetics curve to present the dynamic characteristics of the hydrogen adsorption and desorption process of the hydrogen storage material, providing intuitive visual information; the calculation and evaluation of the hydrogen storage kinetic performance of the material, including adsorption rate, diffusion coefficient, etc., provide necessary quantitative analysis for understanding the transport behavior of hydrogen in the material; the overall evaluation of the hydrogen storage material in the kinetic aspect is realized to ensure that the finally selected material exhibits excellent hydrogen storage capacity under both transient and steady-state conditions. Practical significance: through comprehensive dynamic performance evaluation, the selected hydrogen storage material has good reaction speed in practical application, improving the reliability of industrial application; dynamic evaluation results can guide subsequent material improvement and technological innovation, promoting the overall progress of hydrogen storage technology.

[0161] In summary, the performance analysis module of the present embodiment provides basic data support and material property analysis, the performance calculation module optimizes it to specific hydrogen storage performance indicators, and the performance evaluation module ensures the actual performance and application feasibility of the material through dynamic analysis. The systematic structure coordinates the theoretical research and practical application of the material, and provides comprehensive and detailed hydrogen storage performance evaluation, laying a solid foundation for the future development of hydrogen energy technology and material innovation, which helps to promote the widespread application of renewable energy.

[0162] AsFigure 6 As shown, the present embodiment provides an embodiment of an electronic device, in which the electronic device 4 comprises a processor 41 and a memory 42 coupled to the processor 41.

[0163] The memory 42 stores program instructions for implementing the method for calculating and evaluating the hydrogen storage performance of a solid-state hydrogen storage material according to any of the above embodiments.

[0164] The processor 41 is configured to execute the program instructions stored in the memory 42 to calculate and evaluate the hydrogen storage performance of a solid-state hydrogen storage material.

[0165] The processor 41 can also be referred to as a CPU (Central Processing Unit). The processor 41 can be an integrated circuit chip with signal processing capability. The processor 41 can also be a general-purpose processor, a DSP (Digital Signal Processor), an ASIC (Application-Specific Integrated Circuit), an FPGA (Field Programmable Gate Array) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor.

[0166] Further, Figure 7 The storage medium 5 of the present embodiment stores program instructions 51 capable of implementing all the methods described above. The program instructions 51 can be stored in the form of a software product in the storage medium described above, including a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes a U disk, a mobile hard disk, a ROM (Read-Only Memory), a RAM (Random Access Memory), a magnetic disk or an optical disk, etc. various media that can store program codes, or a computer, a server, a mobile phone, a tablet, etc. terminal device.

[0167] Calculation and evaluation of hydrogen storage performance of Na-modified low-dimensional porous graphene

[0168] Figure 8 Sodium-modified nitrogenated porous graphene cell model structure. (a), (b) and (c) are porous graphite, a single and two Na-modified porous graphene, respectively.

[0169] The present application is a method for calculating and evaluating the hydrogen storage performance of a solid-state hydrogen storage material, which comprises theoretical calculation and evaluation of the electronic properties, hydrogen adsorption properties, thermal conductivity properties, thermal stability and hydrogen kinetic properties of the solid-state hydrogen storage material. Figure 8The figure is a model of nitrogenated holey graphene before and after Na modification. The following will take this model as an example to illustrate the specific embodiments of the present application. The calculation software and methods used in the following examples are obtained from the open source channel if not otherwise specified.

[0170] Figure 9 For the DFT method, the electronic band structure diagram in the energy range of-5-5 eV is calculated by the VASP software package, and the electronic properties of the present application can be analyzed. From Figure 9 It can be seen that the electronic band gaps of the three materials are Eg1=1.65 eV, Eg2=1.52 eV and Eg3=1.22 eV (orange part in the figure) respectively. This indicates that when sodium atoms are modified on the surface of nitrogenated holey graphene, the electronic band gap of the material will decrease, and the electrons are more easily excited from the valence band to the conduction band to participate in heat transport, thus promoting the heat conduction process of the material, and the more the number of sodium atoms modified, the more obvious the effect. From Figure 2 It can be seen from the figure that the band gap position of C2N, C2N+Na and C2N+Na is continuously lowered, and the work function is continuously increased. This indicates that as the number of sodium atoms modified gradually increases, the binding effect of electrons in the material is stronger, and the electron emission is difficult, which is not conducive to the heat conduction of the material. In summary, the electronic thermal conductivity of the material needs to be further calculated to determine which effect is dominant in the heat conduction process of the material, the band gap reduction or the work function increase brought by sodium metal modification. In addition, as shown in Figure 2 There is no band crossing at the Fermi level (orange dotted line) of the nitrogenated holey graphene, while the two sodium-modified nitrogenated holey graphenes have band crossing through the Fermi level. This indicates that the nitrogenated holey graphene is a semiconductor, while the sodium-modified nitrogenated holey graphene is a metal. Therefore, the electronic relaxation time of C2N+Na and C2N+2Na is taken as 10 fs when calculating the electronic properties.

[0171] The electronic properties of the material can also be analyzed by the charge difference density map as shown in Figure 10 From the results in the figure, it can be seen that there is charge transfer between Na atoms and N atoms, so there is strong interaction between Na atoms and N atoms.

[0172] Table 1 Bader charge and binding energy of Na atoms in single and two Na-modified nitrogenated holey graphenes

[0173] Single Na modification Two Na modifications Q Bader,Na (e)]]> +0.78 +0.74 / 0.71 avE bind,Na (eV) 4.83 2.65

[0174] The electronic properties of the materials can also be quantitatively analyzed by the Bader charge and binding energy results in Table 1. From the results in Table 1, the amount of charge transferred from Na atoms to N atoms can be quantitatively determined. The adsorption ability of Na atoms on the surface of the material can be quantitatively analyzed by the calculated results of the binding energy. From the results in the table, it can be seen that the binding energy is greater than 0.5 eV, whether single or two Na modifications, and is in the form of chemical adsorption, which can be stably adsorbed on the surface of the material.

[0175] The hydrogen adsorption performance of the material can be analyzed by the charge difference density map when hydrogen is adsorbed on the surface of the material, and the calculation results are shown in Figure 11 From the results in the figure, it can be seen that when a single Na is modified, the adsorption of hydrogen molecules on the surface of the material is relatively dispersed, and the polarization of hydrogen analysis is small. When two Na are modified, the distribution of hydrogen molecules on the surface of the material is more concentrated, and the polarization of hydrogen molecules is more obvious. Therefore, it is believed that the two Na modified nitrogenated porous graphene has a stronger adsorption effect on hydrogen molecules.

[0176] The thermal conductivity of the material includes two aspects of electronic thermal conductivity and phonon thermal conductivity. The electronic thermal conductivity is obtained by combining the VASP and BoltzTraP2 software. The phonon thermal conductivity is calculated by using the VASP and Alamode software.

[0177] To analyze the electronic thermal conductivity, the electronic transport properties of the material must be calculated first, as shown in Figure 12 The ratio of the conductivity of each material to the electronic relaxation time is calculated by BoltzTraP2, and then multiplied by the electronic relaxation time of the corresponding material to obtain the conductivity and power factor of the material as a function of the carrier concentration in the material, as shown in Figure 12 . Figure 12 (a) of FIG. 1 shows that as the carrier concentration of the material increases, the conductivity of the nitrogenated porous graphene increases continuously. At the same time, the conductivity of the two sodium-modified nitrogenated porous graphene increases slowly at the early stage and then slowly increases with the increase of the carrier concentration. Since the conductivity is proportional to the electronic thermal conductivity, it can be determined that the change trend of the electronic thermal conductivity of the material with the carrier concentration is similar to that of the conductivity.

[0178] Further, the calculation results of the electronic thermal conductivity of the material are shown in Figure 13 From the results in the figure, it can be seen that the electronic thermal conductivity of the nitrogenated porous graphene increases significantly with the increase of the carrier concentration, while the electronic thermal conductivity of the two sodium-modified nitrogenated porous graphene increases gradually, which is similar to the change trend of the conductivity. Under the optimal carrier concentration, the electronic thermal conductivities of the nitrogenated porous graphene, the single Na atom modified and the two Na atom modified are 1.48 Wm -1 K -1 , 1.46 Wm -1 K -1and 1.33Wm - 1 K -1 The results showed that the electronic thermal conductivity of the material decreased slightly after the addition of sodium metal.

[0179] To analyze the phonon thermal conductivity, the phonon dispersion relation of the material must first be calculated, and the results are as follows: Figure 14 As shown in the figure, sodium atom modification leads to three main changes in the phonon properties of the material. First, high-frequency optical phonons (yellow solid box) exhibit a redshift, a phenomenon that becomes more pronounced with increasing sodium atom count. This softening of high-frequency phonons reduces the high-frequency phonon group velocity, thereby decreasing the lattice thermal conductivity. Furthermore, new phonon branches are generated in the low-frequency range. While these new phonon branches contribute to heat transport, their contribution to thermal conductivity is extremely limited due to their small branching slope and low group velocity. Finally, low-frequency acoustic phonons exhibit a softening effect. In solid materials, acoustic phonons play a crucial role in heat transport. Therefore, the softening of acoustic phonons leads to a significant reduction in the material's lattice thermal conductivity.

[0180] Furthermore, to analyze the phonon thermal conductivity, the phonon relaxation time and group velocity of the material were calculated, and the results are as follows: Figure 15 As shown. Figure 15 (a) shows that the phonon relaxation time of nitrided porous graphene is mainly concentrated in the range of 0.1–10 ps. In the low-frequency range (<10 THz), the phonon relaxation time decreases sequentially for nitrided porous graphene, single Na-atom modified graphene, and graphene modified with two Na atoms. This indicates that adding metallic sodium decoration to nitrided porous graphene leads to low-frequency phonon scattering within the material, thereby shortening the phonon relaxation time. Figure 15 As shown in (b), at frequencies below 10 THz, the phonon group velocities of nitrided porous graphene, single Na atom and two Na atom-modified phonon groups show a decreasing trend, resulting in a decrease in lattice thermal conductivity.

[0181] Furthermore, the phonon thermal conductivity of the material is calculated, and the phonon thermal conductivity of the material is quantitatively analyzed. Figure 9 The lattice thermal conductivity of sodium-modified porous graphene nitride is presented. At room temperature (300 K), the lattice thermal conductivity of porous graphene nitride is 17.88 W / m². -1 K -1 The thermal conductivity of single and double Na-modified porous graphene nitride is 6.02 W / m². -1 K -1 and 3.48Wm - 1 K -1At the same temperature, the lattice thermal conductivity of the nitrogenated holey graphene, single and two Na atom modified lattice thermal conductivity decreases in turn. With the increase of temperature, the thermal conductivity of the nitrogenated holey graphene decreases more obviously, while the thermal conductivity of the sodium-modified nitrogenated holey graphene decreases more gently, and the lattice thermal conductivity of the two Na-modified nitrogenated holey graphene almost remains unchanged. Therefore, it can be concluded that the addition of sodium metal reduces the lattice thermal conductivity of the material and reduces its sensitivity to temperature changes. The analysis of the phonon characteristics shows that the sodium atom scatters the phonons in the material, thereby reducing the phonon relaxation time. The simultaneous reduction of the phonon relaxation time and the group velocity leads to a significant reduction in the lattice thermal conductivity of the material, and the sensitivity of the lattice thermal conductivity of the material to temperature decreases.

[0182] The above analysis shows that the modification of metal Na increases the hydrogen storage capacity of the material, but at the same time reduces the thermal conductivity of the material, thereby reducing the hydrogen adsorption kinetics of the material. Further, the hydrogen adsorption kinetics of the material is calculated and analyzed by the MD method.

[0183] The hydrogen adsorption kinetics curve includes hydrogen adsorption isotherm, isobar, adsorption / release rate, etc. Adsorption kinetics mainly studies the diffusion performance of hydrogen in hydrogen storage materials. Since the temperature of the system needs to be controlled during the charging / discharging process of solid-state hydrogen storage materials, the thermal conductivity of the material has a great influence on the hydrogen adsorption kinetics of the hydrogen storage material.

[0184] In several embodiments provided by the present application, it should be understood that the disclosed system, device and method can be implemented by other manners. For example, the device embodiments described above are only illustrative, for example, the division of units is only a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units shown or discussed can be indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0185] In addition, each functional unit in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The above integrated unit can be realized in the form of hardware or in the form of software functional unit. The above is only an embodiment of the present application, and does not limit the patent scope of the present application, and any equivalent structure or equivalent process transformation using the content of the present application specification and drawings, or direct or indirect application in other related technical fields, are also included in the patent protection scope of the present application.

[0186] The above detailed description of the application is only exemplary, and the application is not limited to the specific embodiments described above. Any equivalent modifications or substitutions made by those skilled in the art to the application are also within the scope of the application, and equivalent transformations, modifications, improvements, etc. made without departing from the spirit and principles of the application should be covered within the scope of the application.

Claims

1. A method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials, characterized in that, The method for calculating and evaluating the hydrogen storage performance of the solid hydrogen storage material includes: By utilizing functional density theory and molecular dynamics, we can analyze and design the mechanical properties, electronic distribution, thermal conductivity, and thermal stability of materials by constructing microscopic models. The hydrogen adsorption performance of the newly designed hydrogen storage material was calculated by calculating the adsorption state of hydrogen molecules on the hydrogen storage material, the adsorption energy, and the amount of hydrogen adsorbed by the material under different pressures and temperatures. To plot the hydrogen adsorption kinetics curves of solid hydrogen storage materials in order to calculate and evaluate the hydrogen storage kinetics performance of the materials; The process of calculating the hydrogen adsorption performance of the newly designed hydrogen storage material includes: After obtaining a stable structure, molecular dynamics simulations are performed, with initial temperature and pressure set. The molecular dynamics simulations are then run to obtain data on the kinetic and thermal stability of the material, and to obtain the selected structures of the material at different temperatures. Hydrogen molecules are added to the optimized hydrogen storage material model, and different adsorption sites on the surface, vacancies or three-dimensional channels are calculated. Energy is calculated for each site, the optimal adsorption site is identified, the hydrogen adsorption energy of different sites is evaluated, and the adsorption site is selected by comparing the adsorption energy of different sites. Thermodynamic calculations were performed at different temperatures and pressures to evaluate the amount of hydrogen adsorbed in the material. Adsorption isotherms were used to estimate the amount of adsorption under different conditions, thus quantifying the hydrogen adsorption performance of the material. The process of calculating and evaluating the hydrogen storage kinetics performance of materials includes: The pressure and flow rate changes of hydrogen at different time points are recorded in real time by pressure sensors and flow meters to form a dynamic monitoring dataset; the data collected from the adsorption experiment are processed to calculate the hydrogen adsorption at different time points and record the change in the amount of hydrogen at each time point. By applying the ideal gas law, the amount of substance corresponding to hydrogen adsorption is calculated based on the changes in gas volume and pressure, and compared with the mass of the material. Using the acquired data, a kinetic model is applied to fit the adsorption rate of hydrogen, and the characteristics of the adsorption process are obtained. Plot the relationship between hydrogen adsorption amount and time on the hydrogen storage material on a coordinate scale to show the time dependence of hydrogen adsorption; extract key parameters from the plotted curves; calculate important kinetic parameters such as the hydrogen adsorption rate constant and diffusion coefficient to evaluate the hydrogen adsorption kinetic performance of the material.

2. The method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials according to claim 1, characterized in that, The material microstructure modeling analysis process includes: Geometric optimization was performed using applied functional density theory to determine the optimal lattice structure of the material. Exchange-correlation functional theory was used to calculate the optimized structure. The electron density distribution of the optimized structure was obtained through calculation, and information on electronic states, band structure, and Fermi levels was extracted. The conductivity of the material was analyzed, and its conductivity and insulation properties were determined through density of states and band diagrams. Bader charge analysis was used to evaluate charge transfer and localization phenomena, and to obtain the chemical properties and reaction behavior of the material. The interaction potential between materials was selected based on the characteristics of the materials and the nature of the interactions. The optimal geometry obtained by applying functional density theory is used as the initial configuration for molecular dynamics simulations; temperature, pressure, and time step parameters are set; molecular dynamics simulations are run at different temperatures and pressures to obtain the thermal behavior, phase transition process, and mechanical response of the material; the adsorption and diffusion behavior of gas molecules on the material surface are tested to obtain kinetic information; external stress is applied to generate stress-strain curves and analyze the elastic modulus, yield strength, and fracture behavior of the material; the relative motion between atoms is analyzed to extract displacement field information and obtain changes in the mechanical properties of the material. The nonequilibrium molecular dynamics method was used to analyze the thermal conductivity of materials at different temperatures; lattice vibrations and phonon thermal conduction were calculated to assess the influence of atomic-level thermal motion on macroscopic thermal conductivity; repeated thermal cycling was applied in molecular dynamics to obtain the stability and deformation of materials under high-temperature conditions; after the materials reached thermal equilibrium, their corresponding properties in thermally excited states were evaluated to identify potential phase transition or degradation mechanisms.

3. The method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials according to claim 2, characterized in that, The process of selecting the optimal structure for exchange-correlation functional computation materials includes: The initial structure of the material, including atomic positions and symmetry, is extracted using a database; geometric optimization parameters are set in the calculation software, and force and energy convergence criteria are set; the calculation is started, and geometric optimization is run. Using the optimized crystal structure, self-consistent field calculations are performed to obtain the electron density distribution. The electron density distribution map is viewed and analyzed in the output file. A k-point grid is selected to calculate the band structure along a specific high-symmetry direction. A band structure and density of states diagram are generated, and the filling state of each energy level is analyzed. The Fermi level position is obtained from the density of states calculation and marked on the band structure diagram. The shape of the density of states plot is used to determine the properties of metals, semiconductors, or insulators; the band gap width is analyzed to calculate conductivity and estimate prediction models; Bader charge analysis is used to calculate the charge value of each atom to ensure the correct distribution of local charges, and the charge distribution is presented through visualization tools to analyze which atoms or compounds receive or lose electrons; combined with Bader results, the degree of electron localization between different atoms is analyzed to identify possible reactive sites.

4. The method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials according to claim 1, characterized in that, The process of obtaining a selected structure of a material at different temperatures includes: The preliminary crystal structure of the hydrogen storage material was obtained, and a three-dimensional model was generated. The initial structure was geometrically optimized, and calculations were performed using functional density theory to optimize the coordinates of each atom and obtain the minimum energy configuration. Molecular dynamics simulations were performed for each target temperature. The simulation describes the interactions between atoms in the material and establishes thermal equilibrium under isobaric conditions at a set initial temperature. After thermal equilibrium is reached, the simulation continues to run to obtain the motion and changes of atoms inside the material. Atomic coordinate data is extracted once to record the system configuration under the current temperature conditions. The collected structural data are analyzed to calculate the atomic displacement, square displacement, and average spacing properties of the material at different temperatures. Using the coordination number and distribution between atoms and the energy minimization criterion, the most stable and representative structures at different temperatures are selected. The selected stable structures at different temperatures are summarized, visualized, and temperature spectra are generated.

5. The method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials according to claim 1, characterized in that, The process of identifying optimal adsorption sites includes: Geometric descriptions of the surface and internal structure of hydrogen storage materials are performed, and different possible hydrogen molecule adsorption sites are depicted by utilizing geometric features and spatial symmetry. One or more hydrogen molecules are simultaneously introduced into the model of the hydrogen storage material and orbit around adsorption sites with different labels; dynamic simulations are performed on hydrogen molecules at different adsorption sites; under set initial conditions, the movement of hydrogen molecules is observed and the interaction between them and the hydrogen storage material is recorded. For each adsorption site, the interaction energy between hydrogen molecules and the material is calculated using the potential energy relationship; the relative stability of hydrogen molecules at each adsorption site is obtained through an energy minimization procedure; the calculated adsorption energies are compared, and the site with the lowest energy is identified and marked as the optimal adsorption site.

6. The method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials according to claim 1, characterized in that, The process of quantifying the hydrogen adsorption performance of materials includes: Using a gas adsorption isotherm measuring device, hydrogen gas was introduced into a pre-vacuum-treated hydrogen storage material, and different hydrogen pressures were gradually applied. At each set pressure, the gas volume change, pressure change, and temperature change during the adsorption process were monitored in real time by a measuring instrument. The change in the amount of substance of a gas under a specific pressure is calculated using the ideal gas law. The amount of adsorbed hydrogen is compared with the mass of the material to calculate the amount of hydrogen adsorbed per gram of material. Corresponding gas adsorption experiments are conducted under different temperature and pressure conditions. The adsorption isotherm model is applied to fit the data and extract the thermodynamic parameters from the adsorption isotherm. The maximum adsorption capacity of hydrogen storage and the gas transfer and release characteristics within the material were obtained through the calculation of adsorption isotherms and thermodynamic parameters. The adsorption efficiency under different conditions, including saturated adsorption capacity, kinetic adsorption rate and desorption rate, were recorded and analyzed. The test results were compared with the adsorption performance of hydrogen storage materials.

7. The method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials according to claim 1, characterized in that, The process of obtaining the characteristics of the adsorption process includes: The obtained hydrogen adsorption amount and corresponding time data are used to build a structured data table, including time points, corresponding hydrogen pressure, flow rate, and hydrogen adsorption amount information; the obtained data are preliminarily analyzed, and a curve of hydrogen adsorption amount changing with time is plotted. Select the fitting tool and use the nonlinear least squares method to minimize the error between the predicted model and the experimental data; input the experimental data and select the model equation; To check the degree of fit between the fitted curve and the actual data, output the key parameters of the fit, calculate the goodness of fit, and a value close to 1 indicates that the model predicts adsorption behavior.

8. A system for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials, which is applied to the method for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials as described in any one of claims 1 to 7, characterized in that, The system for calculating and evaluating the hydrogen storage performance of solid hydrogen storage materials includes: The performance analysis module is used to analyze the mechanical properties, electronic distribution, thermal conductivity, and thermal stability of the designed material by constructing a microscopic model of the material using functional density theory and molecular dynamics. The performance calculation module is used to calculate the hydrogen adsorption performance of the newly designed hydrogen storage material by calculating the adsorption state of hydrogen molecules on the hydrogen storage material, the adsorption energy, and the amount of hydrogen adsorbed by the material under different pressures and temperatures. The performance evaluation module is used to plot the hydrogen adsorption kinetics curves of solid hydrogen storage materials in order to calculate and evaluate the hydrogen storage kinetics performance of the materials.

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