Material database construction method and device, equipment and storage medium

Abstract

The invention belongs to the technical field of material analysis, and discloses a material database construction method and device, equipment and a storage medium. The method comprises the steps of obtaining structure information of a target material; performing relaxation calculation on the target material according to the structure information to determine a ground state energy value of a target stable structure; obtaining energy contribution values of lattice vibration of the target stable structure at various temperatures; and determining the Gibbs energy of the target stable structure according to the energy contribution value of the lattice vibration and the ground state energy value, and constructing a material Gibbs energy database based on the Gibbs energy of each stable structure. According to the scheme, through relaxation calculation and high-precision phonon calculation, the high-temperature Gibbs predictability is remarkably improved, and the method is particularly suitable for phase diagram construction under extreme conditions with scarce experimental data. Through a physically-driven parameter generation mechanism, the extrapolation limitation of a traditional empirical model is broken through, a reliable calculation basis is provided for high-throughput new material design, and the calculation precision of Gibbs energy is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of material analysis, and in particular to a material database construction method, device, equipment and storage medium. Background Art

[0002] In the field of high-temperature material synthesis (>1000K), phase diagram construction and prediction of thermodynamic competition relationships are the core foundations of material design. Current technology mainly obtains high-temperature phase diagrams through a combination of experiments and computational simulations, but there are still many bottlenecks. The most critical of these is the insufficient accuracy of Gibbs free energy calculations. Traditional thermodynamic models (such as the CALPHAD method) and first-principles calculations have significant theoretical deviations under high-temperature conditions. Because high-temperature phase transitions involve complex thermodynamic contributions such as lattice vibration entropy and electronic excited states, existing simulation methods have difficulty in accurately quantifying Gibbs free energy (Gibbs energy), resulting in huge errors in phase boundary predictions and excessive reliance on experiments for accuracy. When the temperature exceeds 1000K, the simulation results need to rely on experimental data such as high-temperature X-ray diffraction and thermogravimetry-differential scanning calorimetry for empirical correction.

[0003] Because high-temperature experimental synthesis involves complex equipment and processes, the required equipment and processes become more demanding. Without a method to accurately obtain the Gibbs energy, it is impossible to efficiently obtain the thermodynamic competition relationship between different phases at high temperatures. This requires the use of more experimental data to correct the calculation results. Simulation calculations do not inherently improve the process of obtaining high-temperature phase diagrams, but only provide a partial auxiliary role. The simulation calculation methods currently commonly used to obtain high-temperature phase diagrams have difficulty in obtaining accurate phase relationships and often require a large amount of experimental data to correct the calculation results.

[0004] Because the experimental synthesis temperature for some materials is too high (over 1000K), existing simulation calculations have difficulty in obtaining Gibbs energies close to experimental results. This leads to the possibility that simulations may incorrectly describe the thermodynamic competition relationship between different phases at high temperatures.

[0005] The above content is only used to assist in understanding the technical solution of the present invention and does not constitute an admission that the above content is prior art. Summary of the Invention

[0006] The main purpose of the present invention is to provide a material database construction method, device, equipment and storage medium, aiming to solve the technical problem of low accuracy of Gibbs energy simulation calculation in the prior art.

[0007] To achieve the above object, the present invention provides a method for constructing a material database, the method comprising the following steps:

[0008] In some embodiments, the material database construction method comprises: obtaining structure information of a target material; performing relaxation calculation on the target material according to the structure information to determine a ground state energy value of a target stable structure; obtaining energy contribution values of lattice vibration of the target stable structure at different temperatures; determining a Gibbs energy of the target stable structure according to the energy contribution values of the lattice vibration and the ground state energy value, and constructing a Gibbs energy database of materials based on the Gibbs energy of each stable structure.

[0009] It can be understood that the scheme significantly improves the high-temperature Gibbs energy prediction capability while maintaining the rigor of the first principle through relaxation calculation and high-precision phonon calculation, and is especially suitable for extreme condition phase diagram construction with scarce experimental data. Through the physically driven parameter generation mechanism, the scheme breaks through the extrapolation limitation of traditional empirical models, provides a reliable calculation basis for high-throughput new material design, and improves the calculation accuracy of the Gibbs energy.

[0010] In some embodiments, the determination of the Gibbs energy of the target stable structure according to the energy contribution values of the lattice vibration and the ground state energy value comprises: obtaining energy contribution values of electronic thermal excitation of the target stable structure at different temperatures; determining the Gibbs energy of the target stable structure according to the energy contribution values of the electronic thermal excitation, the energy contribution values of the lattice vibration, and the ground state energy value.

[0011] It can be understood that since the error of the Gibbs energy is affected by the temperature, in general, the higher the temperature, the greater the error, which may be caused by the general simulation calculation process ignoring the contribution of electronic thermal excitation, resulting in an enlarged error. Therefore, by adding the influence of electronic thermal excitation to correct the calculation result, the calculation accuracy of the Gibbs energy is further improved.

[0012] In some embodiments, the obtaining of the energy contribution values of the electronic thermal excitation of the target stable structure at different temperatures comprises: determining electronic state density data according to the structure information of the target stable structure; determining Coulomb interaction energy of the target stable structure at different temperatures according to the electronic state density data; determining electronic entropy of the target stable structure at different temperatures according to the structure information of the target stable structure; and determining the energy contribution values of the electronic thermal excitation at the corresponding temperatures according to the electronic entropy and the Coulomb interaction energy between the electrons.

[0013] It can be understood that by dynamically correlating the structural information with the electronic state density, and calculating the Coulomb interaction energy and the electronic entropy level by level, the electronic thermal excitation energy contribution is finally determined, the atomic position and bond length change based on the target structure (such as high-temperature lattice expansion) is calculated in real time, the electronic state density is accurately reflected, the dynamic shielding effect is derived through the electronic state density, the temperature-dependent Coulomb interaction energy is calculated, the physical model of electronic thermal excitation is constructed, and the precise estimation of energy contribution under electronic thermal excitation is completed.

[0014] In some embodiments, the electronic entropy of the target stable structure at each temperature is determined according to the structural information of the target stable structure, comprising: determining the total number of electrons and the Fermi level corresponding to the target stable structure according to the structural information of the target stable structure; determining the target Fermi level at the corresponding temperature according to the Fermi level, the total number of electrons and the electronic state density data; determining the electronic entropy at the corresponding temperature according to the target Fermi level.

[0015] It can be understood that by dynamic Fermi level correction and quantum accurate electronic entropy integration, this method realizes seamless connection from microscopic electronic state to macroscopic thermodynamic properties, solves the quantization problem of electronic excitation energy contribution in high-temperature phase transition prediction, and reduces the operation cost and improves the calculation speed compared with density functional theory by calculating the electronic excitation energy contribution.

[0016] In some embodiments, the base state energy value of the target stable structure is determined by relaxation calculation of the target material according to the structural information, comprising: predicting the potential crystal structure corresponding to the target material according to the structural information; retrieving the known crystal structure corresponding to the target material according to the material composition in the structural information; performing relaxation calculation according to the potential crystal structure and the known crystal structure to obtain the base state energy value of the target stable structure.

[0017] It can be understood that this scheme determines the crystal structure by two ways to ensure the comprehensiveness of the crystal structure, covers the experimental and theoretical phase space, and avoids missing key competitive phases.

[0018] In some embodiments, after the Gibbs energy of the target stable structure is determined according to the energy contribution value of the lattice vibration and the base state energy value, and the material Gibbs energy database is constructed, it further comprises: obtaining an initial material data set; querying the material Gibbs energy database according to the initial material in the initial material data set to determine the Gibbs energy corresponding to the initial material; determining the stability of the initial material according to the Gibbs energy corresponding to the initial material; screening the initial material data set according to the stability of the initial material to obtain a target recommended material.

[0019] It can be understood that the material database established according to the scheme stores the Gibbs energy change information of a plurality of molecular formulas and a plurality of structures corresponding to the molecular formulas (there are also various allotropes in the same chemical formula) in the molecular formulas, and can be used to characterize the stability or reaction possibility of the material at different temperatures, accelerate the screening work of the material, and improve the efficiency of new material discovery and screening.

[0020] In some embodiments, the acquiring the energy contribution value of the lattice vibration of the target stable structure at each temperature comprises: determining a phonon density of states of the target stable structure according to the structure information corresponding to the target stable structure; and determining the energy contribution value of the lattice vibration at each temperature according to the phonon density of states of the target stable structure.

[0021] It can be understood that the energy contribution value of the lattice vibration can be effectively determined according to the influence of the predicted temperature on the material, the more accurate Gibbs energy data can be determined, and the accuracy of the Gibbs energy calculation is improved.

[0022] In a second aspect, to achieve the above object, the present application further provides a material database construction device, the material database construction device comprises:

[0023] An acquisition module is configured to acquire structure information of a target material.

[0024] A processing module is configured to perform relaxation calculation on the target material according to the structure information to determine a ground state energy value of a target stable structure.

[0025] The processing module is configured to acquire an energy contribution value of the lattice vibration of the target stable structure at each temperature.

[0026] The processing module is configured to determine the Gibbs energy of the target stable structure according to the energy contribution value of the lattice vibration and the ground state energy value, and complete the construction of the material Gibbs energy database.

[0027] In a third aspect, to achieve the above object, the present application further provides a material database construction device, the material database construction device comprises a memory, a processor and a material database construction program stored in the memory and executable on the processor, the material database construction program is configured to implement the steps of the material database construction method as described above.

[0028] In a fourth aspect, to achieve the above object, the present application further provides a storage medium, the storage medium stores a material database construction program, and the material database construction program implements the steps of the material database construction method as described above when executed by a processor. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 Flow chart for the first embodiment of the material database construction method of the present application;

[0030] Figure 2 Flow chart for the Gibbs energy calculation of the first embodiment of the material database construction method of the present application;

[0031] Figure 3 Flow chart for the Gibbs energy calculation based on the electronic excitation contribution energy of the first embodiment of the material database construction method of the present application;

[0032] Figure 4 Flow chart for the material screening of the first embodiment of the material database construction method of the present application;

[0033] Figure 5 Structure block diagram of the first embodiment of the material database construction device of the present application.

[0034] The implementation, functional features and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0035] The embodiments of the technical scheme of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical scheme of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0036] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments of the present application, and are not intended to limit the present application; the terms “include” and “have” and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0037] In the description of the embodiments of the present application, the technical terms “first”, “second”, etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of “a plurality of” is two or more, unless otherwise explicitly and specifically limited.

[0038] 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 present application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative embodiments to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0039] In the description of the embodiments of the present application, the term "and / or" is merely an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0040] In the description of the embodiments of the present application, the term "a plurality of" refers to two or more (including two), and similarly, "a plurality of groups" refers to two or more groups (including two groups), and "a plurality of pieces" refers to two or more pieces (including two pieces).

[0041] In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the present application and simplifying the description, and does not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application.

[0042] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the technical terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0043] The content disclosed in the embodiments of the present application is mainly applied in the process of constructing the Gibbs energy database of the material system. A material system can be regarded as being composed of two basic components, phonons and electrons. Phonons are the part of lattice vibration, representing the collective vibration mode of atoms or molecules in thermal motion in the material, while electrons are charged particles in the material, responsible for important properties such as electrical conductivity and chemical reaction. The total energy of the material system is the sum of the total energy of the electrons and the total energy of the phonons, which reflects the relationship between the microstructure and the macroscopic properties of the material. Therefore, the scheme combines physical principles to construct an algorithm model to describe the contribution of the above different factors to the Gibbs energy.

[0044] Due to the high-temperature experimental synthesis, the required equipment and process become more stringent, and without an accurate method of obtaining Gibbs energy, the thermodynamic competition relationship between different phases at high temperature cannot be efficiently obtained, which requires more experimental data to correct the calculation results. Simulation calculation does not greatly improve the acquisition process of high-temperature phase diagram in essence, but only plays a partial auxiliary role. Therefore, in order to guide the experimental synthesis process and improve the efficiency of high-throughput screening, the high-precision Gibbs energy is obtained by determining the dimension of multiple energy contributions.

[0045] Many potential but not experimentally synthesized crystal structures may have some theoretically excellent properties, but these materials are often difficult to synthesize by conventional experimental processes. Therefore, in order to obtain these materials with excellent target performance, different process means need to be explored, such as different synthesis temperatures and different precursors. However, the current theory gives less guidance to experiments, and the trial-and-error nature and repeatability of experiments lead to high synthesis costs. Therefore, a fast and high-precision method is needed to guide the synthesis of experiments. In order to narrow the gap between theoretical calculation and experiment, the temperature is taken as the most important factor, and the calculation method is improved to guide the experiment to accurately obtain the Gibbs energy.

[0046] According to some embodiments of the present application, a material database construction scheme is provided as shown in Figure 1 The specific content is as follows:

[0047] In some embodiments, the structure information of the target material is obtained; the ground state energy value of the target stable structure is determined by relaxation calculation according to the structure information; the energy contribution value of the lattice vibration of the target stable structure at each temperature is obtained; the Gibbs energy of the target stable structure is determined according to the energy contribution value of the lattice vibration and the ground state energy value, and the material Gibbs energy database is constructed based on the Gibbs energy of each stable structure.

[0048] It should be noted that in the development of high-temperature materials, Gibbs free energy (Gibbs Free Energy) is a core parameter for judging the stability of material phases and thermodynamic competition, and its accurate calculation is the key to constructing a reliable phase diagram. In order to achieve this goal, the method proposes a systematic calculation framework.

[0049] First, the initial structure information of the target material is obtained through experimental characterization, structure generation (such as genetic algorithm) or third-party database, including lattice parameters, atomic coordinates and other key geometric descriptions. Then, the structure is relaxed by using density functional theory (DFT) to determine the ground state energy value, which corresponds to the energy of the material at absolute zero (0K) in the stable state, providing a benchmark for subsequent thermodynamic correction.

[0050] In addition, based on the ground state structure, the phonon density of states (Phonon Density of States) is further obtained through phonon calculation (such as using Phonopy, ATAT, etc.), which quantifies the contribution of lattice vibration to energy. Based on quantum statistical mechanics, the energy contribution of lattice vibration is determined, and the error problem caused by traditional empirical models (such as Debye model) at high temperatures is solved by explicitly calculating the lattice vibration energy contribution value at each temperature. Thus, a relatively accurate free energy data is obtained, and a high-precision material Gibbs energy database is constructed based on the free energy data.

[0051] The energy contribution of lattice vibration refers to the influence of atomic or ionic vibration caused by thermal motion on the total energy of the system, and its physical nature is the sum of kinetic energy and potential energy of atomic collective vibration. Specifically, this contribution can be understood as two parts: the vibration internal energy composed of atomic vibration kinetic energy and potential energy, which increases with temperature, and the other part is the vibration entropy, which reflects the degree of disorder of vibration mode and dominates the Gibbs energy change at high temperatures.

[0052] It can be understood that the present scheme significantly improves the high-temperature Gibbs energy prediction ability while maintaining the rigor of first principles through relaxation calculation and high-precision phonon calculation, and is especially suitable for extreme condition phase diagram construction with scarce experimental data. Through the physically driven parameter generation mechanism, the limitations of traditional empirical models are broken through, providing a reliable calculation basis for high-throughput new material design and improving the calculation accuracy of Gibbs energy.

[0053] In some embodiments, as shown in Figure 2 determining the Gibbs energy of the target stable structure according to the energy contribution value of electronic thermal excitation, the energy contribution value of lattice vibration and the ground state energy value.

[0054] In combination with the above embodiments, the present scheme further improves the accuracy of Gibbs energy, and further adds the energy contribution of electronic thermal excitation. First, the initial structure information of the target material is obtained through experimental characterization, structure generation (such as genetic algorithm) or third-party database, including lattice parameters, atomic coordinates and other key geometric descriptions. Then, the structure is relaxed by using density functional theory (DFT), so as to determine the ground state energy value. The energy corresponds to the lowest energy of the material at absolute zero (0K) when it is in a stable state, which provides a benchmark for subsequent thermodynamic correction.

[0055] In addition, on the basis of the ground state structure, the phonon density of states (Phonon Density of States) is further obtained through phonon calculation (such as using Phonopy, ATAT and other software) to quantify the contribution of lattice vibration to energy. Based on quantum statistical mechanics, the energy contribution of lattice vibration is determined, and the error problem caused by traditional empirical models (such as Debye model) at high temperature is solved by explicitly calculating the lattice vibration energy contribution value at each temperature. Thus, a relatively accurate free energy data is obtained, and a high-precision material Gibbs energy database is constructed based on the free energy data.

[0056] Further, electronic thermal excitation (Electronic Thermal Excitation) refers to the process that the electrons in the material jump to a higher energy level quantum state due to the absorption of heat energy when the temperature rises. This phenomenon is an important influencing factor of the thermodynamic properties (such as Gibbs free energy, electrical conductivity, phase stability) of the material at high temperature. The energy contribution of electronic thermal excitation can also be understood as two parts, the electronic internal energy, i.e. the total energy increase of the system caused by the electronic transition to high energy level, and the electronic entropy, i.e. the increase of the disorder degree of the electronic occupation state, which can be obtained in various ways.

[0057] Further, when calculating the Gibbs energy of the crystal at a certain temperature, in addition to the ground state total energy E0 at 0K and the contribution of lattice vibration to Gibbs energy F ph , the contribution of electronic thermal excitation to Gibbs free energy cannot be ignored. For ordered solid phase: G(T)=E0+F ph (T)+F el (T), wherein G is the Gibbs energy, T is the thermodynamic temperature, E0 is the ground state energy of the system at 0K, F ph is the contribution of lattice vibration to Gibbs free energy, and F el is the contribution of electronic thermal excitation to Gibbs free energy.

[0058] It can be understood that, since the error of Gibbs energy is affected by temperature, generally speaking, the higher the temperature, the greater the error, which may be caused by ignoring the contribution of electronic thermal excitation in general simulation process, resulting in error amplification, therefore, by adding the influence of electronic thermal excitation to modify the calculation result, the calculation accuracy of Gibbs energy is further improved.

[0059] In some embodiments, as Figure 3 shown, the electronic state density data is determined according to the structure information of the target stable structure; the Coulomb interaction energy of the target stable structure at each temperature is determined according to the electronic state density data; the electronic entropy of the target stable structure at each temperature is determined according to the structure information of the target stable structure; and the energy contribution value of the electronic thermal excitation at the corresponding temperature is determined according to the electronic entropy and the Coulomb interaction energy between electrons.

[0060] In a specific implementation, the embodiment proposes a preferred energy contribution value determination scheme of electronic thermal excitation, for example: the contribution of electronic thermal excitation is derived from the transition of electrons from low energy level to high energy level when the temperature rises, specifically, the contribution F el of the Gibbs free energy of the thermal excitation of electrons to higher energy levels can be calculated by the following formula: el (T)=E el (T)-TS el (T), wherein T is the thermodynamic temperature, E el is the Coulomb interaction energy between electrons, and S el is the electronic entropy.

[0061] Wherein, the Coulomb interaction energy between electrons can be determined by calculation, as follows:

[0062]

[0063] Wherein, E el is the Coulomb interaction energy between electrons, and n(ε) is the electronic state density of energy level ε obtained by density functional theory, and ε F is the Fermi level.

[0064] It can be understood that, by dynamically associating the structure information with the electronic state density, and calculating the Coulomb interaction energy and the electronic entropy step by step, the energy contribution of electronic thermal excitation is finally determined, based on the changes of atomic positions and bond lengths of the target structure (such as high-temperature lattice expansion), the electronic state density is calculated in real time, the energy band broadening and Fermi level shift caused by temperature are accurately reflected, the temperature-dependent Coulomb interaction energy is calculated by the dynamic shielding effect derived from the electronic state density, the physical model of electronic thermal excitation is constructed, and the precise estimation of energy contribution under electronic thermal excitation is completed.

[0065] In some embodiments, the total number of electrons and the Fermi level corresponding to the target stable structure are determined based on the structural information of the target stable structure; the target Fermi level at the corresponding temperature is determined based on the Fermi level, the total number of electrons and the electron state density data; and the electron entropy at the corresponding temperature is determined based on the target Fermi level.

[0066] Furthermore, in order to obtain accurate electron entropy, it is necessary to first determine the total number of electrons and the Fermi level. The total number of electrons refers to the total number of valence electrons of all atoms in the material (such as Na in NaCuO2 + 、Cu 3+ , O 2- The Fermi level is defined as the highest energy level occupied by an electron at absolute zero (0 K) and is obtained from density functional theory (DFT) ground-state calculations.

[0067] The specific calculation process is as follows:

[0068] S el (T) = -k B ∫n(ε)[flnf+(1-f)ln(1-f)]dε

[0069] Among them, S el is the electron entropy, n(ε) is the electronic state density of the energy level ε obtained by density functional theory, εF is the Fermi level, k B is the Boltzmann constant, and f is the Fermi level distribution function.

[0070] It is understandable that through dynamic Fermi level correction and quantum precise electron entropy integration, this method achieves a seamless connection from microscopic electronic states to macroscopic thermodynamic properties, and solves the problem of quantifying the contribution of electron excitation energy in high-temperature phase transition predictions. Compared with density functional theory, the calculation of the contribution of electron excitation energy reduces the computational cost and improves the calculation speed.

[0071] In some embodiments, the potential crystal structure corresponding to the target material is predicted based on the structural information; the known crystal structure corresponding to the target material is retrieved based on the material composition in the structural information; and relaxation calculations are performed based on the potential crystal structure and the known crystal structure to obtain the ground state energy value of the target stable structure.

[0072] It should be noted that for the material system of interest, such as the Na-Cu-O system, the structures of all experimentally known phases (Na, O2, Na2O, Na2O2, etc.) and potential phases are obtained, such as the crystal structures of all possible NaCuO2 isomers, because the specific structure of the component at 1500K is often unknown experimentally.

[0073] Specifically, the theoretical possible crystal structure is generated by material composition (such as chemical formula NaCuO2) or known structural fragments (such as local coordination mode) using an algorithm (such as genetic algorithm, particle swarm optimization), and the structural information used here is the composition of the material system.

[0074] In addition, the known crystal structure can be retrieved from the experimental or calculated database (such as ICSD, Materials Project) to retrieve the verified structure corresponding to the target material composition (such as NaCuO2). First, analyze the material composition (such as chemical formula, element ratio); call the database API to match the entry (such as Materials Project); download the file or structure data.

[0075] It can be understood that the scheme determines the crystal structure by two ways, guarantees the comprehensiveness of the crystal structure, covers the experimental and theoretical phase space, and avoids missing key competitive phases.

[0076] In some embodiments, as shown in Figure 4 an initial material data set is obtained; the Gibbs energy database of the material is queried according to the initial material in the initial material data set to determine the Gibbs energy corresponding to the initial material; the stability of the initial material is determined according to the Gibbs energy corresponding to the initial material; and the initial material data set is screened according to the stability of the initial material to obtain a target recommended material.

[0077] It should be noted that after the Gibbs energy is constructed, based on the accurate Gibbs energy calculation, the work of new material discovery can be further supported, because the process basis of new material screening is very large and often reaches a huge number, and it will become impossible to determine the chemical properties of each experiment, and the previous simulation calculation is often very rough, and the recommended materials obtained finally will become very unreliable, therefore, based on the material database constructed in the embodiment, the material screening efficiency can be improved to find the materials meeting the expected effect, and the Gibbs energy has a wide range of uses in the material screening process, for example: the Gibbs energy of the material is obtained by calculation or experiment, and the thermodynamic stability of the material under specific temperature and pressure conditions can be judged. The lower the Gibbs energy, the more stable the material, and the more difficult the spontaneous decomposition or phase change is; for example, screening of high-stability electrode materials (such as solid-state electrolyte) to avoid decomposition during charging and discharging. Based on the above content, the embodiment proposes the following cases to illustrate the scheme, for example: obtaining an initial material data set to obtain the crystal structure and element composition information of the candidate material from the material database (such as Materials Project). Query the Gibbs energy database to obtain the Gibbs energy of the candidate material. Calculate the Gibbs energy of the material and other components (such as O2, H2O) in the environment to predict whether a side reaction will occur. Determine the material stability, if the Gibbs energy of the material is significantly lower than the sum of the Gibbs energies of the decomposition products, the material is stable. For example, if the Gibbs energy of Li3PS4 is lower than that of the decomposition products Li2S and P, it is determined to be stable; otherwise, it is excluded. Screening target recommended materials exclude materials with too high Gibbs energy (such as Li3PO4 which is easy to react with air), and retain stable materials with the lowest Gibbs energy. Screening of high-stability electrolytes suitable for solid-state batteries can avoid capacity attenuation caused by material decomposition during battery cycling.

[0078] It can be understood that the material database established according to the scheme stores the Gibbs energy change information of a plurality of molecular formulas and a plurality of structures corresponding to the molecular formulas (there are also various allotropes in the same chemical formula) in the molecular formulas, which can be used to characterize the stability or reaction possibility of the material at different temperatures, accelerate the material screening work, and improve the new material discovery and screening efficiency.

[0079] In some embodiments, according to the structure information corresponding to the target stable structure; determining the phonon density of states of the target stable structure according to the structure information corresponding to the target stable structure; and determining the energy contribution value of the lattice vibration at each temperature according to the phonon density of states of the target stable structure.

[0080] It should be noted that the target stable structure refers to a crystal structure that can maintain its equilibrium state (without deformation or collapse) under external force or temperature change. Its stability is determined by factors such as geometry, material stiffness, chemical bond strength, etc. Phonon density of states (PDOS) represents the distribution of different frequency phonon modes (lattice vibration modes) in the material. In addition, the energy contribution value of lattice vibration reflects the influence of temperature on the energy of lattice vibration.

[0081] Specifically, the phonon dispersion relation is calculated by software (such as Phonopy, VASP), the phonon frequency of all wave vectors k is integrated and normalized, and the phonon density of states curve is obtained. The total energy contribution of each frequency phonon can be calculated by the phonon density of states. After integrating all frequencies, the total energy of lattice vibration is obtained.

[0082] It can be understood that by calculating the energy contribution value of lattice vibration, the influence of predicted temperature on the material can be effectively determined, and more accurate Gibbs energy data can be obtained, thereby improving the accuracy of Gibbs energy calculation.

[0083] It should be noted that due to the high synthesis temperature (above 1000K) of some materials in experiments, it is difficult to obtain Gibbs energy similar to experimental results by existing simulation and simulation calculation, which leads to the fact that the simulation and simulation may incorrectly describe the thermodynamic competition relationship between different phases at high temperature. Therefore, this scheme starts from the physical principle, analyzes the influence of different factors on Gibbs energy, and obtains the thermodynamic competition relationship between different phases at high temperature. Therefore, the present embodiment proposes the following complete case to illustrate the scheme, for example: for the material system concerned, such as Na-Cu-O system, obtain the structures of all experimentally known phases (Na, O2, Na2O, Na2O2, etc.) and potential phases, such as all possible NaCuO2 isomers crystal structures, because the specific structure of the composition at 1500K is often not known in experiments, then perform DFT relaxation calculation on all structures to obtain the ground state energy E0 of the material at 0K; the phonon calculation process, which uses common simulation programs (such as phonopy, ATAT, etc.) to obtain the contribution F of lattice vibration to Gibbs energy ph ; further, when calculating the Gibbs energy of the crystal at a certain temperature, in addition to the ground state total energy E0 and the contribution F ph of lattice vibration to Gibbs energy, the contribution of electronic thermal excitation to Gibbs free energy cannot be ignored for ordered solid phase: G(T) = E0 + F ph (T) + F el (T) F ph

[0084] where G is Gibbs energy, T is thermodynamic temperature, E0 is the ground state energy of the system at 0K, F ph is the contribution of lattice vibration to Gibbs free energy, F el is the contribution of electronic thermal excitation to Gibbs free energy; the physical model evaluates the contribution of electronic thermal excitation to Gibbs energy: in the electronic metal system, the Fermi level is occupied by some electrons, and the thermal excitation of electrons to a higher energy level contributes to the Gibbs free energy F el which can be calculated by the following formula:

[0085] F el (T)=E el (T)-TS el (T)

[0086]

[0087] where E el is the Coulomb interaction energy between electrons, S el is the electron entropy, n(ε) is the electron state density of the energy level ε obtained by density functional theory, εF is the Fermi level, k B is the Boltzmann constant, and f is the Fermi level distribution function. By processing the contributions of different parts to the Gibbs energy, data post-processing and data analysis, the Gibbs energy obtained by the original general calculation method may have a large deviation from the experimental value, especially in the interval of 1200K-3000K, as the temperature increases, the error also gradually increases, the physical model module is added to evaluate (modified on the phonon and atat two calculation programs, the evaluation can be repeated), the error between the theoretical calculation and the experimental group is reduced.

[0088] In a second aspect, to achieve the above object, as Figure 5 shown, the present application also provides a device, comprising:

[0089] An acquisition module 10 is configured to acquire structural information of a target material.

[0090] A processing module 20 is configured to perform relaxation calculation on the target material according to the structural information to determine a ground state energy value of a target stable structure.

[0091] The processing module 30 is configured to acquire an energy contribution value of lattice vibration of the target stable structure at each temperature.

[0092] The processing module 40 is configured to determine the Gibbs energy of the target stable structure according to the energy contribution value of the lattice vibration and the ground state energy value, and complete the construction of a material Gibbs energy database.

[0093] In some embodiments, the processing module 30 is configured to acquire an energy contribution value of electronic thermal excitation of the target stable structure at each temperature.

[0094] determining a Gibbs energy of the target stable structure according to the energy contribution value of the electronic thermal excitation, the energy contribution value of the lattice vibration, and the ground state energy value.

[0095] In some embodiments, the processing module 30 is configured to determine electronic state density data according to the structure information of the target stable structure.

[0096] determining a Coulomb interaction energy of the target stable structure at each temperature according to the electronic state density data.

[0097] determining an electronic entropy of the target stable structure at each temperature according to the structure information of the target stable structure.

[0098] determining an energy contribution value of the electronic thermal excitation at the corresponding temperature according to the electronic entropy and the Coulomb interaction energy between electrons.

[0099] In some embodiments, the processing module 30 is configured to determine a total number of electrons and a Fermi energy level corresponding to the target stable structure according to the structure information of the target stable structure.

[0100] determining a target Fermi energy level at the corresponding temperature according to the Fermi energy level, the total number of electrons, and the electronic state density data.

[0101] determining an electronic entropy at the corresponding temperature according to the target Fermi energy level.

[0102] In some embodiments, the processing module 30 is configured to predict a potential crystal structure corresponding to the target material according to the structure information.

[0103] retrieving a known crystal structure corresponding to the target material according to the material composition in the structure information.

[0104] performing relaxation calculation according to the potential crystal structure and the known crystal structure to obtain a ground state energy value of the target stable structure.

[0105] In some embodiments, the processing module 30 is configured to obtain an initial material data set.

[0106] querying a material Gibbs energy database according to an initial material in the initial material data set to determine a Gibbs energy corresponding to the initial material.

[0107] determining stability of the initial material according to the Gibbs energy corresponding to the initial material.

[0108] screening the initial material data set according to the stability of the initial material to obtain a target recommended material.

[0109] In some embodiments, the processing module 30 is configured to determine the phonon density of states of the target stable structure according to the structure information corresponding to the target stable structure.

[0110] In some embodiments, the processing module 30 is configured to determine the phonon density of states of the target stable structure according to the structure information corresponding to the target stable structure.

[0111] In some embodiments, the processing module 30 is configured to determine the energy contribution value of the lattice vibration at each temperature according to the phonon density of states of the target stable structure.

[0112] In a third aspect, to achieve the above object, the present application provides a material database construction device, which comprises a memory, a processor, and a material database construction program stored in the memory and executable on the processor, and the material database construction program is configured to implement the steps of the material database construction method as described above.

[0113] In a fourth aspect, to achieve the above object, the present application provides a storage medium having a material database construction program stored thereon, and the material database construction program, when executed by a processor, implements the steps of the material database construction method as described above.

[0114] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should be covered in the scope of the claims and the specification of the present application. In particular, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for constructing a material database, characterized in that: The material database construction method comprises: Obtain structural information of target materials; Performing relaxation calculation on the target material according to the structural information to determine the ground state energy value of the target stable structure; Obtaining energy contribution values ​​of lattice vibration of the target stable structure at various temperatures; The Gibbs energy of the target stable structure is determined according to the energy contribution value of the lattice vibration and the ground state energy value, and a material Gibbs energy database is constructed based on the Gibbs energy of each stable structure.

2. The method according to claim 1, wherein Determining the Gibbs energy of the target stable structure according to the energy contribution value of the lattice vibration and the ground state energy value includes: Obtaining energy contribution values ​​of electron thermal excitation of the target stable structure at various temperatures; The Gibbs energy of the target stable structure is determined according to the energy contribution value of the electron thermal excitation, the energy contribution value of the lattice vibration and the ground state energy value.

3. The method according to claim 2, wherein The obtaining of the energy contribution value of the electron thermal excitation of the target stable structure at each temperature includes: determining electronic state density data based on structural information of the target stable structure; determining the Coulomb interaction energy of the target stable structure at various temperatures based on the electronic density of states data; determining the electronic entropy of the target stable structure at various temperatures based on the structural information of the target stable structure; The energy contribution value of electron thermal excitation at the corresponding temperature is determined based on the electron entropy and the Coulomb interaction energy between electrons.

4. The method according to claim 3, wherein Determining the electronic entropy of the target stable structure at each temperature according to the structural information of the target stable structure includes: Determining the total number of electrons and the Fermi level corresponding to the target stable structure according to the structural information of the target stable structure; Determine the target Fermi level at the corresponding temperature based on the Fermi level, total electron number, and electron state density data; The electron entropy at the corresponding temperature is determined according to the target Fermi level.

5. The method according to claim 1, wherein The performing relaxation calculation on the target material according to the structural information to determine the ground state energy value of the target stable structure includes: predicting a potential crystal structure corresponding to the target material based on the structural information; Retrieving a known crystal structure corresponding to the target material according to the material composition in the structural information; Relaxation calculations are performed based on potential crystal structures and known crystal structures to obtain the ground state energy value of the target stable structure.

6. The method according to claim 1, wherein After determining the Gibbs energy of the target stable structure according to the energy contribution value of the lattice vibration and the ground state energy value and completing the construction of the material Gibbs energy database, the method further includes: Obtaining an initial material dataset; Querying a material Gibbs energy database according to the initial material in the initial material data set to determine the Gibbs energy corresponding to the initial material; determining the stability of the initial material according to the Gibbs energy corresponding to the initial material; The initial material data set is screened according to the stability of the initial material to obtain target recommended materials.

7. The method according to claim 1, wherein The obtaining of the energy contribution value of the lattice vibration of the target stable structure at each temperature includes: According to the structural information corresponding to the target stable structure; determining the phonon state density of the target stable structure according to the structural information corresponding to the target stable structure; The energy contribution value of the lattice vibration at each temperature is determined according to the phonon state density of the target stable structure.

8. A material database construction device, characterized in that: The material database construction device includes: An acquisition module, used to obtain structural information of the target material; a processing module, configured to perform relaxation calculation on the target material according to the structural information to determine a ground state energy value of a target stable structure; The processing module is used to obtain the energy contribution value of the lattice vibration of the target stable structure at various temperatures; The processing module is used to determine the Gibbs energy of the target stable structure according to the energy contribution value of the lattice vibration and the ground state energy value, and complete the construction of the material Gibbs energy database.

9. A material database construction device, characterized in that: The device includes: a memory, a processor, and a material database construction program stored in the memory and executable on the processor, wherein the material database construction program is configured to implement the steps of the material database construction method according to any one of claims 1 to 7.

10. A storage medium, characterized in that: The storage medium stores a material database construction program, which, when executed by a processor, implements the steps of the material database construction method according to any one of claims 1 to 7.

Images