High-throughput screening method and system for polymer thermoelectric materials

Abstract

The invention discloses a high-throughput screening method of a polymer thermoelectric material, which comprises the following steps: firstly, screening out a semiconductor material from disclosed materials according to literatures with low structural complexity and synthesized experiments and an electronic band gap, further screening out a chalcogenide aggregated semiconductor material according to the screening method, and then screening out the chalcogenide aggregated semiconductor material according to the chalcogenide aggregated semiconductor material. The method comprises the following steps: performing mechanical and dynamic stability judgment on a chalcogenide aggregation-containing semiconductor material by utilizing first principle calculation, and determining a stable material at room temperature; then, second-order and third-order inter-atomic force constants of the stable material are obtained through calculation according to the first principle, and the ultra-low lattice thermal conductivity of the material is measured through a phonon Boltzmann transport equation; and finally, finding the target polymer thermoelectric material meeting the requirements by calculating the electrical transport parameters. The target material system can be quickly obtained by combining the high-throughput screening method with the first principle for calculation.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conversion material screening, and in particular to a high-throughput screening method and system for polymer thermoelectric materials. Background Art

[0002] With the rapid development of society, energy crisis and environmental pollution are becoming increasingly serious. Faced with the demand for new renewable energy and waste heat management in industry and life, thermoelectric materials that realize the mutual conversion of thermal energy and electrical energy have attracted widespread attention; thermoelectric devices have the advantages of small size, no noise, long life, and high reliability. These advantages make thermoelectric materials widely used in medicine, military, aerospace and other fields, such as micro-thermostats, vehicle-mounted laser radars, 5G communications, and body temperature power generation watches. However, since the discovery of thermoelectric materials, their conversion efficiency is usually in the range of 5%-20%. The low conversion efficiency limits the practical application of thermoelectric devices. Therefore, improving the thermoelectric properties of materials is of great significance to the development of thermoelectric functional devices.

[0003] Thermoelectric figure of merit provides parametric information about the electrical and thermal properties of materials, and can also be used to evaluate the thermoelectric properties of materials. A good thermoelectric figure of merit requires a large Seebeck coefficient (S), high electrical conductivity (σ) and low thermal conductivity (κ). Therefore, the two main ways to improve the efficiency of thermoelectric conversion are to optimize the electrical transport performance and reduce the lattice thermal conductivity. The mutual coupling of electrical conductivity and Seebeck coefficient increases the difficulty of optimizing electrical transport performance, while lattice thermal conductivity can be independently regulated. Therefore, finding thermoelectric materials with intrinsic low lattice thermal conductivity has become the focus of thermoelectric research. At the same time, in the application of thermal barrier coatings, such low thermal conductivity materials also play an important role. At present, there are methods based on structural descriptors to obtain the phonon transport properties of materials, such as the single atom localized vibration model, which can realize the rapid screening of low lattice thermal conductivity materials, but this ignores the possibility of low thermal conductivity caused by the aggregation of similar atoms.

[0004] In recent years, people have studied the phonon transport and thermoelectric merit of some chalcogen-containing aggregates, such as monolayer CdTe2 and Pd2Se3. However, they have disadvantages such as high thermal conductivity, which also leads to a thermoelectric merit of only about 1. Subsequently, studies have found ultra-low lattice thermal conductivity in three-dimensional chalcogen-containing aggregates such as Ba2X6 (X=S,Se,Te), ASe (A=K,Rb) and ZnSe2, and some of these materials show high thermoelectric performance. In general, in the 5G information age, this type of high ZT chalcogen-containing multi-collective material can significantly optimize the thermoelectric conversion efficiency, mainly reflected in improving the heat dissipation and cooling power of microelectronic devices in the field of integrated circuits and developing efficient waste heat power generation devices. At the same time, this low thermal conductivity chalcogen-containing polymer material can also be used in thermal barrier coating technology, which can improve the operating temperature and service life of the hot end components of aircraft engines. However, there are still some challenges in determining the best target material. It is well known that thermoelectric conversion devices are mainly composed of a P-type and an N-type material. At present, a variety of performance-friendly P-type materials have been discovered, such as SnSe, PbTe and most Heusler alloys; on the contrary, N-type thermoelectric materials with ZT>1 are relatively rare in the market and experimental research and development. Therefore, finding a class of N-type thermoelectric materials with ZT>1 is crucial for building high-performance thermoelectric conversion devices. At present, the materials project gene database has provided 150,000 crystal structures. How to quickly obtain the thermoelectric properties of polymer materials is an important topic worth exploring.

[0005] It is impractical to use traditional experimental procedures to synthesize and test the thermoelectric properties of 150,000 crystal structures. The main reason is that it often takes several days to synthesize and test the performance of just one material. On the other hand, the genetic database does not provide thermoelectric performance data for materials. The traditional high-throughput computing method requires unified calculation of the basic thermoelectric parameters of 150,000 materials. Although this method can obtain the thermoelectric properties of all materials, it still takes at least one day to calculate one material, so the computational cost of this solution is still very high.

[0006] Therefore, we urgently need an effective screening method to find potential thermoelectric materials containing sulfur-containing elements. Summary of the invention

[0007] Purpose of the invention: In order to overcome the above shortcomings, the purpose of the present invention is to provide a high-throughput screening method for polymer thermoelectric materials.

[0008] In order to solve the above technical problems, the present invention provides a high-throughput screening method for polymer thermoelectric materials, comprising:

[0009] Step S1: extracting a preset amount of screening information according to the target database, wherein the screening information at least includes: basic information on the synthesis conditions, atomic number and electronic energy band of the inorganic compound;

[0010] Step S2: using a semiconductor screening method to screen out semiconductor materials from a preset amount of screening information;

[0011] Step S3: using a chalcogen-atom-containing polymer screening method to screen out chalcogen-atom-containing polymer materials from semiconductor materials;

[0012] Step S4: performing stability judgment on the sulfur-containing polymer material and obtaining a polymer material judged to be stable;

[0013] Step S5: Based on the stable polymer material, a lattice thermal conductivity test is performed and the electrical transport parameters of the polymer material are calculated, and then the thermoelectric performance is evaluated using the thermoelectric figure of merit to obtain a target polymer thermoelectric material that meets the preset requirements.

[0014] In one aspect, in step S2, the method comprises the following steps:

[0015] Step S21: According to a preset amount of screening information, a first screening condition is used to screen out the semiconductor materials synthesized in the experiment;

[0016] Step S22: according to a preset amount of screening information, using a second screening condition to screen out semiconductor materials whose atomic number of initial unit cells is within a first preset range;

[0017] Step S22: According to a preset amount of screening information, a third screening condition is used to screen out semiconductor materials with an electronic band gap in a second preset interval, thereby obtaining semiconductor materials.

[0018] In one aspect, in step S3, the method comprises the following steps:

[0019] Step S31: optimizing the semiconductor material using first principle calculation software to obtain spatial structure information data of the semiconductor material, and then constructing force field information data and preset grid density data for each spatial structure contained in the semiconductor material;

[0020] Step S32: In the spatial structure information data of the semiconductor material, the electronic wave function is processed using the projected plane wave and the electronic structure is calculated using the PBE-GGA exchange-correlation functional;

[0021] Step S33: Based on the spatial structure information data of each atom in the semiconductor material, calculate the polymer materials containing sulfur-sulfur, selenium-selenium or tellurium-tellurium bond lengths between preset multiples of the distance between two atoms in the sulfur, selenium or tellurium element, so as to screen out the polymer materials containing at least two sulfur, selenium or tellurium atoms.

[0022] On the one hand, in step S33, based on the spatial structure information data of each atom in the semiconductor material, a material containing sulfur, selenium or tellurium, with a bond length between 1.05 and 1.1 times the distance between two atoms in sulfur, selenium or tellurium, is used as a polymer material.

[0023] In one aspect, in step S4, the method comprises the following steps:

[0024] Step S41: judging the mechanical stability of the material according to the screened polymer material containing at least two sulfur, selenium or tellurium atoms;

[0025] Step S42: judging the material kinetic stability based on the screened-out polymer materials containing at least two sulfur, selenium or tellurium atoms, so as to screen out stable polymer materials.

[0026] In one aspect, in step S41, the method comprises the following steps:

[0027] Step S411: using density functional perturbation theory to calculate the elastic constants of the polymer material;

[0028] Step S412: Determine the elastic constant C ij Does it satisfy the formula:

[0029] C 11 -C 12 >0

[0030]

[0031]

[0032] C 44 >0;

[0033] If so, it is determined that the polymer material has mechanical stability and the material kinetic stability judgment is performed; if not, it is determined that the polymer material does not have mechanical stability and the polymer material without mechanical stability is screened out.

[0034] In one aspect, in step S42, the method comprises the following steps:

[0035] Step S421: Calculate the phonon spectrum of the polymer material with mechanical stability using the finite displacement method;

[0036] Step S422: Determine whether the phonon dispersion curve of the phonon spectrum has an imaginary frequency. If so, determine that the polymer material is not kinetically stable and screen out the polymer material that is not kinetically stable; if not, determine that the polymer material is kinetically stable and screen out the polymer material that is kinetically stable.

[0037] In one aspect, in step S5, the method comprises the following steps:

[0038] Step S51: using a finite displacement method to calculate the phonon spectrum of a stable polymer material, and then calculating the second-order atomic interaction force constant based on the phonon spectrum;

[0039] Step S52: using a finite displacement method to obtain the third-order atomic interaction force constant of a stable polymer material;

[0040] Step S53: Solve the phonon Boltzmann transport equation according to the second-order atomic interaction force constant and the third-order atomic interaction force constant to obtain the lattice thermal conductivity of the stable polymer material.

[0041] In one aspect, in step S5, the method further comprises the following steps:

[0042] Step S54: using density functional perturbation theory to calculate the elastic constants of the stable polymer material;

[0043] Step S55: using basic electrical transport parameters of stable polymer materials to solve electrical conductivity, Seebeck coefficient, and carrier thermal conductivity;

[0044] Step S56: Using the thermoelectric figure of merit Evaluate the thermoelectric properties of stable polymer materials and obtain target polymer thermoelectric materials that meet preset requirements; where σ is conductivity, S is the Seebeck coefficient, T is the temperature at which the material works, and κ l is the lattice thermal conductivity, к e is the electronic thermal conductivity.

[0045] The present application also provides a high-throughput screening system for polymer thermoelectric materials for performing the high-throughput screening method, comprising:

[0046] A data extraction module is used to extract a preset amount of screening information according to a target database, wherein the screening information at least includes: basic information on the synthesis conditions, atomic number and electronic energy band of the inorganic compound;

[0047] A first screening module, used to screen out semiconductor materials from a preset amount of screening information using a semiconductor screening method;

[0048] The second screening module is used to screen out the chalcogenide atom-containing polymer material from the semiconductor material by using the chalcogenide atom-containing polymer screening method;

[0049] A characteristic judgment module, used to judge the stability of the polymer material containing sulfur atoms and obtain the polymer material judged to be stable;

[0050] The material evaluation module is used to perform lattice thermal conductivity tests and calculate the electrical transport parameters of polymer materials based on stable polymer materials, and then use thermoelectric figures of merit to evaluate the thermoelectric performance and obtain target polymer thermoelectric materials that meet preset requirements.

[0051] Beneficial effects of the high-throughput screening method of the present application:

[0052] This application proposes a unique polymer screening method to effectively obtain ultra-low thermal conductivity and high-performance thermoelectric materials. This screening result enriches thermoelectric materials, greatly reduces the computational cost, shortens the development cycle of new n-type thermoelectric materials, and provides a theoretical basis for building high-performance pn-type thermoelectric materials and promoting commercial thermoelectric devices. These high-ZT polymer thermoelectric materials can improve power generation efficiency, especially in industrial production, automobile engines and power plants. These large amounts of waste heat can be directly recycled, thereby improving energy efficiency and reducing dependence on fossil fuels; at the same time, high-ZT polymer thermoelectric materials can achieve precise temperature control in electronic components and precision instruments. For this reason, screening high-performance polymer thermoelectric materials has important practical significance in terms of environmental protection, energy saving and improving energy efficiency. In addition, this application adopts a high-throughput computational screening method based on polymer models and first principles, which can quickly obtain candidate materials, has high efficiency, and has both accuracy. It does not involve complex experimental processes in the entire process, and the operation process is simple and easy to implement. It is also suitable for promotion to other fields of semiconductor materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0054] Figure 1 It is a flow chart of a high-throughput screening method for polymer thermoelectric materials provided in an embodiment of the present invention.

[0055] Figure 2 It is a flow chart of a semiconductor material screening method provided by an embodiment of the present invention.

[0056] Figure 3It is a flow chart of a method for screening sulfur-containing atom polymer materials provided by an embodiment of the present invention.

[0057] Figure 4 It is a flow chart of a stability determination method provided by an embodiment of the present invention.

[0058] Figure 5 It is a flow chart of a material mechanical stability determination method provided by an embodiment of the present invention.

[0059] Figure 6 It is a flow chart of a method for determining the material dynamic stability provided by an embodiment of the present invention.

[0060] Figure 7 It is a flow chart of a method for calculating lattice thermal conductivity provided by an embodiment of the present invention.

[0061] Figure 8 It is a schematic diagram of the generation of the lattice thermal conductivity material provided by an embodiment of the present invention.

[0062] Fig. 9 It is a flow chart of a method for calculating thermoelectric performance provided by an embodiment of the present invention.

[0063] Fig.10 It is a schematic diagram of the relationship between carrier concentration, temperature and ZT in the polymer material provided by the embodiment of the present invention.

[0064] Fig.11 It is a schematic diagram of the module connection of a high-throughput screening system for polymer thermoelectric materials provided in an embodiment of the present invention.

[0065] Description of the Figures in the Specification:

[0066] 100. Data extraction module, 101. First screening module, 102. Second screening module, 103. Characteristic judgment module, 104. Material evaluation module. DETAILED DESCRIPTION

[0067] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0068] Thermoelectric figure of merit It provides information about the parameters between the electrical and thermal properties of the material, and can also be used to evaluate the thermoelectric properties of the material. A good ZT value requires a large Seebeck coefficient (S), high electrical conductivity (σ) and low thermal conductivity (κ).

[0069] The materials project gene database has published basic information about materials, including electronic band gap, atomic number, and whether they have been experimentally synthesized. For this reason, these three conditions can be used for the first step of screening, which directly excludes more than 140,000 materials that do not need to be calculated, saving computing resources and shortening the development cycle of new materials. In addition, the presence of large mass and weak chemical bond ions in semiconductor materials can lead to low thermal conductivity (1Wm -1 K -1 ) and improve the thermoelectric performance of ZT>1; since two sulfur (selenium or tellurium) atoms covalently bonded together can be regarded as a large mass atom, for this reason, in this application, a polymer model of this type of sulfur (selenium or tellurium) atoms is defined and a high-throughput method is used to screen such materials, and then for the screened polymer materials, first-principles calculations are further used to obtain the thermoelectric properties and determine the N-type thermoelectric material with ZT>1.

[0070] Therefore, reference Figure 1 As shown, in some embodiments, a high-throughput screening method for a polymer thermoelectric material includes the following steps:

[0071] Step S1: extracting a preset amount of screening information according to a target database, wherein the screening information at least includes: basic information on synthesis conditions, atomic number and electronic energy band of inorganic compounds.

[0072] Specifically, in step S1, a preset number of inorganic compounds that can be directly queried (the preset number is determined by the number of organic compounds that the materials project database platform allows people to directly query, and in this application, the current 150,000 organic compounds are referenced) are extracted from the public materials project database platform. Basic information on synthesis conditions, atomic numbers and electronic energy bands.

[0073] Step S2: using a semiconductor screening method to screen out semiconductor materials from a preset amount of screening information.

[0074] Specifically, the materials project gene database currently only provides basic physical information such as the number of atoms, whether it has been synthesized experimentally, the electronic band gap, and the crystal structure, but does not have the thermoelectric performance parameters of each material. Therefore, these basic physical information are used to screen semiconductor materials, that is, to obtain semiconductor materials that have been synthesized experimentally and have low crystal structure complexity from the materials project database.

[0075] For example, select theoretical, num_sites and band_gap in the materials project database. Figure 2 As shown, that is:

[0076] In step S21, theoretical=True is selected, which means that the material synthesized by the experiment is selected. The material synthesized by the experiment ensures the energy stability of the thermoelectric material.

[0077] In step S22, select num_sites = [2~20], which means that the number of atoms in the initial unit cell is in the range of 2 to 20, which belongs to a low-complexity structure. Screening low-complexity structures not only facilitates the exploration of material properties and physical origins, but also reduces the computational cost of first-principles simulations. As the number of atoms increases, the calculation time also increases. For this reason, this application selects the number of atoms in the range of 2 to 20, which controls the calculation time for optimizing a material within a few minutes.

[0078] In step S23, since existing research has found that thermoelectric materials with ZT>1 are all semiconductor materials, band_gap=[0.1-3] is selected, which means that the electronic band gap is 0.1-3 eV, which is a semiconductor material.

[0079] Therefore, after satisfying these three screening conditions at the same time, more than 5,000 semiconductor materials that have been experimentally synthesized and have low crystal structure complexity have been obtained from the materials project database. The main purpose of step S2 is to shorten the computational cost of the next step.

[0080] Step S3: using a chalcogen-atom-containing polymer screening method to screen out chalcogen-atom-containing polymer materials from semiconductor materials.

[0081] Although the thermal conductivity, electrical transport parameters and thermoelectric properties of these 5000 materials can be directly calculated using traditional high-throughput methods, the calculation time and resources are huge, because the time cycle for completely calculating the performance of a material takes at least one day; for this reason, in step S3 of the present application, a multi-aggregation model is proposed to obtain a class of sulfur-containing atom polymer materials, which is about 100 or less, which not only effectively saves calculation resources but also can obtain the thermoelectric properties of this type of multi-aggregation; reference Figure 3 As shown, the screening process of obtaining the sulfur-containing atom polymer material from the semiconductor material obtained in the above step S2 is as follows:

[0082] In step S31, the first-principles VASP software is used to optimize the structure. In the screening in step S2, the POSCAR files of 5000 structures have been obtained, which represent the spatial structure information of the material. Then, the corresponding POTCAR files and KPOINTS files are constructed for each structure, which represent the force field information and the grid density respectively. A low-precision grid density is adopted, and it follows that the product of the lattice side length and the K points is equal to 30. The INCAR file represents the control file for the calculation process.

[0083] In step S32, the projected augmented wave (PAW) is used in the POSCAR file to process the electronic wave function. The PBE-GGA exchange-correlation functional is used for the electronic structure calculation. The plane-wave cutoff energy is set to 500 eV in the INCAR file. The force and energy convergence criteria for the crystal structure optimization are and 10-8 eV. In this process, we calculate whether the material contains two or more sulfur (selenium or tellurium) atoms to determine the polymeric material, calculate sulfur, selenium, and tellurium elemental substances. The calculation results show that the sulfur-sulfur bond length of sulfur elemental substance is approximately The selenium-selenium bond length of selenium elemental substance is approximately and the tellurium-tellurium bond length of tellurium elemental substance is approximately Among them, the projected augmented wave (PAW) is used in the POSCAR file to process the electronic wave function. The PBE-GGA exchange-correlation functional is used for the electronic structure calculation, which mainly runs in the VASP software and adopts the existing technology that has been generally accepted by simulation techniques.

[0084] In step S33, it is calculated whether the sulfur-sulfur (selenium-selenium or tellurium-tellurium) bond length in the 5000 materials is between 1.05 and 1.1 times the distance between two atoms in sulfur (selenium or tellurium) elemental substance. If this condition is met, it means that this compound belongs to the polymeric material. It should be noted that the atomic aggregation range of 1.05 - 1.1 is the range of the covalent bond length of sulfur (selenium or tellurium) atoms set in the present invention, and the corresponding mathematical expression is (Dii < F(Ri + Ri) (i = S, Se, Te)), where Dii represents the distance between two sulfur (selenium or tellurium) atoms, Ri represents the covalent radius of sulfur (selenium or tellurium) atoms, and Ri + Ri represents the bond length of sulfur (selenium or tellurium) elemental substance. By calculating the spatial structure information of each atom in the POSCAR file to calculate the distance between two sulfur (selenium or tellurium) atoms and the judgment of the polymeric material, the crystal materials that meet the polymeric model can be directly screened out. Through the polymeric model of this application, we only need to optimize the structures of 5000 compounds and calculate the thermoelectric properties of less than 100 polymers, rather than directly calculating the thermoelectric properties of 5000 materials; through this step of screening, at least an order of magnitude of computing resources is saved.

[0085] Finally, 20 polymer materials were obtained in this screening process, including 10 sulfur atom polymer materials, whose chemical formulas are SrS2, BaS2, NaS, KS, RbS, Ba(PdS2)2, RbS, BaS3, Rb2S3, K2S3; 5 selenium atom polymer materials, whose chemical formulas are MgSe2, RbCuPdSe5, KCuPdSe5, CuSe3Br, AgSe3I; and 5 tellurium atom polymer materials, whose chemical formulas are Rb2Te3, Cs2Te5, K2Te3, RbTe, RbTe.

[0086] Step S4: Perform stability judgment on the sulfur-containing polymer material and obtain a polymer material judged to be stable.

[0087] Specifically, in step S4, the stability of the 20 polymers screened in step S3 is judged; Figure 4-Figure 6 As shown, exemplary:

[0088] In step S41, the mechanical stability of the material is determined. As in step S3, the POSCAR file, POTCAR file, KPOINTS file, and INCAR file are required. In the INCAR file, NSW=1, IBRION=6, and ISIF=3 are set. The elastic constant (Cij) of the material is calculated using density functional perturbation theory in the VASP software. If the formula is satisfied, This means that the material has mechanical stability, and thus the polymer material that does not have mechanical stability is screened out.

[0089] In step S42, the dynamic stability of the material is determined. As in step S3, a POTCAR file, a KPOINTS file, and an INCAR file are required. The difference is that the POSCAR file is a supercell structure. The characteristics of the supercell are that its a-axis, b-axis, and c-axis are nearly equal in length, and the total number of atoms is close to about 100; the k-point grid in the KPOINTS file is 3×3×3; the finite displacement method is used in the Phonopy software to calculate the phonon spectrum. By introducing a small atomic displacement in the optimized structure, the Hellmann-Feynman force acting on each atom is calculated, and the phonon dispersion curve is further calculated from the dynamic matrix. In the INCAR file, NSW=0 and IBRION=-1 are mainly set. If there is no imaginary frequency in the phonon dispersion curve, that is, when the atomic vibration frequency is greater than 0, it means that the material has dynamic stability, and then the polymer material without dynamic stability is screened out and the polymer material with dynamic stability is screened out. Through this step of calculation process, 20 stable polymer materials are obtained.

[0090] Step S5: Based on the stable polymer material, a lattice thermal conductivity test is performed and the electrical transport parameters of the polymer material are calculated, and then the thermoelectric performance is evaluated using the thermoelectric figure of merit to obtain a target polymer thermoelectric material that meets the preset requirements.

[0091] Specifically, in step S5, the lattice thermal conductivity of 20 stable polymer materials is tested, and the input parameters of the lattice thermal conductivity require the second-order atomic interaction force constant and the third-order atomic interaction force constant. Figure 7 As shown, exemplary:

[0092] In step S51, the second-order atomic interaction force constant has been obtained in the phonon dispersion curve calculation process in step S4.

[0093] In step S52, the third-order atomic interaction force constant needs to be determined. As in step S3, POTCAR file, KPOINTS file and INCAR file are required. As in step S4, this step maintains the same supercell characteristics; when the number of supercell atoms is less than 100, the k-point grid of the third-order atomic interaction force constant is 2×2×2, and when the number of supercell atoms is greater than 100, the k-point grid of the third-order atomic interaction force constant is 1×1×1. The cutoff radius of the number of nearest neighbor atoms in the third-order atomic interaction force constant is set to 8. The finite displacement method is used in the thirdorder.py software to obtain the third-order atomic interaction force constant, which is consistent with the INCAR file parameters of the second-order atomic interaction force constant.

[0094] In step S53, after obtaining the second-order atomic interaction force constant and the third-order atomic interaction force constant, the phonon Boltzmann transport equation is solved in ShengBTE software to obtain the lattice thermal conductivity of 20 stable materials. The thermal conductivity is expressed as:

[0095]

[0096] λ is the phonon mode, C represents the heat capacity, υ is the phonon group velocity, and τ is the phonon lifetime. The q-point grid for evaluating the lattice thermal conductivity converges to 9×9×9. Figure 8 As shown in the figure, 15 ultra-low lattice thermal conductivity materials (κ<1Wm -1 K -1 ), 18 of which are lower than the thermal conductivity of commercial material PbTe (2.4 Wm -1 K -1 This demonstrates the advantage of the polymer model in this application in exploring low thermal conductivity.

[0097] In step S5, the electrical transport parameters of 20 polymer materials are calculated and the thermoelectric performance is evaluated. Fig. 9 As shown, exemplary:

[0098] In step S54, as in step S3, POSCAR file, POTCAR file, KPOINTS file and INCAR file are required. The basic electrical transport parameters of phonon frequency, elastic constant, deformation potential energy and wave function coefficient are calculated by first principle in VASP software. As in step S4, the elastic constant of the material is calculated by density functional perturbation theory in VASP software, except that a high-precision grid density is used, and the product of the lattice edge length and K point is equal to 50. In the calculation of elastic constants, INCAR file sets IBRION=6. In the calculation of phonon frequency, INCAR file sets IBRION=8. In the calculation of electrical transport parameters, INCAR file sets NSW=1.

[0099] In step S55, the basic electrical transport parameters are used in the AMSET software to solve the electrical conductivity, Seebeck coefficient, and carrier thermal conductivity; the three electrical transport coefficients are calculated by the Onsager relationship, where the generalized transport coefficient is expressed as:

[0100]

[0101] α and β are atomic coordinates, e represents the atomic charge, ∑ αβ (ε) is the spectral conductivity, ε F is the Fermi level at a specific concentration and temperature, f 0 represents the Fermi-Dirac distribution, and n is the energy band index. The conductivity is expressed as:

[0102]

[0103] The Seebeck coefficient is expressed as:

[0104]

[0105] T represents the system temperature, and the carrier thermal conductivity is expressed as:

[0106]

[0107] The interpolation factor of the electrical transport grid density is set to 20, and 10 new polymer thermoelectric materials with ZT>1 are obtained among 20 polymers.

[0108] In step S56, the thermoelectric figure of merit is used By evaluating the thermoelectric properties of stable polymer materials, nine n-type thermoelectric materials were discovered, with chemical formulas of RbTe, BaS2, KCuPdSe5, RbCuPdSe5, Cs2Te5, CuSe3Br, AgSe3I, Rb2Te3, and K2Te3; and one p-type thermoelectric material, with chemical formula of RbTe. Fig.10As shown, the relationship between carrier concentration, temperature and ZT in 10 polymer materials. Fig.10 The type (n-type or p-type) and chemical formula of the thermoelectric material are also shown. 18 cm -3 ~10 21 cm -3 The interval reaches the maximum value of ZT and ZT>1. The thermoelectric performance of these polymer materials is higher than 0.8 of the material PbTe, which indicates the advantage of the polymer model of this application in exploring high-performance thermoelectric materials.

[0109] Thus, steps S1-S3 of the present application show that the unique two-step screening method proposed by the present application efficiently obtains 20 chalcogen atom-containing polymer materials. Steps S4-S6 show that the first-principles calculation proves the effectiveness of the present screening results, and 15 ultra-low lattice thermal conductivity and 10 high-performance polymer thermoelectric materials are found, especially 9 n-type thermoelectric materials, which enrich the thermoelectric materials. The two-step screening method and screening results of the present application provide a theoretical basis for constructing high-performance pn-type thermoelectric materials and promoting commercial thermoelectric devices.

[0110] In some embodiments, reference Fig.11 As shown, the present application also relates to a high-throughput screening system for polymer thermoelectric materials for performing the high-throughput screening method, comprising:

[0111] The data extraction module 100 is used to extract a preset amount of screening information according to the target database, wherein the screening information at least includes: basic information of the synthesis conditions, atomic number and electronic energy band of the inorganic compound;

[0112] The first screening module 101 is used to screen out semiconductor materials from a preset number of screening information using a semiconductor screening method; it is also used to screen out semiconductor materials that have been synthesized in experiments using a first screening condition based on a preset number of screening information; based on a preset number of screening information, it uses a second screening condition to screen out semiconductor materials whose number of atoms in the initial unit cell is within a first preset interval; based on a preset number of screening information, it uses a third screening condition to screen out semiconductor materials whose electronic band gap is within a second preset interval, thereby obtaining semiconductor materials.

[0113] The second screening module 102 is used to screen out sulfur-containing atom polymer materials from semiconductor materials using a sulfur-containing atom polymer screening method; it is also used to optimize the semiconductor material using first-principle calculation software to obtain spatial structure information data of the semiconductor material, and then construct force field information data and preset grid density data for each spatial structure contained in the semiconductor material; in the spatial structure information data of the semiconductor material, use the projection-added plane wave to process the electronic wave function and use the PBE-GGA exchange-correlation functional to calculate the electronic structure; according to the spatial structure information data of each atom in the semiconductor material, calculate the polymer material containing sulfur-sulfur (selenium-selenium or tellurium-tellurium) bond length between the preset multiples of the distance between two atoms in the sulfur (selenium or tellurium) element, so as to screen out the polymer material containing at least two sulfur (selenium or tellurium) atoms.

[0114] The characteristic judgment module 103 is used to judge the stability of the polymer material containing sulfur atoms and obtain the polymer material judged to be stable; it is also used to judge the mechanical stability of the material based on the screened polymer material containing at least two sulfur (selenium or tellurium) atoms; it is used to judge the kinetic stability of the material based on the screened polymer material containing at least two sulfur (selenium or tellurium) atoms, so as to screen out stable polymer materials.

[0115] The material evaluation module 104 is used to perform lattice thermal conductivity test and calculate the electrical transport parameters of the polymer material based on the stable polymer material, and then use the thermoelectric figure of merit to evaluate the thermoelectric performance to obtain the target polymer thermoelectric material that meets the preset requirements; it is also used to calculate the phonon spectrum of the stable polymer material using the finite displacement method, and then use the second-order atomic interaction force constant based on the phonon spectrum; use the finite displacement method to obtain the third-order atomic interaction force constant of the stable polymer material; solve the phonon Boltzmann transport equation based on the second-order atomic interaction force constant and the third-order atomic interaction force constant to obtain the lattice thermal conductivity of the stable polymer material; use the density functional perturbation theory to calculate the elastic constants of the stable polymer material; use the basic electrical transport parameters of the stable polymer material to solve the electrical conductivity, Seebeck coefficient, and carrier thermal conductivity; use the thermoelectric figure of merit to evaluate the thermoelectric performance of the stable polymer material to obtain the target polymer thermoelectric material that meets the preset requirements.

[0116] In some embodiments, the present application also relates to a computer medium having a computer program stored thereon, and the computer program is executed by a processor to implement the high-throughput screening method for polymer thermoelectric materials.

[0117] In some embodiments, the present application also relates to a computer, comprising the computer medium described above.

[0118] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0119] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A high-throughput screening method for polymer thermoelectric materials, characterized in that: The following steps are involved: Step S1: extracting a preset amount of screening information according to the target database, wherein the screening information at least includes: basic information on the synthesis conditions, atomic number and electronic energy band of the inorganic compound; Step S2: using a semiconductor screening method to screen out semiconductor materials from a preset amount of screening information; Step S3: using a chalcogen-atom-containing polymer screening method to screen out chalcogen-atom-containing polymer materials from semiconductor materials; Step S4: performing stability judgment on the sulfur-containing polymer material and obtaining a polymer material judged to be stable; Step S5: Based on the stable polymer material, a lattice thermal conductivity test is performed and the electrical transport parameters of the polymer material are calculated, and then the thermoelectric performance is evaluated using the thermoelectric figure of merit to obtain a target polymer thermoelectric material that meets the preset requirements.

2. The high-throughput screening method for polymer thermoelectric materials according to claim 1, characterized in that: In step S2, the method comprises the following steps: Step S21: According to a preset amount of screening information, a first screening condition is used to screen out the semiconductor materials synthesized in the experiment; Step S22: according to a preset amount of screening information, using a second screening condition to screen out semiconductor materials whose atomic number of initial unit cells is within a first preset range; Step S22: According to a preset amount of screening information, a third screening condition is used to screen out semiconductor materials with an electronic band gap in a second preset interval, thereby obtaining semiconductor materials.

3. A high-throughput screening method for polymer thermoelectric materials according to claim 1 or 2, characterized in that: In step S3, the method comprises the following steps: Step S31: optimizing the semiconductor material using first principle calculation software to obtain spatial structure information data of the semiconductor material, and then constructing force field information data and preset grid density data for each spatial structure contained in the semiconductor material; Step S32: In the spatial structure information data of the semiconductor material, the electronic wave function is processed using the projected plane wave and the electronic structure is calculated using the PBE-GGA exchange-correlation functional; Step S33: Based on the spatial structure information data of each atom in the semiconductor material, calculate the polymer materials containing sulfur-sulfur, selenium-selenium or tellurium-tellurium bond lengths between preset multiples of the distance between two atoms in the sulfur, selenium or tellurium element, so as to screen out the polymer materials containing at least two sulfur, selenium or tellurium atoms.

4. The high-throughput screening method for polymer thermoelectric materials according to claim 3, characterized in that: In step S33, based on the spatial structure information data of each atom in the semiconductor material, the material containing sulfur-sulfur, selenium-selenium or tellurium-tellurium bond length between 1.05 and 1.1 times the distance between two atoms in sulfur, selenium or tellurium is taken as a polymer material.

5. The high-throughput screening method for polymer thermoelectric materials according to claim 3, characterized in that: In step S4, the method comprises the following steps: Step S41: judging the mechanical stability of the material according to the screened polymer material containing at least two sulfur, selenium or tellurium atoms; Step S42: judging the material kinetic stability based on the screened-out polymer materials containing at least two sulfur, selenium or tellurium atoms, so as to screen out stable polymer materials.

6. The high-throughput screening method for polymer thermoelectric materials according to claim 5, characterized in that: In step S41, the method comprises the following steps: Step S411: using density functional perturbation theory to calculate the elastic constants of the polymer material; Step S412: Determine the elastic constant C ij Does it satisfy the formula: C 11 -C 12 >0 C 44 >0； If so, it is determined that the polymer material has mechanical stability and the material kinetic stability judgment is performed; if not, it is determined that the polymer material does not have mechanical stability and the polymer material without mechanical stability is screened out.

7. The high-throughput screening method for polymer thermoelectric materials according to claim 5, characterized in that: In step S42, the method comprises the following steps: Step S421: Calculate the phonon spectrum of the polymer material with mechanical stability using the finite displacement method; Step S422: Determine whether the phonon dispersion curve of the phonon spectrum has an imaginary frequency. If so, determine that the polymer material is not kinetically stable and screen out the polymer material that is not kinetically stable; if not, determine that the polymer material is kinetically stable and screen out the polymer material that is kinetically stable.

8. A high-throughput screening method for polymer thermoelectric materials according to claim 1 or 5, characterized in that: In step S5, the method comprises the following steps: Step S51: using a finite displacement method to calculate the phonon spectrum of a stable polymer material, and then calculating the second-order atomic interaction force constant based on the phonon spectrum; Step S52: using a finite displacement method to obtain the third-order atomic interaction force constant of a stable polymer material; Step S53: Solve the phonon Boltzmann transport equation according to the second-order atomic interaction force constant and the third-order atomic interaction force constant to obtain the lattice thermal conductivity of the stable polymer material.

9. The high-throughput screening method for polymer thermoelectric materials according to claim 8, characterized in that: In step S5, the method further comprises the following steps: Step S54: using density functional perturbation theory to calculate the elastic constants of the stable polymer material; Step S55: using basic electrical transport parameters of stable polymer materials to solve electrical conductivity, Seebeck coefficient, and carrier thermal conductivity; Step S56: Using the thermoelectric figure of merit Evaluate the thermoelectric properties of stable polymer materials and obtain target polymer thermoelectric materials that meet preset requirements; where σ is conductivity, S is the Seebeck coefficient, T is the temperature at which the material works, and κ l is the lattice thermal conductivity, κ e is the electronic thermal conductivity.

10. A high-throughput screening system for polymer thermoelectric materials for executing the high-throughput screening method according to any one of claims 1 to 9, characterized in that: include: A data extraction module is used to extract a preset amount of screening information according to a target database, wherein the screening information at least includes: basic information on the synthesis conditions, atomic number and electronic energy band of the inorganic compound; A first screening module, used to screen out semiconductor materials from a preset amount of screening information using a semiconductor screening method; The second screening module is used to screen out the chalcogenide atom-containing polymer material from the semiconductor material by using the chalcogenide atom-containing polymer screening method; A characteristic judgment module, used to judge the stability of the polymer material containing sulfur atoms and obtain the polymer material judged to be stable; The material evaluation module is used to perform lattice thermal conductivity tests and calculate the electrical transport parameters of polymer materials based on stable polymer materials, and then use thermoelectric figures of merit to evaluate the thermoelectric performance and obtain target polymer thermoelectric materials that meet preset requirements.

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