Theoretical design method of halide solid electrolyte

Abstract

The invention relates to a theoretical design method of a halide solid electrolyte. The theoretical design method comprises the following steps: S1, carrying out structure optimization on a material; s2, calculating and evaluating the intrinsic characteristics of the most stable structure obtained in the step S1, and performing primary screening on various halide solid electrolyte materials to obtain a material set meeting the requirements of thermodynamic stability, dynamic stability and electronic insulativity; s3, calculating the performance of the materials in the material set obtained in the step S2; and S4, according to the numerical values of the various performance parameters obtained in the step S3, sequentially arranging the various halide solid electrolyte materials, and screening out the halide solid electrolyte material with the optimal comprehensive performance. According to the method, multi-scale calculation simulation is integrated, a complete design method from electrolyte intrinsic characteristic screening to performance calculation is constructed, calculation resources are saved, and discovery and application of the high-performance halide solid electrolyte are accelerated.

Description

Technical Field

[0001] This invention relates to the field of solid electrolyte materials technology, and in particular to a theoretical design method for halide solid electrolytes. Background Technology

[0002] Solid-state electrolytes (SSEs) are the core component of all-solid-state lithium batteries (ASSLBs), and their performance, such as ionic conductivity, electrochemical stability, and interfacial compatibility with electrodes, directly determines the overall performance of the battery. Halogen solid-state electrolytes (such as Li3YCl6, Li3InCl6, Li2ZrCl6, etc.) are particularly advantageous due to their excellent lithium-ion conductivity (up to 10⁻⁶). -3 Materials have attracted widespread attention due to their good deformability (S / cm), wide electrochemical stability window, and potential compatibility with high-voltage cathode materials. However, traditional materials development models rely heavily on trial and error for experimental synthesis and performance testing, resulting in long development cycles, high costs, and low efficiency, making it difficult to achieve rapid, large-scale material screening and optimization.

[0003] In recent years, the development of computational materials science has provided new avenues for the design of electrolyte materials. Existing technologies include methods for predicting electrolyte performance based on first-principles calculations and molecular dynamics simulations. However, these methods often either focus on evaluating only one aspect of performance or, while performing comprehensive calculations on candidate materials, including electrochemical stability, ionic conductivity, and interfacial compatibility, employ parallel or disordered computational strategies. This parallel or disordered computational strategy suffers from the drawback of consuming significant computational resources on intrinsically unstable materials or materials whose fundamental conditions are not met, leading to low research and development efficiency. Summary of the Invention

[0004] Therefore, it is necessary to provide a theoretical design method for halide solid electrolytes to address the aforementioned technical problems in the existing technology. This method integrates multi-scale computational simulations and constructs a complete design method from the screening of intrinsic electrolyte properties to performance calculations, saving computational resources and accelerating the discovery and application of high-performance halide solid electrolytes.

[0005] To solve the above technical problems, the technical solution adopted by the present invention is as follows: A theoretical design method for halide solid electrolytes includes the following steps: S1. Optimize the structure of halide solid electrolyte materials to obtain their most stable structure and lattice constant; S2. Calculate and evaluate the intrinsic properties of the most stable structure of the halide solid electrolyte material obtained in step S1. The intrinsic properties include thermodynamic stability, kinetic stability and electronic insulation. Perform preliminary screening on various halide solid electrolyte materials to obtain a set of materials that meet the requirements of thermodynamic stability, kinetic stability and electronic insulation. S3. Calculate the performance of the halide solid electrolyte material in the material set obtained in step S2. The performance includes the electrochemical window, the diffusion coefficient and activation energy of lithium ions, and the lattice mismatch between the electrolyte material and the negative electrode lithium metal. S4. Based on the numerical values ​​of the various performance parameters obtained in step S3, the various halide solid electrolyte materials are arranged in order to select the optimal halide solid electrolyte material.

[0006] Preferably, step S3 is performed when the intrinsic properties of the halide solid electrolyte material in step S2 meet the screening criteria; otherwise, the calculation is terminated early.

[0007] Preferably, step S2 includes step S21, thermodynamic stability calculation, which involves calculating the thermodynamic phase diagram of the halide solid electrolyte material to determine whether the material will spontaneously decompose or the ease of spontaneous decomposition. Thermodynamic stability calculations employ the formation energy and phase diagram method, which includes the following steps: Step 1: Retrieve data from a crystallography database or calculate the formation energy of all relevant phases of the halide solid electrolyte material based on density functional theory. All relevant phases of the halide solid electrolyte material include elemental substances and compounds. Step 2: Construct the phase diagram; Step 3: Obtain the convex hull energy to determine the thermodynamic stability of the halide solid electrolyte material; If the convex hull energy of a material is less than 0.1 eV / atom, then the material is thermodynamically stable.

[0008] Preferably, step S2 includes step S22, dynamic stability calculation, which involves calculating the phonon spectrum to determine whether there is an imaginary frequency in the material and whether the material has undergone a phase transition or structural deformation. Dynamic stability calculations employ either the linear response method or the finite displacement method.

[0009] Preferably, step S2 includes step S23, electronic insulation calculation, which involves calculating the electronic density of states D(E) and determining whether the material is electronically insulating based on whether the Fermi level crosses the band gap and the width of the band gap. If the Fermi level of a material is located between band gaps and the band gap is greater than 0, then the material is an electronic insulating material. The specific calculation of the electronic density of states D(E) is as follows: ; in, E (k) is the energy corresponding to the wave vector k. δ ( E E k ) is the Dirac function, representing energy. E The number of states at that point d 3 k is a tiny volume in the wave vector space.

[0010] Preferably, the calculations in steps S21, S22, and S23 are not performed in any particular order.

[0011] Preferably, step S3 includes step S31, electrochemical window calculation, which uses electrochemical stoichiometry to obtain the chemical potential of the halide solid electrolyte structure when it undergoes a redox reaction, i.e., the size of the electrochemical window, by performing a migration ion insertion or extraction reaction on the halide solid electrolyte structure.

[0012] Preferably, step S3 includes step S32, calculating the diffusion coefficient and activation energy of lithium ions, using molecular dynamics (MD) simulation to calculate the diffusion coefficient of lithium ions, and using the Arrhenius equation for fitting to calculate the activation energy.

[0013] Preferably, step S3 includes step S33, calculating the lattice mismatch between the electrolyte material and the negative electrode lithium metal. Based on the lattice constant obtained from the structure optimization in step S1, the lattice mismatch between the electrolyte material and the negative electrode lithium metal is calculated using the following formula: in, , These are the lattice constants of the solid electrolyte and the electrode, respectively. n Let be a positive integer, such that it satisfies .

[0014] Preferably, the calculations in steps S31, S32, and S33 are not performed in any particular order.

[0015] Due to the adoption of the above technical solutions, the present invention has the following advantages compared with the prior art: This invention presents a theoretical design method for halide solid electrolytes, integrating multi-scale computational simulations. It constructs a complete design method from screening intrinsic electrolyte properties to performance calculations, and establishes a step-by-step, condition-based screening process that can prioritize the intrinsic stability of solid electrolytes and determine whether to perform subsequent calculations accordingly. This saves computational resources and accelerates the discovery and application of high-performance halide solid electrolytes. Attached Figure Description

[0016] Figure 1This is a flowchart of the theoretical design method of the present invention; Figure 2 The ternary phase diagram of Li₂ZrCl₆ at 0 K; Figure 3 The phonon spectrum of Li₂ZrCl₆; Figure 4 The electronic density of states diagram for Li₂ZrCl₆; Figure 5 Electrochemical window diagram of Li₂ZrCl₆; Figure 6 Arrhenius plots of the diffusion coefficient of Li₂ZrCl₆ at different temperatures. Detailed Implementation

[0017] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0018] 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 this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0019] In recent years, the development of computational materials science has provided new avenues for the design of electrolyte materials. Existing technologies include methods for predicting electrolyte performance based on first-principles calculations and molecular dynamics simulations. However, these methods often either focus on evaluating only one aspect of performance or, while performing comprehensive calculations on candidate materials, including electrochemical stability, ionic conductivity, and interfacial compatibility, employ parallel or disordered computational strategies. This parallel or disordered computational strategy suffers from the drawback of consuming significant computational resources on intrinsically unstable materials or materials whose fundamental conditions are not met, leading to low research and development efficiency.

[0020] Based on this, the present invention provides a theoretical design method for halide solid electrolytes, comprising the following steps: S1. Optimize the structure of halide solid electrolyte materials to obtain their most stable structure and lattice constant; S2. Calculate and evaluate the intrinsic properties of the most stable structure of the halide solid electrolyte material obtained in step S1. The intrinsic properties include thermodynamic stability, kinetic stability and electronic insulation. Perform preliminary screening on various halide solid electrolyte materials to obtain a set of materials that meet the requirements of thermodynamic stability, kinetic stability and electronic insulation. S3. Calculate the performance of the halide solid electrolyte material in the material set obtained in step S2. The performance includes the electrochemical window, the diffusion coefficient and activation energy of lithium ions, and the lattice mismatch between the electrolyte material and the negative electrode lithium metal. S4. Based on the numerical values ​​of the various performance parameters obtained in step S3, the various halide solid electrolyte materials are arranged in order to select the optimal halide solid electrolyte material.

[0021] It is understandable that ranking materials according to numerical values ​​means, for example, arranging them from widest to narrowest for electrochemical windows; from highest to lowest for lithium-ion diffusion coefficients; and from lowest to highest for activation energy and lattice mismatch with lithium metal. Ultimately, the ranking of each material's various indicators can be comprehensively considered, and the material with the best overall ranking can be selected.

[0022] The theoretical design method of halide solid electrolytes in this invention integrates multi-scale computational simulation, and constructs a complete design method from the screening of intrinsic electrolyte properties to performance calculation, which saves computational resources and accelerates the discovery and application of high-performance halide solid electrolytes.

[0023] In a specific embodiment, in step S1, crystal library data is retrieved from the database interface, and the crystal structure of halide solid electrolyte material containing Li element is screened out, and its structure is optimized to obtain its most stable structure and its lattice constant.

[0024] Specifically, the crystal structure file of the halide solid electrolyte material is obtained from the crystal library data, and structural relaxation is performed. By optimizing the atomic positions, the lowest energy configuration, i.e., the most stable structure, is found. The conjugate gradient method is used for structural optimization: first, the atomic positions are initialized and the initial potential energy and residuals are calculated; then, in each iteration, the atomic positions are updated by calculating the step size, and the new residuals are calculated. If the residual is less than a set threshold or the maximum number of iterations is reached, the iteration stops. When updating the search direction, the residuals and the previous search direction are used for adjustment to efficiently find the lowest energy configuration of the system. The specific steps can be found in patent application CN 120412815 A.

[0025] In a specific embodiment, if the intrinsic properties of the halide solid electrolyte material in step S2 meet the screening criteria, step S3 is performed; otherwise, the calculation is terminated early.

[0026] The three intrinsic properties of halide solid electrolyte materials are necessary conditions for a material to serve as a viable electrolyte. These properties are logically linked by an "AND" relationship; therefore, the material must simultaneously meet the requirements of "thermodynamic stability," "kinetic stability," and "electronic insulation" to qualify for the next stage (step S3) of performance calculations. Failure to meet any one of these requirements will result in the premature termination of the calculation for that electrolyte material, avoiding unnecessary waste of resources.

[0027] In a specific embodiment, step S2 includes step S21, thermodynamic stability calculation, which involves calculating the thermodynamic phase diagram of the halide solid electrolyte material to determine whether the material will spontaneously decompose or the ease of spontaneous decomposition.

[0028] Specifically, the thermodynamic stability calculation uses the formation energy and phase diagram method, which includes the following steps: Step 1: Retrieve data from a crystallography database or calculate the formation energy of all relevant phases of the halide solid electrolyte material based on density functional theory. All relevant phases of the halide solid electrolyte material include elemental substances and compounds. Step 2: Construct the phase diagram, such as using Python, MATLAB, Origin, etc. Step 3: Obtain the convex hull energy to determine the thermodynamic stability of the halide solid electrolyte material; If the convex hull energy of a material is less than 0.1 eV / atom, then the material is thermodynamically stable.

[0029] In a specific embodiment, step S2 includes step S22, dynamic stability calculation, which involves calculating the phonon spectrum to determine whether there is an imaginary frequency in the material and whether the material has undergone a phase transition or structural deformation.

[0030] Dynamic stability calculations employ either the linear response method or the finite displacement method.

[0031] In a specific embodiment, step S2 includes step S23, electronic insulation calculation, which calculates the electronic density of states D(E) and determines whether the material is electronically insulating based on whether the Fermi level crosses the band gap and the width of the band gap. If the Fermi level of a material is located between band gaps and the band gap is greater than 0, then the material is an electronic insulating material. The larger the band gap, the better. Generally, a band gap greater than 2 eV is considered a material with good electronic insulation properties.

[0032] The calculation of the electronic density of states D(E) depends on the wave function and band structure, and is defined as the number of states per unit energy interval. For three-dimensional materials, the electronic density of states can be approximated by the relationship between the band structure and the wave vector.

[0033] The specific calculation of the electronic density of states D(E) is as follows: ; in, E (k) is the energy corresponding to the wave vector k. δ ( E E k ) is the Dirac function, representing energy. E The number of states at that point d 3 k is a tiny volume in the wave vector space.

[0034] In a specific embodiment, the calculations in steps S21, S22, and S23 are not sequential, because they evaluate different and independent intrinsic properties of the halide solid electrolyte material.

[0035] In a specific embodiment, step S3 includes step S31, electrochemical window calculation, which uses electrochemical stoichiometry to obtain the chemical potential of the halide solid electrolyte structure when it undergoes a redox reaction, i.e., the size of the electrochemical window, by performing a migration ion insertion or extraction reaction on the halide solid electrolyte structure.

[0036] Using electrochemical stoichiometry, consider reactions involving the insertion or extraction of migrating ions into the structure of solid electrolytes. If A... n M represents the stable composition of the solid electrolyte material, then there are migration ion insertion / extraction reactions: Where A is a migrating ion, and ε < n The reaction equations correspond to the reduction and oxidation reactions that occur in solid electrolytes, respectively.

[0037] For the stoichiometry A of general solid electrolytes n+z When M deviates from z compared to the stable component, the reaction equation can be written as: Equilibrium potential Φ eq The reference potential for the oxidation process of metal A is a function of the stable stoichiometric deviation, written as: in, It is the chemical potential of metal A. The corresponding electrically neutral A atom in the composition Chemical potential in solid electrolytes: When z=0, It has discontinuity. Must be greater than .

[0038] Ultimately, two electrochemical potentials are obtained: A-ion insertion (accompanied by solid electrolyte reduction) and the formation of a stable stoichiometric phase A. n The electric potential of M: And A is removed from the stable solid electrolyte A n The potential after being removed from M: .

[0039] In a specific embodiment, step S3 includes step S32, calculating the diffusion coefficient and activation energy of lithium ions. The diffusion coefficient of lithium ions is calculated using molecular dynamics (MD) simulation, and the activation energy is calculated by fitting the equation using the Arrhenius equation.

[0040] The diffusion coefficient D was calculated using Einstein's relation by simulating the trajectory of lithium ions in the material. in, Δr 2 ( t ) It is lithium ions in time t Mean square displacement (MSD) within the range. Δr(t) = r(t) r(0) is the displacement of the lithium ion relative to its initial position. d It is the dimensionality factor (the d value corresponding to the block structure, d=3).

[0041] Δr 2 ( t ) Calculation method: in, N It represents the number of lithium ions in the system. i ( t ) is the first i lithium ions in time t The position of time, r i (0) is its initial position.

[0042] Obtain the diffusion coefficient at various temperatures D ( T After that, the Arrhenius equation was used for fitting, based on the diffusion coefficient. D ( T The activation energy is derived, and the specific formula is as follows: in,D ( T ) is at temperature T The diffusion coefficient at that point, D 0 refers to the pre-factor, which is usually related to the particle's attempt frequency or the diffusion coefficient of the ground state. E a It is activation energy. k B It is Boltzmann's constant. T It's temperature.

[0043] In a specific embodiment, step S3 includes step S33, calculating the lattice mismatch between the electrolyte material and the negative electrode lithium metal. Based on the lattice constant obtained from the structural optimization in step S1, the lattice mismatch between the electrolyte material and the negative electrode lithium metal is calculated, and the stress in the interface is predicted.

[0044] Lattice mismatch refers to the difference in lattice constants between two crystals, and the calculation formula is as follows: in, , These are the lattice constants of the solid electrolyte and the electrode, respectively. n Let be a positive integer, such that it satisfies .

[0045] In a specific embodiment, the calculations of steps S31, S32 and S33 are not performed in any particular order.

[0046] Finally, based on the numerical values ​​of the various halide solid electrolyte material performance parameters (electrochemical stability window, lithium-ion diffusion coefficient, activation energy, and lattice mismatch with lithium) calculated in steps S31-S33, the various halide solid electrolyte materials are ranked in order, and the optimal halide solid electrolyte material is selected.

[0047] This invention obtains the stable configuration and lattice constant of the material through structural optimization, evaluates the stability of the electrolyte material (including thermodynamic stability and kinetic stability) by combining thermodynamic phase diagrams and phonon spectra, and determines the electronic insulation of the material by electronic density of states.

[0048] For the selected halide solid electrolytes with excellent thermodynamic stability, kinetic stability, and electronic insulation, performance tests are then conducted: the electrochemical window of the electrolyte is calculated, the diffusion coefficient and activation energy of lithium ions are calculated using molecular dynamics simulations to reveal ion migration behavior, and the interfacial compatibility with lithium metal is evaluated through lattice mismatch analysis. Based on the test results, this invention can select halide solid electrolytes with a wide electrochemical window, large diffusion coefficient, low activation energy, and high lattice matching degree with lithium metal.

[0049] The method of this invention prioritizes the selection of electrolyte materials with stability and electronic insulation through a step-by-step process, effectively avoiding the extensive simulation of invalid candidate materials in high-throughput computing, significantly saving computing resources, and improving the design and screening efficiency of high-performance electrolytes.

[0050] The following is in conjunction with the appendix Figure 1 To be continued Figure 6 Taking the halide solid electrolyte Li2ZrCl6 as an example, the specific implementation process of the present invention will be described in detail.

[0051] Step S1: Optimize the structure of Li2ZrCl6 crystal to obtain its most stable crystal structure and lattice constant.

[0052] Step S2: Calculate and evaluate the intrinsic properties of the most stable crystal structure of Li2ZrCl6 obtained in step S1 to determine the stability of the material.

[0053] Step S21: Calculation of thermodynamic stability.

[0054] Using the pymatgen library in Python, data from the Materials Project crystallography database was retrieved to calculate the energies of the Li₂ZrCl₆ system and all decomposition phase products (including elemental and compound forms of Li, Zr, and Cl). The formation energy of the material at 0 K was calculated, and a phase diagram was constructed, as shown in the attached figure. Figure 2 As shown, the convex hull energy was calculated based on the phase diagram. The results show that the convex hull energy of Li2ZrCl6 is -3.55 meV / atom. According to thermodynamic principles, this material has thermodynamic stability.

[0055] Step S22: Calculation of dynamic stability.

[0056] The phonon spectrum of Li₂ZrCl₆ was obtained using the finite displacement method, as shown in the attached figure. Figure 3 As shown in the figure. The results show that all vibrational frequencies of Li₂ZrCl₆ are positive, and no negative frequencies appear, indicating that the material has dynamic stability.

[0057] Step S23: Electronic insulation calculation. The electronic insulation of the material is determined by calculating the density of electronic states using DFT (density functional theory).

[0058] Calculate the electronic density of states D(E), as shown in the attached diagram. Figure 4 As shown, the results reveal the Fermi level. E fermi There are no electronic states present. The valence band top is located at -0.027 eV, the conduction band bottom is located at 3.039 eV, and the band gap is... E g =3.066 eV, therefore Li2ZrCl6 is an electronic insulator.

[0059] Step S3: Calculate and evaluate the performance of the halide solid electrolyte material in step S2.

[0060] Step S31: Obtain the size of the electrochemical window of the material using electrochemical stoichiometry.

[0061] Electrochemical stoichiometry was employed to determine the electrochemical window by performing migration ion insertion or extraction reactions on the structure of Li₂ZrCl₆, based on the magnitude of the electrolyte's chemical potential during redox reactions. (See attached image.) Figure 5 As shown, the electrochemical window range of Li2ZrCl6 is 1.75 V-4.27 V.

[0062] Step S32: Molecular dynamics (MD) simulations were performed on Li₂ZrCl₆ at temperatures of 400 K, 500 K, 800 K, and 1000 K, respectively. The root mean square displacement (MSD) was extracted, and the corresponding diffusion coefficient was calculated. D Subsequently, a fitting was performed based on the Arrhenius equation, as shown in the attached figure. Figure 6 As shown, the activation energy result is: E a =0.32 eV; Finally, the fitted curve was extrapolated to room temperature (300 K), and the corresponding room temperature diffusion coefficient was read. D =1.52*10 -12 m 2 / s.

[0063] Step S33: Calculate the lattice mismatch between Li2ZrCl6 and the negative electrode lithium metal.

[0064] The lattice constants of lithium metal and Li2ZrCl6 obtained from the crystal library data are shown in Table 1. The corresponding lattice mismatch is calculated to be δ≈4.1%. Therefore, when Li2ZrCl6 and Li are in contact, there is a certain stress at the interface.

[0065] Table 1. Lattice constants of Li₂ZrCl₆ and lithium metal anode. The above steps confirmed that Li2ZrCl6 possesses thermodynamic stability, kinetic stability, and electronic insulation. Furthermore, its activation energy, diffusion coefficient, electrochemical window, lithium metal, and material stress were calculated, thus identifying Li2ZrCl6 as a suitable halide solid electrolyte material.

[0066] This embodiment uses a single material as an example for calculation. In practice, a large number of halide electrolyte materials are retrieved from a crystal database, and then all materials are screened and calculated. Finally, the screened results are ranked according to their performance based on electrochemical window, diffusion coefficient, activation energy, and lattice matching degree with lithium metal to select the optimal halide solid electrolyte material.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method of theoretical design of a halide solid-state electrolyte, characterized by, The method comprises the following steps: S1, structure optimization is performed on the halide solid electrolyte material to obtain the most stable structure and the lattice constant thereof; S2, intrinsic properties of the most stable structure of the halide solid electrolyte material obtained in the step S1 are calculated and evaluated, the intrinsic properties include thermodynamic stability, kinetic stability and electronic insulation, primary screening is performed on a plurality of halide solid electrolyte materials to obtain a material set meeting the requirements of thermodynamic stability, kinetic stability and electronic insulation; S3, the performance of the halide solid electrolyte material in the material set obtained in the step S2 is calculated, the performance includes electrochemical window, diffusion coefficient and activation energy of lithium ions, and lattice mismatch degree of the electrolyte material and negative electrode lithium metal; S4, the plurality of halide solid electrolyte materials are sequentially arranged according to the numerical values of the performance parameters obtained in the step S3, and the optimal halide solid electrolyte material is screened out.

2. The method of theoretical design of a halide solid-state electrolyte according to claim 1, wherein When the intrinsic properties of the halide solid electrolyte material in the step S2 meet the screening standard, the step S3 is performed, otherwise, the calculation is terminated in advance.

3. The method of theoretical design of a halide solid-state electrolyte according to claim 1, wherein The step S2 comprises the following steps: S21, thermodynamic stability calculation, whether the halide solid electrolyte material will spontaneously decompose or the difficulty of spontaneous decomposition is determined by calculating the thermodynamic phase diagram of the halide solid electrolyte material; The thermodynamic stability calculation adopts the formation energy and phase diagram method, and specifically comprises the following steps: Step 1, the formation energy of all related phases of the halide solid electrolyte material is calculated according to the crystallographic database data or the density functional theory, and the related phases of the halide solid electrolyte material include the elements and compounds; Step 2, a phase diagram is constructed; Step 3, the convex hull energy is obtained to determine the thermodynamic stability of the halide solid electrolyte material; 4. The method of theoretical design of a halide solid-state electrolyte according to claim 3, wherein If the convex hull energy of the material is less than 0.1 eV / atom, the material belongs to a thermodynamically stable material. The step S2 comprises the following steps:

5. The method of theoretical design of a halide solid-state electrolyte according to claim 4, wherein S22, kinetic stability calculation, whether there is a virtual frequency in the material is determined by calculating the phonon spectrum to determine whether the material will undergo phase transition or structural deformation; The kinetic stability calculation adopts the linear response method or the finite displacement method. The specific calculation of the electronic density of states D(E) is: ; where, E (k) is the energy corresponding to the wave vector k, The step S2 comprises the following steps: E E k ) is the Dirac function, representing the number of states at energy E d 3 k is a small volume of the wave vector space.​​ 6. The method of theoretical design of a halide solid-state electrolyte according to claim 5, wherein, S23, electronic insulation calculation, whether the material is electronically insulated is determined by calculating the electronic density of states D(E) according to whether the Fermi level passes through the band gap and the width of the band gap; 7. The method of theoretical design of a halide solid-state electrolyte according to claim 1, wherein If the Fermi level of the material is located between the band gaps and the band gap is greater than 0, the material belongs to an electronically insulating material; 8. The method of theoretical design of a halide solid-state electrolyte according to claim 7, wherein, The calculation of the steps S21, S22 and S23 is not in a specific order. The step S3 comprises the following steps: S31, electrochemical window calculation, the electrochemical stoichiometry method is adopted to obtain the chemical potential when the halide solid electrolyte structure undergoes ion insertion or extraction reaction, i.e. the size of the electrochemical window. The step S3 comprises the following steps: S32, lithium ion diffusion coefficient and activation energy calculation, the diffusion coefficient of lithium ions is calculated by using molecular dynamics (MD) simulation, and the activation energy is calculated by using the Arrhenius equation for fitting.

9. The method of theoretical design of a halide solid-state electrolyte according to claim 8, wherein, The step S3 includes a step S33 of calculating the lattice mismatch degree of the electrolyte material and the negative electrode lithium metal. The lattice mismatch degree of the electrolyte material and the negative electrode lithium metal is calculated according to the lattice constant obtained by the structure optimization in the step S1. The calculation formula is as follows: wherein , are the lattice constants of the solid-state electrolyte and the electrode, respectively, n is a positive integer, such that .

10. The method of theoretical design of a halide solid-state electrolyte according to claim 9, wherein, The calculation of the step S31, the step S32 and the step S33 is not in the order.

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