Cover screening method, apparatus, storage medium, device, electrolyte material, and secondary battery

Abstract

The invention provides a coating screening method and device, a storage medium, equipment, an electrolyte material and a secondary battery, and the method comprises the steps: obtaining the structural characteristic data of a plurality of candidate coatings for sulfide solid electrolyte, and obtaining a plurality of candidate coatings for sulfide solid electrolyte based on the structural characteristic data; performing thermodynamic stability screening, electrochemical stability screening, air interface stability screening, sulfide interface stability screening, positive electrode interface stability screening and electronic insulativity screening on each candidate coating, and then evaluating the lithium conductivity of the screened candidate coating according to the ionic conductivity of the screened candidate coating. And classifying the screened candidate coating objects according to the lithium conduction capability. Thus, through systematic screening, the optimal coating material can be efficiently screened out, the material screening time and economic cost are effectively reduced, and the rapid iteration battery material research and development requirement can be met.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a coating screening method, device, storage medium, equipment, electrolyte material and secondary battery. Background Art

[0002] Sulfide solid electrolytes, represented by lithium phosphorus sulfur chlorine Li6PS5Cl (LPSC) with a sulfide germanium argentate structure, have high ionic conductivity and excellent mechanical processing properties, and are solid electrolyte materials with good commercial prospects. However, their problems such as interfacial side reactions, air sensitivity and insufficient cycle stability have seriously restricted the industrialization process. Sulfide solid electrolytes have high humidity control requirements during production, transportation and storage. At the same time, when sulfide solid electrolytes are mixed with ternary high-nickel positive electrodes to prepare composite positive electrode sheets with higher energy density, interfacial side reactions are often prone to occur, increasing interfacial impedance. Therefore, coating sulfide solid electrolytes to improve their compatibility and stability is one of the core topics in the current research and development of all-solid-state batteries.

[0003] Currently, the selection of coating modification materials for sulfide solid electrolytes relies on trial-and-error experiments, which results in low material screening efficiency and high economic costs, making it difficult to meet the needs of rapid battery material development. Therefore, the market urgently needs a processing solution that can efficiently screen the best coating material. Summary of the Invention

[0004] The purpose of this application is to provide a coating screening method, device, storage medium, equipment, electrolyte material and secondary battery, aiming to solve the problems of low material screening efficiency, high economic cost and difficulty in meeting the rapid iteration of battery material research and development needs in the sulfide solid electrolyte coating modified material screening method in the related art.

[0005] In a first aspect, the present application provides a coating screening method, comprising: obtaining structural characteristic data of multiple candidate coatings for sulfide solid electrolytes; based on the structural characteristic data, evaluating the thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability and electronic insulation of each candidate coating, and screening the multiple candidate coatings according to the evaluation results; based on the ionic conductivity of the screened candidate coatings, evaluating the lithium conductivity of the screened candidate coatings, and classifying the screened candidate coatings according to the lithium conductivity.

[0006] In the above implementation process, the structural characteristic data of multiple candidate coatings for sulfide solid electrolytes are obtained. Based on the structural characteristic data, each candidate coating is screened for thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, and electronic insulation. Then, based on the ionic conductivity of the screened candidate coatings, the lithium conductivity of the screened candidate coatings is evaluated, and the screened candidate coatings are classified according to the lithium conductivity. In this way, through systematic screening, the best coating material that can improve the material compatibility and stability issues such as interfacial side reactions, air sensitivity, and insufficient cycle stability of sulfide solid electrolytes can be efficiently screened out, effectively reducing the time and economic cost of material screening, and meeting the needs of rapid iteration of battery material research and development.

[0007] Furthermore, in some examples, the thermodynamic stability of the candidate coating is evaluated based on a stable structural energy difference of the candidate coating; the stable structural energy difference is the difference between the formation energy of the candidate coating and the stable energy corresponding to the components of the candidate coating on a target convex hull diagram; the target convex hull diagram is a convex hull diagram composed of the components of the candidate coating; and based on the evaluation results, the multiple candidate coatings are screened, including: if the stable structural energy difference of the currently evaluated candidate coating is greater than or equal to a first preset threshold, the candidate coating is excluded.

[0008] In the above implementation process, the stable structural energy difference of the candidate coatings is calculated, and the candidate coatings are screened for thermodynamic stability according to the size of the stable structural energy difference, so that the effective coatings finally screened out have excellent thermodynamic stability.

[0009] Furthermore, in some examples, the electrochemical stability of the candidate coating is evaluated based on the reduction potential difference and oxidation potential difference of the candidate coating; the reduction potential difference is the difference between the lower limit of the allowable voltage of the electrolyte material and the reduction potential of the candidate coating; the oxidation potential difference is the difference between the upper limit of the allowable voltage of the electrolyte material and the oxidation potential of the candidate coating; based on the evaluation results, the multiple candidate coatings are screened, including: if the reduction potential difference of the currently evaluated candidate coating is less than or equal to a second preset threshold, or the oxidation potential difference is less than or equal to the second preset threshold, then the candidate coating is excluded.

[0010] In the above implementation process, the reduction potential difference and oxidation potential difference of the candidate coating are calculated, and the candidate coating is screened for electrochemical stability based on the reduction potential difference and oxidation potential difference, so that the effective coating finally screened out has excellent electrochemical stability.

[0011] Furthermore, in some examples, the air interface stability of the candidate coating is evaluated based on a first reaction enthalpy of the candidate coating; the first reaction enthalpy is the reaction enthalpy of the reaction between the candidate coating and water; and based on the evaluation result, the multiple candidate coatings are screened, including: if the first reaction enthalpy of the currently evaluated candidate coating is less than or equal to a third preset threshold, the candidate coating is excluded.

[0012] In the above implementation process, the reaction enthalpy of the reaction between the candidate coating and water is calculated, and the candidate coating is screened for air interface stability based on the size of the reaction enthalpy, so that the effective coating finally screened out has excellent air interface stability.

[0013] Furthermore, in some examples, the sulfide interface stability of the candidate coating is evaluated based on a second reaction enthalpy of the candidate coating; the second reaction enthalpy is the reaction enthalpy of the reaction between the candidate coating and the sulfide solid electrolyte; and based on the evaluation result, the multiple candidate coatings are screened, including: if the second reaction enthalpy of the currently evaluated candidate coating is less than or equal to a fourth preset threshold, the candidate coating is excluded.

[0014] In the above implementation process, the reaction enthalpy of the reaction between the candidate coating and the sulfide solid electrolyte is calculated, and the candidate coating is screened for sulfide interface stability based on the size of the reaction enthalpy, so that the effective coating finally screened out has excellent sulfide interface stability.

[0015] Furthermore, in some examples, the cathode interface stability of the candidate coating is evaluated based on the third reaction enthalpy and the fourth reaction enthalpy of the candidate coating; the third reaction enthalpy is the reaction enthalpy of the reaction between the lithium-deficient cathode and the candidate coating; the fourth reaction enthalpy is the reaction enthalpy of the reaction between the lithium-rich cathode and the candidate coating; and based on the evaluation results, the multiple candidate coatings are screened, including: if the third reaction enthalpy of the currently evaluated candidate coating is less than or equal to the fifth preset threshold, or the fourth reaction enthalpy is less than or equal to the sixth preset threshold, then the candidate coating is excluded.

[0016] In the above implementation process, the reaction enthalpy of the reaction between the lithium-poor cathode and the candidate coating, as well as the reaction enthalpy of the reaction between the lithium-rich cathode and the candidate coating, are calculated. Based on the calculation results, the candidate coatings are screened for cathode interface stability, so that the effective coating finally screened out has excellent cathode interface stability.

[0017] Furthermore, in some examples, the electronic insulation of the candidate coating is obtained based on the band gap evaluation of the candidate coating; and based on the evaluation result, the multiple candidate coatings are screened, including: if the band gap of the currently evaluated candidate coating is less than or equal to a seventh preset threshold, the candidate coating is excluded.

[0018] In the above implementation process, the candidate coatings are screened for electronic insulation according to the size of their band gaps, so that the effective coatings finally screened out have excellent electronic insulation.

[0019] Furthermore, in some examples, the lithium conductivity of the screened candidate coating is evaluated based on the ionic conductivity of the screened candidate coating, and the screened candidate coating is classified according to the lithium conductivity, including: calculating the ratio of the ionic conductivity of the screened candidate coating to the ionic conductivity of the sulfide solid electrolyte; if the ratio is greater than or equal to an eighth preset threshold, classifying the screened candidate coating into the first category of coatings; if the ratio is less than the eighth preset threshold and greater than or equal to a ninth preset threshold, classifying the screened candidate coating into the second category of coatings; the eighth preset threshold is greater than the ninth preset threshold; if the ratio is less than the ninth preset threshold, classifying the screened candidate coating into the third category of coatings.

[0020] In the above implementation process, the ratio of the ionic conductivity of the candidate coating to the ionic conductivity of the sulfide solid electrolyte is calculated, and the lithium conductivity of the candidate coating is evaluated and classified according to the size of the ratio, so as to screen out coating modified materials with excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, electronic insulation and excellent lithium conductivity.

[0021] Furthermore, in some examples, it also includes: determining the first type of coating as the first echelon fully coated modified material of the sulfide solid electrolyte; determining the second type of coating as the second echelon fully coated modified material of the sulfide solid electrolyte; and determining the third type of coating as the island coating material of the sulfide solid electrolyte.

[0022] In the above implementation process, a suitable coating method is selected according to the comprehensive performance of the coated object to ensure the performance of the material in the application.

[0023] In a second aspect, the present application provides a coating screening device, comprising: an acquisition module for acquiring structural characteristic data of multiple candidate coatings for sulfide solid electrolytes; a screening module for evaluating the thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability and electronic insulation of each candidate coating based on the structural characteristic data, and screening the multiple candidate coatings according to the evaluation results; a classification module for evaluating the lithium conductivity of the screened candidate coatings according to the ionic conductivity of the screened candidate coatings, and classifying the screened candidate coatings according to the lithium conductivity.

[0024] In a third aspect, the present application provides an electronic device comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the method described in any one of the first aspects when executing the computer program.

[0025] In a fourth aspect, the present application provides a computer-readable storage medium having instructions stored thereon. When the instructions are executed on a computer, the computer executes the method as described in any one of the first aspects.

[0026] In a fifth aspect, the present application provides a computer program product, which, when running on a computer, enables the computer to execute the method as described in any one of the first aspects.

[0027] In a sixth aspect, the present application provides an electrolyte material, which is a core-shell structure, comprising a core of a sulfide solid electrolyte material and a shell layer coated on the outer surface of the core, and the electrolyte coating material of the shell layer is obtained by screening by the method described in any one of the first aspects.

[0028] In a seventh aspect, the present application provides a secondary battery, wherein the secondary battery comprises the electrolyte material as described in the sixth aspect.

[0029] Other features and advantages disclosed in the present application will be described in the following description, or some features and advantages can be inferred or determined without doubt from the description, or can be learned by implementing the above-mentioned technology disclosed in the present application.

[0030] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments of the present application. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 A flow chart of a coating screening method provided in an embodiment of the present application;

[0033] Figure 2Schematic diagram of the chemical formula, space group, and crystal three-dimensional structure of candidate coatings (including Li3TaO4, Al2O3, Li2CO3, and Li2TiO3) selected in a screening scheme for high-performance coating modification materials for sulfide solid electrolytes provided in an embodiment of the present application;

[0034] Figure 3 A block diagram of a device for screening coated objects provided in an embodiment of the present application;

[0035] Figure 4 This is a structural block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0037] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of this application, the terms "first", "second", etc. are only used to distinguish the description and should not be understood as indicating or implying relative importance.

[0038] Sulfide solid electrolytes are promising solid-state battery electrolyte materials, but their interfacial side reactions, air sensitivity, and insufficient cycle stability have seriously restricted the industrialization process. Surface coating modification is a technology that forms a coating layer on the surface of a material through physical or chemical methods to improve its performance. Currently, coating sulfide solid electrolytes to improve their compatibility and stability is one of the core topics in solid-state battery research and development. In related technologies, the method of screening sulfide solid electrolyte coating modification materials is mainly trial and error, that is, technicians select a certain coating modification material based on experience, prepare the coated electrolyte material, and then assemble it into a full battery for testing. The screening efficiency of this method is low, and each trial and error experiment requires a lot of manpower and material resources, and the economic cost is high.

[0039] To address the above issues, the present application provides a coating screening solution that evaluates the thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, electronic insulation, and lithium conductivity of candidate coatings based on their structural property data, thereby screening out effective coatings that can improve material compatibility and stability issues such as interfacial side reactions, air sensitivity, and insufficient cyclic stability of sulfide solid electrolyte materials. In this way, by replacing the traditional trial and error method with systematic screening, the screening efficiency of sulfide solid electrolyte coating modification materials is effectively improved, the time and economic cost of material screening are reduced, and the demand for rapid iteration of battery material research and development is met.

[0040] Next, the embodiments of the present application are introduced:

[0041] like Figure 1 As shown, Figure 1 This is a flow chart of a coating screening method provided in an embodiment of the present application. The method includes:

[0042] Step 101: Acquire structural property data of a plurality of candidate coatings for a sulfide solid electrolyte;

[0043] The sulfide solid electrolyte mentioned in this step is the sulfide solid electrolyte to be modified, which can be LPSC or other types of sulfide solid electrolytes. The candidate coating mentioned in this step is the coating to be screened, which can be an inorganic coating such as an oxide or nitride, such as Li3TaO4, Al2O3, Li2TiO3, etc., or an organic coating, or a composite coating. This embodiment can screen multiple candidate coatings at the same time. When implemented, the structural characteristic data of each candidate coating is obtained. The structural characteristic data here can include the chemical formula of the coating, the space group, and the three-dimensional structure file of the crystal, etc. Through the structural characteristic data, the intrinsic physical and chemical properties of the candidate coating can be calculated, laying a good foundation for the subsequent screening of effective coatings.

[0044] Step 102: Based on the structural characteristic data, evaluating the thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability, and electronic insulation of each candidate coating, and screening the plurality of candidate coatings according to the evaluation results;

[0045] In this embodiment, the candidate coatings are screened for their properties of thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability and electronic insulation, thereby obtaining coatings with excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability and electronic insulation.

[0046] In some embodiments, the thermodynamic stability of the candidate coating mentioned in this step is obtained based on the stable structural energy difference evaluation of the candidate coating; the stable structural energy difference is the difference between the formation energy of the candidate coating and the stable energy corresponding to the components of the candidate coating on the target convex hull diagram; the target convex hull diagram is the convex hull diagram composed of the components of the candidate coating; accordingly, the screening of the multiple candidate coatings based on the evaluation results mentioned in this step may include: if the stable structural energy difference of the currently evaluated candidate coating is greater than or equal to a first preset threshold, then excluding the candidate coating.

[0047] That is, the energy difference of the stable structure of the candidate coating (energy above hull) can be calculated to evaluate the thermodynamic stability of the candidate coating. hill The steps are as follows: Obtain the formation energy E of the candidate coating through first-principles calculation f ; Obtain the convex hull diagram of the candidate coating components through first principle calculation; Obtain the stable energy E corresponding to the ratio of the candidate coating components on the convex hull diagram f0 ; Calculate the stable structural energy difference ΔE of the candidate coating hill =E f -E f0 Then, according to the stable structure energy difference ΔE hull The size of the thermodynamic stability of the candidate coating is screened. Specifically, a threshold is given according to the calculation experience, that is, the first preset threshold, such as 0.1 eV / atom, and the first preset threshold is recorded as ΔE th1 , if ΔE hull <ΔE th1 , indicating that the candidate coating is thermodynamically stable and will not decompose into other compounds, then the candidate coating enters the next round of screening; on the contrary, if ΔE hull ≥ΔE th1 , indicating that the candidate coating is thermodynamically unstable and will decompose into other compounds. Therefore, the candidate coating is not suitable as a high-performance coating modification material for sulfide solid electrolytes and is directly excluded.

[0048] In some embodiments, the electrochemical stability of the candidate coating mentioned in this step is evaluated based on the reduction potential difference and oxidation potential difference of the candidate coating; the reduction potential difference is the difference between the lower limit of the allowable voltage of the electrolyte material and the reduction potential of the candidate coating; the oxidation potential difference is the difference between the upper limit of the allowable voltage of the electrolyte material and the oxidation potential of the candidate coating; accordingly, the screening of the multiple candidate coatings based on the evaluation results mentioned in this step may include: if the reduction potential difference of the currently evaluated candidate coating is less than or equal to the second preset threshold, or the oxidation potential difference is less than or equal to the second preset threshold, then the candidate coating is excluded.

[0049] That is, the reduction potential difference ΔU of the candidate coating can be calculated R and oxidation potential difference ΔU O , in order to evaluate the electrochemical stability of the candidate coating. When implementing, calculate the reduction potential difference ΔU of the candidate coating R and oxidation potential difference ΔU OThe steps are as follows: obtain the reduction reaction of the candidate coating with Li / Li+ under different potentials U through first-principles calculation, gradually increase U from 0V until the reduction reaction just stops, and the corresponding U is the reduction potential U of the candidate coating R ; The lower limit of the allowable voltage of the electrolyte material is U DOWN , then calculate the reduction potential difference ΔU of the candidate coating R =U DOWN -U R The oxidation reaction of the candidate coating with Li / Li+ under different potentials U is obtained by first-principles calculation. U is gradually reduced from 10V until the oxidation reaction just stops. The corresponding U is the oxidation potential U of the candidate coating. O ; The upper limit of the allowable voltage of the electrolyte material is U UP , then calculate the reduction potential difference ΔU of the candidate coating O =U O -U UP Then, according to the reduction potential difference ΔU of the candidate coating R and oxidation potential difference ΔU O The electrochemical stability of the candidate coating is screened based on the size of the voltage. Specifically, a threshold value is given based on computational experience, that is, a second preset threshold value, such as -0.1 V, and the second preset threshold value is recorded as ΔU th , if ΔU R >ΔU th , and ΔU O >ΔU th , indicating that oxidation and reduction reactions are not easy to occur on the interface of the candidate coating, and ΔU R and ΔU O The larger the value, the better the electrochemical stability of the candidate coating, and the candidate coating enters the next round of screening; on the contrary, if ΔU R ≤ΔU th , or ΔU O ≤ΔU th , indicating that the electrochemical stability of the candidate coating is poor, and the candidate coating is not suitable as a high-performance coating modification material for sulfide solid electrolytes and is directly excluded.

[0050] Sulfide solid electrolytes are highly sensitive to air humidity, and the ease of reaction with water determines the air stability of the sulfide solid electrolyte - coating system. Therefore, in some embodiments, the air interface stability of the candidate coatings mentioned in this step is evaluated based on the first reaction enthalpy of the candidate coatings; the first reaction enthalpy is the reaction enthalpy of the candidate coating and water; correspondingly, the screening of the multiple candidate coatings according to the evaluation results in this step may include: if the first reaction enthalpy of the currently evaluated candidate coating is less than or equal to the third preset threshold, then the candidate coating is excluded.

[0051] That is, the reaction enthalpy ΔH of the reaction between water and the candidate coating can be calculated a , so as to evaluate the air interface stability of the candidate coating. In implementation, the steps to calculate the reaction enthalpy ΔH of the reaction between water and the candidate coating are as follows: Obtain the enthalpy H of water through first - principles calculation a ; Obtain the enthalpy H of the candidate coating through first - principles calculation H2O ; Assume that the stoichiometric coefficients of water and the candidate coating during the reaction are x and 1 - x respectively. Given a value of x between 0 and 1, judge whether a reaction can occur through a thermodynamic database or first principles calculation. If a reaction can occur, obtain the candidate product c COATING and the enthalpy H of the product PDax , and calculate the corresponding reaction enthalpy ΔH PDax = H ax - xH PDax - (1 - x)H H2O COATING ; Traverse all x from 0 to 1, obtain all possible candidate products {c PDax |0 < x < 1} and the corresponding reaction enthalpies {ΔH ax |0 < x < 1}, and generate a reaction thermodynamic phase diagram; For the reaction corresponding to the lowest point of the phase diagram, the x corresponding to it is denoted as x0, and the reaction enthalpy corresponding to x0 is the reaction enthalpy of water and the candidate coating, and its calculation formula is After that, the candidate coatings are screened for air interface stability according to the magnitude of the reaction enthalpy ΔH of water and the candidate coating a . Specifically, according to calculation experience, a threshold is given, that is, the third preset threshold, such as - 0.001 eV / atom, and the third preset threshold is denoted as ΔH ath . If ΔH a > ΔH ath , it indicates that the interfacial reaction between the candidate coating and water is not easy to occur thermodynamically, and the larger ΔH a , the better the air interface stability of the candidate coating, and then the candidate coating enters the next round of screening; on the contrary, if ΔH a ≤ ΔH ath ​, indicating poor air interface stability of the candidate coating, then the candidate coating is not suitable as a high-performance coating modification material for sulfide solid electrolytes and is directly excluded.

[0052] In some embodiments, the sulfide interface stability of the candidate coating mentioned in this step is evaluated according to the second reaction enthalpy of the candidate coating; the second reaction enthalpy is the reaction enthalpy of the reaction between the candidate coating and the sulfide solid electrolyte; accordingly, the screening of the multiple candidate coatings according to the evaluation results in this step may include: if the second reaction enthalpy of the currently evaluated candidate coating is less than or equal to the fourth preset threshold, then the candidate coating is excluded.

[0053] That is, the reaction enthalpy ΔH of the reaction between the sulfide solid electrolyte and the candidate coating can be calculated b , so as to evaluate the sulfide interface stability of the candidate coating. In implementation, the steps of calculating the reaction enthalpy ΔH of the reaction between the sulfide solid electrolyte and the candidate coating are as follows: obtaining the enthalpy H of the sulfide solid electrolyte through first-principles calculation b ; obtaining the enthalpy H of the candidate coating through first-principles calculation SSB ; assuming that the stoichiometric coefficients of the sulfide solid electrolyte and the candidate coating during the reaction are x and 1 - x respectively, given a certain x value between 0 and 1, judging whether a reaction can occur through a thermodynamic database or first-principles calculation. If a reaction can occur, obtaining the candidate product c COATING and the enthalpy H of the product PDbx , calculating the corresponding reaction enthalpy ΔH PDbx = H bx - xH PDbx - (1 - x)H SSB ; traversing all x from 0 to 1, obtaining all possible candidate products {c COATING | 0 < x < 1} and the corresponding reaction enthalpies {ΔH PDbx | 0 < x < 1}, generating a reaction thermodynamic phase diagram; for the reaction corresponding to the lowest point of the phase diagram, the x corresponding to it is denoted as x0, and the reaction enthalpy corresponding to x0 is the reaction enthalpy of the sulfide solid electrolyte and the candidate coating, and its calculation formula is bx After that, the sulfide interface stability of the candidate coating is screened according to the magnitude of the reaction enthalpy ΔH of the reaction between the sulfide solid electrolyte and the candidate coating. Specifically, according to calculation experience, a threshold is given, that is, the fourth preset threshold, such as -0.1 eV / atom, and the fourth preset threshold is denoted as ΔH b . If ΔH bth > ΔH b > ΔH bth , it indicates that the interfacial reaction between the candidate coating and the sulfide solid electrolyte is not likely to occur thermodynamically, and ΔH bThe larger it is, the better the sulfide interface stability of the candidate coating, and the candidate coating enters the next round of screening; conversely, if ΔH b ≤ΔH bth , it indicates that the sulfide interface stability of the candidate coating is poor, and the candidate coating is not suitable as a high-performance coating modification material for sulfide solid electrolytes and is directly excluded.

[0054] In some embodiments, the positive electrode interface stability of the candidate coating mentioned in this step is evaluated according to the third reaction enthalpy and the fourth reaction enthalpy of the candidate coating; the third reaction enthalpy is the reaction enthalpy of the lithium-deficient positive electrode and the candidate coating; the fourth reaction enthalpy is the reaction enthalpy of the fully lithiated positive electrode and the candidate coating; accordingly, the screening of the multiple candidate coatings according to the evaluation results in this step may include: if the third reaction enthalpy of the currently evaluated candidate coating is less than or equal to the fifth preset threshold, or the fourth reaction enthalpy is less than or equal to the sixth preset threshold, then the candidate coating is excluded.

[0055] That is to say, the reaction enthalpy ΔH c1 of the lithium-deficient positive electrode and the candidate coating can be calculated, as well as the reaction enthalpy ΔH c2 of the fully lithiated positive electrode and the candidate coating, so as to evaluate the positive electrode interface stability of the candidate coating. In implementation, the steps for calculating the reaction enthalpy ΔH c1 of the lithium-deficient positive electrode and the candidate coating are as follows: obtaining the enthalpy H CA1 of the lithium-deficient positive electrode through first-principles calculation; obtaining the enthalpy H xOATING of the candidate coating through first-principles calculation; setting the stoichiometric numbers of the lithium-deficient positive electrode and the candidate coating during the reaction to be x and 1 - x respectively, given a certain x value between 0 and 1, judging whether a reaction can occur through a thermodynamic database or first-principles calculation. If a reaction can occur, obtaining the candidate product c PDc1x and the enthalpy H PDc1x of the product, and calculating the corresponding reaction enthalpy ΔH c1x = H PDc1x - xH CA1 - (1 - x)H COATING ; traversing all x from 0 to 1, obtaining all possible candidate products {c PDc1x |0 < x < 1} and the corresponding reaction enthalpies {ΔH c1x |0 < x < 1}, generating a reaction thermodynamic phase diagram; for the reaction corresponding to the lowest point of the phase diagram, the x corresponding to it is denoted as x0, and the reaction enthalpy corresponding to x0 is the reaction enthalpy of the lithium-deficient positive electrode and the candidate coating, and its calculation formula is Similarly, the calculation process of the reaction enthalpy ΔH c2 of the fully lithiated positive electrode and the candidate coating is the same as that of ΔH c1The calculation process is similar and will not be repeated here. c1 and ΔH c2 Specifically, a lithium-poor state threshold, i.e., the fifth preset threshold, such as -0.1 eV / atom, and a full lithium state threshold, i.e., the sixth preset threshold, such as -0.01 eV / atom, are given according to computational experience. The fifth preset threshold is denoted as ΔH c1th , the sixth preset threshold is recorded as ΔH c2th , if ΔH c1 >ΔH c1th , and ΔH c2 >ΔH c2th , indicating that the interface reaction between the candidate coating and the positive electrode is not easy to occur thermodynamically, then the candidate coating enters the next round of screening; on the contrary, if ΔH c1 ≤ΔH c1th , or ΔH c2 ≤ΔH c2th , indicating that the positive electrode interface stability of the candidate coating is poor, and the candidate coating is not suitable as a high-performance coating modification material for sulfide solid electrolytes and is directly excluded.

[0056] The coating modification material should avoid introducing an electronic conductor into the sulfide solid electrolyte layer to prevent internal short circuits. Therefore, when screening for effective coatings, the coating's electronic insulation properties must be considered. In some embodiments, the electronic insulation properties of the candidate coatings mentioned in this step are evaluated based on their band gaps. Accordingly, screening the multiple candidate coatings based on the evaluation results mentioned in this step may include: excluding a candidate coating if its band gap is less than or equal to a seventh preset threshold.

[0057] That is, the band gap E of the candidate coating can be calculated g , in order to evaluate the electronic insulation of the candidate coating. In implementation, the charge density of the candidate coating can be obtained through SCF (Self-Consistent Field, self-consistent field) self-consistent calculation, and the charge density can be input to perform energy band calculation on the candidate coating to obtain the band gap E of the candidate coating. g Then, according to the band gap E of the candidate coating g The size of the electronic insulation of the candidate coating is screened. Specifically, a threshold is given according to the calculation experience, that is, the seventh preset threshold, such as 1eV, and the seventh preset threshold is recorded as E gth , if E g >E gth , indicating that the candidate coating has good electronic insulation and is not an electronic conductor, and E gThe larger the E is, the better the electronic insulation of the candidate coating is, and the candidate coating enters the next round of screening; on the contrary, if E g ≤E gth , indicating that the electronic insulation of the candidate coating is poor, and the candidate coating is not suitable as a high-performance coating modification material for sulfide solid electrolytes and is directly excluded.

[0058] The aforementioned thermodynamic stability screening, electrochemical stability screening, air interface stability screening, sulfide interface stability screening, positive electrode interface stability screening and electronic insulation screening can be performed in sequence, that is, the candidate coating is first subjected to thermodynamic stability screening. If the candidate coating is thermodynamically stable, it is then subjected to electrochemical stability screening, and so on; of course, in other embodiments, these screening processes can also be performed simultaneously, and this application does not limit this.

[0059] Step 103 : evaluating the lithium conductivity of the screened candidate coatings according to their ionic conductivity, and classifying the screened candidate coatings according to their lithium conductivity.

[0060] The introduction of a coating is often accompanied by a decrease in ionic conductivity. While the coating can, to some extent, slow the air degradation of the LPSC material and isolate it from the positive electrode, it can significantly reduce the overall ionic conductivity of the solid electrolyte, thereby reducing its overall performance in the battery. Based on this, this embodiment screens for coatings with excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, and electronic insulation. The lithium conductivity of the selected candidate coatings is then evaluated and classified based on their ionic conductivity, thereby selecting coating-modified materials with both excellent lithium conductivity.

[0061] In some embodiments, this step may include: calculating the ratio of the ionic conductivity of the screened candidate coating to the ionic conductivity of the sulfide solid electrolyte; if the ratio is greater than or equal to an eighth preset threshold, classifying the screened candidate coating into the first category of coatings; if the ratio is less than the eighth preset threshold and greater than or equal to a ninth preset threshold, classifying the screened candidate coating into the second category of coatings; the eighth preset threshold is greater than the ninth preset threshold; if the ratio is less than the ninth preset threshold, classifying the screened candidate coating into the third category of coatings. That is, according to the ionic conductivity σ of the sulfide solid electrolyte, S and the ionic conductivity σ of the candidate coating C The lithium conductivity of the candidate coatings is screened and sorted. Specifically, an eighth preset threshold k is set. th1 and the ninth preset threshold k th2 , kth1 >k th2 , optionally, k th1 =1,k th2 =0.01, if The ionic conductivity of the candidate coating is high, and its comprehensive performance is considered to be in the first gradient, which is recorded as Class A coating; if The ionic conductivity of the candidate coating is the second highest, and its comprehensive performance is considered to be in the second gradient, which is recorded as Class B coating; if The candidate coating has poor ionic conductivity and is considered to be in the third tier of comprehensive performance, designated as a Class C coating. This allows the final selected coating-modified material to exhibit excellent lithium conductivity, enabling rapid lithium ion transfer between the sulfide solid electrolyte and the positive and negative electrodes, thereby ensuring the material's performance in applications.

[0062] Among them, the ionic conductivity σ of the sulfide solid electrolyte is calculated S The steps can be as follows: Obtain the lithium ion migration energy barrier E of the sulfide solid electrolyte by first-principles calculation actS ; Calculate the diffusion coefficient D of lithium ions at 300K S , and its calculation formula is Where l is the transition distance, i.e., the migration distance between two adjacent Li, θ0 is the transition frequency, k B is the Boltzmann constant, T is the temperature; calculate the ionic conductivity σ of the sulfide solid electrolyte S , and its calculation formula is Where ρ is the molar density of Li ions diffused within the unit cell, z is the charge of the Li ion (+1), F and R are the Faraday constant and the gas constant, respectively. Similarly, the ionic conductivity σ of the candidate coating is calculated C The steps can be as follows: obtain the lithium ion migration energy barrier E of the candidate coating through first principle calculation actC ; Calculate the diffusion coefficient of lithium ions at 300K Calculate the ionic conductivity of candidate coatings

[0063] Furthermore, in some embodiments, the method may further include: determining the first type of coating as the first-tier fully coated modified material of the sulfide solid electrolyte; determining the second type of coating as the second-tier fully coated modified material of the sulfide solid electrolyte; and determining the third type of coating as the island coating material of the sulfide solid electrolyte. Here, full coating and island coating are two different coating methods, wherein full coating refers to completely covering the target substance with a certain material or structure, while island coating refers to a coating layer with a discontinuous, dispersed island structure. Continuing with the previous example, since Type A coatings have excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability, electronic insulation, and excellent lithium conductivity, they are suitable as the first choice for full-coating modification materials for sulfide solid electrolytes. Type B coatings have excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability, electronic insulation, and suboptimal lithium conductivity, making them suitable as the second choice for full-coating modification materials for sulfide solid electrolytes. While Type C coatings have excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability, and electronic insulation, they have poor lithium conductivity and are therefore suitable as island coating materials for sulfide solid electrolytes. In this way, selecting the appropriate coating method based on the comprehensive performance of the coating ensures the performance of the material in the application.

[0064] The embodiment of the present application provides a coating screening method, in which structural characteristic data of multiple candidate coatings for sulfide solid electrolytes are obtained, and based on the structural characteristic data, each candidate coating is screened for thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, and electronic insulation. Then, based on the ionic conductivity of the screened candidate coatings, the lithium conductivity of the screened candidate coatings is evaluated, and the screened candidate coatings are classified according to the lithium conductivity. In this way, through systematic screening, coating materials that can improve the material compatibility and stability problems of sulfide solid electrolytes, such as interface side reactions, air sensitivity, and insufficient cyclic stability, can be efficiently screened out, effectively reducing the time and economic cost of material screening, and meeting the rapid iteration of battery material research and development needs.

[0065] In order to explain the solution of this application in more detail, a specific embodiment is introduced below:

[0066] This example provides a screening scheme for high-performance coating modification materials for sulfide solid electrolytes. This scheme selects LPSC as the sulfide solid electrolyte to be modified, and selects Li3TaO4, Al2O3, Li2CO3, and Li2TiO3 as candidate coating materials for illustration, including:

[0067] S201, obtain the scheme and structure of each candidate coating; among them, the chemical formula, space group, and three-dimensional structure of the crystal of the candidate coatings such as Li3TaO4, Al2O3, Li2CO3, and Li2TiO3 are as follows: Figure 2 As shown;

[0068] S202. Calculate the stable structural energy difference ΔE of the candidate coating hull , evaluate the thermodynamic stability of the candidate coating, and thus screen the candidate coating; specifically, during screening, determine whether ΔE hull <ΔE th1 , then enter the next round of screening; among them, ΔE th1 =0.1eV / atom. The thermodynamic stability screening results of each candidate coating are shown in Table 1:

[0069] Table 1. Thermodynamic stability screening results of candidate coatings

[0070]

[0071] S203, calculating the reduction potential difference ΔU of the candidate coating R and oxidation potential difference ΔU O , evaluate the electrochemical stability of the candidate coating, and thus screen the candidate coating; specifically, during the screening, determine whether ΔU R >ΔU th , and ΔU O >ΔU th , then enter the next round of screening; where ΔU th =-0.1 V. The electrochemical stability screening results of each candidate coating are shown in Table 2:

[0072] Table 2. Electrochemical stability screening results of candidate coatings

[0073]

[0074] S204. Calculate the reaction enthalpy ΔH of the reaction between water and the candidate coating a , evaluate the air interface stability of the candidate coating, and thus screen the candidate coating; specifically, during the screening, determine whether ΔH a >ΔH ath , then enter the next round of screening; among them, ΔH ath =-0.001eB / atom. The results of the air interface stability screening of each candidate coating are shown in Table 3:

[0075] Table 3. Screening results of air interface stability of candidate coatings

[0076]

[0077] S205. Calculate the reaction enthalpy ΔH of the sulfide solid electrolyte LPSC and the candidate coating b , evaluate the sulfide interface stability of the candidate coating, and thus screen the candidate coating; specifically, during the screening, determine whether ΔH b >ΔH bth , then enter the next round of screening; among them, ΔH bth =-0.1eB / atom. The results of the sulfide interface stability screening of each candidate coating are shown in Table 4:

[0078] Table 4. Screening results of sulfide interface stability of each candidate coating

[0079]

[0080] S206. Calculate the reaction enthalpy ΔH of the reaction between the lithium-poor NCM811 cathode and the candidate coating c1 , and the reaction enthalpy ΔH of the reaction between the fully lithium-rich NCM811 cathode and the candidate coating c2 , evaluate the cathode interface stability of the candidate coating, and thus screen the candidate coating; specifically, during screening, determine whether ΔH c1 >ΔH c1th , and ΔH c2 >ΔH c2th , then enter the next round of screening; among them, ΔH c1th =-0.1eV / atom, ΔH c2th =-0.01eV / atom. The results of the positive electrode interface stability screening of each candidate coating are shown in Table 5:

[0081] Table 5. Screening results of positive electrode interface stability of each candidate coating

[0082]

[0083] S207, calculate the band gap E of the candidate coating g , evaluate the electronic insulation of the candidate coating, and thus screen the candidate coating; specifically, during the screening, determine whether the E g >E gth , then enter the next round of screening; among them, E gth =1eV. The results of the air interface stability screening of each candidate coating are shown in Table 6:

[0084] Table 6. Screening results of electronic insulation properties of candidate coatings

[0085] Chemical formula of coating <![CDATA[Bandgap E g (unit: eV)]]> Whether to enter the next round of screening <![CDATA[Li3TaO4]]> 4.25 yes <![CDATA[Al2O3]]> 6.63 yes <![CDATA[Li2CO3]]> 4.66 yes

[0086] S208. Calculation of the ionic conductivity σ of sulfide solid electrolyte LPSC S and the ionic conductivity σ of the candidate coating C , evaluate the lithium conductivity of candidate coatings and classify them; specifically, if The candidate coating is recorded as a Class A coating; if The candidate coating is recorded as a Class B coating; if The candidate coating is recorded as a type C coating; where k th1 =1,k th2 =0.01, and we can calculate σ S =3ms / cm. The lithium conductivity evaluation results and classification results of each candidate coating are shown in Table 7:

[0087] Table 7. Evaluation results and classification results of lithium conductivity of each candidate coating

[0088]

[0089] S209. According to the classification results, three effective coatings were screened out from four candidate coatings, namely Li3TaO4, Al2O3, Li2CO3, and Li2TiO3. These effective coatings can improve the compatibility and stability of the sulfide solid electrolyte material LPSC. Among them, Li2CO3 is a type A coating, which has excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, electronic insulation and excellent lithium conductivity, and is suitable as the first choice for full-coating modification materials of sulfide solid electrolyte LPSC; Li3TaO4 is a type B coating, which has excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, electronic insulation and suboptimal lithium conductivity, and is suitable as the second choice for full-coating modification materials of sulfide solid electrolyte LPSC; Al2O3 is a type C coating, which has excellent thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, positive electrode interface stability, and electronic insulation, but poor lithium conductivity, and is suitable as an island coating material for sulfide solid electrolyte LPSC.

[0090] In summary, this embodiment utilizes high-performance computers for material simulation and design. By calculating the intrinsic physical and chemical properties of candidate coatings, the effectiveness of the coatings in improving material compatibility and stability issues such as side reactions at the sulfide solid electrolyte interface, air sensitivity, and insufficient cyclic stability is evaluated, and effective coatings are screened out. This greatly improves the screening efficiency and cost of sulfide solid electrolyte coating modification materials, and can meet the needs of rapid iteration of battery material research and development.

[0091] Corresponding to the embodiments of the aforementioned method, the present application also provides embodiments of electrolyte materials and secondary batteries:

[0092] An embodiment of the present application provides an electrolyte material, which has a core-shell structure. The core-shell structure includes a core of a sulfide solid electrolyte material and a shell layer coated on the outer surface of the core. The electrolyte coating material of the shell layer is obtained by screening the coating material screening method described in any of the previous embodiments.

[0093] Compared with electrolyte materials that have not been coated and modified according to the above method, the electrolyte material provided by this embodiment improves material compatibility and stability issues such as interface side reactions, air sensitivity, and insufficient cycle stability. Continuing with the previous example, the screened Li2CO3 coating material is used as the shell structure and the sulfide solid electrolyte LPSC is used as the core structure to prepare a core-shell structure composite electrolyte material including a sulfide solid electrolyte material core and a shell layer coated on the outer surface of the core. The preparation method includes:

[0094] S211, using anhydrous Li2S, P2S5 and LiCl as raw materials to synthesize the original LPSC system;

[0095] S212, adding Li2CO3 nanopowder, and then high-energy ball milling at 600 rpm for 12 hours;

[0096] S213, cold pressing at 200 MPa for 60 seconds;

[0097] S214, heating to 600°C at a rate of 10°C / min in an argon atmosphere and maintaining the temperature for 6 hours;

[0098] S215, cooling to room temperature along with the furnace.

[0099] Based on the electrolyte material, this embodiment also provides a lithium-ion secondary battery, the assembly steps of which include:

[0100] S221, single crystal NCM811, Super P, and electrolyte material SSE were mixed at a mass ratio of 70:1:29 for 1 hour. All processing was completed in an Ar-filled glove box (H2O < 0.1 ppm, O2 < 0.1 ppm).

[0101] S222 is prepared by mixing active material, conductive carbon black and PVDF in a ratio of 8:1:1;

[0102] S223, 100 mg of SSE powder was placed in a PEEK mold and granulated under a pressure of 1.2 T;

[0103] S224, 10 mg of the composite cathode was evenly coated on one side of the SSE and pressed at 1.4 T to form a double-layer particle;

[0104] S225, Li foil was attached to the other side of the SSEs by pressing at 0.25T;

[0105] S226. The three-layer particles were sandwiched between two stainless steel disks as current collectors.

[0106] Air exposure experiments were conducted on the synthesized core-shell composite electrolyte material and the unmodified LPSC material to record the time-dependent ionic conductivity retention. The air dew point was 0°C and the exposure time was 6 hours. The ionic conductivity of the coated and uncoated electrolytes was measured using electrochemical impedance spectroscopy (EIS) on an electrochemical workstation. The measurement results are shown in Table 8:

[0107] Table 8. Electrochemical impedance spectroscopy results

[0108]

[0109] It can be seen from Table 8 that compared with the unmodified LPSC material, the interface compatibility and air stability of the synthesized core-shell structure composite electrolyte material are greatly improved, and the ionic conductivity is slightly improved.

[0110] An embodiment of the present application provides a secondary battery, which includes the electrolyte material described in the previous embodiment.

[0111] The secondary battery proposed in this example has the advantages of high energy density, good cycle stability, and long cycle life. Lithium-ion secondary batteries containing the synthesized core-shell composite electrolyte material and unmodified LPSC material were subjected to room-temperature electrochemical cycling at a charge-discharge rate of 0.33C. The test results are shown in Table 9:

[0112] Table 9. Room temperature electrochemical cycling test results

[0113]

[0114]

[0115] As can be seen from Table 9, compared with the lithium-ion secondary battery containing the unmodified LPSC material, the cycle performance of the lithium-ion secondary battery containing the synthesized core-shell structure composite electrolyte material is greatly improved, indicating that the material compatibility and stability inside the battery have been greatly improved.

[0116] In addition, corresponding to the embodiments of the aforementioned method, the present application also provides embodiments of a package screening device and a terminal for its application:

[0117] Figure 3 As shown, Figure 3 : is a block diagram of a package screening device provided in an embodiment of the present application, the device comprising:

[0118] An acquisition module 31 is used to obtain structural characteristic data of multiple candidate coatings for sulfide solid electrolytes;

[0119] a screening module 32 for evaluating the thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability, and electronic insulation of each candidate coating based on the structural characteristic data, and screening the plurality of candidate coatings based on the evaluation results;

[0120] The classification module 33 is configured to evaluate the lithium conductivity of the screened candidate coatings based on the ionic conductivity of the screened candidate coatings, and classify the screened candidate coatings based on the lithium conductivity.

[0121] The implementation process of the functions and effects of each module in the above-mentioned device is specifically described in the implementation process of the corresponding steps in the above-mentioned method, and will not be repeated here.

[0122] This application also provides an electronic device, see Figure 4 , Figure 4 This is a block diagram of the structure of an electronic device provided in an embodiment of the present application. The electronic device may include a processor 410, a communication interface 420, a memory 430, and at least one communication bus 440. The communication bus 440 is used to enable direct communication between these components. The communication interface 420 of the electronic device in this embodiment of the present application is used to communicate signaling or data with other node devices. The processor 410 may be an integrated circuit chip with signal processing capabilities.

[0123] The processor 410 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, or a discrete hardware component. It can implement or execute the various methods, steps, and logic block diagrams disclosed in the embodiments of this application. A general-purpose processor can be a microprocessor, or the processor 410 can also be any conventional processor.

[0124] The memory 430 may be, but is not limited to, a random access memory (RAM), a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), etc. The memory 430 stores computer-readable instructions. When the computer-readable instructions are executed by the processor 410, the electronic device can perform the above-mentioned operations. Figure 1 The various steps involved in the method embodiment.

[0125] Optionally, the electronic device may further include a storage controller and an input / output unit.

[0126] The memory 430, storage controller, processor 410, peripheral interface, and input / output units are electrically connected to each other directly or indirectly to enable data transmission or interaction. For example, these components can be electrically connected to each other via one or more communication buses 440. The processor 410 is used to execute executable modules stored in the memory 430, such as software function modules or computer programs included in the electronic device.

[0127] The input and output unit is used to provide users with the ability to create tasks and to create optional time periods or preset execution times for the tasks to enable interaction between the user and the server. The input and output unit can be, but is not limited to, a mouse and a keyboard.

[0128] I understand. Figure 4 The structure shown is only for illustration, and the electronic device may also include Figure 4 More or fewer components than shown, or with Figure 4 Different configurations shown. Figure 4 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0129] An embodiment of the present application further provides a storage medium having instructions stored thereon. When the instructions are run on a computer, the computer program is executed by a processor to implement the method described in the method embodiment. To avoid repetition, details are not given here.

[0130] The present application also provides a computer program product, which, when running on a computer, enables the computer to execute the method described in the method embodiment.

[0131] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to the multiple embodiments of the present application. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a part of the code, and the module, program segment or a part of the code contains one or more executable instructions for implementing the specified logical functions. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0132] In addition, the functional modules in each embodiment of the present application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.

[0133] If the functions are implemented in the form of software function modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes various media that can store program codes, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0134] The foregoing is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application. It should be noted that similar reference numerals and letters represent similar items in the following figures. Therefore, once an item is defined in one figure, it does not need to be further defined or explained in subsequent figures.

[0135] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

[0136] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

Claims

1. A method for screening coated materials, characterized in that: include: Obtain structural property data for multiple candidate coatings for sulfide solid electrolytes; Based on the structural characteristic data, evaluating the thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability and electronic insulation of each candidate coating, and screening the multiple candidate coatings according to the evaluation results; According to the ionic conductivity of the screened candidate coatings, the lithium conductivity of the screened candidate coatings is evaluated, and the screened candidate coatings are classified according to the lithium conductivity.

2. The method according to claim 1, characterized in that The thermodynamic stability of the candidate coating is evaluated based on the stable structural energy difference of the candidate coating; the stable structural energy difference is the difference between the formation energy of the candidate coating and the stable energy corresponding to the component of the candidate coating on the target convex hull graph; The target convex hull map is a convex hull map composed of components of the candidate coating; The step of screening the plurality of candidate coatings according to the evaluation results includes: If the stable structural energy difference of the candidate coating currently being evaluated is greater than or equal to a first preset threshold, the candidate coating is excluded.

3. The method according to claim 1, characterized in that The electrochemical stability of the candidate coating is evaluated based on the reduction potential difference and oxidation potential difference of the candidate coating; the reduction potential difference is the difference between the lower limit of the allowable voltage of the electrolyte material and the reduction potential of the candidate coating; The oxidation potential difference is the difference between the upper limit of the allowable voltage of the electrolyte material and the oxidation potential of the candidate coating; The step of screening the plurality of candidate coatings according to the evaluation results includes: If the reduction potential difference of the candidate coating currently being evaluated is less than or equal to the second preset threshold, or the oxidation potential difference is less than or equal to the second preset threshold, the candidate coating is excluded.

4. The method according to claim 1, wherein The air interface stability of the candidate coating is evaluated based on the first reaction enthalpy of the candidate coating; the first reaction enthalpy is the reaction enthalpy of the candidate coating and water; The step of screening the plurality of candidate coatings according to the evaluation results includes: If the first reaction enthalpy of the candidate coating currently being evaluated is less than or equal to a third preset threshold, the candidate coating is excluded.

5. The method according to claim 1, wherein The sulfide interface stability of the candidate coating is evaluated based on the second reaction enthalpy of the candidate coating; the second reaction enthalpy is the reaction enthalpy of the reaction between the candidate coating and the sulfide solid electrolyte; The step of screening the plurality of candidate coatings according to the evaluation results includes: If the second reaction enthalpy of the candidate coating currently being evaluated is less than or equal to a fourth preset threshold, the candidate coating is excluded.

6. The method according to claim 1, characterized in that The cathode interface stability of the candidate coating is evaluated based on the third reaction enthalpy and the fourth reaction enthalpy of the candidate coating; the third reaction enthalpy is the reaction enthalpy of the reaction between the lithium-deficient cathode and the candidate coating; the fourth reaction enthalpy is the reaction enthalpy of the reaction between the lithium-rich cathode and the candidate coating; The step of screening the plurality of candidate coatings according to the evaluation results includes: If the third reaction enthalpy of the candidate coating currently being evaluated is less than or equal to the fifth preset threshold, or the fourth reaction enthalpy is less than or equal to the sixth preset threshold, the candidate coating is excluded.

7. The method according to claim 1, characterized in that The electronic insulation of the candidate coating is evaluated based on the band gap of the candidate coating; The step of screening the plurality of candidate coatings according to the evaluation results includes: If the band gap of the candidate cladding currently being evaluated is less than or equal to a seventh preset threshold, the candidate cladding is excluded.

8. The method according to claim 1, characterized in that The step of evaluating the lithium conductivity of the screened candidate coatings according to the ionic conductivity of the screened candidate coatings, and classifying the screened candidate coatings according to the lithium conductivity, comprises: Calculating the ratio of the ionic conductivity of the screened candidate coating to the ionic conductivity of the sulfide solid electrolyte; If the ratio is greater than or equal to an eighth preset threshold, classifying the screened candidate coating into the first category of coatings; If the ratio is less than the eighth preset threshold and greater than or equal to the ninth preset threshold, the screened candidate coating is classified as a second type of coating; and the eighth preset threshold is greater than the ninth preset threshold; If the ratio is less than the ninth preset threshold, the screened candidate coatings are classified as the third type of coatings.

9. The method according to claim 8, characterized in that Also includes: Determine the first type of coating as the first echelon fully coated modified material of the sulfide solid electrolyte; Determine the second type of coating as the second echelon fully coated modified material of the sulfide solid electrolyte; The third type of coating is determined to be the island coating material of the sulfide solid electrolyte.

10. A device for screening coated objects, characterized in that: include: An acquisition module, configured to acquire structural characteristic data of a plurality of candidate coatings for the sulfide solid electrolyte; a screening module for evaluating the thermodynamic stability, electrochemical stability, air interface stability, sulfide interface stability, cathode interface stability, and electronic insulation of each candidate coating based on the structural characteristic data, and screening the multiple candidate coatings based on the evaluation results; The classification module is used to evaluate the lithium conductivity of the screened candidate coatings according to their ionic conductivity, and classify the screened candidate coatings according to their lithium conductivity.

11. A computer-readable storage medium, characterized in that A computer program is stored thereon, and when the computer program is executed by a processor, the method according to any one of claims 1 to 9 is implemented.

12. An electronic device, characterized in that: The method comprises a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method according to any one of claims 1 to 9 is implemented.

13. An electrolyte material, characterized in that The electrolyte material is a core-shell structure, which includes a core of a sulfide solid electrolyte material and a shell layer coated on the outer surface of the core. The electrolyte coating material of the shell layer is screened by the method according to any one of claims 1 to 9.

14. A secondary battery, characterized in that: The secondary battery includes the electrolyte material according to claim 13 .

Images