Polymer electrolyte material screening method and device, storage medium, equipment, composite solid electrolyte material and secondary battery

Abstract

The invention provides a polymer electrolyte material screening method and device, a storage medium, equipment, a composite solid electrolyte material and a secondary battery. In the method, chemical structure data of multiple candidate polymer electrolytes are obtained, and based on the chemical structure data, adsorption energy of each candidate polymer electrolyte on a sulfide crystal face is calculated; according to a calculation result, a polymer electrolyte capable of forming a strong adsorption effect with a sulfide solid electrolyte is screened out, and then screening is carried out again according to the bond breaking energy difference of the screened candidate polymer electrolyte, so that the interface optimization material capable of keeping stable bonding with a sulfide substrate in the electrochemical cycle process is screened out. Thus, systematic screening is used for replacing experience trial and error, the polymer electrolyte material capable of forming a stable composite solid electrolyte with sulfide can be efficiently screened out, the screening efficiency and the material design accuracy are effectively improved, and therefore the rapid iteration battery material research and development requirement is met.

Description

Technical Field

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

[0002] Sulfide solid electrolytes, represented by lithium phosphorus sulfur chloride Li6PS5Cl (LPSC) with a sulfide germanium structure, have high ionic conductivity and excellent mechanical processing properties, making them solid electrolyte materials with good commercial prospects. However, their interfacial stability issues and insufficient mechanical strength have become key bottlenecks restricting their actual large-scale commercial application. To solve this problem, the industry has proposed the strategy of constructing a "sulfide-polymer" composite solid electrolyte. By introducing polymer electrolyte components, the mechanical brittleness of sulfides can be effectively improved, and interfacial side reactions can be suppressed. At the same time, the amorphous polymer regions and sulfide crystal channels form a "double continuous conductive network", which is conducive to further improving ionic conductivity.

[0003] Currently, the screening of polymer solid electrolyte materials compatible with sulfide electrolytes is mainly based on trial and error. Technicians select a certain polymer solid electrolyte material based on experience, prepare a composite electrolyte with sulfide, and then assemble it into a full battery for testing. In order to screen out a polymer material that meets the compatibility requirements, it may be necessary to repeat the process hundreds of times. The operation is cumbersome and extremely inefficient, and it cannot meet the needs of rapid iteration of battery material research and development. Therefore, the market is in urgent need of a processing solution that can efficiently screen out polymer solid electrolyte materials compatible with sulfide electrolytes. Summary of the Invention

[0004] The purpose of this application is to provide a polymer electrolyte material screening method, device, storage medium, equipment, composite solid electrolyte material and secondary battery, aiming to solve the problem in the related art that the screening efficiency of polymer electrolyte materials compatible with sulfide solid electrolytes is low and it is difficult to meet the needs of rapid iteration of battery material research and development.

[0005] In a first aspect, the present application provides a method for screening polymer electrolyte materials, comprising: obtaining chemical structure data of a plurality of candidate polymer electrolytes; the candidate polymer electrolytes are candidate doping materials for sulfide solid electrolytes; based on the chemical structure data, calculating the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface, and screening the plurality of candidate polymer electrolytes according to the adsorption energy; screening the screened candidate polymer electrolytes according to the bond breaking energy difference of the screened candidate polymer electrolytes to obtain a target polymer electrolyte; the bond breaking energy difference is the difference between the bond breaking energy of the candidate polymer electrolyte in the adsorbed state and the bond breaking energy in the vacuum state.

[0006] In the above implementation process, chemical structure data for multiple candidate polymer electrolytes is obtained. Based on this chemical structure data, the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface is calculated. Based on the calculated results, polymer electrolytes that can form strong adsorption interactions with sulfide solid electrolytes are screened. Subsequently, the screened candidate polymer electrolytes are screened again based on the bond breaking energy difference, thereby screening out interface-optimized materials that can maintain stable bonding with the sulfide substrate during electrochemical cycling. In this way, using systematic screening instead of empirical trial and error can efficiently screen polymer electrolyte materials that can form stable composite solid electrolytes with sulfides, effectively improving screening efficiency and the accuracy of material design, thereby meeting the needs of rapid iteration of battery material research and development.

[0007] Furthermore, in some examples, the calculation of the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface includes: cutting the surface of the bulk model of the sulfide solid electrolyte to obtain multiple surface models; different surface models have exposed surfaces with different crystal plane indices; calculating the surface energy of the exposed surface of each surface model, determining the exposed surface with the lowest surface energy as the target exposed surface, and determining the surface model with the target exposed surface as the sulfide surface model; and calculating the adsorption energy of each candidate polymer electrolyte on the target exposed surface based on the sulfide surface model.

[0008] In the above implementation process, the surface model corresponding to the crystal plane with the lowest surface energy is selected as the sulfide surface model for adsorption energy calculation, which can effectively improve the reliability of the adsorption energy calculation.

[0009] Furthermore, in some examples, the adsorption energy of each candidate polymer electrolyte on the target exposed surface is calculated based on the sulfide surface model, including: for any one of the multiple candidate polymer electrolytes, building a pure surface model with a vacuum layer, placing the candidate polymer electrolyte at the target position in the vacuum layer to obtain a pre-adsorption model, and using first-principles calculations to perform structural optimization and energy calculations on the pre-adsorption model to obtain a first ground-state energy; horizontally adsorbing the candidate polymer electrolyte on the sulfide surface model according to the initial adsorption spacing to obtain a post-adsorption model, and using first-principles calculations to perform structural optimization and energy calculations on the post-adsorption model to obtain a second ground-state energy; and determining the difference obtained by subtracting the first ground-state energy from the second ground-state energy as the adsorption energy of the candidate polymer electrolyte on the target exposed surface.

[0010] In the above implementation process, high-throughput calculations based on first-principles calculation methods can efficiently and accurately evaluate whether the candidate polymer electrolyte can form a strong adsorption effect with the sulfide solid electrolyte.

[0011] Furthermore, in some examples, the screening of the multiple candidate polymer electrolytes based on the adsorption energy includes: if the adsorption energy corresponding to any candidate polymer electrolyte is less than a first preset threshold, retaining the candidate polymer electrolyte; if the adsorption energy corresponding to any candidate polymer electrolyte is greater than or equal to the first preset threshold, excluding the candidate polymer electrolyte.

[0012] In the above implementation process, among a plurality of candidate polymer electrolytes, a candidate polymer electrolyte having an adsorption energy less than a first preset threshold is selected, so that the finally selected polymer electrolyte can be strongly adsorbed and bonded with sulfide.

[0013] Further, in some examples, the bond breaking energy difference of the screened candidate polymer electrolyte is calculated based on the following method: calculating the third ground state energy, fourth ground state energy, fifth ground state energy and sixth ground state energy of the screened candidate polymer electrolyte; the third ground state energy and the fourth ground state energy are the unbroken ground state energy and the broken ground state energy of the screened candidate polymer electrolyte in a vacuum state, respectively; the fifth ground state energy and the sixth ground state energy are the unbroken ground state energy and the broken ground state energy of the screened candidate polymer electrolyte in an adsorbed state, respectively; calculating the bond breaking energy of the screened candidate polymer electrolyte in a vacuum state based on the third ground state energy and the fourth ground state energy, and calculating the bond breaking energy of the screened candidate polymer electrolyte in an adsorbed state based on the fifth ground state energy and the sixth ground state energy; subtracting the bond breaking energy of the screened candidate polymer electrolyte in a vacuum state from the bond breaking energy of the screened candidate polymer electrolyte in an adsorbed state to obtain the bond breaking energy difference of the screened candidate polymer electrolyte.

[0014] In the above implementation process, a specific method for calculating the bond breaking energy difference of the polymer electrolyte is provided.

[0015] Furthermore, in some examples, the calculation of the third ground state energy, fourth ground state energy, fifth ground state energy and sixth ground state energy of the screened candidate polymer electrolyte includes: constructing a vacuum unbroken bond model of the screened candidate polymer electrolyte, and using first-principles calculation to perform structural optimization and energy calculation on the vacuum unbroken bond model to obtain the third ground state energy; dividing the polymer chain in the vacuum unbroken bond model into two segments to obtain a vacuum broken bond model, and using first-principles calculation to perform structural optimization and energy calculation on the vacuum broken bond model to obtain the fourth ground state energy; determining the adsorption model corresponding to the screened candidate polymer electrolyte as an adsorption state unbroken bond model, and using first-principles calculation to perform structural optimization and energy calculation on the adsorption state unbroken bond model to obtain the fifth ground state energy; dividing the polymer chain in the adsorption state unbroken bond model into two segments and adsorbing them on the corresponding target exposed surfaces respectively to obtain an adsorption state broken bond model, and using first-principles calculation to perform structural optimization and energy calculation on the adsorption state broken bond model to obtain the sixth ground state energy.

[0016] In the above implementation process, high-throughput calculations based on first-principles calculation methods can efficiently and accurately evaluate the interfacial stability of the candidate polymer electrolyte after combination with sulfide.

[0017] Furthermore, in some examples, the screening of the screened candidate polymer electrolytes based on their bond breaking energy differences includes: screening out candidate polymer electrolytes having bond breaking energy differences greater than a second preset threshold value among the screened candidate polymer electrolytes.

[0018] In the above implementation process, for the screened candidate polymer electrolytes, if the bond breaking energy difference of any one of the candidate polymer electrolytes is greater than the second preset threshold, indicating that the interfacial stability of the candidate polymer electrolyte is improved after combining with the sulfide, and the candidate polymer electrolyte is suitable for forming a composite solid electrolyte with the sulfide, the candidate polymer electrolyte is determined as the target polymer electrolyte. In this way, the target polymer electrolyte finally screened can form a stable composite solid electrolyte with the sulfide.

[0019] In a second aspect, the present application provides a polymer electrolyte material screening device, comprising: an acquisition module for acquiring chemical structure data of a plurality of candidate polymer electrolytes; the candidate polymer electrolytes are candidate doping materials for sulfide solid electrolytes; a calculation module for calculating the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface based on the chemical structure data, and screening the plurality of candidate polymer electrolytes according to the adsorption energy; a screening module for screening the screened candidate polymer electrolytes according to the bond breaking energy difference of the screened candidate polymer electrolytes to obtain a target polymer electrolyte; the bond breaking energy difference is the difference between the bond breaking energy of the candidate polymer electrolyte in the adsorbed state and the bond breaking energy in the vacuum state.

[0020] 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.

[0021] 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.

[0022] 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.

[0023] In a sixth aspect, the present application provides a composite solid electrolyte material, which is a composite system of a sulfide solid electrolyte and a polymer electrolyte; the polymer electrolyte is screened by the method described in any one of the first aspects.

[0024] In a seventh aspect, the present application provides a secondary battery, wherein the secondary battery comprises the composite solid electrolyte material as described in the sixth aspect.

[0025] 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.

[0026] 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

[0027] 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 creative work.

[0028] Figure 1 A flow chart of a polymer electrolyte material screening method provided in an embodiment of the present application;

[0029] Figure 2 Schematic diagram of the three-dimensional structure of a sulfide solid electrolyte (LPSC) and candidate doping materials (including PEO, PEI, and PTMC) selected in a screening scheme for polymer solid electrolyte materials compatible with sulfide electrolytes provided in an embodiment of the present application;

[0030] Figure 3 A block diagram of a polymer electrolyte material screening device provided in an embodiment of the present application;

[0031] Figure 4 This is a structural block diagram of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] 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.

[0033] 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.

[0034] Sulfide solid electrolytes are promising solid-state battery electrolyte materials, but their interfacial stability and insufficient mechanical strength seriously restrict their large-scale application. The development of composite solid electrolytes formed by mixing sulfide solid electrolytes and polymer electrolytes can solve this problem. The introduction of polymer electrolyte components can effectively improve the mechanical brittleness of sulfides and inhibit interfacial side reactions. At the same time, the amorphous regions of the polymer and the sulfide crystal channels form a "double continuous conductive network", which is conducive to further improving ionic conductivity. Since sulfide electrolytes have extremely strong chemical activity and easily react with polymer electrolytes, resulting in poor interfacial compatibility, obstructed ion transport, and even polymer degradation and failure during circulation, when constructing this composite solid electrolyte, it is necessary to accurately screen polymer electrolyte materials that are compatible with sulfide electrolytes.

[0035] Currently, the selection of polymer solid electrolyte materials compatible with sulfide electrolytes relies primarily on trial and error. Technicians select a polymer solid electrolyte material based on experience, prepare a composite electrolyte with the sulfide, and then assemble it into a full battery for testing. Finding a polymer material that meets compatibility requirements can require hundreds of repetitions, a cumbersome and inefficient process that makes it difficult to meet the demands of rapidly iterating battery material development.

[0036] To address the above issues, the present invention provides a polymer electrolyte material screening scheme. Using adsorption energy as the primary screening indicator, polymer electrolytes that can form strong adsorption interactions with sulfide solid electrolytes are screened out. Bond scission energy difference is then introduced as a key evaluation indicator for interfacial stability to screen out interface-optimized materials that can maintain stable bonding with the sulfide substrate during electrochemical cycling, thereby enhancing interfacial bonding strength while ensuring long-term cycling stability. In this way, polymer electrolyte materials that are compatible with sulfide solid electrolytes can be efficiently screened out, effectively improving screening efficiency and the accuracy of material design.

[0037] Next, the embodiments of the present application are introduced:

[0038] like Figure 1 As shown, Figure 1 This is a flow chart of a polymer electrolyte material screening method provided in an embodiment of the present application. The method can be applied to a high-performance computer capable of material simulation and design. The method includes:

[0039] Step 101: Acquire chemical structure data of a plurality of candidate polymer electrolytes; the candidate polymer electrolytes are candidate doping materials for sulfide solid electrolytes;

[0040] The sulfide solid electrolyte mentioned in this step is a sulfide solid electrolyte to be modified, which can be LPSC or other types of sulfide solid electrolytes. The candidate polymer electrolyte mentioned in this step is a polymer electrolyte to be screened and composited with a sulfide solid electrolyte, such as PEO (polyethylene oxide), PEI (polyetherimide), PTMC (polytrimethyl carbonate), etc. This embodiment can screen a variety of candidate polymer electrolytes at the same time. When implemented, the chemical structure data of each candidate polymer electrolyte is obtained. The chemical structure data here can include the molecular formula and atomic structure of the candidate polymer electrolyte. Based on the chemical structure data, material simulation can be performed by a high-performance computer to calculate the adsorption energy and bond breaking energy difference between the candidate polymer electrolyte and the sulfide substrate, laying a good foundation for the subsequent screening of the target polymer electrolyte.

[0041] Step 102: Calculate the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface based on the chemical structure data, and screen the multiple candidate polymer electrolytes according to the adsorption energy;

[0042] In this embodiment, the adsorption energy of the candidate polymer electrolyte on the sulfide crystal surface is used as the primary screening indicator. Adsorption energy is an important physical quantity that describes the energy change when a molecule or atom is adsorbed on a solid surface. Therefore, by screening a variety of candidate polymer electrolytes based on the adsorption energy, polymer electrolytes that can form a strong adsorption effect with the sulfide solid electrolyte can be identified to ensure the initial bonding strength.

[0043] In some embodiments, the calculation of the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface mentioned in this step may include: cutting the surface of the bulk model of the sulfide solid electrolyte to obtain multiple surface models; different surface models have exposed surfaces with different crystal plane indices; calculating the surface energy of the exposed surface of each surface model, determining the exposed surface with the lowest surface energy as the target exposed surface, and determining the surface model with the target exposed surface as the sulfide surface model; based on the sulfide surface model, calculating the adsorption energy of each candidate polymer electrolyte on the target exposed surface.

[0044] In other words, when calculating the adsorption energy of a candidate polymer electrolyte on a sulfide crystal face, one can first slice the sulfide solid phase model within a reasonable range of crystal face indices, such as taking a maximum Miller index of 10. This will yield a series of surface models with exposed faces of varying crystal face indices, with the number of surface models being n. The surface energies of these n different sulfide crystal faces are then calculated. These n surface energy results are then sorted, and the face with the lowest surface energy (denoted as h0k0l0) is identified as the target exposed face. The surface model with exposed face h0k0l0 is then extracted as the sulfide surface model, and the adsorption energy of the candidate polymer electrolyte on the target exposed face h0k0l0 is calculated using this sulfide surface model. Because the crystal face with the lowest surface energy is the most thermodynamically stable exposed face and its adsorption behavior is more similar to that of the actual material, selecting its corresponding surface model as the sulfide surface model for adsorption energy calculations can effectively improve the reliability of the adsorption energy calculations.

[0045] Furthermore, in some embodiments, the aforementioned calculation of the adsorption energy of each candidate polymer electrolyte on the target exposed surface based on the sulfide surface model may include: for any one of the multiple candidate polymer electrolytes, building a pure surface model with a vacuum layer, placing the candidate polymer electrolyte at the target position in the vacuum layer to obtain a pre-adsorption model, and using first-principles calculations to perform structural optimization and energy calculations on the pre-adsorption model to obtain a first ground-state energy; according to the initial adsorption spacing, horizontally adsorbing the candidate polymer electrolyte on the sulfide surface model to obtain a post-adsorption model, and using first-principles calculations to perform structural optimization and energy calculations on the post-adsorption model to obtain a second ground-state energy; and determining the difference obtained by subtracting the first ground-state energy from the second ground-state energy as the adsorption energy of the candidate polymer electrolyte on the target exposed surface.

[0046] That is, the steps for calculating the adsorption energy ΔE1 of the candidate polymer electrolyte on the target exposed surface h0k0l0 can be as follows: build a pure surface model with a vacuum layer, place the polymer molecule at the target position in the vacuum layer, where the vacuum layer can be a vacuum layer with a thickness of not less than 20 angstroms, and correspondingly, the target position can be a position not less than 10 angstroms away from the target exposed surface. The model at this time is recorded as the pre-adsorption model; use first-principles calculations, such as DFT (Density Functional Theory) method to optimize the structure of the pre-adsorption model, and then perform energy calculations to obtain the first ground state energy E slab The polymer is horizontally adsorbed on the sulfide surface model. The initial adsorption distance can be no more than 2 angstroms. The model at this time is recorded as the adsorption model. The first principle calculation is used to optimize the structure and calculate the energy of the adsorption model to obtain the second ground state energy E adsorption ; Calculate the adsorption energy ΔE1=E adsorption -E slab In this way, high-throughput calculations based on first-principles calculations can efficiently and accurately evaluate whether candidate polymer electrolytes can form strong adsorption interactions with sulfide solid electrolytes.

[0047] In some embodiments, the screening of the plurality of candidate polymer electrolytes according to the adsorption energy mentioned in this step may include: if the adsorption energy corresponding to any candidate polymer electrolyte is less than a first preset threshold, then retaining the candidate polymer electrolyte; if the adsorption energy corresponding to any candidate polymer electrolyte is greater than or equal to the first preset threshold, then excluding the candidate polymer electrolyte. That is, when screening the adsorption performance of the polymer according to the adsorption energy ΔE1, a threshold value is pre-set, namely, the first preset threshold value E th1 If ΔE1 <E th1, indicating that the candidate polymer electrolyte forms a strong adsorption effect with the sulfide solid electrolyte and the combination is good, then the candidate polymer electrolyte enters the next round of screening; on the contrary, if ΔE1≥E th1 , indicating that the candidate polymer electrolyte has weak binding ability with the sulfide solid electrolyte, and thus the candidate polymer electrolyte is excluded. Optionally, the first preset threshold value may be -0.5eV. Experiments have found that using an adsorption energy of -0.5eV as the threshold value can effectively screen out polymer electrolytes that can form strong adsorption interactions with sulfide solid electrolytes. Of course, in other embodiments, the first preset threshold value may also be set differently according to the needs of different scenarios.

[0048] Step 103 , screening the screened candidate polymer electrolytes according to their bond breaking energy differences to obtain target polymer electrolytes; the bond breaking energy difference is the difference between the bond breaking energy of the candidate polymer electrolyte in an adsorbed state and the bond breaking energy in a vacuum state.

[0049] In this embodiment, the bond breaking energy difference is introduced as an evaluation index of interface stability. The bond breaking energy difference can quantify the ability of the interface to resist cyclic stress. Therefore, further screening is performed based on the bond breaking energy difference of the screened candidate polymer electrolytes. The screened target polymer electrolyte can not only be strongly adsorbed and bonded with the sulfide solid electrolyte, but also have good interface stability after forming a composite solid electrolyte with the sulfide solid electrolyte and is not easy to decompose.

[0050] In some embodiments, the bond breaking energy difference of the screened candidate polymer electrolyte mentioned in this step can be calculated based on the following method: calculate the third ground state energy, fourth ground state energy, fifth ground state energy and sixth ground state energy of the screened candidate polymer electrolyte; the third ground state energy and the fourth ground state energy are the unbroken ground state energy and the broken ground state energy of the screened candidate polymer electrolyte in the vacuum state, respectively; the fifth ground state energy and the sixth ground state energy are the unbroken ground state energy and the broken ground state energy of the screened candidate polymer electrolyte in the adsorption state, respectively; calculate the bond breaking energy of the screened candidate polymer electrolyte in the vacuum state based on the third ground state energy and the fourth ground state energy, and calculate the bond breaking energy of the screened candidate polymer electrolyte in the adsorption state based on the fifth ground state energy and the sixth ground state energy; subtract the bond breaking energy of the screened candidate polymer electrolyte in the vacuum state from the bond breaking energy of the screened candidate polymer electrolyte in the adsorption state to obtain the bond breaking energy difference of the screened candidate polymer electrolyte.

[0051] That is to say, when calculating the bond breaking energy difference ΔE2 of the polymer electrolyte, the unbroken bond ground state energy of the polymer electrolyte in the vacuum state can be calculated. and the ground state energy of the broken bond From this, the bond breaking energy of the polymer electrolyte in vacuum state can be calculated Similarly, calculate the unbroken bond ground state energy of the polymer electrolyte in the adsorption state and the ground state energy of the broken bond From this, the bond breaking energy of the polymer electrolyte in the adsorption state can be calculated Then, the bond breaking energy difference of the polymer electrolyte ΔE2 = ΔE 2b -ΔE 2a In this way, the bond breaking energy difference of the polymer electrolyte can be calculated quickly and accurately.

[0052] Furthermore, in some embodiments, the aforementioned calculation of the third ground state energy, fourth ground state energy, fifth ground state energy and sixth ground state energy of the screened candidate polymer electrolyte may include: constructing a vacuum unbroken bond model of the screened candidate polymer electrolyte, and performing structural optimization and energy calculation on the vacuum unbroken bond model using first-principles calculation to obtain the third ground state energy; dividing the polymer chain in the vacuum unbroken bond model into two segments to obtain a vacuum broken bond model, and performing structural optimization and energy calculation on the vacuum broken bond model using first-principles calculation to obtain the fourth ground state energy; determining the adsorption model corresponding to the screened candidate polymer electrolyte as an adsorption state unbroken bond model, and performing structural optimization and energy calculation on the adsorption state unbroken bond model using first-principles calculation to obtain the fifth ground state energy; dividing the polymer chain in the adsorption state unbroken bond model into two segments and adsorbing them on the corresponding target exposed surfaces respectively to obtain an adsorption state broken bond model, and performing structural optimization and energy calculation on the adsorption state broken bond model using first-principles calculation to obtain the sixth ground state energy.

[0053] In other words, the steps for calculating the bond breaking energy difference ΔE2 of the polymer electrolyte can be as follows: build a three-dimensional box model with a side length of not less than 30 angstroms, place the complete polymer with limited polymerization degree in the center of the box, and record the model at this time as the unbroken bond model under vacuum. Use first-principles calculations, such as DFT method, to optimize the structure of the unbroken bond model under vacuum, and then perform energy calculation to obtain The unbroken bond model under vacuum is disconnected, and the polymer chain is separated into two segments. The model at this time is recorded as the bond-broken model under vacuum, and the first-principles calculation is used to optimize it to obtain The bond breaking energy ΔE in vacuum state is calculated according to the formula 2a ; Using the post-adsorption model built in the previous adsorption energy calculation process, recorded as the adsorption state unbroken bond model, the first principle calculation was used to optimize the obtained Based on the adsorption state unbroken bond model, the polymer chain is divided into two segments and adsorbed on the corresponding sulfide crystal surface h0k0l0 respectively. The model at this time is recorded as the adsorption state broken bond model, and the first principle calculation is used to optimize it to obtain The bond breaking energy ΔE in the adsorption state is calculated according to the formula 2b , and then calculate the bond breaking energy difference ΔE2. In this way, high-throughput calculations based on first-principles calculations can efficiently and accurately evaluate the interfacial stability of candidate polymer electrolytes after combining with sulfides.

[0054] Furthermore, in some embodiments, the step of screening the selected candidate polymer electrolytes according to the bond breaking energy difference of the selected candidate polymer electrolytes may include: screening the candidate polymer electrolytes having a bond breaking energy difference greater than a second preset threshold value from the selected candidate polymer electrolytes. That is, when the selected candidate polymers are screened again according to the bond breaking energy difference ΔE2, a threshold value, i.e., the second preset threshold value E2, is pre-set. th2 ; If ΔE2>E th2 , indicating that the interface stability of the candidate polymer electrolyte is improved after combining with sulfide, and it is suitable for compounding with sulfide to form a composite solid electrolyte, then the candidate polymer electrolyte is determined as the target polymer electrolyte; on the contrary, if ΔE2≤E th2 , indicating that the interface stability of the candidate polymer electrolyte deteriorates after combining with sulfide, and it is not suitable for compounding with sulfide to form a composite solid electrolyte. th2 It can be 0eV. Of course, in other embodiments, the second preset threshold E th2 Different settings can also be made according to the needs of different scenarios, and this application does not limit this.

[0055] In this embodiment of the present application, chemical structure data for multiple candidate polymer electrolytes are obtained. Based on this chemical structure data, the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface is calculated. Based on the calculated results, polymer electrolytes that can form strong adsorption interactions with sulfide solid electrolytes are screened. Subsequently, the screened candidate polymer electrolytes are screened again based on the bond breaking energy difference, thereby screening out interface-optimized materials that can maintain stable bonding with the sulfide substrate during the electrochemical cycle. In this way, using systematic screening instead of empirical trial and error can efficiently screen polymer electrolyte materials that can form stable composite solid electrolytes with sulfides, effectively improving screening efficiency and the accuracy of material design, thereby meeting the needs of rapid iteration of battery material research and development.

[0056] In order to explain the solution of this application in more detail, a specific embodiment is introduced below:

[0057] This example provides a screening scheme for polymer solid electrolyte materials compatible with sulfide electrolytes. This scheme selects LPSC as the sulfide solid electrolyte to be modified, and selects organic electrolytes PEO, PEI, and PTMC as candidate doping materials for LPSC composites. The three-dimensional structures of the sulfide solid electrolyte LPSC and several polymer electrolytes are shown in Figure 2. Figure 2 The program includes:

[0058] S201, selecting LPSC-PEO, LPSC-PEI, and LPSC-PTMC as candidate composite materials;

[0059] S202, selecting a maximum Miller index of 10, performing surface sectioning on the LPSC bulk model, obtaining surface models of exposed surfaces with different crystal plane indices, calculating the surface energies of different crystal planes of the sulfide, determining the surface with the lowest surface energy as the target exposed surface, and extracting the surface model with the target exposed surface as the sulfide surface model for subsequent calculations;

[0060] S203. Calculate the adsorption energy ΔE1 of the polymer electrolyte on the target exposed surface to evaluate the bonding strength between the polymer and the LPSC, thereby screening the polymer electrolyte. Specifically, during the screening, determine whether ΔE1 < -0.5 eV is satisfied. If so, proceed to the next round of screening. The adsorption energy calculation and screening results of each candidate composite material are shown in Table 1:

[0061] Table 1. Adsorption energy calculation and screening results of candidate composite materials

[0062] Candidate composite material chemical formula <![CDATA[Adsorption energy ΔE1 (unit: eV)]]> Whether to enter the next round of screening LPSC-PEO -1.44 yes LPSC-PEI -0.661 yes LPSC-PTMC -0.443 no

[0063] S204. Calculate the bond breaking energy ΔE of polymer electrolytes in vacuum state 2a , and the bond breaking energy ΔE of the adsorbed state on the LPSC surface 2b , we get the bond breaking energy difference ΔE2=ΔE 2b -ΔE 2a , in order to evaluate the interface stability of the candidate composite materials; specifically, determine whether ΔE2>0 is satisfied. If so, it indicates that the polymer electrolyte can improve the interface stability after combining with LPSC. The interface stability evaluation results of the screened candidate composite materials are shown in Table 2:

[0064] Table 2. Interface stability evaluation results of the selected candidate composite materials

[0065]

[0066] S205. Sorting out the screening results to obtain a target polymer electrolyte material, namely PEO. This target polymer electrolyte material can not only strongly adsorb and bond with the sulfide solid electrolyte LPSC, but also has good interface stability after forming a composite solid electrolyte with the sulfide and is not easy to decompose.

[0067] In summary, this embodiment overcomes the limitations of the traditional single adsorption energy criterion by introducing the bond breaking energy difference as a key evaluation indicator for interface stability. High-performance computers are used for material simulation and design to calculate the adsorption energy and bond breaking energy difference between candidate polymers and sulfide substrates, thereby achieving an accurate prediction of the interface stability of the composite material. In this way, the degradation resistance of the interface during electrochemical cycling is effectively evaluated, significantly improving the screening efficiency and the accuracy of material design.

[0068] Corresponding to the embodiments of the aforementioned method, the present application also provides embodiments of a composite solid electrolyte material and a secondary battery:

[0069] An embodiment of the present application provides a composite solid electrolyte material, which is a composite system of a sulfide solid electrolyte and a polymer electrolyte; the polymer electrolyte is screened by the method described in any of the previous embodiments.

[0070] This sulfide-polymer composite solid electrolyte material has excellent interfacial stability. Compared with similar materials that have not been polymer-modified using the above method, it improves interfacial compatibility while still maintaining excellent intrinsic electrochemical performance. Continuing with the previous example, the screened PEO is used as a doping and modification material and mixed with the sulfide solid electrolyte LPSC to produce a sulfide-polymer composite electrolyte material, namely LPSC-PEO. The preparation method includes:

[0071] S211, using anhydrous Li2S, P2S5 and LiCl as raw materials, accurately weighed according to the stoichiometric ratio, the raw materials were mixed in an argon-protected glove box and loaded into a high-energy ball mill, and mechanical alloying was carried out at 500 rpm for 10 hours;

[0072] S212, then pre-pressing and forming for 30 seconds using a cold press at a pressure of 150 MPa;

[0073] S213, finally heating to 550°C at 5°C / min under argon protection in a tube furnace and keeping the temperature for 5 hours, cooling in the furnace and then grinding to obtain solid electrolyte powder;

[0074] S214, the synthesized LPSC and PEO slurry were thoroughly mixed and dried in a drying oven at 70° C. for 18 hours to obtain an LPSC-PEO composite solid electrolyte. All processes were carried out in an argon-filled glove box.

[0075] An embodiment of the present application provides a secondary battery, which includes the composite solid electrolyte material described in the previous embodiment.

[0076] The secondary battery proposed in this embodiment, due to its use of the aforementioned composite solid electrolyte material, has advantages such as high energy density, good cycle stability, and long cycle life. Two all-solid-state lithium-ion batteries were prepared. The first all-solid-state lithium-ion battery was produced by assembling a single-layer solid-state soft pack using a composite electrode of a lithium nickel manganese cobalt oxide material (LiNi0.8Mn0.1Co0.1O2) and LPSC as the positive electrode, LPSC as the electrolyte layer, and a Li-In-LPSC composite electrode as the negative electrode. The second all-solid-state lithium-ion battery was produced by assembling a single-layer solid-state soft pack using a composite electrode of a lithium nickel manganese cobalt oxide material (LiNi0.8Mn0.1Co0.1O2) and LPSC as the positive electrode, LPSC-PEO as the electrolyte layer, and a Li-In-LPSC composite electrode as the negative electrode. Both all-solid-state lithium-ion batteries were subjected to constant current charge and discharge tests in the voltage range of 2.8-4.3V. At 25°C and a voltage range of 2.8-4.3V (vs. Li / Li+), 0.1C and 1C cycle performance data were obtained. The test results are shown in Table 3:

[0077] Table 3. Test results of constant current charge and discharge test

[0078]

[0079] It can be seen from Table 3 that compared with the unmodified sulfide electrolyte battery, the polymer modified battery screened based on the bond breaking energy difference criterion has a lower capacity decay rate and an improved energy density in the room temperature cycle test.

[0080] In addition, corresponding to the embodiments of the aforementioned method, the present application also provides embodiments of a polymer electrolyte material screening device and a terminal for its application:

[0081] Figure 3 As shown, Figure 3 : is a block diagram of a polymer electrolyte material screening device provided in an embodiment of the present application, the device comprising:

[0082] An acquisition module 31 is used to acquire chemical structure data of a plurality of candidate polymer electrolytes; the candidate polymer electrolytes are candidate doping materials for sulfide solid electrolytes;

[0083] a calculation module 32 for calculating the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface based on the chemical structure data, and screening the plurality of candidate polymer electrolytes according to the adsorption energy;

[0084] The screening module 33 is used to screen the screened candidate polymer electrolytes according to their bond breaking energy differences to obtain target polymer electrolytes; the bond breaking energy difference is the difference between the bond breaking energy of the candidate polymer electrolyte in the adsorption state and the bond breaking energy in the vacuum state.

[0085] 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.

[0086] 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.

[0087] 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.

[0088] 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 1The various steps involved in the method embodiment.

[0089] Optionally, the electronic device may further include a storage controller and an input / output unit.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] 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.

[0097] 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.

[0098] 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.

[0099] 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.

[0100] 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 polymer electrolyte materials, characterized in that: include: Obtaining chemical structure data of a plurality of candidate polymer electrolytes; the candidate polymer electrolytes are candidate doping materials for sulfide solid electrolytes; calculating the adsorption energy of each candidate polymer electrolyte on a sulfide crystal surface based on the chemical structure data, and screening the plurality of candidate polymer electrolytes according to the adsorption energy; The screened candidate polymer electrolytes are screened according to their bond breaking energy differences to obtain target polymer electrolytes; the bond breaking energy difference is the difference between the bond breaking energy of the candidate polymer electrolyte in an adsorbed state and the bond breaking energy in a vacuum state.

2. The method according to claim 1, characterized in that The calculation of the adsorption energy of each candidate polymer electrolyte on the sulfide crystal surface includes: Cutting the surface of the bulk model of the sulfide solid electrolyte to obtain multiple surface models; different surface models have exposed surfaces with different crystal plane indices; Calculating the surface energy of the exposed surface of each surface model, determining the exposed surface with the lowest surface energy as the target exposed surface, and determining the surface model having the target exposed surface as the sulfide surface model; According to the sulfide surface model, the adsorption energy of each candidate polymer electrolyte on the target exposed surface is calculated.

3. The method according to claim 2, characterized in that Calculating the adsorption energy of each candidate polymer electrolyte on the target exposed surface according to the sulfide surface model includes: For any one of the multiple candidate polymer electrolytes, construct a pure surface model with a vacuum layer, place the candidate polymer electrolyte at a target position in the vacuum layer to obtain a pre-adsorption model, and perform structural optimization and energy calculation on the pre-adsorption model using first-principles calculations to obtain a first ground-state energy; adsorbing the candidate polymer electrolyte horizontally on the sulfide surface model according to the initial adsorption spacing to obtain a post-adsorption model, and performing structural optimization and energy calculation on the post-adsorption model using first-principles calculations to obtain a second ground-state energy; The difference obtained by subtracting the first ground state energy from the second ground state energy is determined as the adsorption energy of the candidate polymer electrolyte on the target exposed surface.

4. The method according to claim 1, wherein The screening of the plurality of candidate polymer electrolytes according to the adsorption energy comprises: If the adsorption energy corresponding to any candidate polymer electrolyte is less than a first preset threshold, retain the candidate polymer electrolyte; If the adsorption energy corresponding to any candidate polymer electrolyte is greater than or equal to a first preset threshold, the candidate polymer electrolyte is excluded.

5. The method according to claim 3, characterized in that The bond breaking energy difference of the screened candidate polymer electrolytes is calculated based on the following method: Calculating the third ground state energy, fourth ground state energy, fifth ground state energy, and sixth ground state energy of the screened candidate polymer electrolyte; the third ground state energy and the fourth ground state energy are, respectively, the unbroken bond ground state energy and the broken bond ground state energy of the screened candidate polymer electrolyte in a vacuum state; the fifth ground state energy and the sixth ground state energy are, respectively, the unbroken bond ground state energy and the broken bond ground state energy of the screened candidate polymer electrolyte in an adsorbed state; Calculating the bond breaking energy of the screened candidate polymer electrolyte in a vacuum state according to the third ground state energy and the fourth ground state energy, and calculating the bond breaking energy of the screened candidate polymer electrolyte in an adsorbed state according to the fifth ground state energy and the sixth ground state energy; The bond breaking energy of the screened candidate polymer electrolyte in the adsorption state is subtracted from the bond breaking energy of the screened candidate polymer electrolyte in the vacuum state to obtain the bond breaking energy difference of the screened candidate polymer electrolyte.

6. The method according to claim 5, characterized in that The calculating of the third ground state energy, the fourth ground state energy, the fifth ground state energy and the sixth ground state energy of the screened candidate polymer electrolyte comprises: Constructing a vacuum unbroken bond model of the screened candidate polymer electrolyte, performing structural optimization and energy calculation on the vacuum unbroken bond model using first-principles calculations to obtain a third ground state energy; The polymer chain in the unbroken bond model under vacuum is divided into two segments to obtain a broken bond model under vacuum, and the broken bond model under vacuum is subjected to structural optimization and energy calculation using first principles calculation to obtain a fourth ground state energy; Determining the adsorption model corresponding to the screened candidate polymer electrolyte as an adsorption state unbroken bond model, performing structural optimization and energy calculation on the adsorption state unbroken bond model using first-principles calculations to obtain a fifth ground state energy; The polymer chain in the adsorption state unbroken bond model is divided into two segments and adsorbed on the corresponding target exposed surfaces respectively to obtain an adsorption state broken bond model. The adsorption state broken bond model is structurally optimized and energy calculated using first-principles calculations to obtain the sixth ground state energy.

7. The method according to claim 1, characterized in that The step of screening the screened candidate polymer electrolytes according to the bond breaking energy differences of the screened candidate polymer electrolytes comprises: Among the screened candidate polymer electrolytes, candidate polymer electrolytes having a bond breaking energy difference greater than a second preset threshold are screened out.

8. A polymer electrolyte material screening device, characterized in that: include: An acquisition module, configured to acquire chemical structure data of a plurality of candidate polymer electrolytes; the candidate polymer electrolytes are candidate doping materials for sulfide solid electrolytes; a calculation module, configured to calculate the adsorption energy of each candidate polymer electrolyte on a sulfide crystal surface based on the chemical structure data, and screen the plurality of candidate polymer electrolytes according to the adsorption energy; A screening module is used to screen the screened candidate polymer electrolytes according to their bond breaking energy differences to obtain target polymer electrolytes; the bond breaking energy difference is the difference between the bond breaking energy of the candidate polymer electrolyte in an adsorbed state and the bond breaking energy in a vacuum state.

9. 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 7 is implemented.

10. 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 7 is implemented.

11. A composite solid electrolyte material, characterized in that: The composite solid electrolyte material is a composite system of a sulfide solid electrolyte and a polymer electrolyte; the polymer electrolyte is screened by the method according to any one of claims 1 to 7.

12. A secondary battery, characterized in that: The secondary battery includes the composite solid electrolyte material according to claim 11.

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