Coating screening method and device, electronic equipment, storage medium, electrode material and secondary battery

Abstract

The invention provides a coating screening method and device, electronic equipment, a storage medium, an electrode material and a secondary battery, and the coating screening method comprises the steps: obtaining the structural characteristic data of a candidate coating; calculating a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coating, the first reaction enthalpy being the reaction enthalpy of hydrofluoric acid in an electrolyte and the candidate coating, and the second reaction enthalpy being the reaction enthalpy of hydrofluoric acid and a cobalt-free positive electrode; and determining the use type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy. According to the application, the screening of the coating can be realized. Meanwhile, compared with a screening method in the related technology, the screening process does not need to be manually and repeatedly operated, and the method has the advantages of being high in effect, easy to operate and the like.

Description

Technical Field

[0001] The present application relates to the technical field of power battery systems, and more specifically, to a method and device for screening a coating, an electronic device and a storage medium, an electrode material, and a secondary battery. Background Art

[0002] As an important component of lithium-ion batteries, the energy density and cost of cathode materials have a key impact on the energy density and cost of the entire battery and vehicle. Compared with lithium iron phosphate cathodes and ternary cathode materials that have been widely used, cobalt-free cathode materials represented by spinel lithium nickel manganese oxide (hereinafter referred to as LNMO) have the advantages of high theoretical voltage and high energy density, and because they do not contain expensive and toxic cobalt elements, they also have the advantage of low cost.

[0003] The stability of the interface between the cobalt-free cathode and the electrolyte is a key issue that restricts the large-scale application of cobalt-free cathode materials. On the one hand, LNMO material particles easily react with HF in the electrolyte, resulting in the dissolution of manganese and the destruction of the LNMO material structure; on the other hand, the voltage of the cobalt-free cathode can reach up to 4.7V, which makes the conventional electrolyte easily decomposed. The above stability issues will cause battery capacity decay and reduce service life. In order to improve the stability of the interface between the cobalt-free cathode and the electrolyte, it needs to be coated and modified.

[0004] At present, the screening of LNMO coating modification materials for cobalt-free cathodes is mainly based on trial and error. Technicians select a certain coating modification material based on experience, prepare the coated LNMO electrode material, and then assemble it into a full battery for testing. In order to screen out a coating material that meets the stability modification requirements, it may take hundreds of repetitive processes, which is cumbersome and inefficient, and cannot meet the needs of rapid iteration of battery material research and development. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a method, device, electronic device and storage medium, electrode material, and secondary battery for screening coated objects. At the same time, compared with the screening methods in the related art, the present application does not require manual repeated screening process, and has the advantages of high effect and simple operation.

[0006] In a first aspect, the present invention provides a method for screening a coating, the method comprising:

[0007] Acquiring structural property data of candidate coatings;

[0008] Calculating a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with the cobalt-free positive electrode;

[0009] A usage type of the candidate coating is determined based on the first reaction enthalpy and the second reaction enthalpy.

[0010] The method of the present application obtains the structural characteristic data of the candidate coating, and then calculates the first reaction enthalpy and the second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with the cobalt-free positive electrode, and then the usage type of the candidate coating can be determined based on the first reaction enthalpy and the second reaction enthalpy, thereby realizing automatic screening of the coating. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0011] In an optional embodiment, determining the target coating based on the first reaction enthalpy and the second reaction enthalpy includes:

[0012] Determining whether the first reaction enthalpy is greater than a first preset threshold value, if the first reaction enthalpy is greater than the first preset threshold value, determining the use type of the candidate coating as a first type, wherein the first type characterizes that the candidate coating is a cobalt-free positive electrode full-coating modified material;

[0013] When the first reaction enthalpy is less than or equal to the first preset threshold, the usage type of the candidate coating is determined as a second type based on the second reaction enthalpy, wherein the second type characterizes that the candidate coating is a cobalt-free positive electrode island coating modified material.

[0014] This optional implementation can determine whether the first reaction enthalpy is greater than a first preset threshold value. If the first reaction enthalpy is greater than the first preset threshold value, the usage type of the candidate coating is determined to be the first type, wherein the first type characterizes that the candidate coating is a cobalt-free positive electrode full-coating modified material. On the other hand, when the first reaction enthalpy is less than or equal to the first preset threshold value, the usage type of the candidate coating can be determined as the second type based on the second reaction enthalpy, wherein the second type characterizes that the candidate coating is a cobalt-free positive electrode island-shaped coating modified material.

[0015] In an optional embodiment, the method comprises:

[0016] Calculating a target band gap difference based on the structural characteristic data of the candidate coating, wherein the target band gap difference represents the band gap difference between the candidate coating and the cobalt-free positive electrode;

[0017] Determine whether the target band gap difference is greater than a second preset threshold value. If the target band gap difference is less than or equal to the second preset threshold value, exclude the candidate coating. If the target band gap difference is greater than the second preset threshold value, determine whether the first reaction enthalpy is greater than the first preset threshold value.

[0018] This optional implementation can calculate the target band gap difference based on the structural characteristic data of the candidate coating, wherein the target band gap difference represents the band gap difference between the candidate coating and the cobalt-free positive electrode, and then can determine whether the target band gap difference is greater than a second preset threshold value. If the target band gap difference is less than or equal to the second preset threshold value, the candidate coating is excluded; if the target band gap difference is greater than the second preset threshold value, the determination of whether the first reaction enthalpy is greater than the first preset threshold value is performed.

[0019] In an optional embodiment, the method further comprises:

[0020] Calculating the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating;

[0021] Determine whether the reduction potential difference of the candidate coating is greater than a third preset threshold, and whether the oxidation potential difference of the candidate coating is greater than a fourth preset threshold. If the reduction potential difference of the candidate coating is greater than the third preset threshold, and the oxidation potential difference of the candidate coating is greater than the fourth preset threshold, trigger the execution of the target band gap difference calculation based on the structural characteristic data of the candidate coating. If the reduction potential difference of the candidate coating is less than or equal to the third preset threshold, or the oxidation potential difference of the candidate coating is less than or equal to the fourth preset threshold, exclude the candidate coating.

[0022] This optional implementation can calculate the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating, and then can determine whether the reduction potential difference of the candidate coating is greater than a third preset threshold, and whether the oxidation potential difference of the candidate coating is greater than a fourth preset threshold. If the reduction potential difference of the candidate coating is greater than the third preset threshold, and the oxidation potential difference of the candidate coating is greater than the fourth preset threshold, then the calculation of the target band gap difference based on the structural characteristic data of the candidate coating is triggered. If the reduction potential difference of the candidate coating is less than or equal to the third preset threshold, or the oxidation potential difference of the candidate coating is less than or equal to the fourth preset threshold, then the candidate coating is excluded.

[0023] In an optional embodiment, the method further comprises:

[0024] Calculating a third reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the third reaction enthalpy is the reaction enthalpy of the cobalt-free positive electrode reacting with the candidate coating;

[0025] Determine whether the third reaction enthalpy is greater than a fifth preset threshold value. If the third reaction enthalpy is less than or equal to the fifth preset threshold value, exclude the candidate coating. If the third reaction enthalpy is greater than the fifth preset threshold value, trigger the execution of calculating the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating.

[0026] This optional implementation can calculate a third reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the third reaction enthalpy is the reaction enthalpy of the reaction between the cobalt-free positive electrode and the candidate coating, and thus can determine whether the third reaction enthalpy is greater than a fifth preset threshold value. If the third reaction enthalpy is less than or equal to the fifth preset threshold value, the candidate coating is excluded; if the third reaction enthalpy is greater than the fifth preset threshold value, the calculation of the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating is triggered.

[0027] In an optional embodiment, the cobalt-free positive electrode island-shaped coating modified material includes a first type of island-shaped coating modified material and a second type of island-shaped coating modified material.

[0028] This optional implementation manner may use the first type of island-shaped coating modified material and the second type of island-shaped coating modified material as the cobalt-free positive electrode island-shaped coating modified material.

[0029] In an optional embodiment, determining the use type of the candidate coating as the second type based on the second reaction enthalpy comprises:

[0030] Determine whether the second reaction enthalpy is less than or equal to a sixth preset threshold value. If the second reaction enthalpy is less than or equal to the sixth preset threshold value, the usage type of the candidate coating is the first type of island-shaped coating modified material. If the second reaction enthalpy is greater than the sixth preset threshold value, the usage type of the candidate coating is the second type of island-shaped coating modified material.

[0031] This optional implementation can determine whether the second reaction enthalpy is less than or equal to a sixth preset threshold value. If the second reaction enthalpy is less than or equal to the sixth preset threshold value, the usage type of the candidate coating is the first type of island-shaped coating modified material. If the second reaction enthalpy is greater than the sixth preset threshold value, the usage type of the candidate coating is the second type of island-shaped coating modified material.

[0032] In a second aspect, the present invention provides a screening device for a coating, the device comprising:

[0033] An acquisition module, used to acquire structural characteristic data of candidate coatings;

[0034] A calculation module, for calculating a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with the cobalt-free positive electrode;

[0035] A determination module is used to determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy.

[0036] The device of the present application can obtain structural characteristic data of candidate coatings by executing a method for screening coatings, and can further calculate a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coatings, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with a cobalt-free positive electrode, and can further determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy, thereby realizing automatic screening of coatings. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0037] In a third aspect, the present invention provides an electronic device, comprising:

[0038] Processor; and

[0039] The memory is configured to store machine-readable instructions, and when the instructions are executed by the processor, the method for screening the coating as described in any one of the aforementioned embodiments is performed.

[0040] The electronic device of the present application can obtain structural characteristic data of candidate coatings by executing a method for screening coatings, and can further calculate a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coatings, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with a cobalt-free positive electrode, and can further determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy, thereby realizing automatic screening of coatings. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0041] In a fourth aspect, the present invention provides a storage medium storing a computer program, wherein the computer program is executed by a processor to perform the method for screening packages as described in any one of the aforementioned embodiments.

[0042] The storage medium of the present application can obtain structural characteristic data of candidate coatings by executing a method for screening coatings, and can further calculate a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coatings, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with the cobalt-free positive electrode, and can further determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy, thereby realizing automatic screening of coatings. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0043] In a fifth aspect, the present application provides an electrode material, which is a core-shell structure, comprising a core of a cobalt-free positive electrode active material and a shell layer coated on the outer surface of the core, and the electrode coating material of the shell layer is obtained by the screening method of the coating described in the first aspect of the present application.

[0044] The electrode material has the characteristics of good interface stability between the cobalt-free positive electrode and the electrolyte. Compared with the cobalt-free positive electrode material that has not been coated and modified according to the above method, the electrode material improves the corrosion of HF in the electrolyte on the structure of the cobalt-free positive electrode material and the decomposition of the electrolyte by the high voltage of the cobalt-free positive electrode.

[0045] In a sixth aspect, the present application provides a secondary battery, wherein the secondary battery comprises the electrode material of the fifth aspect of the present application. Due to the use of the electrode material, the secondary battery has the advantages of high energy density, good cycle stability, long cycle life, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. 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 related drawings can be obtained based on these drawings without paying creative work.

[0047] Figure 1 It is a schematic flow chart of a method for screening a coating disclosed in an embodiment of the present application;

[0048] Figure 2 is a three-dimensional structure table of candidate coatings provided in the embodiments of the present application;

[0049] Figure 3 is a three-dimensional structure table of candidate coatings provided in the embodiments of the present application;

[0050] Figure 4 It is a structural schematic diagram of an electronic device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0051] 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.

[0052] Embodiment 1

[0053] See also Figure 1 , Figure 1 is a schematic diagram of a method for screening a coating disclosed in an embodiment of the present application, such as Figure 1 As shown, the method of the embodiment of the present application includes the following steps:

[0054] 101. Obtain structural characteristic data of a candidate coating;

[0055] 101. Calculate a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction between the hydrofluoric acid in the electrolyte and the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction between the hydrofluoric acid and the cobalt-free positive electrode;

[0056] 103. Determine a usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy.

[0057] The method of the embodiment of the present application obtains the structural characteristic data of the candidate coating, and then calculates the first reaction enthalpy and the second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid with the cobalt-free positive electrode. Based on the first reaction enthalpy and the second reaction enthalpy, the usage type of the candidate coating can be determined, thereby realizing automatic screening of the coating. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0058] In an embodiment of the present application, a candidate coating refers to a coating that may be used as a coating material for a cobalt-free positive electrode, wherein the number of candidate coatings may be multiple, for example, there may be 10 candidate coatings, and accordingly, 5 first-type coatings, 3 first-type coatings, and 2 coatings that cannot be used as coating materials for a cobalt-free positive electrode can be screened out from the 10 candidate coatings.

[0059] In the embodiment of the present application, the structural characteristic data of the candidate coating includes the chemical formula, space group, and three-dimensional structure file of the crystal of the coating.

[0060] In an optional embodiment, determining the target coating based on the first reaction enthalpy and the second reaction enthalpy includes:

[0061] Determine whether the first reaction enthalpy is greater than a first preset threshold value, and if the first reaction enthalpy is greater than the first preset threshold value, determine the use type of the candidate coating as a first type, wherein the first type characterizes that the candidate coating is a cobalt-free positive electrode full-coating modified material;

[0062] When the first reaction enthalpy is less than or equal to the first preset threshold, the use type of the candidate coating is determined as a second type based on the second reaction enthalpy, wherein the second type characterizes that the candidate coating is a cobalt-free positive electrode island coating modified material.

[0063] This optional implementation can determine whether the first reaction enthalpy is greater than a first preset threshold value. If the first reaction enthalpy is greater than the first preset threshold value, the usage type of the candidate coating is determined to be the first type, wherein the first type characterizes that the candidate coating is a cobalt-free positive electrode fully coated modified material. On the other hand, when the first reaction enthalpy is less than or equal to the first preset threshold value, the usage type of the candidate coating can be determined as the second type based on the second reaction enthalpy, wherein the second type characterizes that the candidate coating is a cobalt-free positive electrode island coated modified material.

[0064] In an optional embodiment, the method comprises:

[0065] Calculating a target band gap difference based on the structural characteristic data of the candidate coating, wherein the target band gap difference represents the band gap difference between the candidate coating and the cobalt-free positive electrode;

[0066] Determine whether the target band gap difference is greater than a second preset threshold. If the target band gap difference is less than or equal to the second preset threshold, exclude the candidate coating. If the target band gap difference is greater than the second preset threshold, determine whether the first reaction enthalpy is greater than the first preset threshold.

[0067] This optional implementation can calculate the target band gap difference based on the structural characteristic data of the candidate coating, wherein the target band gap difference represents the band gap difference between the candidate coating and the cobalt-free positive electrode, and then can determine whether the target band gap difference is greater than a second preset threshold value. If the target band gap difference is less than or equal to the second preset threshold value, the candidate coating is excluded. If the target band gap difference is greater than the second preset threshold value, a determination is performed as to whether the first reaction enthalpy is greater than the first preset threshold value.

[0068] In an optional implementation manner, the method of the embodiment of the present application further includes:

[0069] Calculating a reduction potential difference of the candidate coating and an oxidation potential difference of the candidate coating based on the structural property data of the candidate coating;

[0070] Determine whether the reduction potential difference of the candidate coating is greater than a third preset threshold, and whether the oxidation potential difference of the candidate coating is greater than a fourth preset threshold. If the reduction potential difference of the candidate coating is greater than the third preset threshold, and the oxidation potential difference of the candidate coating is greater than the fourth preset threshold, trigger the execution of calculating the target band gap difference based on the structural characteristic data of the candidate coating. If the reduction potential difference of the candidate coating is less than or equal to the third preset threshold, or the oxidation potential difference of the candidate coating is less than or equal to the fourth preset threshold, exclude the candidate coating.

[0071] This optional implementation can calculate the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating, and then can determine whether the reduction potential difference of the candidate coating is greater than a third preset threshold, and whether the oxidation potential difference of the candidate coating is greater than a fourth preset threshold. If the reduction potential difference of the candidate coating is greater than the third preset threshold, and the oxidation potential difference of the candidate coating is greater than the fourth preset threshold, then the calculation of the target band gap difference based on the structural characteristic data of the candidate coating is triggered. If the reduction potential difference of the candidate coating is less than or equal to the third preset threshold, or the oxidation potential difference of the candidate coating is less than or equal to the fourth preset threshold, then the candidate coating is excluded.

[0072] In an optional implementation manner, the method of the embodiment of the present application further includes the following steps:

[0073] Calculating a third reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the third reaction enthalpy is the reaction enthalpy of the cobalt-free positive electrode reacting with the candidate coating;

[0074] Determine whether the third reaction enthalpy is greater than the fifth preset threshold value. If the third reaction enthalpy is less than or equal to the fifth preset threshold value, exclude the candidate coating. If the third reaction enthalpy is greater than the fifth preset threshold value, trigger the execution of calculating the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating.

[0075] This optional implementation can calculate the third reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the third reaction enthalpy is the reaction enthalpy of the reaction between the cobalt-free positive electrode and the candidate coating, and thus can determine whether the third reaction enthalpy is greater than a fifth preset threshold value. If the third reaction enthalpy is less than or equal to the fifth preset threshold value, the candidate coating is excluded. If the third reaction enthalpy is greater than the fifth preset threshold value, it triggers the execution of calculating the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating.

[0076] In an optional embodiment, the cobalt-free positive electrode island-shaped coating modified material includes a first type of island-shaped coating modified material and a second type of island-shaped coating modified material.

[0077] This optional implementation manner may use the first type of island-shaped coating modified material and the second type of island-shaped coating modified material as the cobalt-free positive electrode island-shaped coating modified material.

[0078] In an optional embodiment, determining the use type of the candidate coating as the second type based on the second reaction enthalpy comprises the following sub-steps:

[0079] Determine whether the second reaction enthalpy is less than or equal to the sixth preset threshold. If the second reaction enthalpy is less than or equal to the sixth preset threshold, the usage type of the candidate coating is the first type of island-shaped coating modified material. If the second reaction enthalpy is greater than the sixth preset threshold, the usage type of the candidate coating is the second type of island-shaped coating modified material.

[0080] This optional implementation can determine whether the second reaction enthalpy is less than or equal to the sixth preset threshold value. If the second reaction enthalpy is less than or equal to the sixth preset threshold value, the usage type of the candidate coating is the first type of island-shaped coating modified material. If the second reaction enthalpy is greater than the sixth preset threshold value, the usage type of the candidate coating is the second type of island-shaped coating modified material.

[0081] In the embodiment of the present application, as an example, the screening of the coating is specifically as follows:

[0082] Obtain the scheme and structure of candidate coatings, including the chemical formula, space group, and three-dimensional structure file of the crystal, etc. Multiple coatings can be screened at the same time.

[0083] Calculate the reaction enthalpy ΔH of the cobalt-free cathode and the candidate coating a , evaluate the chemical stability of the cobalt-free cathode / coating interface, where the reaction enthalpy ΔH of the reaction between the cobalt-free cathode and the candidate coating is calculated a The steps are as follows:

[0084] Obtaining Cobalt-free Cathode by First-Principles Calculation LNMO Enthalpy H LNMO , and obtain the candidate coating C through first-principles calculation COATING Enthalpy H COATING , assuming no cobalt cathode C LNMO and candidate coating C COATING The stoichiometric coefficients of the reaction are x and 1-x respectively. Given a value of x between 0 and 1, determine whether the reaction can occur through the thermodynamic database or first principle calculation. If the reaction can occur, obtain the candidate product C PDax and the enthalpy of the product H PDax , calculate the corresponding reaction enthalpy ΔH ax =H PDax -xH LNMO -(1-x)H COATING ; Further, traverse all x from 0-1 to obtain all possible candidate products {CPDax |0<x<1} and the corresponding reaction enthalpy {H PDax |0<x<1}, generate the reaction thermodynamic phase diagram.

[0085] Furthermore, the reaction corresponding to the lowest point of the phase diagram is denoted by x0, and the corresponding reaction enthalpy is LNMO and coating C COATING The interfacial reaction enthalpy of the reaction is calculated by

[0086] Furthermore, according to the reaction enthalpy ΔH of the cobalt-free cathode and the candidate coating, a The size of the candidate coating is used to screen the chemical stability of the cobalt-free cathode / coating interface; a threshold of -0.1 eV / atom is given based on calculation experience and is recorded as ΔH th , if ΔH a >ΔH th , then the interfacial reaction between the candidate coating and the cobalt-free cathode is thermodynamically not easy to occur, and ΔH a The larger the cobalt-free cathode / coating interface chemical stability is, the better the candidate coating will enter the next round of screening; conversely, if ΔH a ≤ΔH th , the chemical stability of the cobalt-free positive electrode / coating interface of the candidate coating is poor, and the candidate coating is not suitable as a cobalt-free positive electrode stability coating modification material, and the screening is completed.

[0087] Further, the reduction potential difference ΔU of the coating is calculated R and oxidation potential difference ΔU O , evaluating the electrochemical stability of the Co-free cathode / coating interface.

[0088] Further, the reduction potential difference ΔU of the coating is calculated R and oxidation potential difference ΔU O The steps are as follows:

[0089] Furthermore, the candidate coating c is calculated by first principles at different potentials U. COATING For the reduction reaction involving Li / Li+, U is gradually increased from 0V until the reduction reaction just stops. The corresponding U is the reduction potential U of the candidate coating. R ;

[0090] Furthermore, the lower limit of the working voltage of the cobalt-free cathode is U DOWN , calculate the reduction potential difference ΔU R =U DOWN -U R ;

[0091] Furthermore, the candidate coating c is calculated by first principles at different potentials U.COATING For the oxidation reaction involving Li / Li+, 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 ;

[0092] Furthermore, the upper limit of the working voltage of the cobalt-free cathode is U UP , calculate the oxidation potential difference ΔU O =U O -U UP ;

[0093] Further, according to the reduction potential difference ΔU R and oxidation potential difference ΔU O The size of the candidate coating is used to screen the electrochemical stability of the cobalt-free cathode / coating interface; a threshold of -0.1V is given based on calculation experience and is recorded as ΔU th , if the reduction potential difference ΔU R >ΔU th , and the oxidation potential difference ΔU O >ΔU th , then the oxidation reaction and reduction reaction at the interface between the candidate coating and the cobalt-free cathode are not easy to occur, and ΔU R and ΔU O The larger the reduction potential difference ΔU is, the better the electrochemical stability of the cobalt-free cathode / coating interface is, and the candidate coating enters the next round of screening. R ≤ΔU th , or oxidation potential difference ΔU O ≤ΔU th , the electrochemical stability of the cobalt-free positive electrode / coating interface of the candidate coating is poor, and the candidate coating is not suitable as a cobalt-free positive electrode stability coating modification material, and the screening is completed.

[0094] Furthermore, the band gap difference ΔE between the coating and the cobalt-free cathode was calculated. g , determine the electrochemical stability of the electrolyte / coating interface, and evaluate the effect of the candidate coating on improving the decomposition problem of the electrolyte caused by the high voltage of the cobalt-free cathode.

[0095] Furthermore, the band gap difference ΔE between the coating and the cobalt-free cathode was calculated. g The steps are as follows:

[0096] Furthermore, the charge density of the coating is obtained by SCF self-consistent calculation, and the charge density is input to calculate the energy band of the coating to obtain the electronic band gap E of the coating. g ;

[0097] Furthermore, the charge density of the cobalt-free cathode was obtained by SCF self-consistent calculation, and the energy band gap E of the electronic band of the cobalt-free cathode was obtained by inputting the cobalt-free cathode into the coating.g0 ;

[0098] Furthermore, the band gap difference ΔE between the coating and the cobalt-free cathode was calculated. g =E g -E g0 ;

[0099] Furthermore, the candidate coatings were screened for electrochemical stability at the electrolyte / coating interface to determine the band gap difference ΔE between the coating and the cobalt-free cathode. g As an indicator, the lower the electronic energy band gap, the better the electronic conductivity. According to the band gap difference ΔE between the coating and the cobalt-free positive electrode, g The size of can determine whether the high voltage of the positive electrode will be transmitted to the electrolyte and cause the electrolyte to decompose, thereby judging the electrochemical stability of the electrolyte / coating interface and evaluating the effect of the candidate coating on improving the decomposition problem of the high voltage of the cobalt-free positive electrode; a threshold of -0.1eV is given based on calculation experience, recorded as ΔE th , if the band gap difference between the coating and the cobalt-free cathode is ΔE g >ΔE th , the high voltage of the cobalt-free positive electrode is difficult to be transmitted to the electrolyte, causing the electrolyte to decompose, and ΔE g The larger the size, the better the electrochemical stability of the electrolyte / coating interface, and the better the effect of improving the decomposition problem of the electrolyte by the high voltage of the cobalt-free cathode, the candidate coating will enter the next round of screening; conversely, if the band gap difference ΔE between the coating and the cobalt-free cathode is g ≤ΔE th , the electrolyte / coating interface electrochemical stability of the candidate coating is poor, and the candidate coating is not suitable as a cobalt-free positive electrode stability coating modification material, and the screening is completed.

[0100] Furthermore, the reaction enthalpy ΔH of the HF and coating in the electrolyte, which is the most corrosive to the cobalt-free cathode, is calculated. b , and the reaction enthalpy ΔH of HF and the cobalt-free cathode c , analyze the chemical stability of the electrolyte / coating interface, and evaluate and classify the effectiveness of candidate coatings in improving the corrosion problem of HF in the electrolyte on the structure of cobalt-free cathode materials.

[0101] Furthermore, the reaction enthalpy ΔH of HF and the candidate coating is calculated. b The steps are as follows:

[0102] Furthermore, the enthalpy of HF H is obtained by first-principles calculation. HF ;

[0103] Furthermore, the candidate coating C is obtained by first-principles calculation. COATING Enthalpy H COATING ; Further, let HF and candidate coating CCOATING The stoichiometric coefficients of the reaction are x and 1-x respectively. Given a value of x between 0 and 1, determine whether the reaction can occur through the thermodynamic database or first-principles calculation. If the reaction can occur, obtain the candidate product c PDbx and the enthalpy of the product H PDbx , calculate the corresponding reaction enthalpy ΔH bx =H PDbx -xH HF -(1-x)H COATING ;

[0104] Further, traverse all x from 0-1 to obtain all possible candidate products {c PDbx |0<x<1} and the corresponding reaction enthalpy {H PDbx |0<x<1}, generate the reaction thermodynamic phase diagram;

[0105] Furthermore, the reaction corresponding to the lowest point of the phase diagram is denoted by x0, and the corresponding reaction enthalpy is HF and the coating C COATING The interfacial reaction enthalpy of the reaction is calculated by

[0106] Furthermore, the reaction enthalpy ΔH of HF and the cobalt-free cathode is calculated. c The steps are as follows:

[0107] Furthermore, the enthalpy of HF H is obtained by first-principles calculation. HF ;

[0108] Furthermore, the cobalt-free cathode C was obtained by first-principles calculation. LNMO Enthalpy H LNMO ;

[0109] Furthermore, assuming that HF ​​and the cobalt-free cathode C LNMO The stoichiometric coefficients of the reaction are x and 1-x respectively. Given a value of x between 0 and 1, determine whether the reaction can occur through the thermodynamic database or first-principles calculation. If the reaction can occur, obtain the candidate product c PDcx and the enthalpy of the product H PDcx , calculate the corresponding reaction enthalpy ΔH cx =H PDcx -xH HF -(1-x)H LNMO ;

[0110] Further, traverse all x from 0-1 to obtain all possible candidate products {c PDcx |0<x<1} and the corresponding reaction enthalpy {H PDcx |0<x<1}, generate the reaction thermodynamic phase diagram;

[0111] Furthermore, the reaction corresponding to the lowest point of the phase diagram is denoted by x0, and the corresponding reaction enthalpy is HF and cobalt-free cathode C LNMO The interfacial reaction enthalpy of the reaction is calculated by

[0112] Furthermore, according to the reaction enthalpy ΔH of the reaction between HF and the coating b And the reaction enthalpy ΔH of HF and cobalt-free cathode c The candidate coatings were screened for chemical stability at the electrolyte / coating interface, and the effect of the coatings on improving the corrosion of the cobalt-free cathode material structure by HF in the electrolyte was classified; a threshold of -0.1 eV / atom was given based on calculation experience, denoted as ΔH th , if ΔH b >ΔH th , then the interface reaction between the candidate coating and HF is not easy to occur thermodynamically, the interface between the candidate coating and HF is chemically stable, and it is regarded as pure physical isolation of HF, recorded as type A coating, which is suitable; if ΔH b ≤ΔH th And ΔH b ≤ΔH c , then the candidate coating reacts with HF, and the coating reacts with HF preferentially compared with the cobalt-free cathode, and is regarded as an active sacrificial agent consuming HF, and is recorded as a type B coating; if ΔH b ≤ΔH th And ΔH b >ΔH c , then the candidate coating reacts with HF, but the coating reacts with HF later than the cobalt-free cathode and is regarded as an active sacrificial agent consuming HF, and is recorded as a type C coating.

[0113] Furthermore, the screening results were sorted out to obtain coatings with the effect of improving the interface stability between the cobalt-free positive electrode and the electrolyte, among which Type A coatings purely physically isolate HF and are suitable as candidates for full-coating modification materials for the cobalt-free positive electrode; Type B coatings are regarded as active sacrificial agents that consume HF and are suitable as candidates for island-shaped coating modification materials for the cobalt-free positive electrode; Type C coatings are regarded as suboptimal active sacrificial agents that consume HF and are suitable as candidates for island-shaped coating modification materials for the cobalt-free positive electrode. Among them, the effective coatings screened out can improve the corrosion of HF in the electrolyte on the structure of the cobalt-free positive electrode material and the decomposition of the electrolyte by the high voltage of the cobalt-free positive electrode.

[0114] In the embodiment of the present application, as another example, the scheme and structure of the candidate coating are obtained, and Al2O3, Li2TiO3, YF3, and Li2W2O4 are selected as candidate coatings. The chemical formula, space group, and three-dimensional structure of the crystal are as follows: Figure 2 As shown, Figure 2It is a three-dimensional structure table of candidate coatings provided in the embodiments of the present application.

[0115] Furthermore, the reaction enthalpy ΔH of the reaction between the cobalt-free cathode and the candidate coating is calculated. a , the chemical stability of the cobalt-free cathode / coating interface was evaluated, as shown in Table 1 below:

[0116]

[0117] Table 1

[0118] Further, the reduction potential difference ΔU of the coating is calculated R and oxidation potential difference ΔU O , the electrochemical stability of the cobalt-free cathode / coating interface was evaluated, as shown in Table 2, which is disclosed in the examples of this application.

[0119]

[0120] Table 2

[0121] Furthermore, the band gap difference ΔE between the coating and the cobalt-free cathode was calculated. g , judge the electrochemical stability of the electrolyte / coating interface, and evaluate the effect of the candidate coating on improving the decomposition problem of the electrolyte caused by the high voltage of the cobalt-free positive electrode, as shown in Table 3.

[0122]

[0123] Table 3

[0124] Furthermore, the reaction enthalpy ΔH of the HF and coating in the electrolyte, which is the most corrosive to the cobalt-free cathode, is calculated. b , the chemical stability of the electrolyte / coating interface was analyzed, and the effect of the candidate coatings on improving the corrosion problem of HF in the electrolyte on the structure of the cobalt-free cathode material was evaluated and classified, as shown in Table 4.

[0125]

[0126] Table 4

[0127] Finally, from the four candidate coatings, Al2O3, Li2TiO3, YF3, and Li2W2O4, two effective coatings, Al2O3 and YF3, were screened out, which can improve the corrosion of HF in the electrolyte on the structure of the cobalt-free cathode material and the decomposition of the electrolyte by the high voltage of the cobalt-free cathode. YF3 is a type A coating, suitable as a candidate for the full coating modification material of the cobalt-free cathode; Al2O3 is a type B coating, suitable as a candidate for the island coating modification material of the cobalt-free cathode.

[0128] Embodiment 2

[0129] See also Figure 3 , Figure 3 is a schematic diagram of the structure of a screening device for a package disclosed in an embodiment of the present application, such as Figure 3 As shown, the device of the embodiment of the present application includes the following functional modules:

[0130] An acquisition module 201 is used to acquire structural characteristic data of a candidate coating;

[0131] A calculation module 202, for calculating a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid with the cobalt-free positive electrode;

[0132] The determination module 203 is used to determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy.

[0133] The device of the embodiment of the present application can obtain structural characteristic data of candidate coatings by executing a screening method for coatings, and can further calculate a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coatings, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid with a cobalt-free positive electrode, and can further determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy, thereby realizing automatic screening of coatings. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0134] Embodiment 3

[0135] See also Figure 4 , Figure 4 is a schematic diagram of the structure of an electronic device disclosed in an embodiment of the present application, such as Figure 4 As shown, the electronic device of the embodiment of the present application includes:

[0136] Processor 301; and

[0137] The memory 301 is configured to store machine-readable instructions. When the instructions are executed by the processor 301, the method for screening the coating according to any one of the aforementioned embodiments is performed.

[0138] The electronic device of the embodiment of the present application can obtain structural characteristic data of candidate coatings by executing the screening method of coatings, and can further calculate the first reaction enthalpy and the second reaction enthalpy based on the structural characteristic data of the candidate coatings, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid with the cobalt-free positive electrode, and can further determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy, thereby realizing automatic screening of coatings. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0139] Embodiment 4

[0140] An embodiment of the present application provides a storage medium, wherein the storage medium stores a computer program, and the computer program is executed by a processor as in the method for screening a package according to any one of the aforementioned embodiments.

[0141] The storage medium of the embodiment of the present application can obtain the structural characteristic data of the candidate coating by executing the screening method of the coating, and can then calculate the first reaction enthalpy and the second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid with the cobalt-free positive electrode, and then the usage type of the candidate coating can be determined based on the first reaction enthalpy and the second reaction enthalpy, thereby realizing automatic screening of the coating. At the same time, it does not require manual repeated operation of the screening process, and has the advantages of high effect and simple operation.

[0142] Embodiment 5

[0143] An electrode material according to an embodiment of the present application is prepared by using an Al2O3 coating material selected by the coating material screening method according to the first embodiment of the present application as a shell structure and a cobalt-free positive electrode material as a core structure to prepare a core-shell structure composite electrode material including a core of a cobalt-free positive electrode active material and a shell layer coated on the outer surface of the core. The preparation method thereof is as follows:

[0144] Li2CO3, NiO, and MnO2 powders were mixed in anhydrous ethanol at a molar ratio of 1.05:1:3, and the mixture was then ball-milled at 400 rpm for 18 h and then dried at 100 °C for 4 h to obtain the LNMO precursor.

[0145] Further, the LNMO precursor was calcined at 500 °C for 5 h and then calcined at 800 °C for 8 h in an air atmosphere to obtain raw LNMO powder.

[0146] Further, aluminum isopropoxide was dissolved in ethanol heated at 60 °C, and then the pristine LNMO powder was put into the solution, stirred vigorously for 2 h, and then dried at 100 °C for 4 h.

[0147] Furthermore, the mixture was calcined at 500° C. for 4 hours to obtain a core-shell structure composite electrode material having the screened Al 2 O 3 coating material as a shell structure and the cobalt-free positive electrode material as a core structure.

[0148] Embodiment 6

[0149] The present invention discloses a lithium-ion secondary battery, and the assembly steps are as follows:

[0150] Weigh 0.8g of a core-shell composite electrode material with the screened Al2O3 coating material as the shell structure and the cobalt-free positive electrode material as the core structure, 0.1g of a carbon black conductive agent, and 0.1g of a PVDF binder, mix them evenly in an NMP solvent, apply them on an aluminum foil, and make a positive electrode sheet after drying.

[0151] The diaphragm is a PE diaphragm, the counter electrode is a lithium metal sheet, and the electrolyte is 1M LiPF6 / (EC:DMC=1:1). A button cell is assembled in an inert gas glove box to obtain a lithium ion secondary battery.

[0152] As a control group, button cells prepared using uncoated cobalt-free positive electrode materials were simultaneously prepared.

[0153] The scanning electron microscopy results showed that the Al2O3 coating formed relatively uniform dot-shaped or island-shaped substances coated on the surface of the cobalt-free positive electrode material, and the cobalt-free positive electrode did not undergo obvious phase change, which improved the corrosion of HF in the electrolyte on the structure of the cobalt-free positive electrode material, and the decomposition of the electrolyte by the high voltage of the cobalt-free positive electrode.

[0154] The coated and uncoated cobalt-free cathodes were subjected to room temperature electrochemical cycles at a charge and discharge rate of 0.33C, and the test results are shown in Table 5. The experimental results show that compared with the uncoated cobalt-free cathode, the room temperature cycle performance of the coated cobalt-free cathode is greatly improved, indicating that the corrosion of the cobalt-free cathode material structure by HF in the electrolyte and the decomposition of the electrolyte by the high voltage of the cobalt-free cathode are improved.

[0155]

[0156] Table 5

[0157] In the embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. The device embodiments described above are merely schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some communication interfaces, and the indirect coupling or communication connection of devices or units can be electrical, mechanical or other forms.

[0158] In addition, the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0159] Furthermore, the functional modules in the various embodiments of the present application may be integrated together to form an independent part, or each module may exist separately, or two or more modules may be integrated to form an independent part.

[0160] It should be noted that if the function is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application can essentially be embodied in the form of a software product, or in other words, the part that contributes to the prior art or the part of the technical solution. The computer software product is stored in a storage medium, including a number of instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM) random access memory (RAM), disk or optical disk, and other media that can store program codes.

[0161] In this document, relational terms such as first and second, etc. are used merely to distinguish one entity or operation from another entity or operation, but do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0162] The above are only embodiments of the present application and are not intended to limit the scope of protection of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of protection of the present application.

Claims

1. A method for screening a coating, characterized in that: The method comprises: Acquiring structural property data of candidate coatings; Calculating a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with the cobalt-free positive electrode; A usage type of the candidate coating is determined based on the first reaction enthalpy and the second reaction enthalpy.

2. The method according to claim 1, characterized in that The determining of the target coating based on the first reaction enthalpy and the second reaction enthalpy comprises: Determining whether the first reaction enthalpy is greater than a first preset threshold value, if the first reaction enthalpy is greater than the first preset threshold value, determining the use type of the candidate coating as a first type, wherein the first type characterizes that the candidate coating is a cobalt-free positive electrode full-coating modified material; When the first reaction enthalpy is less than or equal to the first preset threshold, the usage type of the candidate coating is determined as a second type based on the second reaction enthalpy, wherein the second type characterizes that the candidate coating is a cobalt-free positive electrode island coating modified material.

3. The method according to claim 1, characterized in that The method comprises: Calculating a target band gap difference based on the structural characteristic data of the candidate coating, wherein the target band gap difference represents the band gap difference between the candidate coating and the cobalt-free positive electrode; Determine whether the target band gap difference is greater than a second preset threshold value. If the target band gap difference is less than or equal to the second preset threshold value, exclude the candidate coating. If the target band gap difference is greater than the second preset threshold value, determine whether the first reaction enthalpy is greater than the first preset threshold value.

4. The method according to claim 1, characterized in that The method further comprises: Calculating the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating; Determine whether the reduction potential difference of the candidate coating is greater than a third preset threshold, and whether the oxidation potential difference of the candidate coating is greater than a fourth preset threshold; if the reduction potential difference of the candidate coating is greater than the third preset threshold, and the oxidation potential difference of the candidate coating is greater than the fourth preset threshold, trigger the execution of the calculation of the target band gap difference based on the structural characteristic data of the candidate coating; if the reduction potential difference of the candidate coating is less than or equal to the third preset threshold, or the oxidation potential difference of the candidate coating is less than or equal to the fourth preset threshold, exclude the candidate coating; And, the method further comprises: calculating a third reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the third reaction enthalpy is the reaction enthalpy of the reaction between the cobalt-free positive electrode and the candidate coating; Determine whether the third reaction enthalpy is greater than a fifth preset threshold value. If the third reaction enthalpy is less than or equal to the fifth preset threshold value, exclude the candidate coating. If the third reaction enthalpy is greater than the fifth preset threshold value, trigger the execution of calculating the reduction potential difference of the candidate coating and the oxidation potential difference of the candidate coating based on the structural characteristic data of the candidate coating.

5. The method according to claim 2, characterized in that The cobalt-free positive electrode island-shaped coating modified material includes a first type of island-shaped coating modified material and a second type of island-shaped coating modified material; And, determining the use type of the candidate coating as a second type based on the second reaction enthalpy comprises: Determine whether the second reaction enthalpy is less than or equal to a sixth preset threshold value. If the second reaction enthalpy is less than or equal to the sixth preset threshold value, the usage type of the candidate coating is the first type of island-shaped coating modified material. If the second reaction enthalpy is greater than the sixth preset threshold value, the usage type of the candidate coating is the second type of island-shaped coating modified material.

6. A screening device for coated objects, characterized in that: The device comprises: An acquisition module, used to acquire structural characteristic data of candidate coatings; A calculation module, for calculating a first reaction enthalpy and a second reaction enthalpy based on the structural characteristic data of the candidate coating, wherein the first reaction enthalpy is the reaction enthalpy of the reaction of hydrofluoric acid in the electrolyte with the candidate coating, and the second reaction enthalpy is the reaction enthalpy of the reaction of the hydrofluoric acid with the cobalt-free positive electrode; A determination module is used to determine the usage type of the candidate coating based on the first reaction enthalpy and the second reaction enthalpy.

7. An electronic device, characterized in that: include: processor; as well as A memory configured to store machine-readable instructions, wherein when the instructions are executed by the processor, the method for screening the package as described in any one of claims 1 to 5 is executed.

8. A storage medium, characterized in that: The storage medium stores a computer program, and the computer program is executed by a processor to implement the method for screening packages as described in any one of claims 1 to 5.

9. An electrode material, characterized in that: The electrode material is a core-shell structure, which includes a cobalt-free positive electrode active material core and a shell layer coated on the outer surface of the core, and the electrode coating material of the shell layer is obtained by the screening method of the coating according to any one of claims 1 to 5.

10. A secondary battery, characterized in that: The secondary battery comprises the electrode material as claimed in claim 9.

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