Design method of infinite layer nickel oxide with low sodium ion migration barrier

Abstract

The invention relates to a design method of an infinite layer nickel oxide with a low sodium ion migration barrier, which comprises the following steps of: constructing an infinite layer rare earth nickel oxide and titanium carbide model and expanding cells to ensure that contact surfaces are consistent; constructing a heterojunction model and converting the heterojunction model into a three-dimensional atomic coordinate file; optimizing the surface structures of the two materials, combining and adding a vacuum layer, and then calculating the interface energy; structural changes and sodium ion migration barriers are analyzed, the ionic conductivity optimization rate is calculated, and a theoretical basis is provided for sodium ion battery negative electrode material design. Compared with the prior art, the ion conduction capability of the titanium carbide two-dimensional material as the sodium ion battery negative electrode is calculated and optimized through the first principle, the migration potential barrier is reduced, the infinite layer nickelate and titanium carbide heterojunction is constructed, the sodium ion conduction performance is improved, and a new thought is provided for the design of the sodium ion battery negative electrode material.

Description

Technical Field

[0001] The invention relates to the field of analysis and characterization of inorganic functional materials, and in particular to a design method for an infinite layer nickel oxide with a low sodium ion migration barrier. Background Art

[0002] Sodium-ion battery is an emerging energy storage technology, and the selection and development of its negative electrode materials is one of the key research directions. In recent years, two-dimensional transition metal titanium carbide has become one of the hot spots in the research of sodium-ion battery negative electrode materials due to its unique layered structure and excellent electrochemical properties.

[0003] Rare earth nickelate (ReNiO3) is a perovskite-type oxide with strong electron correlation in its d orbital. In 2019, we successfully used SrTiO3 as a substrate to obtain nanoscale infinite-layer nickelate thin films Nd 0.8 Sr 0.2 NiO2. It has the same structure as infinite layer copper oxide. The measurements of resistivity, critical current density and magnetic field response indicate that the superconducting transition temperature is about 9 to 15K. The rich electronic properties of ReNiO3 give it a series of potential applications such as electronic devices, energy storage, and high-temperature superconductors.

[0004] As an emerging energy storage technology, the selection and development of negative electrode materials for sodium-ion batteries is one of the key research directions. Existing negative electrode materials for sodium-ion batteries, such as hard carbon-based materials, have certain sodium storage properties, but still have problems such as poor cycle stability and low rate performance. In addition, two-dimensional transition metal titanium carbide has become one of the hot topics in the research of negative electrode materials for sodium-ion batteries due to its unique layered structure and excellent electrochemical properties, but it still faces the challenges of low ion diffusion rate and poor structural stability in practical applications.

[0005] A heterojunction is an interface structure formed by the direct bonding of two or more different materials with different energy band structures and physical properties. The formation of a heterojunction is due to the existence of energy band discontinuities between materials, which results in a potential barrier for charge carriers at the interface of the materials. When two different thin films are stacked to form a heterojunction, the differences in lattice constants and symmetry cause their physical properties to change significantly. This change in potential barriers and physical properties at the interface makes it possible to regulate sodium ion migration and helps develop new high-performance sodium ion battery anode materials.

[0006] In the prior art, the ion conductivity of the negative electrode material of the sodium ion battery is insufficient and the migration barrier is high, that is, there is a lack of efficient heterostructure design to improve the conductivity of sodium ions and thus optimize the overall performance and efficiency of the battery. Summary of the invention

[0007] The purpose of the present invention is to provide a design method for an infinite layer nickel oxide with a low sodium ion migration barrier in order to overcome the defects of the above-mentioned prior art. The design method optimizes the ion conductivity of the existing titanium carbide two-dimensional material as the negative electrode of the sodium ion battery, and further reduces the migration barrier of sodium ions at the negative electrode of the battery; through first-principles calculations, the infinite layer nickelate and titanium carbide are cut separately on the surface and then form a heterojunction. By studying the interlayer migration energy barrier and the surface migration energy barrier, a new material structure is obtained so that its sodium ion conductivity is doubly improved, which provides a deeper understanding for the sodium ion migration design and optimization of infinite layer nickel oxide, and also has more expansion for the application of negative electrode materials of sodium ion batteries.

[0008] The purpose of the present invention can be achieved by the following technical solutions:

[0009] The present invention provides a method for designing an infinite layer nickel oxide with a low sodium ion migration barrier, comprising the following steps:

[0010] S1: Constructing a model of infinite layers of rare earth nickel oxide and titanium carbide: Use crystal structure visualization software to construct a model of perovskite-type infinite layers of rare earth nickel oxide and titanium carbide, and perform cell expansion operations to ensure the consistency of the contact surface area of ​​the two materials;

[0011] S2: Constructing an infinite layer rare earth nickel oxide / titanium carbide heterojunction model: The expanded model is constructed into an infinite layer rare earth nickel oxide / titanium carbide heterojunction model through crystal structure visualization software and converted into a three-dimensional atomic coordinate file;

[0012] S3: Calculate the interface energy of infinite layer rare earth nickel oxide / titanium carbide heterojunction: Optimize the surface structures of infinite layer rare earth nickel oxide and titanium carbide respectively to obtain stable surface structure coordinate files. After merging the surface structure coordinate files, add a vacuum layer to isolate the periodic boundary effect, calculate the optimal structure, and analyze the surface binding energy of infinite layer rare earth nickel oxide heterojunction;

[0013] S4: Result processing and analysis: The optimized system structure is displayed through crystal structure visualization software, and the changes in bond length, bond angle and lattice constant of infinite layers composed of different rare earth elements are analyzed. The charge density diagram, state density diagram, sodium ion migration barrier diagram and electronic conductivity diagram are drawn. The migration barrier of sodium ions between heterojunction layers and the surface and between titanium carbide layers is compared to obtain the change of sodium ion migration barrier, so as to calculate the ion conductivity optimization rate. Based on the ion conductivity optimization rate, infinite layer rare earth nickel oxide is designed as the negative electrode material of sodium ion battery.

[0014] Furthermore, in S3 and S4, the interface energy, result processing and analysis of the infinite layer rare earth nickel oxide / titanium carbide heterojunction are calculated by calculating the electronic and ionic characteristics. The calculation process of the electronic and ionic characteristics calculation includes: structure optimization, static self-consistent calculation, characteristic calculation based on the generated charge density data file, and ion mobility calculation.

[0015] Furthermore, in S1 to S4:

[0016] The crystal structure visualization software is Materials Studio software;

[0017] The software used to convert the heterojunction structure model into three-dimensional atomic coordinates is VESTA;

[0018] The computational software for the calculation of electronic and ionic properties is VASP software;

[0019] The software used to process the data results was P4V and ORIGIN.

[0020] Furthermore, in S1 to S4: the infinite layer nickel oxide design method for the low sodium ion migration barrier adopts a screening method, the screening method is based on the first principle calculation of density functional theory, and the screening object is a heterojunction model with different vacuum layer thicknesses and different Sr doping concentrations.

[0021] Furthermore, the screening process includes: changing the doping Sr concentration and the vacuum layer thickness in the heterojunction model to examine the influence of these variables on the stability of the infinite layer nickel oxide heterojunction structure.

[0022] Furthermore, in S4, when calculating the ionic characteristics, the Na ion migration point is used as a variable, and the change of the variable in the ionic conductivity of the sodium ions migrating between the layers and at different points on the surface is examined.

[0023] Furthermore, in S3 and S4, the design method of infinite-layer nickel oxide for regulating the low sodium ion migration barrier is to describe the interaction between ions and valence electrons using the augmented plane wave method, and the exchange-correlation functional uses the generalized gradient approximation method.

[0024] Furthermore, in S1, perovskite-type rare earth nickel oxide and titanium carbide models are constructed respectively, and then the top oxygen atom of the rare earth nickel oxide is deleted and then the cell expansion operation is performed.

[0025] Furthermore, in S3, in the process of calculating the optimized structure, the high symmetry points are generated by the reciprocal space origin method. During the structural optimization, the high symmetry points of the infinite layer rare earth nickel oxide are set to 2×3×5, and the high symmetry points of the titanium carbide are set to 2×3×1.

[0026] Furthermore, in S4, the ion mobility calculation process includes: selecting five nearest migration sites between the layers and on the surface of the heterojunction, performing CINEB calculations, calculating each point as a saddle point for migration to the potential energy surface, i.e., a transition state, and finally drawing the overall migration barrier.

[0027] Compared with the prior art, the present invention has the following technical advantages:

[0028] 1) The present invention applies first-principles calculations directly based on the basic crystal structure information of the infinite-layer rare earth nickel oxide material and titanium carbide system, without relying on additional empirical parameters, and can accurately calculate key information such as the spatial structure, electronic state, ionic state and total energy of the system, thereby improving the accuracy and reliability of the calculations.

[0029] 2) The present invention reveals the key factors affecting the energy barrier of sodium ion migration in infinite layer rare earth nickel oxide through computational analysis, which provides in-depth theoretical guidance and design basis for experimental research and development of new sodium ion battery negative electrode materials, and helps to optimize the performance of the materials.

[0030] 3) The present invention combines atomic structure characterization and surface binding energy calculation to verify the stability and preparability of the new infinite layer nickel oxide material under study at room temperature, providing a solid theoretical basis for the experimental preparation and application of negative electrode materials for sodium ion batteries.

[0031] 4) The present invention adopts a computational simulation method, which only requires the use of a computer for experiments, without the need for actual experimental raw materials, significantly reducing the experimental cost. At the same time, the computational process is efficient and controllable, and can quickly iterate and optimize the design, accelerating the transformation process of new materials from theory to practical application.

[0032] 5) The design method of the present invention can predict and optimize the electronic structure and ion diffusion path of infinite-layer nickel oxide materials, providing a new strategy for improving the performance of negative electrode materials for sodium-ion batteries, which helps to improve the overall performance and life of the battery.

[0033] 6) The present invention provides a low-cost, high-efficiency material design and screening method, which replaces or reduces the trial and error process in traditional experiments through computational simulation, shortens the new material development cycle, and improves R&D efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the whole method of the embodiment of the present invention;

[0035] Figure 2 Schematic diagram of infinite layer rare earth nickel oxide heterojunction setup;

[0036] Figure 3Schematic diagram of differential density charge between layers of an infinite layer rare earth nickel oxide heterojunction;

[0037] Figure 4 (a) and (b) are schematic diagrams of the migration structure of sodium ions between the layers and the surface of an infinite layer of rare earth nickel oxide heterojunction and the migration energy barrier diagram. Figure 4 (c) is the energy barrier diagram for the migration of sodium ions in titanium carbide. DETAILED DESCRIPTION

[0038] In the overall implementation process, the present invention provides a method for designing an infinite layer nickel oxide with a low sodium ion migration barrier, including the construction of an infinite layer nickel oxide / MXene material heterojunction using different rare earth elements, and the screening of rare earth element types for infinite layer heterojunctions using fourteen rare earth groups. The present invention clarifies the influence of the types of rare earth elements and whether Sr is doped on the sodium ion migration barrier of the heterojunction, and can characterize the relationship between the intrinsic physical parameters of the infinite layer nickel oxide / MXene heterojunction and its sodium ion migration barrier through machine learning, providing a deeper understanding for designing a negative electrode material for sodium ion batteries with a low sodium ion migration barrier and regulating its electronic and ion conduction properties.

[0039] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to specifically illustrate the technical solution of the present invention. The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The component models, material names, connection structures, control methods, algorithms and other features not clearly described in this technical solution are all regarded as common technical features disclosed in the prior art.

[0040] In this embodiment, the " / " symbol is used to represent the interface or contact between two different materials. In this context, "infinite layer rare earth nickel oxide / titanium carbide heterojunction model" refers to a model in which two materials, infinite layers of rare earth nickel oxide and titanium carbide, are designed to contact each other at the atomic level to form a heterostructure.

[0041] Example 1

[0042] The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier in the present invention comprises:

[0043] S1: Construction of infinite layer models of rare earth nickel oxide and titanium carbide; using the material's crystal structure visualization software to construct the perovskite type rare earth nickel oxide and titanium carbide models respectively, then deleting the top oxygen atoms of the rare earth nickel oxide and performing a cell expansion operation to ensure that the contact surface area of ​​the rare earth nickel oxide and titanium carbide is exactly the same.

[0044] S2: Construction of infinite layer rare earth nickel oxide / titanium carbide heterojunction model: The above processed separate files are constructed into infinite layer rare earth nickel oxide heterojunction model with the help of crystal visualization software, and then the heterojunction model is converted into a three-dimensional atomic coordinate file with the help of crystal structure visualization software of the material;

[0045] S3: Calculation and design of the interface energy of infinite-layer rare earth nickel oxide / titanium carbide heterojunction: Set input files for the infinite-layer rare earth nickel oxide surface structure and titanium carbide surface structure respectively, optimize the material structure, and obtain the coordinate files of two stable material surface structures; merge the above two stable material surface structures, and then add a vacuum layer of a certain thickness to isolate the influence of the lattice periodic effect, and use this as the input file of the infinite-layer rare earth nickel oxide / titanium carbide heterojunction, calculate the optimal structure of the material, and analyze and calculate the surface binding energy of the infinite-layer rare earth nickel oxide heterojunction;

[0046] S4: Result processing and analysis: The optimized system structure can be displayed by crystal structure visualization software, and the changes in bond length, bond angle and lattice constant of infinite layers composed of different rare earth elements can be analyzed; the charge density diagram, state density diagram, sodium ion migration barrier diagram and electronic conductivity diagram can be drawn to obtain the charge transfer situation between heterojunction layers and specific transfer data. After sodium ions are inserted into the heterojunction interlayer and surface respectively, they are compared with the migration of sodium ions between titanium carbide layers, and the changes in the sodium ion migration barrier caused by the insertion of infinite layers of rare earth elements are analyzed. Finally, the ion conductivity optimization rate is obtained, which provides strong theoretical support for the design of a new infinite layer rare earth nickel oxide as the negative electrode of sodium ion batteries.

[0047] In S3, the computational design of the interface energy of the infinite layer rare earth nickel oxide / titanium carbide heterojunction involves structural optimization of the infinite layer rare earth nickel oxide and titanium carbide surface structure, including the calculation of the electronic structure to ensure that the obtained structure is the most energetically stable. The distribution of electrons is calculated during the structural optimization process to ensure that the interaction energy between atoms is minimized.

[0048] In S4, result processing and analysis, in this step, the optimized system structure will be analyzed, including drawing charge density diagram, state density diagram, sodium ion migration barrier diagram and electronic conductivity diagram. These analyses require calculation of the characteristics of electrons and ions to obtain the charge transfer between heterojunction layers, the change of sodium ion migration barrier and the ion conductivity optimization rate.

[0049] In the specific implementation, the crystal structure visualization software is Materials Studio software, the software for converting the heterojunction structure model into three-dimensional atomic coordinates is VESTA, and the calculation software for electronic properties is VASP (Vienna Ab-initioSimulation Package) software, which is simple to operate, accurate, and relatively general software.

[0050] In the specific implementation, the processing software for processing the data results is P4V software, which is simple to operate, has good performance in processing state density data, and has good accuracy. It is a relatively general software.

[0051] In specific implementation, the calculation process of electronic properties is as follows: first, optimize the material structure, then perform static self-consistent calculations, and then perform property calculations based on the generated charge density data file to minimize the energy of the model structure, ensure the correctness and accuracy of the calculations of each property, and prevent sudden changes in the physical properties of the system.

[0052] In the specific implementation, the design method of infinite layer nickel oxide for regulating the low sodium ion migration barrier adopts a screening method. The screening method is based on the first principle calculation of density functional theory. The screening objects are the concentration of doped Sr and the thickness of the vacuum layer. Considering that the thickness of the vacuum layer and the doping concentration have extremely profound effects on the structural stability of its basic material and the electronic and ionic conductivity, the scientific nature of the screening is improved.

[0053] In the specific implementation, the electronic properties calculation uses the vacuum layer thickness and doped Sr concentration of the heterojunction as variables, and examines the influence of these two variables on the structural stability of the infinite-layer rare earth nickel oxide heterojunction and the sodium ion migration energy barrier, thereby improving the calculation efficiency. The design method for regulating the sodium ion mobility of the infinite-layer rare earth nickel oxide heterojunction model is to describe the interaction between ions and valence electrons by adopting the method of adding plane waves, and the exchange-correlation functional uses the generalized gradient approximation method to ensure that the calculation results of the system achieve sufficient calculation accuracy within the controllable calculation amount.

[0054] In specific implementation, the infinite layer nickel oxide design method for regulating the low sodium ion migration barrier is used for structural optimization. The reciprocal space origin method is used to generate high symmetry points during calculation. This method can quickly generate grid points and avoid special points, thereby improving calculation efficiency.

[0055] In specific implementation, the ion migration barrier characteristics are to select the migration end point and starting point in the infinite layer rare earth nickelate heterojunction, set the connection mode, and insert five fixed migration points to improve its calculation accuracy. And analyze the improvement ratio of its performance compared with the existing sodium ion battery negative electrode materials.

[0056] The characteristics of the design method of the present invention are as follows: (1) Infinite-layer rare earth nickel oxide heterojunction is set up. According to the first-principle calculation method of density functional theory, the structure of the infinite-layer rare earth nickel oxide heterojunction is geometrically optimized and written using the relevant data read from the data manual. (2) The convergence of the model is tested, and several heterojunction models composed of different vacuum layer thicknesses are constructed, and then the convergence of the heterojunction model is tested. During the test, the valence electrons of the material are clearly calculated, the corresponding plane wave cutoff energy is selected according to the material, the size of the grid of the high symmetry point in the reciprocal space is selected, and the convergence standard of the atomic interaction force and the convergence standard of the energy are modified. (3) The heterojunction structure with different doping concentrations is calculated, and its surface binding energy is calculated respectively to select the most stable state and comply with the basic physics principles. (4) According to the charge transfer between the heterojunction layers obtained by calculation, the overall heterojunction differential charge density schematic diagram is calculated and drawn. (5) According to the energy barrier difference of the sodium ion point position obtained by calculation, the overall sodium ion migration energy barrier diagram is calculated and drawn.

[0057] Read the relevant data about infinite layer rare earth nickel oxide from the data book, write the calculation input file, the overall process of the present invention is as follows Figure 1 As shown. An infinite layer rare earth nickel oxide heterojunction model was constructed, and its structure is shown Figure 2 As shown, six different vacuum layers were then used for testing, and the most energy stable state was selected for the next step of calculation. 15%-25% Sr substitution doping was performed on the infinite layer rare earth nickel oxide, and the heterojunction model after doping was constructed to test the structural convergence of the model. During the test, sufficient plane wave cutoff energy was selected according to the concentration of the doping element. When calculating the heterojunction, the reciprocal space grid size was set to 2×2×1, and the convergence criterion for the interaction force between atoms was The energy convergence standard is 1.0×10-6eV / atom. After optimizing the material stability structure, the charge density is calculated to read the charge transfer of each atom in the entire heterojunction, and the interlayer charge transfer is selected to draw the differential density charge diagram. Figure 3 Under the environmental charge and discharge conditions simulating the negative electrode of the sodium ion battery, the migration sites of sodium ions are divided into interlayer migration and surface migration. The specific sodium ion migration barrier data of sodium ions on the surface and between the layers of the infinite layer rare earth nickel oxide heterojunction are as follows: Figure 4 (a)(b) As shown. At the same time, for the convenience of comparison, the titanium carbide simulation calculation of the existing sodium ion negative electrode two-dimensional material was carried out. Figure 4 (c) as shown.

[0058] First, the different vacuum layer thicknesses of the same heterojunction are investigated, and the infinite layer rare earth nickel oxide heterojunction model is used for calculation. Then, 15%-25% Sr is doped and replaced in the infinite layer part, where the replaced element is Nd, and the bond length and bond angle of the Ni-O bond are kept unchanged. The first principle calculation of density functional theory is used to verify and determine the most stable heterojunction model with the lowest surface binding energy. Again, the electronic behavior and ionic behavior calculations are performed to investigate the influence of its atomic microstructure on its sodium ion migration barrier. Finally, data processing and analysis are performed, and we find that the heterojunction structure tends to be the most stable at a vacuum layer thickness of 15 angstroms, and the surface binding energy of the heterojunction is the lowest when the Sr doping concentration is 25%, which means that its material structure is the most stable. The analysis of the electron and ion calculations of the heterojunction shows that the electronegativity difference between titanium and oxygen atoms is between 1.0 and 1.9. According to the bond energy judgment principle, it belongs to an ionic covalent mixed bond. In theory, ionic bonds provide strong electrostatic attraction, while covalent bonds provide strong chemical bonding. This combination can make the compound have a higher binding energy as a whole. The infinite layer rare earth nickel oxide heterojunction shows that its migration barrier is improved by 63% compared with the existing two-dimensional material titanium carbide and has a 26% improvement in dual-channel performance between layers. The screening method is based on the first-principles calculation of density functional theory, and the screening object is the heterojunction model with different vacuum layer thickness and Sr doping concentration. The convergence of the model size is measured, and the influence of the microstructure on the sodium ion migration barrier of the infinite layer rare earth nickel oxide heterojunction is investigated and controlled with the vacuum layer thickness and doping concentration as variables.

[0059] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for designing an infinite layer nickel oxide with a low sodium ion migration barrier, characterized in that: The following steps are involved: S1: Constructing a model of infinite layers of rare earth nickel oxide and titanium carbide: Use crystal structure visualization software to construct a model of perovskite-type infinite layers of rare earth nickel oxide and titanium carbide, and perform cell expansion operations to ensure the consistency of the contact surface area of ​​the two materials; S2: Constructing an infinite layer rare earth nickel oxide / titanium carbide heterojunction model: The expanded model is constructed into an infinite layer rare earth nickel oxide / titanium carbide heterojunction model through crystal structure visualization software and converted into a three-dimensional atomic coordinate file; S3: Calculate the interface energy of infinite layer rare earth nickel oxide / titanium carbide heterojunction: Optimize the surface structures of infinite layer rare earth nickel oxide and titanium carbide respectively to obtain stable surface structure coordinate files. After merging the surface structure coordinate files, add a vacuum layer to isolate the periodic boundary effect, calculate the optimal structure, and analyze the surface binding energy of infinite layer rare earth nickel oxide heterojunction; S4: Result processing and analysis: The optimized system structure is displayed through crystal structure visualization software, and the changes in bond length, bond angle and lattice constant of infinite layers composed of different rare earth elements are analyzed. The charge density diagram, state density diagram, sodium ion migration barrier diagram and electronic conductivity diagram are drawn. The migration barrier of sodium ions between heterojunction layers and the surface and between titanium carbide layers is compared to obtain the change of sodium ion migration barrier, so as to calculate the ion conductivity optimization rate. Based on the ion conductivity optimization rate, infinite layer rare earth nickel oxide is designed as the negative electrode material of sodium ion battery.

2. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S3 and S4, the interface energy, result processing and analysis of the infinite layer rare earth nickel oxide / titanium carbide heterojunction are calculated by calculating the electronic and ionic characteristics. The calculation process of the electronic and ionic characteristics calculation includes: structure optimization, static self-consistent calculation, characteristic calculation based on the generated charge density data file, and ion mobility calculation.

3. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S1 to S4: The crystal structure visualization software is Materials Studio software; The software used to convert the heterojunction structure model into three-dimensional atomic coordinates is VESTA; The computational software for the calculation of electronic and ionic properties is VASP software; The software used to process the data results was P4V and ORIGIN.

4. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S1 to S4: the infinite layer nickel oxide design method for low sodium ion migration barrier adopts a screening method, the screening method is based on the first principle calculation of density functional theory, and the screening object is a heterojunction model with different vacuum layer thicknesses and different Sr doping concentrations.

5. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 4, characterized in that: The screening process includes: changing the doping Sr concentration and the vacuum layer thickness in the heterojunction model to examine the influence of these variables on the stability of the infinite layer nickel oxide heterojunction structure.

6. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S4, when calculating the ionic characteristics, the Na ion migration point is used as a variable, and the change of the variable in the ionic conductivity of the sodium ions migrating between the layers and at different points on the surface is examined.

7. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S3 and S4, the design method of infinite-layer nickel oxide for regulating the low sodium ion migration barrier is to describe the interaction between ions and valence electrons using the method of augmented plane waves, and the exchange-correlation functional uses the generalized gradient approximation method.

8. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S1, perovskite-type rare earth nickel oxide and titanium carbide models are constructed respectively, and then the top oxygen atom of the rare earth nickel oxide is deleted and the cell expansion operation is performed.

9. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S3, during the process of calculating the optimized structure, the high symmetry points were generated using the reciprocal space origin method. During structural optimization, the high symmetry points of the infinite layer rare earth nickel oxide were set to 2×3×5, and the high symmetry points of the titanium carbide were set to 2×3×1.

10. The method for designing an infinite layer nickel oxide with a low sodium ion migration barrier according to claim 1, characterized in that: In S4, the ion mobility calculation process includes: selecting five nearest migration sites between the layers and on the surface of the heterojunction, performing CINEB calculations, calculating each point as a saddle point for migration to the potential energy surface, that is, a transition state, and finally drawing the overall migration barrier.

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