Method, device and storage medium for predicting difficulty of oxygen release of lithium-rich manganese-based positive electrode material

Abstract

The application provides a method and device for predicting the oxygen release difficulty of a lithium-rich manganese-based positive electrode material and a storage medium, and relates to the technical field of new energy. The method simulates the charging process of the material through first-principle calculation, finds the structure of the lithium-rich manganese-based positive electrode material when lithium vacancies appear, makes transition metals migrate within or between layers on the structure to construct oxygen, and then judges the difficulty of oxygen generation of the material through the migration energy barrier of the transition metals. Through the method, the oxygen release difficulty of the lithium-rich manganese-based positive electrode material can be more accurately calculated, the safety and cycle performance of the lithium-rich manganese-based positive electrode material under high voltage can be more accurately predicted, and in theory, the structure which is not easy to generate oxygen can be found, and then the material with the structure is synthesized through experiments, thereby assisting the development of new materials with high safety.

Description

Technical Field

[0001] This application relates to the field of new energy technology, and in particular to methods, equipment and storage media for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials. Background Technology

[0002] With the development of new energy vehicles and other energy storage facilities, the energy density requirements for lithium-ion batteries are increasing. Compared with traditional ternary cathode materials, lithium-rich manganese-based cathode materials have attracted widespread attention due to their theoretical capacity exceeding 300 mAh / g. However, the most advanced research on lithium-rich manganese-based cathode materials has only completed pilot-scale testing. One of the reasons hindering the industrialization of lithium-rich manganese-based cathode materials is the problem of oxygen release under high voltage. Oxygen release under high voltage can seriously affect the safety and cycle life of batteries, requiring in-depth research into the electrochemical mechanism of lithium-rich manganese-based cathode materials and corresponding performance improvements.

[0003] Traditional experimental research struggles to observe the internal structure of materials and elucidate their mechanisms. First-principles calculations, however, can reveal the formation mechanisms of intrinsic properties at the atomic scale, predict physicochemical characteristics, guide experiments, and significantly improve research efficiency. However, current calculations often investigate oxygen stability by calculating oxygen vacancy formation energies. Research has shown that oxygen release is often accompanied by transition metal migration, meaning that intralayer or interlayer migration of transition metals affects oxygen release. Existing calculation methods do not consider the impact of transition metal migration, resulting in inaccurate predictions of oxygen release ease in lithium-rich manganese-based cathode materials and hindering an understanding of the oxygen generation mechanism. Summary of the Invention

[0004] The purpose of this application is to provide a method, apparatus and storage medium for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials, aiming to solve the problem that existing calculation methods do not consider the influence of transition metal migration, resulting in inaccurate predictions of the ease of oxygen release from lithium-rich manganese-based cathode materials and difficulty in understanding the oxygen generation mechanism.

[0005] To achieve the above objectives, this application provides a method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials, comprising:

[0006] The initial cell structure of the lithium-rich manganese-based cathode material was subjected to a delithiation and charging process to generate lithium vacancies, resulting in the first configuration.

[0007] Transition metal ions migrate to the lithium vacancy and generate oxygen, resulting in a second configuration;

[0008] Calculate the migration barrier of the transition metal ion based on the first configuration and the second configuration;

[0009] Predict the ease of oxygen release of the lithium-rich manganese-based cathode material based on the migration energy barrier of the transition metal ions.

[0010] Preferably, the initial unit cell structure is established according to the chemical formula of the lithium-rich manganese-based cathode material; the space group of the lithium-rich manganese-based cathode material is C2 / m, and the chemical formula of the lithium-rich manganese-based cathode material is xLi2MnO3·(1-x)LiTMO2, or Li 1+x TM y Mn 1-x-y O2, where TM is a transition metal, 0 < x < 1, 0 < y < 1; the initial unit cell structure is the configuration with the lowest free energy obtained after structural optimization under this chemical formula.

[0011] Preferably, the process of simulating the charging of the initial unit cell structure of the lithium-rich manganese-based cathode material and generating lithium vacancies to obtain the first configuration includes:

[0012] During each de-lithiation, de-lithiate each lithium ion in the initial unit cell structure and compare the configuration energies after de-lithiation of each lithium ion. The configuration with the lowest free energy is the most stable de-lithiated structure generated by this de-lithiation, and this most stable de-lithiated structure is used as the basis for the next de-lithiation until the charging cut-off voltage is reached and de-lithiation stops.

[0013] Preferably, the lithium vacancies are transition metal layer lithium vacancies or lithium layer lithium vacancies. The process of migrating the transition metal ions to the lithium vacancies and generating oxygen to obtain the second configuration includes:

[0014] Migrate the transition metal ions to the lithium vacancies to generate a cavity in the transition metal layer, and there are isolated oxygen atoms in the cavity;

[0015] Move the isolated oxygen atoms to bond with the surrounding oxygen atoms to generate oxygen, obtaining the second configuration.

[0016] Preferably, the process of moving the isolated oxygen atoms to bond with the surrounding oxygen atoms to generate oxygen and obtaining the second configuration includes:

[0017] Move the isolated oxygen atoms to bond with all the surrounding oxygen atoms respectively, and compare the configuration energies after bonding of each isolated oxygen atom. The configuration with the lowest free energy is the second configuration.

[0018] Preferably, the number of migrated transition metal ions is 2 - 3, and the number of isolated oxygen atoms generated after the migration of the transition metal ions is 1 - 2.

[0019] Preferably, the calculation of the migration energy barrier of the transition metal ions based on the first configuration and the second configuration includes:

[0020] Using the first configuration as the initial configuration and the second configuration as the final configuration, the migration barrier of the transition metal ions is calculated using the climbing image micro-motion elastic method.

[0021] Preferably, predicting the oxygen release ease of the lithium-rich manganese-based cathode material based on the migration barrier of the transition metal ions includes:

[0022] If the migration barrier of the transition metal ions is less than 1 eV, the lithium-rich manganese-based cathode material readily releases oxygen.

[0023] If the migration barrier of the transition metal ions is greater than or equal to 1 eV, then the lithium-rich manganese-based cathode material is unlikely to release oxygen.

[0024] This application also provides an apparatus including a memory and a processor, the memory storing a computer program that, when executed on the processor, performs any of the above-described methods for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials.

[0025] This application also provides a storage medium storing a computer program that, when run on a processor, executes any of the above-described methods for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials.

[0026] Compared with the prior art, the beneficial effects of this application include:

[0027] The method provided in this application for predicting the ease of oxygen release in lithium-rich manganese-based cathode materials uses first-principles calculations to simulate the material charging process, identifying the structure of the lithium-rich manganese-based cathode material when lithium vacancies appear. Oxygen is then generated by the migration of transition metals within or between layers of this structure. The ease of oxygen generation is then determined by the transition metal migration barrier. This method can more accurately calculate the ease of oxygen release in lithium-rich manganese-based cathode materials, more precisely predict the safety and cycle performance of these materials at high voltages, and theoretically assist in identifying structures that are less prone to oxygen generation. This guidance can then lead to the experimental synthesis of materials with such structures, contributing to the development of new, highly safe materials.

[0028] Compared with the calculation method of oxygen vacancy formation energy, this method is more accurate in predicting the ease of oxygen release in lithium-rich manganese-based cathode materials; compared with traditional experiments, this method can quantify the ease of oxygen release in lithium-rich manganese-based cathode materials; and this method helps to understand the mechanism of oxygen generation in lithium-rich manganese-based cathode materials, pointing the way for the next experimental step and greatly reducing experimental trial and error. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation on the scope of this application.

[0030] Figure 1 This is a flowchart illustrating the method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials according to this application.

[0031] Figure 2 A schematic diagram of the initial unit cell structure of a lithium-rich manganese-based cathode material;

[0032] Figure 3 This is a schematic diagram of the (100) and (001) crystal planes of the initial unit cell structure of the lithium-rich manganese-based cathode material of Example 1 of this application;

[0033] Figure 4 This is a schematic diagram of isolated oxygen atoms and formed oxygen generated by the migration of transition metal ions after lithium vacancies are generated in the lithium-rich manganese-based cathode material structure of Embodiment 1 of this application. P1-P4 represent four different migration paths of transition metal ions, and A, B, C, and D represent the cases where isolated oxygen atoms bond with different oxygen atoms around them to generate oxygen.

[0034] Figure 5 This is a schematic diagram of the (100) and (001) crystal planes of the initial unit cell structure of the lithium-rich manganese-based cathode material of Example 2 of this application;

[0035] Figure 6 This is a schematic diagram of isolated oxygen atoms and formed oxygen gas generated by the migration of transition metal ions after lithium vacancies are generated in the lithium-rich manganese-based cathode material structure of Embodiment 2 of this application. P1-P6 represent six different migration paths of transition metal ions, and A, B, and C represent the cases where isolated oxygen atoms bond with different oxygen atoms around them to generate oxygen gas.

[0036] Figure 7 The results are from the in-situ gas generation test of the lithium-rich manganese-based cathode material in Example 1 of this application. Detailed Implementation

[0037] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0038] The components of the embodiments of the invention described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0039] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of the invention, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0040] Furthermore, the terms "first," "second," and "third" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0041] Unless otherwise specified, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which the various embodiments of the invention pertain. Terms (such as those defined in commonly used dictionaries) shall be interpreted as having the same meaning as in their contextual meaning in the relevant technical field and shall not be interpreted as having an idealized or overly formal meaning, unless clearly defined in the various embodiments of the invention.

[0042] This application provides a method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials. Please refer to [link to relevant documentation]. Figure 1 ,include:

[0043] S100: The initial cell structure of the lithium-rich manganese-based cathode material is subjected to a delithiation and charging process to generate lithium vacancies, resulting in the first configuration.

[0044] Among them, the space group of the lithium-rich manganese-based cathode material is C2 / m, and it has a monoclinic phase structure. The lithium-rich manganese-based cathode material can be a two-phase coexisting structure with the chemical formula xLi2MnO3·(1-x)LiTMO2, or it can be a solid solution with the chemical formula Li... 1+x TM y Mn 1-x-y O2, where TM is a transition metal, 0 <x<1,0<y<1。

[0045] The initial unit cell structure of the lithium-rich manganese-based cathode material was derived from its chemical formula. Please refer to [link / reference]. Figure 2, Figure 2 This is a general structural diagram of the initial unit cell structure of lithium-rich manganese-based cathode materials, based on... Figure 2 It is known that the initial cell structure of lithium-rich manganese-based cathode materials is a layered structure, including a transition metal layer, an oxygen layer, and a lithium layer. In the initial cell structure of lithium-rich manganese-based cathode materials with the same chemical formula, the atomic arrangement of the lithium layer and oxygen layer is the same; the difference lies in the different atomic arrangements of the transition metal layer.

[0046] Under the same chemical formula, the free energy of the initial unit cell structure will be different due to the different atomic arrangements of the transition metal layer. By comparing the free energy of the configurations obtained by different atomic arrangements of the transition metal layer, the configuration with the lowest free energy, i.e. the most stable configuration, is selected as the initial unit cell structure of the lithium-rich manganese-based cathode material.

[0047] In the process of simulating delithiation charging of the initial cell structure of lithium-rich manganese-based cathode material, each lithium ion in the initial cell structure is delithiated during each delithiation, and the configuration energy of each lithium ion after delithiation is compared. The configuration with the lowest free energy is the most stable delithiation structure generated in that delithiation, and the most stable delithiation structure is used as the basis for the next delithiation until the charging cutoff voltage is reached and delithiation stops.

[0048] To illustrate this, consider the first delithiation of the initial unit cell structure. Each of the N lithium ions in the initial unit cell structure is delithiated individually, resulting in N configurations that remove one lithium ion. The free energies of these N configurations are compared, and the configuration with the lowest free energy is the most stable delithiation structure produced in the first delithiation. The number of lithium ions in this structure is N-1.

[0049] Based on the most stable delithiation structure generated by the first delithiation, a second delithiation is performed on the structure, delithiating each of the N-1 lithium ions individually, resulting in N-1 configurations that remove two lithium ions. The free energies of these N-1 configurations are compared, and the configuration with the lowest free energy is taken as the most stable delithiation structure generated by the second delithiation, which contains N-2 lithium ions.

[0050] Based on the most stable delithiation structure generated by the second delithiation, a third delithiation is performed on the structure, delithiating each of the N-2 lithium ions individually, resulting in N-2 configurations with three lithium ions removed. The free energies of these N-2 configurations are compared, and the configuration with the lowest free energy is taken as the most stable delithiation structure generated by the third delithiation, which contains N-3 lithium ions.

[0051] This process continues until the charging cutoff voltage is reached, at which point lithium removal stops. The structure formed by the complete lithium removal and the creation of lithium vacancies is the first configuration. For lithium-rich manganese-based cathode materials, the charging cutoff voltage must be greater than 4.5V. The number of lithium ions removed at this voltage is the minimum number of ions that must be removed. For example, lithium removal can be stopped after removing 18, 20, 22, 24, 26, or 28 ions, etc. When lithium removal reaches a certain level, such as after removing 16, 18, 20, or 22 ions, lithium vacancies will appear. These vacancies can be lithium vacancies in the lithium layer or in the transition metal layer. When lithium removal reaches a certain level, lithium ions in the transition metal layer will migrate to or be extracted from the lithium layer, resulting in lithium vacancies in the transition metal layer.

[0052] It is understandable that when the number of lithium vacancies generated by the transition metal layer is less than 3, isolated oxygen atoms will not appear after the transition metal migrates. Therefore, the number of lithium vacancies generated by the transition metal layer should be greater than or equal to 3.

[0053] S200: Transition metal ions migrate to lithium vacancies and generate oxygen, resulting in the second configuration.

[0054] Specifically, the lithium vacancy is a lithium vacancy in the transition metal layer or a lithium vacancy in the lithium layer, and this step includes:

[0055] Step 1: Transition metal ions migrate to lithium vacancies, creating cavities within the transition metal layer, and these cavities contain isolated oxygen atoms. It's understandable that to produce oxygen, isolated oxygen atoms must first be generated; isolated oxygen atoms are those without any ions to form bonds with them. Figure 4 In this case, four vacancies produce two isolated oxygen atoms, such as... Figure 6 In this process, three vacancies create one isolated oxygen atom. Every possible migration path by which a transition metal ion can generate an isolated oxygen atom after migrating to a lithium vacancy must be considered, such as... Figure 4 The document shows four migration paths, such as Figure 6 Six migration paths are shown. Among them, the cavity can be viewed as a triangle, quadrilateral or other irregular polygon when viewed from the (001) crystal plane.

[0056] In this process, 2-3 transition metal ions migrate, and 1-2 isolated oxygen atoms are generated after the transition metal ions migrate. Specifically, when there are 3 lithium vacancies, 2 transition metal ions need to migrate and 1 isolated oxygen atom is generated; when there are 4 lithium vacancies, 4 transition metal ions need to migrate and 2 isolated oxygen atoms are generated.

[0057] Step 2: Move the isolated oxygen atom to form bonds with the surrounding oxygen atoms to produce oxygen gas, thus obtaining the second configuration.

[0058] Specifically, isolated oxygen atoms are moved to form bonds with all surrounding oxygen atoms, and the configuration energies of each isolated oxygen atom after bonding are compared. The configuration with the lowest free energy is designated as the second configuration. The first configuration is the configuration before the transition metal migration, and the second configuration is the configuration after the transition metal migration.

[0059] S300: Calculate the migration barrier of transition metal ions based on the first and second configurations.

[0060] In this study, the first configuration was used as the initial configuration, and the second configuration was used as the final configuration. The migration barrier of the transition metal ion was calculated using the climbing image microelasticity method (CI-NEB). Based on the initial and final configurations, the trajectory of the configuration change can be obtained, thus yielding the transition configuration. The migration barrier of the transition metal ion is then obtained based on the free energies of the transition configuration and the initial configuration.

[0061] S400: Predicting the ease of oxygen release in lithium-rich manganese-based cathode materials based on the migration energy barrier of transition metal ions.

[0062] If the migration barrier of transition metal ions is less than 1 eV, then lithium-rich manganese-based cathode materials are prone to releasing oxygen.

[0063] If the migration barrier of transition metal ions is greater than or equal to 1 eV, then lithium-rich manganese-based cathode materials are unlikely to release oxygen.

[0064] The method provided in this application for predicting the ease of oxygen release in lithium-rich manganese-based cathode materials uses first-principles calculations to simulate the material charging process, identifying the structure of the lithium-rich manganese-based cathode material when lithium vacancies appear. Oxygen is then generated by the migration of transition metals within or between layers of this structure. The ease of oxygen generation is then determined by the transition metal migration barrier. This method can more accurately calculate the ease of oxygen release in lithium-rich manganese-based cathode materials, more precisely predict the safety and cycle performance of these materials at high voltages, and theoretically assist in identifying structures that are less prone to oxygen generation. This guidance can then lead to the experimental synthesis of materials with such structures, contributing to the development of new, highly safe materials.

[0065] Compared with the calculation method of oxygen vacancy formation energy, this method is more accurate in predicting the ease of oxygen release in lithium-rich manganese-based cathode materials; compared with traditional experiments, this method can quantify the ease of oxygen release in lithium-rich manganese-based cathode materials; and this method helps to understand the mechanism of oxygen generation in lithium-rich manganese-based cathode materials, pointing the way for the next experimental step and greatly reducing experimental trial and error.

[0066] The device in this embodiment includes a memory and a processor. The memory stores a computer program, which, in conjunction with the processor, is used to execute the method described in the above embodiment for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials. The implementation schemes and beneficial effects involved in the above embodiments are also applicable in this embodiment, and will not be repeated here.

[0067] This application also provides a storage medium storing a computer program that, when run on a processor, executes the method described in the above embodiments for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials. The implementation schemes and beneficial effects involved in the above embodiments are also applicable in this embodiment and will not be repeated here.

[0068] The implementation schemes of this application will be described in detail below with reference to specific embodiments. However, those skilled in the art will understand that the following embodiments are only for illustrating this application and should not be regarded as limiting the scope of this application. Unless otherwise specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments used without specified manufacturers are all conventional products that can be purchased commercially.

[0069] Example 1

[0070] Example 1 provides a method for predicting Li 1.17 Ni 0.17 Fe 0.17 Mn 0.49 The method for facilitating oxygen release from O2 cathode materials includes the following steps:

[0071] (1) For Li 1.17 Ni 0.17 Fe 0.17 Mn 0.49 O2 cathode material is processed into a 2×2×1 supercell to obtain Li 28 Ni4Fe4Mn 12 O 48 The initial unit cell structure was determined, and structural optimization was performed, such as... Figure 3 As shown.

[0072] (2) For Li 28 Ni4Fe4Mn 12 O 48 The initial unit cell structure begins to gradually delithiate; in this embodiment, the planar cutoff energy is set to 500 eV; the energy convergence is set to 1 × 10⁻⁶ eV. -4 eV; maximum force convergence is set to eV; For all transition metals, an antiferromagnetic state was selected; the Brillouin zone K point was set to 4×2×8; and the U values ​​for the transition metals Mn, Fe, and Ni in the structure were selected to be 4.9 eV, 4.9 eV, and 6.0 eV, respectively.

[0073] (3) When the structure is de-lithiated by 22 lithium atoms (molecular formula is Li6Ni4Fe4Mn) 12 O 48 Four lithium vacancies appeared in the transition metal layer. Manually moving transition metal ions to these vacancies resulted in isolated oxygen atoms, such as... Figure 4 As shown, there are a total of 4 migration paths.

[0074] (4) Move the oxygen atom to form bonds with the oxygen atoms on the surrounding octahedrons to produce oxygen gas, such as... Figure 4 As shown.

[0075] (5) Perform relaxation calculations on the structure generated in step (4) to determine the energy, and find the structure with the lowest energy as the final state structure for the transition state calculation in this step. Then calculate the energy of Li6Ni4Fe4Mn. 12 O 48 The energy barrier required for transition metal migration in the structure is determined to assess the difficulty of oxygen release. This step uses the CI-NEB method, with the following calculation parameters: plane cutoff energy set to 500 eV; energy convergence set to 1 × 10⁻⁶ eV. -7 eV; maximum force convergence is set to eV; The Brillouin zone K point was set to 2×1×4; the number of interpolation points was 5. The migration barriers of the transition metal ions calculated in Example 1 were P1: 0.778 eV, P2: 0.735 eV, P3: 0.691 eV and P4: 0.832 eV, as shown in Table 1, indicating that oxygen release is likely to occur at this time (migration barrier less than 1 eV).

[0076] Example 2

[0077] Example 2 provides a method for predicting Li 1.13 Ni 0.21 Fe 0.21 Mn 0.45 The method for facilitating oxygen release from O2 cathode materials includes the following steps:

[0078] (1) For Li 113 Ni 021 Fe 021 Mn 045 O2 cathode material is processed into a 2×2×1 supercell to obtain Li 27 Ni5Fe5Mn 11 O 48 The initial unit cell structure was determined, and structural optimization was performed, such as... Figure 5 As shown.

[0079] (2) For Li 27 Ni5Fe5Mn 11 O 48The initial unit cell structure begins to gradually delithiate; in this embodiment, the planar cutoff energy is set to 500 eV; the energy convergence is set to 1 × 10⁻⁶ eV. -4 eV; maximum force convergence is set to eV; For all transition metals, an antiferromagnetic state was selected; the Brillouin zone K point was set to 4×2×8; and the U values ​​for the transition metals Mn, Fe, and Ni in the structure were selected to be 4.9 eV, 4.9 eV, and 6.0 eV, respectively.

[0080] (3) When the structure is de-lithiated by 20 lithium atoms (molecular formula is Li7Ni5Fe5Mn) 11 O 48 Three lithium vacancies appeared in the transition metal layer. Manually moving transition metal ions to these vacancies resulted in isolated oxygen atoms, such as... Figure 6 As shown, there are a total of 6 migration paths.

[0081] (4) Move the oxygen atom to form bonds with the oxygen atoms on the surrounding octahedrons to produce oxygen gas, such as... Figure 6 As shown.

[0082] (5) Perform relaxation calculations on the structure generated in step (4) to determine the energy of the structure with the lowest energy. Then, calculate the energy of Li7Ni5Fe5Mn. 11 O 48 The energy barrier required for transition metal migration in the structure is determined to assess the difficulty of oxygen release. This step uses the CI-NEB method, with the following calculation parameters: plane cutoff energy set to 500 eV; energy convergence set to 1 × 10⁻⁶ eV. -7 eV; maximum force convergence is set to eV; The Brillouin zone K-point was set to 2×1×4; the number of interpolation points was 5. The migration barriers of the transition metal ions calculated in Example 2 were P1: 2.762 eV, P2: 2.614 eV, P3: 2.412 eV, P4: 2.476 eV, P5: 3.143 eV and P6: 2.753 eV, as shown in Table 1, indicating that oxygen release is not likely to occur at this time (migration barrier greater than 1 eV).

[0083] Comparative Example 1

[0084] The difference between Comparative Example 1 and Example 1 is that the calculation of Li6Ni4Fe4Mn starts from step (2). 12 O 48 The vacancy formation energy of the most active oxygen is 0.327 eV, indicating that the material has not yet released oxygen at this time, as shown in Table 1.

[0085] Since the predicted conclusions of Example 1 and Comparative Example 1 differed, gas production was subsequently studied using an in-situ electrochemical mass spectrometer. First, the material from Example 1 and a lithium metal anode were assembled into a half-cell in a glove box using a mold compatible with the in-situ mass spectrometer and left to stand for approximately 10 hours. Then, the molded battery was connected to both the in-situ electrochemical mass spectrometer and the electrochemical workstation. Before charging, the pipeline was purged with argon gas for approximately one hour to eliminate interference from air in the instrument and gas path. After the purging process, charging, discharging, and oxygen detection were initiated. The results are as follows: Figure 7 As shown, the material begins to release oxygen after about 7 hours. This result is consistent with the prediction in Example 1, indicating that the method of predicting the ease of oxygen release from lithium-rich manganese-based cathode materials in this application is more accurate.

[0086] Table 1. Migration barriers of transition metal ions and difficulties in oxygen release.

[0087]

[0088] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials, characterized in that, include: The initial cell structure of the lithium-rich manganese-based cathode material was subjected to a delithiation and charging process to generate lithium vacancies, resulting in the first configuration. Transition metal ions migrate to the lithium vacancy and generate oxygen, resulting in a second configuration; Calculate the migration barrier of the transition metal ion based on the first configuration and the second configuration; The ease of oxygen release from the lithium-rich manganese-based cathode material is predicted based on the migration energy barrier of the transition metal ions. The process of performing a delithiation and simulated charging on the initial cell structure of the lithium-rich manganese-based cathode material to generate lithium vacancies and obtain a first configuration includes: During each delithiation, each lithium ion in the initial unit cell structure is delithiated, and the configuration energy of each lithium ion after delithiation is compared. The configuration with the lowest free energy is the most stable delithiation structure generated in that delithiation, and the most stable delithiation structure is used as the basis for the next delithiation until the charging cutoff voltage is reached to stop delithiation. The lithium vacancy is a transition metal layer lithium vacancy or a lithium layer lithium vacancy. The process of migrating transition metal ions to the lithium vacancy and generating oxygen to obtain the second configuration includes: The transition metal ions are migrated to the lithium vacancies, creating cavities in the transition metal layer, and isolated oxygen atoms are present in the cavities. The isolated oxygen atom is moved to form bonds with surrounding oxygen atoms to produce oxygen, thus obtaining the second configuration; The step of moving the isolated oxygen atom to form bonds with surrounding oxygen atoms to produce oxygen gas, thereby obtaining the second configuration, includes: The isolated oxygen atom is moved to form bonds with all the surrounding oxygen atoms, and the configuration energies of each isolated oxygen atom after bonding are compared. The configuration with the lowest free energy is selected as the second configuration.

2. The method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials according to claim 1, characterized in that, The initial unit cell structure is established according to the chemical formula of the lithium-rich manganese-based cathode material; the space group of the lithium-rich manganese-based cathode material is C2 / m, and the chemical formula of the lithium-rich manganese-based cathode material is xLi2MnO3•(1-x)LiTMO2, or Li 1+x TM y Mn 1-x-y O2, where TM is a transition metal, 0 < x < 1, 0 < y < 1; the initial unit cell structure is the configuration with the lowest free energy obtained after structural optimization under this chemical formula.

3. The method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials according to claim 1, characterized in that, The number of migrations of the transition metal ions is 2-3, and the number of isolated oxygen atoms generated after the migration of the transition metal ions is 1-2.

4. The method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials according to any one of claims 1-3, characterized in that, The calculation of the migration barrier of the transition metal ion based on the first configuration and the second configuration includes: Using the first configuration as the initial configuration and the second configuration as the final configuration, the migration barrier of the transition metal ions is calculated using the climbing image micro-motion elastic method.

5. The method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials according to claim 1, characterized in that, The method of predicting the oxygen release ease of the lithium-rich manganese-based cathode material based on the migration barrier of the transition metal ions includes: If the migration barrier of the transition metal ions is less than 1 eV, the lithium-rich manganese-based cathode material readily releases oxygen. If the migration barrier of the transition metal ions is greater than or equal to 1 eV, then the lithium-rich manganese-based cathode material is unlikely to release oxygen.

6. A device, characterized in that, The method includes a memory and a processor, the memory storing a computer program that, when executed on the processor, performs the method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials as described in any one of claims 1 to 5.

7. A storage medium, characterized in that, It stores a computer program that, when run on a processor, executes the method for predicting the ease of oxygen release from lithium-rich manganese-based cathode materials as described in any one of claims 1 to 5.

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