High-entropy layered oxide material with anion-cation covalency, preparation method, and use thereof

Abstract

The present invention discloses a high entropy layered oxide material with covalent cation and anion valence, a preparation method and a use thereof. The general chemical formula of the high entropy layered oxide material is: Na a [Li b Mg c Ni d Mn e M f ]O 2+β ; Wherein, M is a transition metal element, including one or more elements selected from Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W; a, b, c, d, e, f, and 2+β are the molar percentages of the corresponding elements respectively; the relationship between a, b, c, d, e, f, and 2+β satisfies b+c+d+e+f=1, and a+b+2c+2d+4e+mf=2(2+β); wherein 0.85≤a≤1; 0.05≤b≤0.2; 0.05≤c≤0.2; 0.05≤d≤0.2; 0.2≤e≤0.6; 0.05≤f≤0.2; 0≤β≤0.1, and m is the valence state of M; and a, b, c, d, e, and f satisfy the definition of high entropy, that is, the formula: wherein R is the gas constant, N≥6, and x i is any value among a, b, c, d, e, and f; the high entropy layered oxide material is an O3 phase layered oxide material, and the space group is a high entropy layered oxide material used for positive electrode active materials of sodium ion secondary batteries.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a high-entropy layered oxide material with covalent valence of anions and cations, a preparation method and an application thereof. Background Art

[0002] Under the background of "dual carbon", the development of sustainable clean energy (such as wind power, solar power and tidal power) is of great significance to reducing carbon emissions. However, these renewable energy sources are greatly restricted by natural conditions and have characteristics such as intermittent and fluctuating nature. As the most efficient and convenient energy storage and conversion devices, high-performance secondary batteries are crucial to the establishment of a clean energy system and the realization of large-scale energy storage. Among the many energy storage technologies, physical energy storage such as pumped storage, compressed air energy storage and flywheel energy storage are all limited by factors such as geographical location and actual conditions. In contrast, electrochemical energy storage has the advantages of easy modularization, high energy conversion efficiency, high flexibility and environmental friendliness. It is one of the most promising energy storage methods and an important guarantee for achieving the dual carbon goals.

[0003] Among electrochemical energy storage technologies, lithium-ion batteries (LIBs) are currently widely used in daily life due to their high energy density, long cycle life, small size, light weight, and pollution-free properties. However, lithium reserves in the Earth's crust are relatively low, with more than half of the world's lithium resources located in South America. my country relies on imports for 80% of its lithium resources, and the price of lithium carbonate has been rising annually, from approximately 50,000 yuan per ton in 2015 to approximately 500,000 yuan per ton today (2022). Consequently, LIBs, limited by their resource availability, are unable to simultaneously support the development of electric vehicles and large-scale energy storage. Sodium-ion batteries, with their abundant resources, widespread distribution, and low cost, are considered a promising complement to LIBs and an ideal device for large-scale energy storage applications. The research and development of LIB technology is of strategic importance and has garnered renewed attention in recent years.

[0004] The development of high-performance electrode materials is crucial to the commercialization of sodium-ion batteries. In particular, cathode materials play a decisive role in the overall energy density and electrochemical performance of batteries. To date, the research on sodium-ion cathode materials is still in the early stages of laboratory exploration. Currently, the research on cathode materials mainly focuses on transition metal oxides Na with layered structures. x MO2 (M represents one or more of 3d or 4d transition metals). Further improving the specific capacity and energy density of layered oxide materials is an effective means to reduce costs and unlock more application scenarios for sodium-ion batteries. Inspired by the high specific capacity of lithium-ion battery "lithium-rich" positive electrodes provided by anionic redox, activating the redox of lattice oxygen in sodium-based oxides has opened up new strategies for improving the energy density of sodium-ion batteries. For example, P2-type Na 0.72 Li0.24 Mn 0.76 As a positive electrode material for sodium-ion batteries, O2 has a high reversible specific capacity (270mAh / g) and a maximum energy density (700Wh / kg) between 1.5V and 4.5V. However, triggering the redox of lattice oxygen with a higher capacity usually requires a higher charge cutoff voltage (4.4V), resulting in unnecessary structural degradation and serious side reactions. Therefore, most oxygen valence-varying material electrodes have practical problems such as kinetic hysteresis, voltage hysteresis, oxygen release, and severe capacity decay. These problems have greatly hindered the practical application of oxygen valence-varying materials in sodium-ion batteries. Summary of the Invention

[0005] The embodiment of the present invention provides a high-entropy layered oxide material with co-valence of anions and cations, as well as a preparation method and use. The present invention is mainly based on the valence change of electrochemically active transition metal cations and anions (lattice oxygen) to provide charge compensation during the charging and discharging process; the configuration of the transition metal high entropy enables the material to have excellent structural stability and long cycle performance. The half-cell assembled with the positive electrode prepared by using the material and the metal sodium negative electrode has basically no capacity decay after 400 cycles, and the cycle life is 4 to 5 times that of ordinary oxygen valence change materials, indicating that it has excellent cycle stability and cycle life, and has great practical use value. In addition, the preparation method of the high-entropy layered oxide material of the present invention is simple. Sodium ion batteries containing the high-entropy layered oxide material of the present invention can be used in large-scale energy storage equipment such as solar power generation, wind power generation, smart grid peak regulation, distributed power stations, backup power supplies or communication base stations.

[0006] In the first aspect, the embodiment of the present invention provides a high entropy layered oxide material with covalent cation and anion valence, the chemical formula of the high entropy layered oxide material is: Na a [Li b Mg c Ni d Mn e M f ]O 2+β ;

[0007] Wherein, M is a transition metal element, including one or more elements selected from Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W; a, b, c, d, e, f, and 2+β are the molar percentages of the corresponding elements, respectively; the relationship between a, b, c, d, e, f, and 2+β satisfies b+c+d+e+f=1, and a+b+2c+2d+4e+mf=2(2+β); wherein 0.85≤a≤1; 0.05≤b≤0.2; 0.05≤c≤0.2; 0.05≤d≤0.2; 0.2≤e≤0.6; 0.05≤f≤0.2; and 0≤β≤0.1, and m is the valence state of M;

[0008] And a, b, c, d, e, f meet the definition of high entropy, that is, they meet the formula:

[0009]

[0010] Where R is the gas constant, N≥6, x i Any value among a,b,c,d,e,f;

[0011] The high entropy layered oxide material is an O3 phase layered oxide material, and the space group is

[0012] The high-entropy layered oxide material is used as a positive electrode active material for a sodium ion secondary battery. During the first cycle of charging, the electrochemically active M transition metal ions first lose electrons, followed by oxygen ions in the lattice losing electrons, and the average valence of the oxygen ions increases from -2 to a valence between -2 and -1. During the first cycle of discharge, the electrochemically active M transition metal ions and the oxygen ions with a higher valence regain electrons. Starting from the second cycle, the oxygen ions and the electrochemically active M transition metal ions gain and lose electrons during the charge and discharge process.

[0013] In a second aspect, an embodiment of the present invention provides a method for preparing the high-entropy layered oxide material with covalent anion and cation valence as described in the first aspect above, wherein the method is a solid-phase method, comprising:

[0014] A sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a lithium source material having a stoichiometric amount of 100% to 108% of the required lithium, a magnesium source material, a nickel source material, a manganese source material and a compound of M in the required stoichiometric amount are mixed in proportion, and the mixture is uniformly mixed to obtain a precursor powder;

[0015] The obtained precursor powder is placed in a crucible, placed in a high-temperature furnace, and heat-treated in an air atmosphere. After cooling and discharging, the material is ground to obtain a high-entropy layered oxide material with co-valence of anions and cations.

[0016] Preferably, the sodium source material is sodium carbonate;

[0017] The lithium source material includes lithium carbonate and / or lithium hydroxide;

[0018] The magnesium source material includes magnesium oxide and / or magnesium carbonate;

[0019] The nickel source material is nickel oxide;

[0020] The manganese source material is manganese dioxide and / or manganese trioxide;

[0021] The compound of M includes an oxide of M and / or a carbonate of M, wherein M is a transition metal element, including one or more elements selected from the group consisting of Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W;

[0022] The method of uniform mixing is grinding mixing or ball milling mixing;

[0023] The heat treatment specifically includes heat treatment at a temperature of 800° C. to 1000° C. for 2 hours to 24 hours.

[0024] In a third aspect, an embodiment of the present invention provides a method for preparing the high-entropy layered oxide material with covalent anion and cation valence as described in the first aspect above, wherein the method is a sol-gel method, comprising:

[0025] A sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a water-soluble salt or tetrabutyl titanate containing lithium having a stoichiometric amount of 100% to 108% of the required lithium, and a water-soluble salt or tetrabutyl titanate containing magnesium, nickel, manganese, and M having a stoichiometric amount are dissolved in a solvent, and citric acid is added to form a precursor gel;

[0026] The precursor gel is placed in a crucible, placed in a high-temperature furnace, and subjected to low-temperature pretreatment in an air atmosphere to obtain a pretreated powder;

[0027] The pretreated powder is subjected to high-temperature heat treatment in an air atmosphere, and after cooling and discharging, the powder is ground to obtain a high-entropy layered oxide material with co-valence of anions and cations.

[0028] Preferably, the sodium source material is one or more of sodium acetate, sodium nitrate, sodium carbonate, and sodium sulfate;

[0029] M is a transition metal element, including one or more elements selected from Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W;

[0030] The solvent includes anhydrous ethanol or deionized water;

[0031] The low temperature pretreatment is specifically: pre-calcining at a temperature of 250°C-500°C for 2 hours-6 hours;

[0032] The high temperature heat treatment specifically includes heat treatment at 800° C.-1000° C. for 2 hours-24 hours.

[0033] In a fourth aspect, an embodiment of the present invention provides a method for preparing the high-entropy layered oxide material with covalent anion and cation valence as described in the first aspect above, the method being a spray drying method, comprising:

[0034] A sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a lithium source material having a stoichiometric amount of 100% to 108% of the required lithium, a magnesium source material, a nickel source material, a manganese source material and a compound of M having a stoichiometric amount thereof are mixed in proportion, and the mixture is uniformly mixed to obtain a precursor;

[0035] Adding a certain proportion of solvent to the precursor and stirring evenly to form a slurry;

[0036] The slurry is placed in a spray dryer for spray drying to obtain a precursor powder;

[0037] The precursor powder is placed in a crucible, placed in a high-temperature furnace, and subjected to heat treatment in an air atmosphere;

[0038] The heat-treated precursor powder is ground to obtain a high-entropy layered oxide material.

[0039] Preferably, the sodium source material is sodium carbonate;

[0040] The lithium source material includes lithium carbonate and / or lithium hydroxide;

[0041] The magnesium source material includes magnesium oxide and / or magnesium carbonate;

[0042] The nickel source material is nickel oxide;

[0043] The manganese source material is manganese dioxide and / or manganese trioxide;

[0044] The compound of M includes an oxide of M and / or a carbonate of M, wherein M is a transition metal element, including one or more elements selected from the group consisting of Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W;

[0045] The method of uniform mixing is grinding mixing or ball milling mixing;

[0046] The solvent includes anhydrous ethanol or deionized water;

[0047] The heat treatment method is specifically: heat treatment at a temperature of 800°C-1000°C for 2 hours-24 hours;

[0048] The inlet temperature of the spray dryer is 150° C.-190° C., the outlet temperature is 70° C.-100° C., and the feed rate is 200 mL / h-600 mL / h.

[0049] In a fifth aspect, an embodiment of the present invention provides a positive electrode plate for a sodium ion secondary battery, the positive electrode plate comprising: a current collector, a conductive additive and a binder coated on the current collector, and the high-entropy layered oxide material with co-variable valence of anions and cations as described in the first aspect above.

[0050] In a sixth aspect, an embodiment of the present invention provides a sodium ion secondary battery, wherein the sodium ion secondary battery comprises the positive electrode sheet described in the fifth aspect.

[0051] In a seventh aspect, an embodiment of the present invention provides a use of the sodium ion secondary battery described in the sixth aspect above, wherein the sodium ion secondary battery is used in mobile devices, vehicles, renewable energy power generation, smart grid peak regulation, distributed power stations, backup power supplies or energy storage devices for communication base stations.

[0052] The transition metal layers of the high-entropy layered oxide material with covalent anion and cation valence provided by the present invention exhibit a disordered distribution of elements. During charging, nickel and M transition metal elements provide charge compensation first, followed by lattice oxygen. The high-entropy configuration of the transition metal effectively reduces the onset voltage of oxygen valence change, allowing the material to complete the charging process when charged to 4.2V, avoiding the severe decomposition of the electrolyte caused by charging above 4.2V required for conventional oxygen valence change materials, and providing a specific capacity of approximately 200mAh / g. In addition, the high-entropy configuration can mitigate structural changes in the material, resulting in excellent structural stability. Ultimately, the material exhibits excellent long-term cycling stability, maintaining a capacity retention rate of over 95% after 400 cycles under 1C charge and discharge conditions, demonstrating significant practical value. Sodium-ion secondary batteries using the high-entropy layered oxide material of the present invention can be used for smart grid peak regulation, backup power supplies, or large-scale energy storage devices for communication base stations, such as renewable energy generation.

[0053] The method for preparing a high-entropy layered oxide material with covalent cation and anion valence provided by the embodiment of the present invention is simple to operate and easy to achieve large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The technical solutions of the embodiments of the present invention are further described in detail below through the accompanying drawings and examples.

[0055] Figure 1 A schematic diagram of high entropy configuration of interlayer elements in a high entropy layered oxide material provided by an embodiment of the present invention;

[0056] Figure 2 A flow chart of a method for preparing a high-entropy layered oxide material by a solid-phase method according to an embodiment of the present invention;

[0057] Figure 3 A flow chart of a method for preparing high-entropy layered oxide materials by a sol-gel method according to an embodiment of the present invention;

[0058] Figure 4 A flow chart of a method for preparing a high-entropy layered oxide material by a spray drying method according to an embodiment of the present invention;

[0059] Figure 5 X-ray diffraction (XRD) patterns of the high-entropy layered oxide materials provided in Examples 1-5 of the present invention;

[0060] Figure 6 A spherical aberration-corrected transmission electron microscope image of the high-entropy layered oxide material provided in Example 1 of the present invention in the (100) crystal orientation;

[0061] Figure 7 A charge and discharge curve diagram of the first week of a sodium ion secondary battery provided in Example 1 of the present invention;

[0062] Figure 8 A cycle capacity curve diagram of a sodium ion secondary battery provided in Example 1 of the present invention;

[0063] Figure 9 A charge and discharge curve diagram of the first week of a sodium ion secondary battery provided in Example 2 of the present invention;

[0064] Figure 10 This is a charge and discharge curve diagram of the first week of a sodium ion secondary battery provided in Example 3 of the present invention.

[0065] Figure 11 A charge and discharge curve diagram of the first week of a sodium ion secondary battery provided in Example 4 of the present invention;

[0066] Figure 12 A charge and discharge curve diagram of the first week of a sodium ion secondary battery provided in Example 5 of the present invention;

[0067] Figure 13 This is a charge and discharge curve diagram of the first week of a sodium ion secondary battery provided in Example 6 of the present invention. DETAILED DESCRIPTION

[0068] The present invention will be further described in detail below with reference to the embodiments, but it is not intended to limit the scope of protection of the present invention.

[0069] The embodiment of the present invention provides a high entropy layered oxide material with covalent cation and anion valence, the general chemical formula of which is: Na a [Li b Mg c Ni d Mn e M f ]O 2+β; Wherein, M is a transition metal element, including one or more elements selected from Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W; a, b, c, d, e, f, and 2+β are respectively the molar percentages of the corresponding elements; the relationship between a, b, c, d, e, f, and 2+β satisfies b+c+d+e+f=1, and a+b+2c+2d+4e+mf=2(2+β); wherein 0.85≤a≤1; 0.05≤b≤0.2; 0.05≤c≤0.2; 0.05≤d≤0.2; 0.2≤e≤0.6; 0.05≤f≤0.2; 0≤β≤0.1, and m is the valence state of M.

[0070] And the above a, b, c, d, e, f must meet the definition of high entropy, that is, meet the requirements of the following formula:

[0071]

[0072] Where R is the gas constant, N≥6, x i It can be any value among a,b,c,d,e,f.

[0073] It should be noted that the gas constant is equivalent to the Boltzmann constant, and its value is 8.314 J / (mol·K).

[0074] x1…x N represent the molar percentages of Na, Li, Mg, Ni, Mn, and M, respectively.

[0075] In the above formula, x i lnx i It is a repeatable value that reflects the disorder of Li, Mg, Ni, Mn, and M transition metal elements in the transition metal layer of the high entropy layered oxide.

[0076] Schematic diagram of transition metal high entropy configuration, such as Figure 1 As shown in the figure, M1, M2, M3, M4, M5, and M6 represent transition metals Mn, Ni, Li, Mg, and two of the above-mentioned transition metal elements M, respectively. It can be seen that the transition metal layer contains at least 5 or more different transition metal elements, and the arrangement of elements in each layer is irregular, and the types of elements can be repeated.

[0077] The present invention adopts the above-mentioned transition metal high entropy configuration. During the charge and discharge process, due to the high disorder in the types and arrangements of the transition metal elements, some elements change valence while some elements do not change valence during the cycle, which can slow down the change in unit cell volume to avoid lattice collapse, and further alleviate the structural changes of the material, so that the high entropy layered oxide material of the present invention exhibits excellent structural stability.

[0078] The high entropy layered oxide material of the present invention is an O3 phase layered oxide material, and the space group is

[0079] The high-entropy layered oxide material is used as the positive electrode active material of a sodium-ion secondary battery. During the first cycle of charging, the electrochemically active M transition metal ions first lose electrons, followed by the oxygen ions in the lattice losing electrons, and the average valence of the oxygen ions increases from -2 to a valence between -2 and -1; during the first cycle of discharge, the electrochemically active M transition metal ions and the oxygen ions with a higher valence regain electrons; starting from the second cycle, the oxygen ions and the electrochemically active M transition metal ions gain and lose electrons during the charge and discharge process.

[0080] The embodiments of the present invention provide three methods for preparing the above-mentioned high-entropy layered oxide material: solid phase method, sol-gel method and spray drying method. The preparation method for obtaining the material is described below.

[0081] The embodiment of the present invention provides a method for preparing the above-mentioned high entropy layered oxide material with covalent cation and anion valence, which is a solid phase method, such as Figure 2 As shown, the specific steps include:

[0082] Step 210, mixing a sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a lithium source material having a stoichiometric amount of 100% to 108% of the required lithium, a magnesium source material, a nickel source material, a manganese source material, and a compound of M in the required stoichiometric amounts in proportion, and mixing them uniformly to obtain a precursor powder;

[0083] Wherein, the sodium source material is sodium carbonate; the lithium source material includes lithium carbonate and / or lithium hydroxide; the magnesium source material includes magnesium oxide and / or magnesium carbonate; the nickel source material is nickel oxide; and the manganese source material is manganese dioxide and / or manganese trioxide.

[0084] The compound of M includes an oxide of M and / or a carbonate of M, wherein M is a transition metal element, including one or more elements selected from the group consisting of Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W;

[0085] The method for uniform mixing is grinding mixing or ball milling mixing.

[0086] In step 220 , the obtained precursor powder is placed in a crucible, placed in a high-temperature furnace, and heat-treated in an air atmosphere. After cooling, the material is ground to obtain a high-entropy layered oxide material with covalent cation and anion valence.

[0087] The heat treatment specifically includes heat treatment at a temperature of 800° C. to 1000° C. for 2 hours to 24 hours.

[0088] The present invention provides another method for preparing the above-mentioned high entropy layered oxide material with covalent anion and cation valence, which is a sol-gel method, such as Figure 3 As shown, the specific steps include:

[0089] Step 310 , dissolving a sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a water-soluble salt or tetrabutyl titanate containing lithium having a stoichiometric amount of 100% to 108%, and a water-soluble salt or tetrabutyl titanate containing magnesium, nickel, manganese, and M having a stoichiometric amount in a solvent, respectively, and adding citric acid to form a precursor gel;

[0090] Wherein, the sodium source material is one or more of sodium acetate, sodium nitrate, sodium carbonate, and sodium sulfate;

[0091] M is a transition metal element, including one or more elements selected from Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W;

[0092] Solvents include anhydrous ethanol or deionized water.

[0093] Step 320 , placing the precursor gel into a crucible, placing it in a high-temperature furnace, and performing low-temperature pretreatment in an air atmosphere to obtain a pretreated powder;

[0094] The low temperature pretreatment specifically includes: pre-calcining at a temperature of 250° C. to 500° C. for 2 hours to 6 hours.

[0095] Step 330 , subjecting the pretreated powder to a high-temperature heat treatment in an air atmosphere, cooling the discharged material, and then grinding it to obtain a high-entropy layered oxide material with covalent cation and anion valence;

[0096] Specifically, the high temperature heat treatment is heat treatment at 800° C.-1000° C. for 2 hours-24 hours.

[0097] The present invention provides a method for preparing the high entropy layered oxide material with covalent anion and cation valence, which is a spray drying method, such as Figure 4 As shown, the specific steps include:

[0098] Step 410, mixing a sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a lithium source material having a stoichiometric amount of 100% to 108% of the required lithium, a magnesium source material, a nickel source material, a manganese source material, and a compound of M in the required stoichiometric amounts in proportion, and mixing them uniformly to obtain a precursor;

[0099] Wherein, the sodium source material is sodium carbonate; the lithium source material includes lithium carbonate and / or lithium hydroxide; the magnesium source material includes magnesium oxide and / or magnesium carbonate; the nickel source material is nickel oxide; and the manganese source material is manganese dioxide and / or manganese trioxide.

[0100] The compound of M includes an oxide of M and / or a carbonate of M, wherein M is a transition metal element, including one or more elements selected from the group consisting of Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W;

[0101] The method for uniform mixing is grinding mixing or ball milling mixing.

[0102] Step 420: Add a certain proportion of solvent to the precursor and stir evenly to form a slurry;

[0103] Wherein, the solvent includes anhydrous ethanol or deionized water.

[0104] Step 430 , placing the slurry in a spray dryer for spray drying to obtain a precursor powder;

[0105] The inlet temperature of the spray dryer is 150℃-190℃, the outlet temperature is 70℃-100℃, and the feed rate is 200mL / h-600mL / h.

[0106] Step 440 , placing the precursor powder into a crucible, placing it in a high-temperature furnace, and performing heat treatment under an air atmosphere;

[0107] The heat treatment method is specifically: heat treatment at a temperature of 800° C. to 1000° C. for 2 hours to 24 hours.

[0108] Step 450 , grinding the heat-treated precursor powder to obtain a high-entropy layered oxide material.

[0109] The above-mentioned high-entropy layered oxide material with co-valence of anions and cations provided in an embodiment of the present invention can be used as a positive electrode active material to prepare a slurry together with a conductive additive and a binder, and the slurry is coated on a current collector to obtain a positive electrode plate; the positive electrode plate is combined with a negative electrode, a separator placed between the positive and negative electrodes, and an electrolyte to form a sodium ion secondary battery according to a conventional process; specifically, the negative electrode uses metallic sodium, or the negative electrode includes a negative electrode current collector and a negative electrode material on the negative electrode current collector, and the negative electrode material includes a negative electrode active material, a conductive agent and a binder.

[0110] The sodium ion secondary battery composed above can be used in mobile devices, vehicles, renewable energy generation, smart grid peak regulation, distributed power stations, backup power supplies or energy storage devices for communication base stations.

[0111] To better understand the technical solution provided by the present invention, the preparation process and characteristics of the high-entropy layered oxide material with covalent cation and anion valence of the present invention are respectively described below with multiple specific examples.

[0112] Example 1

[0113] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent cation and anion valence, specifically using a solid-phase method, including the following steps:

[0114] (1) Na2CO3 (analytical grade, 3% excess), Li2CO3 (analytical grade, 3% excess), MgO (analytical grade), NiO (analytical grade), CuO (analytical grade), MnO2 (analytical grade), and TiO2 (analytical grade) were uniformly mixed in the desired stoichiometric ratio to obtain a precursor powder.

[0115] (2) The obtained precursor powder was placed in a crucible, placed in a high-temperature furnace, and treated at 900 ° C for 15 hours in an air atmosphere. After cooling and discharging, the material was ground to obtain a high-entropy layered oxide material with anion-cation covalency, the chemical formula of which is Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Cu 0.1 Mn 0.4 Ti 0.2 O2.

[0116] The high entropy layered oxide material Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Cu 0.1 Mn 0.4 Ti 0.2 XRD of O2, such as Figure 5 As shown, from the X-ray diffraction pattern analysis, Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Cu 0.1 Mn 0.4 Ti 0.2 The crystal structure of O2 is O3 phase layered oxide.

[0117] The high entropy layered oxide material Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Cu 0.1 Mn 0.4 Ti 0.2 The spherical aberration corrected transmission electron microscope image of O2 in the (100) crystal orientation shows that due to the different atomic masses of different elements in the transition metal layer, the atomic points show a disordered arrangement of bright and dark brightness, indicating the disordered arrangement of different transition metals.

[0118] Calculate the high entropy layered oxide material Na in this embodiment 0.9 Li 0.1 Mg0.1 Ni 0.1 Cu 0.1 Mn 0.4 Ti 0.2 Entropy of O2:

[0119] S=-R(0.9ln0.9+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.4ln0.4+0.2ln0.2)=1.70R, which meets the requirements of high entropy design of the material of the present invention.

[0120] The high entropy layered oxide material prepared above is used as the active material of the battery positive electrode material to prepare a sodium ion secondary battery, and the specific steps are as follows:

[0121] The prepared Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Cu 0.1 Mn 0.4 Ti 0.2 O2 powder, acetylene black and binder polyvinylidene fluoride (PVDF) were mixed in a mass ratio of 80:10:10, and an appropriate amount of N-methylpyrrolidone (NMP) solution was added. The mixture was ground in a dry environment at room temperature to form a slurry. The slurry was then evenly coated on the current collector aluminum foil and dried under an infrared lamp before being cut into (8×8) mm 2 The electrode was dried at 110°C under vacuum for 10 hours and then transferred to a glove box for later use.

[0122] The assembly of the simulated battery was carried out in a glove box with Ar atmosphere, using metallic sodium as the counter electrode, 1 mol / L NaClO4 polycarbonate PC / ethylene carbonate EC / diethyl carbonate DEC (PC:EC:DEC volume ratio of 1:1:1) solution as the electrolyte, GF / D glass fiber membrane as the battery separator, and assembled into CR2032 button batteries according to conventional processes.

[0123] The specific battery testing method is: using constant current charge and discharge mode, charge and discharge tests are performed at a current density of 20mA / g, the discharge cut-off voltage is 2.0V, and the charge cut-off voltage is 4.2V.

[0124] The charge and discharge curves of the first week are as follows: Figure 7 As shown, it can be seen that the first-week reversible capacity of the battery is 165mAh / g.

[0125] The cycle curve is as follows Figure 8 As shown in the figure, it can be seen that the capacity of the battery has almost no decay after 130 cycles.

[0126] Example 2

[0127] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent cation and anion valence, specifically using a solid-phase method, including the following steps:

[0128] (1) Na2CO3 (analytical grade, 3% excess), Li2CO3 (analytical grade, 3% excess), MgO (analytical grade), NiO (analytical grade), ZnO (analytical grade), MnO2 (analytical grade), and TiO2 (analytical grade) were uniformly mixed in the desired stoichiometric ratio to obtain a precursor powder.

[0129] (2) The obtained precursor powder was placed in a crucible, placed in a high-temperature furnace, and treated at 900 ° C for 15 hours in an air atmosphere. After cooling and discharging, the material was ground to obtain a high-entropy layered oxide material with anion-cation covalency, the chemical formula of which is Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Zn 0.1 Mn 0.4 Ti 0.2 O2.

[0130] The high entropy layered oxide material Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Zn 0.1 Mn 0.4 Ti 0.2 XRD of O2, such as Figure 5 As shown, from the X-ray diffraction pattern analysis, Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Zn 0.1 Mn 0.4 Ti 0.2 The crystal structure of O2 is O3 phase layered oxide.

[0131] Calculate the Na prepared in this example 0.9 Li 0.1 Mg 0.1 Ni 0.1 Zn 0.1 Mn 0.4 Ti 0.2 The entropy value of O2 is: S = -R(0.9ln0.9+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.4ln0.4+0.2ln0.2) = 1.70R, which meets the definition of high entropy.

[0132] The high entropy layered oxide material prepared above was used as the active material of the battery positive electrode material to prepare a sodium ion secondary battery and was tested. The specific process of CR2032 button battery assembly and testing was the same as in Example 1.

[0133] The charge and discharge curves of the first week are as follows: Figure 9 As shown, it can be seen that the battery's first-week charging capacity is 165.6mAh / g, and the first-week discharge capacity is 139mAh / g.

[0134] Example 3

[0135] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent cation and anion valence, specifically using a solid-phase method, including the following steps:

[0136] (1) Na2CO3 (analytical grade, 3% excess), Li2CO3 (analytical grade, 3% excess), MgO (analytical grade), NiO (analytical grade), Fe2O3 (analytical grade), MnO2 (analytical grade), and TiO2 (analytical grade) were uniformly mixed in the desired stoichiometric ratio to obtain a precursor powder.

[0137] (2) The obtained precursor powder was placed in a crucible, placed in a high-temperature furnace, and treated at 900 ° C for 15 hours in an air atmosphere. After cooling and discharging, the material was ground to obtain a high-entropy layered oxide material with anion-cation covalency, the chemical formula of which is Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.1 O2.

[0138] The high entropy layered oxide material Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.1 XRD of O2, such as Figure 5 As shown, from the X-ray diffraction pattern analysis, Na 0.9 Li 0.1 Mg 0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.1 The crystal structure of O2 is O3 phase layered oxide.

[0139] Calculate the Na prepared in this example 0.9 Li 0.1 Mg0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.1 The entropy value of O2: S = -R(0.9ln0.9+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.2ln0.2+0.4ln0.4+0.1ln0.1) = 1.70R, which meets the definition of high entropy.

[0140] The high entropy layered oxide material prepared above was used as the active material of the battery positive electrode material to prepare a sodium ion secondary battery and was tested. The specific process of CR2032 button battery assembly and testing was the same as in Example 1.

[0141] The charge and discharge curves of the first week are as follows: Figure 10 As shown, it can be seen that the battery's first-week charging capacity is 166.2mAh / g, and the first-week discharge capacity is 155mAh / g.

[0142] Example 4

[0143] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent cation and anion valence, specifically using a solid-phase method, including the following steps:

[0144] (1) Na2CO3 (analytical grade, 3% excess), Li2CO3 (analytical grade, 3% excess), MgO (analytical grade), NiO (analytical grade), Fe2O3 (analytical grade), MnO2 (analytical grade), TiO2 (analytical grade), and Nb2O5 (analytical grade) were uniformly mixed in the desired stoichiometric ratio to obtain a precursor powder.

[0145] (2) The obtained precursor powder was placed in a crucible, placed in a high-temperature furnace, and treated at 900 ° C for 15 hours in an air atmosphere. After cooling and discharging, the material was ground to obtain a high-entropy layered oxide material with anion-cation covalency, the chemical formula of which is Na 0.95 Li 0.1 Mg 0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.05 Nb 0.05 O2.

[0146] The high entropy layered oxide material Na 0.95 Li 0.1 Mg 0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.05 Nb 0.05XRD of O2, such as Figure 5 As shown, from the X-ray diffraction pattern analysis, it can be seen that Na 0.95 Li 0.1 Mg 0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.05 Nb 0.0 The crystal structure of 5O2 is O3 phase layered oxide.

[0147] Calculate the Na prepared in this example 0.95 Li 0.1 Mg 0.1 Ni 0.1 Fe 0.2 Mn 0.4 Ti 0.05 Nb 0.05 The entropy value of O2 is: S = -R(0.95ln0.95+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.2ln0.2+0.4ln0.4+0.05ln0.05+0.05ln0.05) = 1.73R, which meets the definition of high entropy.

[0148] The high entropy layered oxide material prepared above was used as the active material of the battery positive electrode material to prepare a sodium ion secondary battery and was tested. The specific process of CR2032 button battery assembly and testing was the same as in Example 1.

[0149] The charge and discharge curves of the first week are as follows: Figure 11 As shown, it can be seen that the battery's first-week charging capacity is 158.7mAh / g, and the first-week discharge capacity is 128.5mAh / g.

[0150] Example 5

[0151] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent cation and anion valence, specifically using a solid-phase method, including the following steps:

[0152] (1) Na2CO3 (analytical grade, 3% excess), Li2CO3 (analytical grade, 3% excess), MgO (analytical grade), NiO (analytical grade), CuO (analytical grade), MnO2 (analytical grade), RuO2 (analytical grade), and MoO3 (analytical grade) were uniformly mixed in the desired stoichiometric ratio to obtain a precursor powder.

[0153] (2) The obtained precursor powder was placed in a crucible, placed in a high-temperature furnace, and treated at 900 ° C for 15 hours in an air atmosphere. After cooling and discharging, the material was ground to obtain a high-entropy layered oxide material with anion-cation covalency, the chemical formula of which is Na0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.1 Mo 0.05 O2.

[0154] The high entropy layered oxide material Na 0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.1 Mo 0.05 XRD of O2, such as Figure 5 As shown, from the X-ray diffraction pattern analysis, it can be seen that Na 0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.1 Mo 0.05 The crystal structure of O2 is O3 phase layered oxide.

[0155] Calculate the Na prepared in this example 0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.1 Mo 0.05 The entropy value of O2 is: S = -R(0.9ln0.9+0.1ln0.1+0.1ln0.1+0.15ln0.15+0.1ln0.1+0.4ln0.4+0.1ln0.1+0.05ln0.05) = 1.82R, which meets the definition of high entropy.

[0156] The high entropy layered oxide material prepared above was used as the active material of the battery positive electrode material to prepare a sodium ion secondary battery and was tested. The specific process of CR2032 button battery assembly and testing was the same as in Example 1.

[0157] The charge and discharge curves of the first week are as follows: Figure 12 As shown, it can be seen that the battery's first-week charging capacity is 186.5mAh / g, and the first-week discharge capacity is 156mAh / g.

[0158] Example 6

[0159] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent cation and anion valence, specifically using a solid-phase method, including the following steps:

[0160] (1) Na2CO3 (analytical grade, 3% excess), Li2CO3 (analytical grade, 3% excess), MgO (analytical grade), NiO (analytical grade), CuO (analytical grade), MnO2 (analytical grade), RuO2 (analytical grade), TiO2 (analytical grade), and WO3 (analytical grade) were uniformly mixed in the desired stoichiometric ratio to obtain a precursor powder.

[0161] (2) The obtained precursor powder was placed in a crucible, placed in a high-temperature furnace, and treated at 900 ° C for 15 hours in an air atmosphere. After cooling and discharging, the material was ground to obtain a high-entropy layered oxide material with anion-cation covalency, the chemical formula of which is Na 0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.05 Ti 0.05 W 0.05 O2.

[0162] The high entropy layered oxide material Na prepared in this example 0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.05 Ti 0.05 W 0.05 XRD of O2, such as Figure 5 As shown, from the X-ray diffraction pattern analysis, it can be seen that Na 0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.05 Ti 0.05 W 0.05 The crystal structure of O2 is O3 phase layered oxide.

[0163] Calculate the Na prepared in this example 0.9 Li 0.1 Mg 0.1 Ni 0.15 Cu 0.1 Mn 0.4 Ru 0.05 Ti 0.05 W 0.05The entropy value of O2: S = -R(0.9ln0.9+0.1ln0.1+0.1ln0.1+0.15ln0.15+0.1ln0.1+0.4ln0.4+0.05ln0.05+0.05ln0.05+0.05ln0.05) = 1.89R, which meets the definition of high entropy.

[0164] The high entropy layered oxide material prepared above was used as the active material of the battery positive electrode material to prepare a sodium ion secondary battery and was tested. The specific process of CR2032 button battery assembly and testing was the same as in Example 1.

[0165] The charge and discharge curves of the first week are as follows: Figure 13 As shown, it can be seen that the battery's first-week charging capacity is 190mAh / g, and the first-week discharge capacity is 148mAh / g.

[0166] Example 7

[0167] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent anion and cation valence, specifically using a sol-gel method, including the following steps:

[0168] (1) NaC2H3O2 (analytical grade, 3% excess), LiC2H3O2 (analytical grade, 3% excess), Mg(C2H3O2)2 (analytical grade), Ni(C2H3O2)2 (analytical grade), Cu(C2H3O2)2 (analytical grade), Mn(C2H3O2)2 (analytical grade), and Sb(C2H3O2)3 (analytical grade) were dissolved in deionized water in stoichiometric proportions, and citric acid was added to form a precursor gel.

[0169] (2) The precursor gel was placed in a crucible, placed in a high-temperature furnace, and pre-calcined at 300°C for 3 hours in an air atmosphere to obtain a pretreated powder.

[0170] (3) The pretreated powder was heat treated at 900 ° C for 5 hours in an air atmosphere, cooled and ground to obtain a high entropy layered oxide material with anion and cation covalency, the chemical formula of which is NaLi 0.1 Mg 0.1 Ni 0.1 Cu 0.1 Mn 0.5 Sb 0. 1O2.

[0171] Calculate the NaLi prepared in this example 0.1 Mg 0.1 Ni 0.1 Cu 0.1 Mn 0.5 Sb 0.1The entropy value of O2: S = -R(ln1+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.5ln0.5+0.1ln0.1) = 1.5R, which meets the definition of high entropy.

[0172] Example 8

[0173] The present invention provides a preparation process and performance testing of a high-entropy layered oxide material with covalent anion and cation valence, specifically using a spray drying method, including the following steps:

[0174] (1) Na2CO3 (analytical grade, 3% excess), Li2CO3 (analytical grade, 3% excess), MgO (analytical grade), NiO (analytical grade), ZnO (analytical grade), MnO2 (analytical grade), and La2O3 (analytical grade) were uniformly mixed in the desired stoichiometric ratio to obtain a precursor.

[0175] (2) Add a certain proportion of anhydrous ethanol to the precursor and stir evenly to form a slurry.

[0176] (3) The slurry was placed in a spray dryer for spray drying to obtain a precursor powder, wherein the inlet temperature of the spray dryer was 160°C, the outlet temperature was 80°C, and the feed rate was 400 mL / h.

[0177] (4) The precursor powder was placed in a crucible, placed in a high-temperature furnace, and heat treated at 900 ° C for 10 hours in an air atmosphere. After cooling and grinding, a high-entropy layered oxide material with the chemical formula of NaLi was obtained. 0.1 Mg 0.1 Ni 0.1 Zn 0.1 Mn 0.5 La 0.1 O2.

[0178] Calculate the NaLi prepared in this example 0.1 Mg 0.1 Ni 0.1 Zn 0.1 Mn 0.5 La 0.1 The entropy value of O2: S = -R(ln1+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.1ln0.1+0.5ln0.5+0.1ln0.1) = 1.5R, which meets the definition of high entropy.

[0179] The high-entropy layered oxide material with co-valence of anions and cations provided in an embodiment of the present invention uses Li and Mg to activate the redox reaction of lattice oxygen, and cooperates with the redox reaction of transition metals with electrochemical activity and high disorder between other layers to provide a higher specific capacity, thereby improving energy density and cycle stability; the sodium ion secondary battery using the high-entropy layered oxide material of the present invention has a suitable voltage range, relatively low cost, and high energy density, and can be used for smart grid peak regulation, backup power supply, large-scale energy storage equipment for communication base stations, or power supply for low-speed electric vehicles, electric boats, two-wheeled vehicles, etc.

[0180] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high entropy layered oxide material with covalent anion and cation valence, characterized in that: The general chemical formula of the high entropy layered oxide material is: Na a [Li b Mg c Ni d Mn e M f ]O 2+β ; Wherein, M is a transition metal element, including one or more elements selected from Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W; a, b, c, d, e, f, and 2+β are the molar percentages of the corresponding elements, respectively; the relationship between a, b, c, d, e, f, and 2+β satisfies b+c+d+e+f=1, and a+b+2c+2d+4e+mf=2(2+β); wherein 0.85≤a≤1; 0.05≤b≤0.2; 0.05≤c≤0.2; 0.05≤d≤0.2; 0.2≤e≤0.6; 0.05≤f≤0.2; and 0≤β≤0.1, and m is the valence state of M; And a, b, c, d, e, f meet the definition of high entropy, that is, they meet the formula: Where R is the gas constant, N≥6, x i Any value among a,b,c,d,e,f; The high entropy layered oxide material is an O3 phase layered oxide material, and the space group is The high-entropy layered oxide material is used as a positive electrode active material for a sodium ion secondary battery. During the first cycle of charging, the electrochemically active M transition metal ions first lose electrons, followed by oxygen ions in the lattice losing electrons, and the average valence of the oxygen ions increases from -2 to a valence between -2 and -1. During the first cycle of discharge, the electrochemically active M transition metal ions and the oxygen ions with a higher valence regain electrons. Starting from the second cycle, the oxygen ions and the electrochemically active M transition metal ions gain and lose electrons during the charge and discharge process.

2. A method for preparing the high entropy layered oxide material with covalent cation and anion valence according to claim 1, characterized in that: The method is a solid phase method, comprising: A sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a lithium source material having a stoichiometric amount of 100% to 108% of the required lithium, a magnesium source material, a nickel source material, a manganese source material and a compound of M in the required stoichiometric amount are mixed in proportion, and the mixture is uniformly mixed to obtain a precursor powder; The obtained precursor powder is placed in a crucible, placed in a high-temperature furnace, and heat-treated in an air atmosphere. After cooling and discharging, the material is ground to obtain a high-entropy layered oxide material with co-valence of anions and cations.

3. The preparation method according to claim 2, characterized in that The sodium source material is sodium carbonate; The lithium source material includes lithium carbonate and / or lithium hydroxide; The magnesium source material includes magnesium oxide and / or magnesium carbonate; The nickel source material is nickel oxide; The manganese source material is manganese dioxide and / or manganese trioxide; The compound of M includes an oxide of M and / or a carbonate of M, wherein M is a transition metal element, including one or more elements selected from the group consisting of Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W; The method of uniform mixing is grinding mixing or ball milling mixing; The heat treatment specifically includes heat treatment at a temperature of 800° C. to 1000° C. for 2 hours to 24 hours.

4. A method for preparing the high entropy layered oxide material with covalent cation and anion valence according to claim 1, characterized in that: The method is a sol-gel method, comprising: A sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a water-soluble salt or tetrabutyl titanate containing lithium having a stoichiometric amount of 100% to 108% of the required lithium, and a water-soluble salt or tetrabutyl titanate containing magnesium, nickel, manganese, and M having a stoichiometric amount are dissolved in a solvent, and citric acid is added to form a precursor gel; The precursor gel is placed in a crucible, placed in a high-temperature furnace, and subjected to low-temperature pretreatment in an air atmosphere to obtain a pretreated powder; The pretreated powder is subjected to high-temperature heat treatment in an air atmosphere, and after cooling and discharging, the powder is ground to obtain a high-entropy layered oxide material with co-valence of anions and cations.

5. The preparation method according to claim 4, characterized in that The sodium source material is one or more of sodium acetate, sodium nitrate, sodium carbonate, and sodium sulfate; M is a transition metal element, including one or more elements selected from Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W; The solvent includes anhydrous ethanol or deionized water; The low temperature pretreatment is specifically: pre-calcining at a temperature of 250°C-500°C for 2 hours-6 hours; The high temperature heat treatment specifically includes heat treatment at 800° C.-1000° C. for 2 hours-24 hours.

6. A method for preparing the high entropy layered oxide material with covalent cation and anion valence according to claim 1, characterized in that: The method is a spray drying method, comprising: A sodium source material having a stoichiometric amount of 100% to 108% of the required sodium, a lithium source material having a stoichiometric amount of 100% to 108% of the required lithium, a magnesium source material, a nickel source material, a manganese source material and a compound of M having a stoichiometric amount thereof are mixed in proportion, and the mixture is uniformly mixed to obtain a precursor; Adding a certain proportion of solvent to the precursor and stirring evenly to form a slurry; The slurry is placed in a spray dryer for spray drying to obtain a precursor powder; The precursor powder is placed in a crucible, placed in a high-temperature furnace, and subjected to heat treatment in an air atmosphere; The heat-treated precursor powder is ground to obtain a high-entropy layered oxide material.

7. The preparation method according to claim 6, characterized in that The sodium source material is sodium carbonate; The lithium source material includes lithium carbonate and / or lithium hydroxide; The magnesium source material includes magnesium oxide and / or magnesium carbonate; The nickel source material is nickel oxide; The manganese source material is manganese dioxide and / or manganese trioxide; The compound of M includes an oxide of M and / or a carbonate of M, wherein M is a transition metal element, including one or more elements selected from the group consisting of Cu, Fe, Zn, Nb, Mo, Ru, Sb, Ta, Bi, Ti, La, and W; The method of uniform mixing is grinding mixing or ball milling mixing; The solvent includes anhydrous ethanol or deionized water; The heat treatment method is specifically: heat treatment at a temperature of 800°C-1000°C for 2 hours-24 hours; The inlet temperature of the spray dryer is 150° C.-190° C., the outlet temperature is 70° C.-100° C., and the feed rate is 200 mL / h-600 mL / h.

8. A positive electrode plate for a sodium ion secondary battery, characterized in that: The positive electrode plate includes: a current collector, a conductive additive and a binder coated on the current collector, and the high entropy layered oxide material with anion-cation co-valence variation according to claim 1.

9. A sodium ion secondary battery, characterized in that: The sodium ion secondary battery comprises the positive electrode sheet according to claim 8.

10. Use of the sodium ion secondary battery according to claim 9, characterized in that: The sodium ion secondary battery is used in mobile devices, vehicles, renewable energy generation, smart grid peak regulation, distributed power stations, backup power supplies or energy storage devices for communication base stations.

Images