A high-entropy cathode material for sodium / potassium ion batteries doped with multiple anions, and its preparation method and application

Abstract

The present invention discloses a high entropy cathode material for sodium / potassium ion batteries doped with multiple anions, a preparation method thereof and an application thereof, belonging to the technical field of sodium / potassium ion batteries. The chemical formula of the high entropy cathode material is A 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.85 S 0.05 N 0.05 F 0.05 wherein A is K or Na. The present invention significantly improves the structural stability, ion diffusion performance, and electrochemical activity of high-entropy layered oxide cathode materials by introducing multiple anion synergistic doping, combined with multiple high-temperature quenching and re-firing treatments. This material not only exhibits a highly uniform anion and cation distribution and a single-phase P63 / mmc layered structure, but also achieves comprehensive performance improvements such as controllable particle size, high specific surface area, long cycle life, and excellent rate capability.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium / potassium ion batteries, and more specifically to a high-entropy positive electrode material for sodium / potassium ion batteries doped with multiple anions, and a preparation method and application thereof. Background Art

[0002] In recent years, with the large-scale development of renewable energy and the rapid adoption of electric vehicles, the demand for high-performance secondary batteries has been growing. Lithium-ion batteries (LIBs) have been widely used in portable electronic devices and electric vehicles due to their high energy density and excellent cycle life. However, the uneven distribution of lithium resources and rising costs have limited the further popularization of LIBs. In contrast, sodium-ion batteries (SIBs) and potassium-ion batteries (KIBs) have become important research directions to supplement LIBs due to their abundant raw materials, low cost, and excellent electrochemical properties.

[0003] In sodium / potassium ion batteries, the performance of the cathode material has a decisive influence on the overall energy density, cycle life and rate performance of the battery. x MO2, K x MO2 (M is a transition metal) was one of the earliest cathode materials explored due to its structural similarity to lithium layered oxides. However, these materials generally suffer from poor structural stability, rapid capacity decay, and insufficient rate performance, significantly limiting their practical application.

[0004] To improve the performance of cathode materials, researchers have proposed a design strategy for high-entropy materials (HEMs). By introducing multiple metal elements (usually five or more) into the lattice to form a near-equimolar mixture, HEMs can significantly enhance the thermodynamic stability and phase transition resistance of the crystal structure, thereby improving electrochemical performance. Therefore, high-entropy design has been introduced into sodium / potassium layered oxide cathode materials, aiming to enhance the material's cycling stability and rate capability through multi-element synergy.

[0005] In addition to cation high-entropy strategies, anion regulation is also considered an effective means of improving material performance. By introducing heterogeneous anion doping, the charge distribution, lattice parameters, electronic structure, and ion diffusion dynamics of the material can be adjusted, thereby further optimizing the electrochemical reaction characteristics of the cathode material. In particular, the electronegativity and size effect of the anion play an important role in stabilizing the structure and improving electronic and ionic conductivity.

[0006] However, the current research on the coordinated doping of multiple anions in high-entropy sodium / potassium layered oxide cathode materials is still relatively limited. Traditional methods are mainly based on simple mixed doping, which has the following problems: (1) It is difficult to achieve efficient and orderly doping of multiple anions, the efficiency of anion introduction is low, the doping degree and material structure are not controllable enough, and it is easy to cause abnormal particle growth during heat treatment, making the particle size difficult to control, increasing the ion diffusion resistance, reducing the rate performance and cycle stability, and resulting in limited improvement in the actual performance of the material. (2) It is difficult to achieve a uniform distribution of anions and cations, and there are certain limitations in doping uniformity and doping depth, which can easily cause local phase separation or crystal defects. (3) The existing preparation technology has high requirements for atmosphere and equipment, a narrow process window, and a complex preparation process, making it difficult to balance the doping effect and the needs of large-scale material preparation.

[0007] Therefore, there is an urgent need to develop a new preparation method that can achieve efficient multi-anion doping, moderate particle size, stable structure and simple process, so as to achieve uniform and stable anion and cation distribution in high-entropy layered oxide positive electrode materials, so as to further improve the comprehensive performance and application prospects of high-entropy sodium / potassium ion battery positive electrode materials. Summary of the Invention

[0008] The purpose of the present invention is to overcome the above-mentioned defects of the prior art and provide an efficient and controllable high-entropy cathode material for sodium / potassium ion batteries doped with multiple anions and its preparation method and application, so as to solve the problems of uneven multi-anion doping, low doping efficiency, poor material structure stability, difficult to control particle size and complex process in the prior art. By introducing multiple anions for synergistic doping, combined with multiple high-temperature quenching and re-firing treatment processes based on the electronegativity sequence of anions, efficient and uniform doping of multiple anions and cations in a single-phase layered oxide structure is achieved, while optimizing the particle size, effectively improving the material structure stability, enhancing the ion migration rate and cycle stability of the material, thereby significantly improving the comprehensive electrochemical performance and practical application potential of the high-entropy sodium / potassium ion battery cathode material.

[0009] To achieve the above object, the technical solution of the present invention is as follows:

[0010] A method for preparing a high entropy cathode material for sodium / potassium ion batteries doped with multiple anions, wherein the chemical formula of the high entropy cathode material is A 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.85 S 0.05 N 0.05 F 0.05 ; Wherein, A is K or Na; The method for preparing the high entropy cathode material comprises the following steps:

[0011] S1. Mixing an alkali metal salt, a Mn source, a Co source, a Fe source, a Cu source, a Ti source, and a Li source according to a chemical ratio, and grinding the mixture to obtain a mixture powder;

[0012] S2, calcining the mixture powder to obtain a precursor;

[0013] S3. Dissolve the S source in deionized water, stir and dissolve, and then refrigerate at 5°C to 8°C for 30 min to 50 min to enhance the thermal shock effect during high-temperature quenching to obtain mixed solution A;

[0014] S4, heating the precursor to 650°C-950°C according to the chemical ratio, then adding it to the mixed solution A for quenching at 25°C-30°C, filtering and drying;

[0015] S5. Dissolve the nitrogen source in deionized water, stir to dissolve, and then refrigerate at 5°C to 8°C for 30 min to 50 min to enhance the thermal shock effect during high-temperature quenching, to obtain a mixed solution B.

[0016] S6. According to the chemical ratio, the material obtained in step S4 is heated to 650°C to 950°C, then added to the mixed solution B for quenching at 25°C to 30°C, and filtered and dried;

[0017] S7. Dissolve the F source in deionized water, stir to dissolve, and then refrigerate at 5°C to 8°C for 30 min to 50 min to enhance the thermal shock effect during high-temperature quenching, to obtain a mixed solution C;

[0018] S8. According to the chemical ratio, the material obtained in step S6 is heated to 650° C. to 950° C., then added to the mixed solution C for quenching at 25° C. to 30° C., and filtered and dried to obtain a quenched material;

[0019] S9, sintering the quenched material obtained in step S8 at 300° C. to 1500° C. for 8 h to 15 h to obtain a sintered material;

[0020] S10. Repeat steps S3 to S9 on the sintered material to obtain the high-entropy positive electrode material; the high-entropy positive electrode material has a single-phase layered oxide structure, a space group of P63 / mmc, unit cell parameters a=2.8Å~3.0Å, c=13.8Å~14.5Å; the particle size of the high-entropy positive electrode material is 5μm~20μm.

[0021] Specifically, the order of anion doping is from small to large according to electronegativity, that is, the order of anion doping is S 2- 、N3- 、F - , to avoid the early doping of high-electronegative anions that makes it difficult to introduce low-electronegative anions, thereby improving doping efficiency and uniformity; after multiple high-temperature quenching treatments, the material needs to be re-fired to stabilize the structure. Since there is a tendency for particles to grow during the re-firing process, the present invention effectively suppresses excessive particle growth by optimizing the re-firing temperature and re-firing time, ensuring that the particle size of the obtained material is controlled within the range of 5μm~20μm, maintaining a high specific surface area and ion migration rate, and further improving the battery rate performance and cycle stability.

[0022] Optionally, in step S1, the particle size of the mixture powder is 5 μm~15 μm; the alkali metal salt includes Na2CO3 or K2CO3; the Mn source, the Co source, the Fe source, the Cu source, the Ti source and the Li source are respectively at least one of the carbonates and oxides of the corresponding transition metals.

[0023] Optionally, in step S2, the calcination heating rate is 1°C / min~10°C / min, preferably 3°C / min~7°C / min, the calcination temperature is 200°C~1200°C, preferably 700°C~1000°C, and the calcination time is 3h~20h, preferably 8h~12h.

[0024] Optionally, in step S4, step S6 and step S8, the drying temperature is 70°C to 180°C, preferably 100°C to 150°C, and the drying time is 5h to 24h, preferably 8h to 12h.

[0025] Optionally, in step S9, the sintering temperature is preferably 500° C. to 1000° C., and the sintering time is 8 h to 15 h.

[0026] Optionally, in step S10, the operation is repeated 2 to 20 times, preferably 2 to 8 times.

[0027] Optionally, the S source, the N source and the F source are S 2- 、N 3- 、F - corresponding salt; the concentrations of the mixed solution A, the mixed solution B and the mixed solution C are 0.01mol / L~2mol / L, preferably 0.05mol / L~1mol / L.

[0028] The present invention also discloses a high-entropy positive electrode material for sodium / potassium ion batteries doped with multiple anions, which is prepared by the above-mentioned preparation method.

[0029] The present invention also discloses an application of a high-entropy positive electrode material for sodium / potassium ion batteries doped with multiple anions, prepared by the above-mentioned preparation method, in positive electrode materials for sodium / potassium ion batteries.

[0030] The implementation of the present invention will have the following beneficial effects:

[0031] This invention significantly improves the structural stability, ion diffusion properties, and electrochemical activity of high-entropy layered oxide cathode materials by introducing multiple anion synergistic doping, combined with multiple high-temperature quenching and re-firing treatments. The resulting material not only exhibits a highly uniform anion and cation distribution and a single-phase P63 / mmc layered structure, but also achieves comprehensive performance improvements such as controllable particle size (5μm-20μm), high specific surface area, long cycle life, and excellent rate capability. The details are as follows:

[0032] First, S is introduced in order from small to large electronegativity. 2- 、N 3- 、F - Anions effectively improve doping efficiency and uniformity, optimizing the material's electronic structure and ion diffusion properties. Secondly, multiple high-temperature quenching and re-firing processes are used to promote stable anion doping. Excessive particle growth is suppressed by precisely controlling the re-firing temperature and time, stabilizing the material's particle size within the 5μm to 20μm range, maintaining a high specific surface area and excellent rate performance. At the same time, the high-entropy design of multiple transition metals enhances the material's structural stability and cycle life. The overall process is simple and highly controllable, with good prospects for large-scale application.

[0033] Compared with traditional preparation methods, the present invention has a simple process and high doping efficiency. It can effectively inhibit the structural collapse and performance degradation of the material during long-term cycling, significantly enhancing the practicality and competitiveness of sodium / potassium ion batteries in high energy density and long life application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the refined X-ray diffraction (XRD) pattern of the final product prepared in Example 1 of the present invention.

[0035] Figure 2 This is a scanning electron microscope (SEM) image of the final product prepared in Example 1 of the present invention.

[0036] Figure 3 This is a line scan SEM image of a single particle of the final product prepared in Example 1 of the present invention.

[0037] Figure 4 This is a line scan result of a single particle of the final product prepared in Example 1 of the present invention.

[0038] Figure 5This is the TEM EDS image of the final product prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to specific examples, but the present invention is not limited thereto in any way.

[0040] Comparative Example 1

[0041] The chemical formula of the high entropy cathode material of this comparative example is K 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.9 S 0.1 .

[0042] The preparation method of the high entropy cathode material of this comparative example comprises the following steps:

[0043] S1. Weigh K2CO3, MnO2, Fe2O3, CuO, TiO2, Co2O3 and Li2O according to the chemical ratio, place the above metal oxides in an agate mortar and grind them for 30 minutes to obtain a uniform mixture powder.

[0044] S2. Place the mixture powder in an alumina crucible and place it in the center of a high-temperature tube furnace. Raise the temperature to 950°C at a rate of 6°C / min and calcine in one step. Keep the temperature for 12 hours to form a preliminary layered oxide structure to obtain a precursor.

[0045] S3. Dissolve the sulfur salt in deionized water, stir to dissolve, and then refrigerate in a refrigerator at 5°C for 30 minutes to obtain a sulfur salt solution with a concentration of 0.1 mol / L.

[0046] S4. According to the chemical ratio, the precursor is heated to 950° C., then added to an anionic salt solution for quenching at 25° C., filtered and dried at 120° C. for 12 h to obtain a quenched material;

[0047] S5, sintering the quenched material obtained in step S4 at 950° C. for 10 hours to obtain a sintered material;

[0048] S6. Repeat steps S3 to S5 twice on the sintered material to obtain a high entropy cathode material (A-1).

[0049] Comparative Example 2

[0050] The only difference between this comparative example and comparative example 1 is that no anion is doped, and the rest is the same as comparative example 1. The chemical formula of the prepared high entropy positive electrode material is K0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O2. (B-1).

[0051] Comparative Example 3

[0052] The only difference between this comparative example and comparative example 1 is that the sulfur salt in step S3 is replaced by nitrogen salt, and the rest is the same as comparative example 1. The chemical formula of the prepared high entropy positive electrode material is K 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.9 N 0.1 , recorded as A-2.

[0053] Comparative Example 4

[0054] The only difference between this comparative example and comparative example 1 is that the sulfur salt in step S3 is replaced by a fluoride salt. The rest is the same as comparative example 1. The chemical formula of the obtained high entropy positive electrode material is K 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.9 F 0.1 , recorded as A-3.

[0055] Comparative Example 5

[0056] The only difference between this comparative example and comparative example 1 is that the sulfur salt in step S3 is replaced by a phosphate salt. The rest is the same as comparative example 1. The chemical formula of the obtained high entropy positive electrode material is K 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.9 P 0.1 , recorded as B-2.

[0057] Comparative Example 6

[0058] The only difference between this comparative example and comparative example 1 is that the sulfur salt in step S3 is replaced by chloride salt, and the rest is the same as comparative example 1. The chemical formula of the obtained high entropy positive electrode material is K 0.5 Mn0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.9 Cl0 .1 , recorded as B-3.

[0059] Comparative Example 7

[0060] The only difference between this comparative example and comparative example 1 is that the sulfur salt in step S3 is replaced by sulfur salt and nitrogen salt, and the rest is the same as comparative example 1. The chemical formula of the prepared high entropy positive electrode material is K 0.5 Mn 0. Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.0 6O 1.9 B 0.1 ; Wherein, B is an equimolar amount of S 2- and N 3- . Recorded as A-4.

[0061] The preparation method of the high entropy cathode material of this comparative example comprises the following steps:

[0062] S1-S2, same as Comparative Example 1.

[0063] Steps S3 to S5 specifically include the following steps:

[0064] (1) Dissolve the sulfur salt in deionized water, stir to dissolve, and then refrigerate at 5°C for 30 minutes to obtain a sulfur salt solution with a concentration of 0.1 mol / L.

[0065] (2) According to the chemical ratio, the precursor is heated to 950 ° C, then added into a sulfur salt solution for quenching at 25 ° C, and then filtered and dried.

[0066] (3) Dissolve the nitrogen salt in deionized water, stir to dissolve, and refrigerate at 5°C for 30 minutes to obtain a nitrogen salt solution with a concentration of 0.1 mol / L.

[0067] (4) According to the chemical ratio, the material obtained in step (2) is heated to 950°C, then added to a nitrogen salt solution for quenching at 25°C, and filtered and dried.

[0068] (5) The material obtained in step (4) was sintered at 950° C. for 10 h to obtain a sintered material.

[0069] S6, same as Comparative Example 1.

[0070] Comparative Example 8

[0071] The only difference between this comparative example and comparative example 1 is that the sulfur salt in step S3 is replaced by sulfur salt and fluoride salt, and the rest is the same as comparative example 1. The chemical formula of the prepared high entropy positive electrode material is K 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.0 6O 1.9 B 0.1 ; Wherein, B is an equimolar amount of S 2- and F - . Recorded as A-5.

[0072] The preparation method of the high entropy cathode material of this comparative example comprises the following steps:

[0073] S1-S2, same as Comparative Example 1.

[0074] Steps S3 to S5 specifically include the following steps:

[0075] (1) Dissolve the sulfur salt in deionized water, stir to dissolve, and then refrigerate at 5°C for 30 minutes to obtain a sulfur salt solution with a concentration of 0.1 mol / L.

[0076] (2) According to the chemical ratio, the precursor is heated to 950 ° C, then added into a sulfur salt solution for quenching at 25 ° C, and then filtered and dried.

[0077] (3) Dissolve the fluoride salt in deionized water, stir to dissolve, and refrigerate at 5°C for 30 minutes to obtain a fluoride salt solution with a concentration of 0.1 mol / L.

[0078] (4) According to the chemical ratio, the material obtained in step (2) is heated to 950°C, then added to a fluoride salt solution for quenching at 25°C, and filtered and dried.

[0079] (5) The material obtained in step (4) was sintered at 950° C. for 10 h to obtain a sintered material.

[0080] S6, same as Comparative Example 1.

[0081] Comparative Example 9

[0082] The only difference between this comparative example and comparative example 1 is that the sulfur salt in step S3 is replaced by nitrogen salt and fluorine salt, and the rest is the same as comparative example 1. The chemical formula of the prepared high entropy positive electrode material is K 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu0.06 Ti 0.06 Li 0.0 6O 1.9 B 0.1 ; Wherein, B is an equimolar amount of N 3- and F - . Recorded as A-6.

[0083] The preparation method of the high entropy cathode material of this comparative example comprises the following steps:

[0084] S1-S2, same as Comparative Example 1.

[0085] Steps S3 to S5 specifically include the following steps:

[0086] (1) Dissolve the nitrogen salt in deionized water, stir to dissolve, and refrigerate at 5°C for 30 minutes to obtain a nitrogen salt solution with a concentration of 0.1 mol / L.

[0087] (2) According to the chemical ratio, the precursor is heated to 950 ° C, then added to the nitrogen salt solution for quenching at 25 ° C, and then filtered and dried.

[0088] (3) Dissolve the fluoride salt in deionized water, stir to dissolve, and refrigerate at 5°C for 30 minutes to obtain a fluoride salt solution with a concentration of 0.1 mol / L.

[0089] (4) According to the chemical ratio, the material obtained in step (2) is heated to 950°C, then added to a fluoride salt solution for quenching at 25°C, and filtered and dried.

[0090] (5) The material obtained in step (4) was sintered at 950° C. for 10 h to obtain a sintered material.

[0091] S6, same as Comparative Example 1.

[0092] Example 1

[0093] The only difference between this embodiment and comparative example 1 is that the sulfur salt in step S3 is replaced by sulfur salt, nitrogen salt and fluoride salt, and the rest is the same as comparative example 1. The chemical formula of the prepared high entropy positive electrode material is K 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.0 6Li 0.06 O 1.85 B 0.15 ; Wherein, B is an equimolar amount of S 2- 、N 3- 、F - . Recorded as A-7.

[0094] The preparation method of the high entropy cathode material of this embodiment comprises the following steps:

[0095] S1-S2, same as Comparative Example 1.

[0096] Steps S3 to S5 specifically include the following steps:

[0097] (1) Dissolve the sulfur salt in deionized water, stir to dissolve, and then refrigerate at 5°C for 30 minutes to obtain a sulfur salt solution with a concentration of 0.1 mol / L.

[0098] (2) According to the chemical ratio, the precursor is heated to 950 ° C, then added into a sulfur salt solution for quenching at 25 ° C, and then filtered and dried.

[0099] (3) Dissolve the nitrogen salt in deionized water, stir to dissolve, and refrigerate at 5°C for 30 minutes to obtain a nitrogen salt solution with a concentration of 0.1 mol / L.

[0100] (4) According to the chemical ratio, the material obtained in step (2) is heated to 950°C, then added to a nitrogen salt solution for quenching at 25°C, and filtered and dried.

[0101] (5) Dissolve the fluoride salt in deionized water, stir to dissolve, and refrigerate at 5°C for 30 minutes to obtain a fluoride salt solution with a concentration of 0.1 mol / L.

[0102] (6) According to the chemical ratio, the material obtained in step (4) is heated to 950°C, then added to a fluoride salt solution for quenching at 25°C, and filtered and dried.

[0103] (7) The material obtained in step (6) was sintered at 950°C for 10 hours to obtain a sintered material.

[0104] S6, same as Comparative Example 1.

[0105] Comparative Example 10

[0106] The only difference between this comparative example and Example 1 is that: 2- 、N 3- 、F - The molar ratios of the above compounds were set to 3:1:1, 1:3:1, and 1:1:3, respectively. They were designated as B-4, B-5, and B-6, respectively.

[0107] Comparative Example 11

[0108] The only difference between this comparative example and comparative example 7 is that: 2- 、N 3- The molar ratios of the two compounds were set to 2:1 and 1:2, respectively. They were designated as B-7 and B-8, respectively.

[0109] Comparative Example 12

[0110] The only difference between this comparative example and comparative example 8 is that: 2 The molar ratios of ⁻ and F⁻ were set to 2:1 and 1:2, respectively, and were denoted as B-9 and B-10.

[0111] Comparative Example 13

[0112] The only difference between this comparative example and comparative example 9 is that: 3- 、F - The molar ratios were set to 2:1 and 1:2 and were recorded as B-11 and B-12 respectively.

[0113] Comparative Example 14

[0114] The chemical formula of the high entropy cathode material of this comparative example is K 0.5 Mn 0.7 (CoFeCuTiLi) 0.3 O 1.9 S 0.1 , wherein the molar ratios of the elements Co, Fe, Cu, Ti, and Li are set to 1:1:1:1:0.5, 1:1:1:1:1.5, and 1:1:1:1:2, respectively, and are denoted as B-13, B-14, and B-15.

[0115] Example 2

[0116] This example illustrates the effect of different M elements on the preparation of high entropy cathode materials. Except for the use of different M elements, everything else is the same as Example 1.

[0117] The high entropy cathode material was prepared according to the method of Example 1, and the results are shown in Table 1.

[0118] Table 1

[0119]

[0120] Example 3

[0121] This example illustrates the effect of different anion source ratios on the preparation of high entropy cathode materials. Except for the use of different anion source ratios, everything else is the same as Example 1.

[0122] The high entropy cathode material was prepared according to the method of Example 1. The results are shown in Table 2.

[0123] Table 2

[0124]

[0125] Example 4

[0126] This example illustrates the effect of different transition metal source ratios on the preparation of high entropy cathode materials. Except for the use of different transition metal source ratios, everything else is the same as Example 1.

[0127] The high entropy cathode material was prepared according to the method of Example 1. The results are shown in Table 3.

[0128] Table 3

[0129]

[0130] Comparative Example 15

[0131] This comparative example is different from Example 1 in that it is prepared by a simple mixed doping method, which is denoted as B-18 and specifically includes the following steps:

[0132] The preparation method of the high entropy cathode material of this comparative example comprises the following steps:

[0133] S1. According to the chemical ratio, weigh K2CO3, MnO2, Fe2O3, CuO, TiO2, Co2O3, Li2O, sulfur salt, nitrogen salt and fluoride salt, place the above metal oxides in an agate mortar and grind them to obtain a mixture powder.

[0134] S2. The mixture powder was placed in an alumina crucible and placed in the center of a high-temperature tube furnace. The temperature was raised to 950°C at a rate of 6°C / min and calcined in one step. The temperature was kept for 15 hours to form a preliminary layered oxide structure to obtain material B-18.

[0135] Comparative Example 16

[0136] The difference between this comparative example and Example 1 is that the order of anion doping is different, and the first fluorine (F - ) salt solution, nitrogen (N 3- ) salt solution and finally sulfur (S 2- ) salt solution for doping. Recorded as B-19.

[0137] Comparative Example 17

[0138] This comparative example differs from Example 1 only in that the refrigeration process in steps (1), (3), and (5) is omitted, and the sulfur salt, nitrogen salt, and fluoride salt are dissolved in deionized water, stirred, and dissolved, to directly obtain a corresponding salt solution with a concentration of 0.1 mol / L. This is designated as B-20.

[0139] Comparative Example 18

[0140] The only difference between this comparative example and Example 1 is that step S6 is omitted.

[0141] Example 5

[0142] This example illustrates the effect of different calcination temperatures on the preparation of high entropy cathode materials.

[0143] The only difference between this embodiment and embodiment 1 is that the calcination temperatures are set to 100°C and 1300°C respectively, and the rest are the same as embodiment 1. They are respectively denoted as B-22 and B-23.

[0144] Example 6

[0145] This embodiment illustrates the effect of different precursor heating temperatures on the preparation of high entropy cathode materials in step S4.

[0146] The difference between this embodiment and embodiment 1 is that the precursor heating temperature is set to 100°C and 1100°C respectively, and the rest is the same as embodiment 1. They are respectively denoted as B-24 and B-25.

[0147] Example 7

[0148] This example illustrates the effect of different sintering temperatures on the preparation of high entropy cathode materials.

[0149] The only difference between this embodiment and embodiment 1 is that the sintering temperatures are set to 100°C and 1600°C respectively, and the rest are the same as embodiment 1. They are respectively denoted as B-26 and B-27.

[0150] Example 8

[0151] The only difference between this embodiment and embodiment 1 is that the chemical formula of the high entropy cathode material of this embodiment is Na 0. 5Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.85 S 0.05 N 0.05 F 0.05 .

[0152] The preparation method of the high entropy cathode material of this embodiment comprises the following steps:

[0153] S1. According to the chemical ratio, weigh Na2CO3, MnO2, Fe2O3, CuO, TiO2, Co2O3 and Li2O, place the above metal oxides in an agate mortar and grind them for 30 minutes to obtain a uniform mixture powder.

[0154] The rest is the same as Example 1.

[0155] The effect of this embodiment is the same as that of embodiment 1.

[0156] Test Case

[0157] The material obtained in Example 1 was tested. Figure 1 is the refined X-ray diffraction (XRD) pattern of the final product prepared in Example 1 of the present invention; Table 4 is the material crystal structure parameters obtained by refinement of the final product prepared in Example 1 of the present invention; Figure 2 is a scanning electron microscope (SEM) image of the final product prepared in Example 1 of the present invention; Figure 3 is a line scan SEM image of a single particle of the final product prepared in Example 1 of the present invention; Figure 4 This is a line scan result of a single particle of the final product prepared in Example 1 of the present invention; Figure 5 This is the TEM EDS image of the final product prepared in Example 1 of the present invention; it can be found that the high entropy positive electrode material prepared in Example 1 is a single-phase layered oxide structure with a space group of P63 / mmc, unit cell parameters a=2.8Å~3.0Å, c=13.8Å~14.5Å; and a particle size of 5μm~20μm.

[0158] Table 4

[0159]

[0160] A-1-A-13 and B-1-B-27, acetylene black, and PVDF were mixed in NMP at a mass ratio of 7:2:1 at room temperature and stirred evenly to prepare a cathode slurry. The slurry was then coated onto aluminum foil, dried under vacuum at 120°C, cooled, and then rolled to form a cathode sheet. The electrolyte consisted of 0.8M KPF6 dissolved in an EC / PC solution with a volume ratio of 1:1. Finally, a half-cell was constructed using the cathode sheet, a separator (GF / D glass microfiber filter paper from Whatman), and potassium metal. The half-cell was assembled into a coin cell in a glove box and tested on a blue battery test system at 25°C. The results are shown in Tables 5-6.

[0161] Table 5

[0162]

[0163] Table 6

[0164]

[0165] The above-described embodiments merely represent several implementation methods of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A method for preparing a high entropy cathode material for sodium / potassium ion batteries doped with multiple anions, characterized in that: The chemical formula of high entropy cathode material is A 0.5 Mn 0.7 Co 0.06 Fe 0.06 Cu 0.06 Ti 0.06 Li 0.06 O 1.85 S 0.05 N 0.05 F 0.05 ; Wherein, A is K or Na; The preparation method of the high entropy cathode material comprises the following steps: S1. Mixing an alkali metal salt, a Mn source, a Co source, a Fe source, a Cu source, a Ti source, and a Li source according to a chemical ratio, and grinding the mixture to obtain a mixture powder; S2, calcining the mixture powder to obtain a precursor; S3. Dissolve the S source in deionized water, stir to dissolve, and refrigerate at 5°C to 8°C for 30 min to 50 min to obtain a mixed solution A; S4, heating the precursor to 650°C-950°C according to the chemical ratio, then adding it to the mixed solution A for quenching at 25°C-30°C, filtering and drying; S5. Dissolve the nitrogen source in deionized water, stir to dissolve, and refrigerate at 5°C to 8°C for 30 min to 50 min to obtain a mixed solution B. S6. According to the chemical ratio, the material obtained in step S4 is heated to 650°C to 950°C, then added to the mixed solution B for quenching at 25°C to 30°C, and filtered and dried; S7. Dissolve the F source in deionized water, stir to dissolve, and refrigerate at 5°C to 8°C for 30 min to 50 min to obtain a mixed solution C; S8. According to the chemical ratio, the material obtained in step S6 is heated to 650° C. to 950° C., then added to the mixed solution C for quenching at 25° C. to 30° C., and filtered and dried to obtain a quenched material; S9, sintering the quenched material obtained in step S8 at 300° C. to 1500° C. for 8 h to 15 h to obtain a sintered material; S10, repeating the operations of step S3 to step S9 on the sintered material to obtain the high entropy cathode material; the high entropy cathode material has a single-phase layered oxide structure, a space group of P63 / mmc, and unit cell parameters a=2.8Å~3.0Å, c=13.8Å~14.5Å; The particle size of the high entropy positive electrode material is 5 μm to 20 μm.

2. The method for preparing a high entropy cathode material for sodium / potassium ion batteries doped with multiple anions according to claim 1, characterized in that: In step S1, the particle size of the mixture powder is 5 μm to 15 μm; The alkali metal salt includes Na2CO3 or K2CO3; The Mn source, the Co source, the Fe source, the Cu source, the Ti source, and the Li source are at least one of carbonates and oxides of corresponding transition metals.

3. The method for preparing a high entropy cathode material for sodium / potassium ion batteries doped with multiple anions according to claim 1, wherein: In step S2, the calcination temperature is 1°C / min to 10°C / min, the calcination temperature is 200°C to 1200°C, and the calcination time is 3h to 20h; In step S4, step S6 and step S8, the drying temperature is 70°C to 180°C, and the drying time is 5h to 24h; In step S9, the sintering temperature is 500° C. to 1000° C., and the sintering time is 8 h to 15 h; In step S10, the operation is repeated 2 to 20 times.

4. The method for preparing a high entropy cathode material for sodium / potassium ion batteries doped with multiple anions according to claim 1, characterized in that: The S source, the N source and the F source are S 2- 、N 3- 、F - corresponding salt; The concentrations of the mixed solution A, the mixed solution B, and the mixed solution C are 0.01 mol / L to 2 mol / L, respectively.

5. A high entropy cathode material for sodium / potassium ion batteries doped with multiple anions, obtained by the preparation method according to any one of claims 1 to 4.

6. Use of a high entropy cathode material for sodium / potassium ion batteries doped with multiple anions, prepared by the preparation method according to any one of claims 1 to 4, in cathode materials for sodium / potassium ion batteries.

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