A high-osmotic sodium and high-structural entropy sodium vanadium oxyfluorophosphate cathode material and its preparation method

Abstract

A high permeability sodium and high structural entropy sodium vanadium oxyfluorophosphate cathode material and its preparation method, the molecular formula of the material is Na3V 2‑x (TM) x (PO4)2F 3‑η O η / 2 , where 0

Description

Technical Field

[0001] The present invention relates to the preparation and application of high-performance positive electrode materials for sodium batteries, and in particular to a high-permeability sodium and high-structural entropy sodium vanadium oxyfluorophosphate positive electrode material and a preparation method thereof. Background Art

[0002] With the advancement of industrialization and modernization, global demand for energy is rapidly increasing. Energy storage technologies for renewable energy generation and novel power systems, such as large-scale pumped hydropower storage, battery energy storage, and hydrogen energy storage, have garnered widespread attention. As an emerging battery energy storage technology, rechargeable sodium batteries, with their advantages such as long cycle life, wide temperature range, and low cost, are suitable for applications such as low-speed, short-range electric vehicles and large-scale energy storage power stations, demonstrating broad application prospects.

[0003] The positive electrode material is the key to determining the performance and cost of sodium batteries. The sodium battery positive electrode materials that are currently widely studied mainly include polyanion compounds, layered oxides and Prussian materials. Among them, polyanion positive electrode materials have excellent thermal stability, safety and good cycle performance. In particular, the polyanion sodium vanadium oxyfluorophosphate positive electrode material has a super stable three-dimensional framework structure and significant advantages such as high operating voltage, high energy density, and small charge and discharge volume change. It is a sodium battery positive electrode material with great potential. However, the intrinsic conductivity of sodium vanadium oxyfluorophosphate is low, resulting in its electrochemical performance such as rate performance being less than ideal, which limits its development and application.

[0004] To this end, traditional modification techniques such as ion doping, surface coating and material composites have been used to enhance the conductivity of sodium vanadium oxyfluorophosphate, thereby improving its actual electrochemical performance. For example, Yang Ju et al. prepared iron-doped Na3V 2-x Fe x (PO4)2F3 (《Chemical Engineering Journal, 2024, 485:149834.》), promoted the Na + The transfer of the material reduces the structural deterioration of the material during the charge and discharge process; Zhuang Shuhan et al. prepared aluminum-doped Na3V by the sol-gel method. 2-x Al x (PO4)2F3 (Surface & Coatings Technology, 2022, 434: 128184.), which improves the electronic conductivity and sodium ion diffusion rate of the material, thereby improving the electrochemical performance of sodium vanadium oxyfluorophosphate; He Jiarong et al. prepared rGO-coated stacked Na3(VO x PO4)2F 3-2x@NVP fine core-shell structure, based on the synergistic effect of the core-shell structure and rGO, improves the rate performance of the material (《ACS Applied Materials & Interfaces, 2021, 13(50): 60099 - 114.》). However, this type of modification method has problems such as harsh modification conditions, limited performance improvement, complex preparation process, and large cost increase, and fails to effectively promote the industrial production and application of sodium vanadium oxyfluorophosphate. Summary of the Invention

[0005] Aiming at the problems in the prior art, the purpose of the present invention is to provide a high-sodium and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material and its preparation method. By selecting a variety of adjustable transition metal elements to replace part of vanadium, a high-sodium and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material with stable morphology, excellent performance, and good uniformity is prepared through a one-step solid-phase thermal coupling sintering method, which has the characteristics of simplicity and controllability.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high-sodium and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material, with the molecular formula Na3V 2-x (TM) x (PO4)2F 3-η O η / 2 , where 0 < x < 2, 0 < η < 3, and TM is a variety of adjustable transition metal elements, including Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Mg, Li, Ca, Zr, Nb, Mo, Cd, Ga, In, Y, Ba, Sn, Sb, or Bi;

[0008] For the high-sodium and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material, the configurational entropy ΔS conf is 1.4R - 1.8R;

[0009] For the high-sodium and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material, D Na + is 1×10 -8 -1×10 -11 cm 2 s -1 .

[0010] A preparation method of a high-sodium and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material, comprising the following steps:

[0011] Step S1, mixing and dissolving a sodium source, a vanadium source, a phosphorus source, a fluorine source, and a transition metal source in a solvent, adding an additive and a reducing agent, and wet-mixing and grinding evenly to obtain a mixed solution;

[0012] Step S2, subjecting the mixed solution obtained in Step S1 to microwave-controlled drying to obtain a mixed powder;

[0013] Step S3, grinding the mixed powder obtained in step S2 and pressing it into a sheet precursor;

[0014] Step S4, under atmosphere protection conditions, the sheet precursor obtained in step S3 is subjected to thermomechanical coupling sintering, then cooled to room temperature, and ground and sieved to obtain a high-permeability sodium and high-structural entropy sodium vanadium oxyfluorophosphate positive electrode material with uniform particle size.

[0015] The sodium source in step S1 includes: a mixture of one or more of NaCl, Na2O, NaNO3, Na2S2O3, Na2SO4, Na2CO3, Na3PO4, Na2HPO4, CH3COONa, C6HNaO7, NaOH, NaF, sodium lauryl sulfate, and sodium glycinate in any proportion.

[0016] The vanadium source in step S1 includes: a mixture of one or more of V2O5, V2O3, VOSO4, NH4VO3, Na3VO4, vanadium acetylacetonate, and vanadyl acetylacetonate in any proportion.

[0017] The phosphorus source in step S1 includes: a mixture of one or more of Na3PO4, Na2HPO4, Na4P2O7, NH4H2PO4, (NH4)2HPO4, H3PO4, (NH4)2HPO3, NH4H2PO2, and diphenyl phosphite in any proportion.

[0018] The fluorine source in step S1 includes: a mixture of one or more of NaF, H2SiF6, HF, NH4F, CF4, CaF2, AlF3, CHF3, C2F6, tetrabutylammonium fluoride, and polytetrafluoroethylene in any proportion.

[0019] The transition metal source in step S1 includes a mixture of carbonates, nitrates, sulfates, oxides or hydroxides of five or more different metal elements; the carbonates, nitrates, sulfates, oxides or hydroxides of different metal elements specifically include: NiCO3, Ni(NO3)2·6H2O, MgCO3, MgSO4, Mg(NO3)2·6H2O, Al(NO3)3·9H2O, Al2(CO3)3, Cr(NO3)3·9H2O, CuSO4, Cu(NO3)2·3H2O, Fe(NO3)3·9H2O, Li2CO3, LiNO3, Li2SO4, CoCO3, Co(NO3)2·6H2O, MnCO3, Mn(NO3)2, CaCO3, Ca(NO3)2.

[0020] In the transition metal sources of five or more different metal elements, the content of each element is in an equimolar ratio.

[0021] The solvent in the step S1 is one or a mixture of any proportion of anhydrous ethanol, acetone, and deionized water.

[0022] The additives in the step S1 include one or a mixture of any proportion of benzene, ethyl benzoate, ethyl acetate, PVDF, DMSO, chloroform, DMF, PTFE, PEG, THF, and EC.

[0023] The reducing agents in the step S1 include one or a mixture of any proportion of graphene, acetylene black, conductive carbon black, graphite, mesoporous carbon, carbon nanotubes, sucrose, glucose, sucrose, sodium thiosulfate, and sodium nitrite.

[0024] In the step S1, the molar ratio of the added sodium source, vanadium source, phosphorus source, fluorine source, and transition metal source is 3:2 - x:2:3 - η:x, where 0 < x < 2 and 0 < η < 3.

[0025] In the step S1, the mass fraction of the additive is 0.2% - 25% of the total mass of the raw materials.

[0026] In the step S1, the mass fraction of the reducing agent is 1% - 35% of the total mass of the raw materials.

[0027] In the step S2, the working power w of the microwave drying is adjusted, where 0 < w ≤ 2 kW, and the drying time is 3 - 30 min.

[0028] The atmosphere in the step S4 includes one of nitrogen, argon, hydrogen - argon mixture, or nitrogen - hydrogen mixture; the hydrogen - argon mixture is a hydrogen - argon mixture with a hydrogen volume concentration of 2%; the nitrogen - hydrogen mixture is a nitrogen - hydrogen mixture with a nitrogen volume concentration of 5%.

[0029] In the step S4, the thermomechanical coupling sintering is carried out using one - stage, two - stage, or three - stage temperature ramps. If using one - stage temperature ramp, the sintering temperature is 500 - 950 °C and the sintering time is 0.2 - 20 h; if using two - stage temperature ramps, the sintering temperatures are 300 - 600 °C and 500 - 950 °C respectively, and the sintering times are 0.1 - 6 h and 0.1 - 20 h respectively; if using three - stage temperature ramps, the sintering temperatures are 100 - 400 °C, 300 -​​​​​(1) The present invention adopts crystal structure engineering and high entropy material theory and technology to design a high sodium permeability and high structural entropy sodium vanadium oxyfluorophosphate positive electrode material. By using equal proportions of transition metal elements such as Ni, Mg, Al, Cr, Cu, Fe, Li, Co, Mn, and Ca, the intrinsic crystal structure and electrochemical performance of sodium vanadium oxyfluorophosphate are cleverly and effectively regulated. The molecular composition and crystal structure are special, which can significantly increase the material configuration entropy and sodium permeability, improve the structural stability, charge and discharge voltage, sodium ion diffusion rate and electronic conductivity, and obtain a sodium battery positive electrode material with excellent performance. △S conf 1.4R~1.8R, stable structure, high charge and discharge voltage; high sodium permeation rate, D Na + 1×10 -8 ~1×10 -11 cm 2 s -1 , the sodium ion diffusion rate and electronic conductivity are high, and the charge and discharge rates are fast.

[0032] (2) The high-permeability sodium and high-structural entropy sodium vanadium oxyfluorophosphate positive electrode material of the present invention is prepared by sintering using a one-step high-temperature solid-phase thermomechanical coupling method. The raw material source is abundant, the process is simple, the preparation cost is low, and it is easy to produce on a large scale.

[0033] (3) The present invention uses solvents to ensure uniform mixing and dissolution of raw materials, and further regulates the nucleation and growth of high-osmotic sodium and high-structural entropy materials through additives to improve the product synthesis rate.

[0034] (4) The present invention utilizes microwave-controlled drying to not only address traditional drying issues such as uneven drying and the internal generation of charred materials, but also facilitates the formation of a homogeneous precursor. Furthermore, the puffing effect of microwave-controlled drying facilitates subsequent grinding, improving the quality and efficiency of material preparation.

[0035] (5) The present invention utilizes the combination of pressed sheet precursors and temperature step control to perform thermomechanical coupled sintering, which effectively improves the kinetics of seed nucleation, growth, and agglomeration, and obtains a synthetic product with precise structure, good crystallization, and uniform particles.

[0036] In summary, the present invention utilizes crystal structure engineering and high entropy material theory and technology to design and improve the intrinsic electronic conductivity and sodium permeability of sodium vanadium oxyfluorophosphate from the source of the material crystal structure, and suppresses its adverse phase transition during charging and discharging, and develops high-sodium-high structural entropy sodium vanadium oxyfluorophosphate, which effectively improves the structural entropy, stability, conductivity and sodium permeability of sodium vanadium oxyfluorophosphate, and significantly improves the specific capacity, rate and cycle of sodium vanadium oxyfluorophosphate. The actual electrochemical performance. The present invention adopts a one-step solid-phase thermomechanical coupling sintering method to cleverly and controllably prepare high-sodium-high structural entropy sodium vanadium oxyfluorophosphate, which has simple process, stable structure, uniform morphology, low cost and excellent performance, and is expected to promote and accelerate the scale production and application process of such materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is the XRD spectrum of the high-permeability sodium and high-structural entropy sodium vanadium oxyfluorophosphate material according to Example 1 of the present invention.

[0038] Figure 2 This is an SEM image of the hypertonic sodium and high structural entropy sodium vanadium oxyfluorophosphate material according to Example 2 of the present invention.

[0039] Figure 3 This is the constant current charge and discharge curve of the high-osmotic sodium and high-structural entropy sodium vanadium oxyfluorophosphate material of Example 2 of the present invention.

[0040] Figure 4 This is a long cycle performance diagram of the high-osmotic sodium and high-structural entropy sodium oxyvanadium fluorophosphate material of Example 3 of the present invention. DETAILED DESCRIPTION

[0041] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] Example 1

[0043] The hypertonic sodium and high structural entropy sodium vanadium oxyfluorophosphate material of this embodiment is expressed as follows:

[0044] 3V 1.5 (Ni,Mg,Al,Cr,Cu) 0.5 (PO4)2F2O

[0045] The preparation method of the hypertonic sodium and high structural entropy sodium vanadium oxyfluorophosphate material of this embodiment comprises the following steps:

[0046] 1. Mix and dissolve a sodium source, a vanadium source, a phosphorus source, a fluorine source, and a transition metal source in a molar ratio of 3:1.5:2:2:0.5 in a solvent, add 5 wt.% of an additive and 8 wt.% of a reducing agent, and wet-mix and grind them uniformly;

[0047] 2. The mixed solution was dried by microwave control with a working power of 1 kW and a drying time of 20 min;

[0048] 3. Grind the mixed powder evenly and press it into a sheet precursor;

[0049] Fourth, the precursor flakes were subjected to two stages of thermomechanically coupled sintering under protective atmosphere. The first stage was held at 350°C for 1 hour. The second stage was sintered at 750°C for 6 hours. The precursor flakes were then cooled to room temperature. After grinding and screening, a uniformly sized, high-permeability, high-structural-entropy sodium vanadium oxyfluorophosphate cathode material was obtained.

[0050] The sodium source is a mixture of Na2CO3 and NaF.

[0051] The vanadium source is V2O5.

[0052] The phosphorus source is NH4H2PO4.

[0053] The fluorine source is NaF.

[0054] The transition metal source is a mixture of NiCO3, MgCO3, Al(NO3)3·9H2O, Cr(NO3)3·9H2O and Cu(NO3)2·3H2O.

[0055] The solvent is a mixed solvent of anhydrous ethanol and deionized water in a mass ratio of 8:2.

[0056] The additive is a mixture of PVDF and PTFE in a mass ratio of 4:6.

[0057] The reducing agent is a mixture of conductive carbon black and sucrose in a mass ratio of 7:3.

[0058] The protective atmosphere is argon.

[0059] Figure 1 The XRD pattern of the high-permeability sodium and high-structural entropy sodium vanadium oxyfluorophosphate material prepared in Example 1 of the present invention has sharp diffraction peaks, good crystallinity, and no obvious by-products, indicating that the increase in entropy is conducive to promoting the formation of a single-phase material.

[0060] Example 2

[0061] The hypertonic sodium and high structural entropy sodium vanadium oxyfluorophosphate material of this embodiment is expressed as follows:

[0062] 3V 1.9 (Ni,Mg,Al,Fe,Mn) 0.1 (PO4)2F2O

[0063] The high permeability sodium and high structural entropy sodium oxyfluorophosphate cathode material has high structural entropy, △S conf 1.4R~1.8R, stable structure, high charge and discharge voltage;

[0064] The high sodium permeability and high structural entropy sodium vanadium oxyfluorophosphate positive electrode material has a high sodium permeability. Na + 1×10 -8 ~1×10 - 11 cm 2 s -1 , the sodium ion diffusion rate and electronic conductivity are high, and the charge and discharge rates are fast.

[0065] The preparation method of the hypertonic sodium and high structural entropy sodium vanadium oxyfluorophosphate material of this embodiment comprises the following steps:

[0066] 1. Mix and dissolve a sodium source, a vanadium source, a phosphorus source, a fluorine source, and a transition metal source in a molar ratio of 3:1.9:2:2:0.1 in a solvent, add 10 wt.% of an additive and 10 wt.% of a reducing agent, and wet-mix and grind until uniform;

[0067] 2. The mixed solution was dried by microwave control with an operating power of 1 kW and a drying time of 16 min.

[0068] 3. Grind the mixed powder evenly and press it into a sheet precursor;

[0069] Fourth, the precursor was subjected to thermomechanical coupling sintering under protective atmosphere conditions, using a temperature step at 750°C for 10 hours, followed by cooling to room temperature. After grinding and screening, a uniformly sized, high-permeability, high-structural entropy sodium vanadium oxyfluorophosphate cathode material was obtained.

[0070] The sodium source is a mixture of NaOH, Na2CO3 and NaF.

[0071] The vanadium source is NH4VO3.

[0072] The phosphorus source is a mixture of H3PO4 and NH4H2PO4.

[0073] The fluorine source is a mixture of NaF and NH4F.

[0074] The transition metal source is a mixture of Ni(NO3)2·6H2O, Mg(NO3)2·6H2O, Al(NO3)3·9H2O, Fe(NO3)3·9H2O and Mn(OH)2.

[0075] The solvent is anhydrous ethanol solvent.

[0076] The additive is a mixture of PEG and PVDF in a mass ratio of 2:8.

[0077] The reducing agent is a mixture of graphene, glucose and acetylene black in a mass ratio of 0.5:2.5:7.

[0078] The protective atmosphere is a hydrogen-argon mixed gas with a volume concentration of 2% hydrogen.

[0079] Figure 2 、 Figure 3 They are respectively the SEM image and the constant current charge-discharge curve of the high-osmotic sodium and high-structural entropy sodium oxyfluorophosphate material prepared in Example 2 of the present invention. Figure 2 From the SEM image, it can be seen that the sample morphology is irregularly shaped secondary particles with some slight agglomeration. Figure 3The charge-discharge curves show that the material has a high charge-discharge voltage platform and a first-cycle coulombic efficiency of 95.37%. The reversible specific capacities at 0.1C, 1C, 5C, 10C, 20C, and 40C rates are 132, 108, 83, 70, 56, and 41 mAh g, respectively. -1 After 500 cycles at a current density of 1C, the capacity retention rate is as high as 81.2%, indicating that the high sodium permeability and high structural entropy sodium vanadium oxyfluorophosphate material has effectively improved the material's structural entropy, sodium permeability and actual electrochemical performance by regulating the crystal structure of sodium vanadium oxyfluorophosphate.

[0080] Example 3

[0081] The hypertonic sodium and high structural entropy sodium vanadium oxyfluorophosphate material of this embodiment is expressed as follows:

[0082] 3V 1.85 (Ni,Mg,Al,Cr,Cu,Li) 0.15 (PO4)2F2O

[0083] The method for preparing the sodium vanadium oxyfluorophosphate material with high permeability and high structural entropy comprises the following steps:

[0084] 1. Mix and dissolve a sodium source, a vanadium source, a phosphorus source, a fluorine source, and a transition metal source in a solvent at a molar ratio of 3:1.85:2:2:0.15, add 10 wt.% of an additive and 5 wt.% of a reducing agent, and wet-mix and grind until uniform;

[0085] Second, the mixed solution was dried by microwave control with a working power of 1.5 kW and a drying time of 8 minutes;

[0086] 3. Grind the mixed powder evenly and press it into a sheet precursor;

[0087] Fourth, the precursor was subjected to thermomechanical coupling sintering at 700°C for 8 hours under protective atmosphere, and then cooled to room temperature. After grinding and screening, a high-permeability sodium, high-structural entropy sodium vanadium oxyfluorophosphate cathode material with uniform particle size was obtained.

[0088] Fourth, the precursor was subjected to three stages of thermomechanically coupled sintering under protective atmosphere. The first stage was held at 400°C for 0.5 hours; the second stage was sintered at 500°C for 5 hours; and the third stage was sintered at 700°C for 8 hours. The precursor was then cooled to room temperature. After grinding and screening, a uniformly sized, high-permeability, high-structural-entropy sodium vanadium oxyfluorophosphate cathode material was obtained.

[0089] The sodium source is a mixture of Na2CO3 and NaF.

[0090] The vanadium source is a mixture of V2O5 and NH4VO3 in a molar ratio of 1:1.

[0091] The phosphorus source is NH4H2PO4.

[0092] The fluorine source is NaF.

[0093] The transition metal source is a mixture of six types: Ni(NO3)2·6H2O, Mg(NO3)2·6H2O, Al(NO3)3·9H2O, Cr(NO3)3·9H2O, Cu(NO3)2·3H2O, and Li2CO3.

[0094] The solvent is a mixed solvent of anhydrous ethanol and deionized water.

[0095] The additive is a mixture of PTFE and DMSO in a mass ratio of 9:1.

[0096] The reducing agent is a mixture of conductive carbon black, sucrose and carbon nanotubes in a mass ratio of 8:1.5:0.5.

[0097] The protective atmosphere is a nitrogen-argon mixed gas with a nitrogen content of 5% by volume.

[0098] Figure 4 This is a long cycle performance diagram of the hypertonic sodium and high-structural entropy sodium vanadium oxyfluorophosphate material of Example 3 of the present invention. After 500 cycles at a rate of 1C, the capacity retention rate is as high as 80%, and the Coulombic efficiency is basically always maintained at around 100%, indicating that the hypertonic sodium and high-structural entropy sodium vanadium oxyfluorophosphate material effectively improves the cycle stability of the material and significantly improves the electrochemical performance of the sodium vanadium oxyfluorophosphate material.

Claims

1. A method for preparing a high-osmotic sodium and high-structural entropy sodium vanadium oxyfluorophosphate cathode material, characterized in that: It includes the following steps: Step S1: Mix and dissolve a sodium source, a vanadium source, a phosphorus source, a fluorine source, and a transition metal source in a solvent, add an additive and a reducing agent, and perform wet mixing and grinding evenly to obtain a mixed solution; Step S2: Perform microwave-controlled drying on the mixed solution obtained in Step S1 to obtain a mixed powder; Step S3: Grind the mixed powder obtained in Step S2 and press it into a sheet-shaped precursor; Step S4: Under the condition of atmosphere protection, perform thermal-mechanical coupling sintering on the sheet-shaped precursor obtained in Step S3, then cool it to room temperature, and after grinding and sieving, obtain a sodium-rich and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material with uniform particle size; The transition metal source in Step S1 includes a mixture of carbonates, nitrates, sulfates, oxides, or hydroxides of five or more different metal elements; the carbonates, nitrates, sulfates, oxides, or hydroxides of different metal elements specifically include: NiCO3, Ni(NO3)2·6H2O, Al(NO3)3·9H2O, Al2(CO3)3, Cr(NO3)3·9H2O, CuSO4, Cu(NO3)2·3H2O, Fe(NO3)3·9H2O, CoCO3, Co(NO3)2·6H2O, MnCO3, Mn(NO3)2; The additive in Step S1 includes one or a mixture of any proportion of benzene, ethyl benzoate, ethyl acetate, PVDF, DMSO, chloroform, DMF, PTFE, PEG, THF, EC; The reducing agent in Step S1 includes one or a mixture of any proportion of graphene, acetylene black, conductive carbon black, graphite, mesoporous carbon, carbon nanotubes, sucrose, glucose, sucrose, sodium thiosulfate, sodium nitrite; In the transition metal source of five or more different metal elements, the content of each element is in an equimolar ratio; In Step S2, the working power w of the microwave drying is adjusted, 0 < w ≤ 2 kW, and the drying time is 3 - 30 min; In Step S4, the thermal-mechanical coupling sintering is carried out using one-stage, two-stage or three-stage temperature ramps for sintering; for one-stage temperature ramp, the sintering temperature is 500 - 950 °C and the sintering time is 0.2 - 20 h; for two-stage temperature ramps, the sintering temperatures are 300 - 600 °C and 500 - 950 °C respectively, and the sintering times are 0.1 - 6 h and 0.1 - 20 h respectively; for three-stage temperature ramps, the sintering temperatures are 100 - 400 °C, 300 - 700 °C, and 600 - 950 °C respectively, and the sintering times are 0.1 - 6 h, 0.1 - 6 h, and 0.1 - 20 h respectively.

2. The preparation method of a sodium-rich and high-configurational-entropy sodium vanadium oxyfluorophosphate cathode material according to claim 1, wherein The sodium source in Step S1 includes one or a mixture of any proportion of NaCl, Na2O, NaNO3, Na2S2O3, Na2SO4, Na2CO3, Na3PO4, Na2HPO4, CH3COONa, C6HNaO7, NaOH, NaF, sodium dodecyl sulfate, sodium glycinate; The vanadium source in step S1 includes: a mixture of one or more of V2O5, V2O3, VOSO4, NH4VO3, Na3VO4, vanadium acetylacetonate, and vanadyl acetylacetonate in any proportion; The phosphorus source in step S1 includes: a mixture of one or more of Na3PO4, Na2HPO4, Na4P2O7, NH4H2PO4, (NH4)2HPO4, H3PO4, (NH4)2HPO3, NH4H2PO2, and diphenyl phosphite in any proportion; The fluorine source in step S1 includes: a mixture of one or more of NaF, H2SiF6, HF, NH4F, CF4, CaF2, AlF3, CHF3, C2F6, tetrabutylammonium fluoride, and polytetrafluoroethylene in any proportion; The solvent in step S1 is a mixed solvent of one or more of anhydrous ethanol, acetone, and deionized water in any proportion.

3. The method for preparing a high-osmotic sodium and high-structural entropy sodium vanadium oxyfluorophosphate cathode material according to claim 1, characterized in that: In the step S1, the molar ratio of the added sodium source, vanadium source, phosphorus source, fluorine source, and transition metal source is 3:2-x:2:3-η:x, 0 <x<2,0<η<3。 4. The method for preparing a high-osmotic sodium and high-structural entropy sodium vanadium oxyfluorophosphate cathode material according to claim 1, characterized in that: In the step S1, the mass fraction of the additive is 0.2% to 25% of the total mass of the raw material.

5. The method for preparing a high-osmotic sodium and high-structural entropy sodium vanadium oxyfluorophosphate cathode material according to claim 1, characterized in that: In step S1, the mass fraction of the reducing agent is 1% to 35% of the total mass of the raw materials.

6. The method for preparing a high-osmotic sodium and high-structural entropy sodium vanadium oxyfluorophosphate cathode material according to claim 1, characterized in that: The atmosphere in step S4 includes: one of nitrogen, argon, hydrogen-argon mixture or nitrogen-hydrogen mixture; the hydrogen-argon mixture is a hydrogen-argon mixture with a volume concentration of 2% hydrogen; the nitrogen-hydrogen mixture is a nitrogen-argon mixture with a volume concentration of 5% nitrogen.

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