Preparation method of high-performance sodium vanadium phosphate positive electrode material of sodium-ion battery

Abstract

The invention discloses a preparation method of a high-performance sodium vanadium phosphate positive electrode material of a sodium-ion battery, and relates to the field of sodium-ion batteries, and the method comprises the following steps: weighing raw materials for preparation according to the stoichiometric ratio of the sodium vanadium phosphate positive electrode material, and the raw materials for preparation comprise a sodium source, a vanadium source and a phosphorus source; the method comprises the following steps: adding a vanadium source, a reaction auxiliary agent, a sodium source, a phosphorus source and rhodamine as additive substances into deionized water according to a preset adding sequence, and accelerating the mixing process of the additive substances and the deionized water to obtain a sodium vanadium phosphate precursor; and treating the sodium vanadium phosphate precursor by using a drying technology and a grinding technology, placing the ground sodium vanadium phosphate precursor in an inert atmosphere, and sequentially carrying out heating treatment and sintering treatment to obtain the sodium vanadium phosphate positive electrode material of the sodium-ion battery. The rhodamine is used for performing carbon coating on the sodium vanadium phosphate, and the coated material is small in particle size, so that the contact with an electrolyte is increased, the rate capability and the cycle performance of the material are improved, and the service life of the material is prolonged.

Description

Technical Field

[0001] The invention relates to the field of sodium ion batteries, and in particular to a method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries. Background Art

[0002] With the development of science and technology, the demand for sustainable energy and large-scale energy storage is growing rapidly. Lithium-ion batteries have become the preferred energy storage material for portable electronic devices and electric vehicles due to their higher energy density, better cycle performance and wider charge and discharge window. However, the scarcity and uneven distribution of lithium resources have caused the price to soar, and the general stability of lithium batteries has limited the application of lithium-ion batteries.

[0003] Therefore, considering the abundant sodium resources and low price, sodium-ion batteries are expected to become a candidate material for large-scale energy storage in the future, and sodium-ion batteries are currently a hot research topic. More than a decade ago, the research on sodium-ion batteries re-attracted the attention of scientific researchers. At the same time, some large battery manufacturers began to invest in sodium-ion battery technology to promote its commercial development. These batteries are designed for grid energy storage, electric vehicles and other applications as a substitute or supplement to lithium-ion batteries. So far, more than 20 companies around the world have invested in the industrial research and development of sodium-ion batteries. This phenomenon indicates that sodium-ion batteries are gradually moving towards a practical stage.

[0004] The working principle of sodium ion batteries is similar to that of lithium ion batteries, both of which are "rocking chair" batteries. + It is repeatedly released and embedded between the positive and negative electrodes of the battery in a continuous cycle. Sodium-ion batteries are mainly composed of four parts: positive electrode sheet, negative electrode sheet, electrolyte and separator. The positive electrode material is a very critical component of the battery and plays a key role in the performance of sodium-ion batteries. Common positive electrode materials mainly include layered metal oxides, transition metal salts and polyanionic compounds with three-dimensional channels. Among them, polyanionic compounds have an open three-dimensional crystal structure with a large spatial gap, which is convenient for the rapid diffusion of sodium ions with a large radius. The XO covalent bond structure is stable, and the induction effect on redox electron pairs is significant. It exhibits a high redox potential, and the volume changes little during the sodium ion deintercalation process. The material has excellent electrochemical properties and can meet the requirements for long cycle life of electrode materials. It has been favored by scholars in recent years. Polyanionic compounds, representative materials include sodium vanadium phosphate Na3V2(PO4)3, with a theoretical specific capacity of up to 117.6mAhg -1 , the voltage platform is as high as 3.4V, and it has the characteristics of thermal stability and structural stability. However, since the radius of sodium ions is larger than that of lithium ions, Na + The slow diffusion rate makes the electronic conductivity of the material poor, resulting in poor cycle stability and high-rate performance of the material.

[0005] In order to improve the electrochemical performance of Na3V2 (PO4) 3 materials, they are modified. The commonly used modification methods in existing patents include carbon source and nitrogen source coating, anion and cation doping, material morphology nano-sizing and heteroatom doping. For the carbon coating of sodium vanadium phosphate Na3V2 (PO4) 3, commonly used materials include glucose, sucrose, ascorbic acid, citric acid, etc. Although the performance of Na3V2 (PO4) 3 materials after carbon coating has made significant progress, it still faces two major challenges: low cycle stability and rate performance.

[0006] Currently, no effective solution has been proposed for the problems in the related technologies. Summary of the invention

[0007] In view of the problems in the related art, the present invention proposes a method for preparing a high-performance sodium vanadium phosphate positive electrode material for a sodium ion battery to overcome the above-mentioned technical problems existing in the existing related technology.

[0008] To this end, the specific technical solution adopted by the present invention is as follows: A method for preparing a high-performance sodium vanadium phosphate positive electrode material for a sodium ion battery, the method comprising: According to the stoichiometric ratio of the sodium vanadium phosphate positive electrode material, raw materials for preparation are weighed, and the raw materials for preparation include a sodium source, a vanadium source and a phosphorus source; According to a preset order of addition, a vanadium source, a reaction auxiliary agent, a sodium source, a phosphorus source and rhodamine are added as additives to deionized water, and the mixing process of the additives and the deionized water is accelerated to obtain a sodium vanadium phosphate precursor, wherein the reaction auxiliary agent includes a reducing agent and a complexing agent; The sodium vanadium phosphate precursor is processed by drying technology and grinding technology, and the ground sodium vanadium phosphate precursor is placed in an inert atmosphere, and is heated and sintered in sequence to obtain the sodium vanadium phosphate positive electrode material for sodium ion batteries.

[0009] Among them, rhodamine is a compound with a red to brown powder appearance and is soluble in water and ethanol.

[0010] Furthermore, the sodium source includes at least one of sodium carbonate, sodium acetate, sodium hydroxide, sodium phosphate and sodium dihydrogen phosphate.

[0011] Among them, sodium carbonate is an inorganic compound, usually a white powder, easily soluble in water. Sodium acetate is an organic substance, usually a white crystal or a colorless transparent crystal. Sodium hydroxide is an inorganic compound, usually in the form of flakes or blocks. Sodium phosphate is an inorganic compound. In aqueous solution, sodium phosphate is almost completely decomposed into disodium hydrogen phosphate and sodium hydroxide. Sodium dihydrogen phosphate is an inorganic acid salt, easily soluble in water.

[0012] Furthermore, the vanadium source includes at least one of vanadium pentoxide and ammonium metavanadate.

[0013] Among them, vanadium pentoxide is a metal oxide, belonging to vanadium oxide. Ammonium metavanadate is an inorganic compound, which is a white or slightly yellow crystalline powder at room temperature and easily decomposes when heated. Furthermore, the phosphorus source includes at least one of ammonium dihydrogen phosphate, phosphoric acid, sodium dihydrogen phosphate and ammonium hydrogen phosphate.

[0014] Among them, ammonium dihydrogen phosphate is an inorganic compound, which is a white crystal. Phosphoric acid is a common inorganic acid. Sodium dihydrogen phosphate is an inorganic acid salt, which is easily soluble in water and almost insoluble in ethanol. Ammonium hydrogen phosphate is an inorganic compound, which usually exists in the form of colorless transparent monoclinic crystals or white powder.

[0015] Furthermore, the reducing agent and the complexing agent are both citric acid, and the ratio of citric acid to vanadium source is 1.8-2.5:1.

[0016] Among them, citric acid is an important organic weak acid, colorless crystal, odorless, and easily soluble in water.

[0017] Further, according to a preset order of addition, a vanadium source, a reaction auxiliary agent, a sodium source, a phosphorus source and rhodamine are added as additives to deionized water, and the mixing process of the additives and the deionized water is accelerated to obtain a sodium vanadium phosphate precursor, including: Dissolve the vanadium source in deionized water and add a preset proportion of citric acid; heat and stir the deionized water until it is evenly mixed; A sodium source, a phosphorus source and rhodamine are added to deionized water, and the deionized water is stirred until the mixture is mixed into a gel, thereby obtaining a sodium vanadium phosphate precursor.

[0018] Furthermore, when the deionized water is heated and stirred, the heating temperature is 60-80°C.

[0019] Furthermore, after the sodium source, the phosphorus source and rhodamine are added into deionized water, the mass percentage concentration of rhodamine is 5-15%.

[0020] Furthermore, the sodium vanadium phosphate precursor is treated by drying technology and grinding technology, and the ground sodium vanadium phosphate precursor is placed in an inert atmosphere, and is sequentially heated and sintered to obtain a sodium vanadium phosphate positive electrode material for a sodium ion battery, including: According to preset conditions, the sodium vanadium phosphate precursor is dried and ground in sequence, and the sodium vanadium phosphate precursor is heated in an inert atmosphere; The heated sodium vanadium phosphate precursor is treated in a sintering environment to obtain a carbon-coated sodium vanadium phosphate positive electrode material after a predetermined time; Wherein, the inert atmosphere includes argon, nitrogen and argon-hydrogen mixture; The sintering environment includes a sintering temperature of 720-850°C and a sintering time of 6-12h.

[0021] Furthermore, the preconditions include: The drying temperature is 80-120℃ and the drying time is 12-18h; The heating temperature is 300-400°C and the heating time is 3-5h.

[0022] The beneficial effects of the present invention are: (1) The present invention uses rhodamine to carbon-coat sodium vanadium phosphate, and the preparation method adopted is the sol-gel method. The prepared sodium vanadium phosphate / C positive electrode material has small particle size, uniform distribution, good crystallinity, and significantly improved electronic conductivity of the material, so that the battery has high rate performance, good cycle stability, and long life. The present invention is simple, low-cost, high-efficiency, and excellent product comprehensive performance.

[0023] (2) The preparation method of the high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries provided by the present invention is simple and easy to operate, and has simple equipment requirements. Only stirring, drying and calcining are required to obtain a carbon-coated sodium vanadium phosphate positive electrode material with excellent performance, and the preparation method is easy to promote and apply. The coated material has a small particle size, which can increase the contact with the electrolyte, improve the electronic conductivity of the material, and thus significantly improve the rate performance, cycle performance and service life of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a flow chart of a method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to an embodiment of the present invention; Figure 2 is the X-ray diffraction pattern of the positive electrode material prepared in Example 1; Figure 3 is the cycle performance curve of the positive electrode material prepared in Example 1; Figure 4 is the X-ray diffraction pattern of the positive electrode material prepared in Example 2; Figure 5 : are different magnification diagrams of the positive electrode material prepared in Example 2 and the uncoated comparative sample; Figure 6This is the high rate cycle performance curve of the positive electrode material prepared in Example 2; Figure 7 is the X-ray diffraction pattern of the positive electrode material prepared in Example 3; Figure 8 is a scanning electron microscope image of the positive electrode material prepared in Example 1; Fig. 9 is a scanning electron microscope image of the positive electrode material prepared in Example 2; Fig.10 is a scanning electron microscope image of an uncoated control sample; Fig.11 This is a scanning electron microscope image of the positive electrode material prepared in Example 3. DETAILED DESCRIPTION

[0026] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention and are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these contents, ordinary technicians in the field should be able to understand other possible implementations and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0027] According to an embodiment of the present invention, a method for preparing a high-performance sodium vanadium phosphate positive electrode material for a sodium ion battery is provided. The sodium vanadium phosphate is coated with rhodamine, and the material performance is significantly improved, especially at high current density.

[0028] The present invention is further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to the method for preparing a high-performance sodium vanadium phosphate positive electrode material for a sodium ion battery according to an embodiment of the present invention, the method comprises: According to the stoichiometric ratio of the sodium vanadium phosphate positive electrode material, raw materials for preparation are weighed, and the raw materials for preparation include a sodium source, a vanadium source and a phosphorus source; According to a preset order of addition, a vanadium source, a reaction auxiliary agent, a sodium source, a phosphorus source and rhodamine are added as additives to deionized water, and the mixing process of the additives and the deionized water is accelerated to obtain a sodium vanadium phosphate precursor, wherein the reaction auxiliary agent includes a reducing agent and a complexing agent; The sodium vanadium phosphate precursor is processed by drying technology and grinding technology, and the ground sodium vanadium phosphate precursor is placed in an inert atmosphere, and is heated and sintered in sequence to obtain the sodium vanadium phosphate positive electrode material for sodium ion batteries.

[0029] In one embodiment, the sodium source includes at least one of sodium carbonate, sodium acetate, sodium hydroxide, sodium phosphate and sodium dihydrogen phosphate.

[0030] In one embodiment, the vanadium source includes at least one of vanadium pentoxide and ammonium metavanadate.

[0031] In one embodiment, the phosphorus source includes at least one of ammonium dihydrogen phosphate, phosphoric acid, sodium dihydrogen phosphate, and ammonium hydrogen phosphate.

[0032] In one embodiment, the reducing agent and the complexing agent are both citric acid, and the ratio of citric acid to vanadium source is 1.8-2.5:1.

[0033] In one embodiment, according to a preset order of addition, a vanadium source, a reaction auxiliary agent, a sodium source, a phosphorus source and rhodamine are added as additives to deionized water, and the mixing process of the additives and the deionized water is accelerated to obtain a sodium vanadium phosphate precursor, which includes: Dissolve the vanadium source in deionized water and add a preset proportion of citric acid; heat and stir the deionized water until it is evenly mixed; A sodium source, a phosphorus source and rhodamine are added to deionized water, and the deionized water is stirred until the mixture is mixed into a gel, thereby obtaining a sodium vanadium phosphate precursor.

[0034] In one embodiment, when the deionized water is heated and stirred, the heating temperature is 60-80°C.

[0035] In one embodiment, after the sodium source, the phosphorus source and rhodamine are added into deionized water, the mass percentage concentration of rhodamine is 5-15%.

[0036] In one embodiment, a sodium vanadium phosphate precursor is treated by a drying technology and a grinding technology, and the ground sodium vanadium phosphate precursor is placed in an inert atmosphere, and is sequentially subjected to a heating treatment and a sintering treatment to obtain a sodium vanadium phosphate positive electrode material for a sodium ion battery, comprising: According to preset conditions, the sodium vanadium phosphate precursor is dried and ground in sequence, and the sodium vanadium phosphate precursor is heated in an inert atmosphere; The heated sodium vanadium phosphate precursor is treated in a sintering environment to obtain a carbon-coated sodium vanadium phosphate positive electrode material after a predetermined time; Wherein, the inert atmosphere includes argon, nitrogen and argon-hydrogen mixture; The sintering environment includes a sintering temperature of 720-850°C and a sintering time of 6-12h.

[0037] In one embodiment, the preset conditions include: The drying temperature is 80-120℃ and the drying time is 12-18h; The heating temperature is 300-400°C and the heating time is 3-5h.

[0038] In order to more clearly understand the above technical solution of the present invention, the above solution of the present invention is described in detail below through specific examples.

[0039] Embodiment 1 According to the stoichiometric ratio of sodium vanadium phosphate positive electrode material, the required raw materials are weighed. The sodium source is sodium carbonate, the vanadium source is vanadium pentoxide, and the phosphorus source is ammonium dihydrogen phosphate. Dissolve 3nmol of vanadium pentoxide in a certain amount of deionized water, add 5.4nmol of citric acid as a reducing agent and complexing agent, heat and stir at 60°C, then add 4.5nmol of sodium carbonate, 9nmol of ammonium dihydrogen phosphate and 5% of rhodamine, stir and mix thoroughly until gelled, and obtain a sodium vanadium phosphate precursor, which is dried at 100°C for 12h. After grinding, pre-treat at 300°C / 4h in an argon atmosphere, and then sinter at 720°C for 6h to obtain a carbon-coated sodium vanadium phosphate positive electrode material.

[0040] Embodiment 2 According to the stoichiometric ratio of sodium vanadium phosphate positive electrode material, the required raw materials are weighed. The sodium source is sodium hydroxide, the vanadium source is ammonium metavanadate, and the phosphorus source is ammonium dihydrogen phosphate. Dissolve 3nmol of ammonium metavanadate in a certain amount of deionized water, add 6.5nmol of citric acid as a reducing agent and complexing agent, heat and stir at 70°C, then add 4.5nmol of sodium carbonate, 4.5nmol of ammonium dihydrogen phosphate and 11% of rhodamine, stir and mix thoroughly until gelled, and obtain a sodium vanadium phosphate precursor, which is dried at 100°C for 15h. After grinding, pre-treat at 350°C / 5h in an argon atmosphere, and then sinter at 780°C for 10h to obtain a carbon-coated sodium vanadium phosphate positive electrode material.

[0041] Embodiment 3 According to the stoichiometric ratio of sodium vanadium phosphate positive electrode material, weigh the required raw materials. The sodium source is sodium hydroxide, the vanadium source is ammonium metavanadate, and the phosphorus source is ammonium dihydrogen phosphate. Dissolve 3nmol of ammonium metavanadate in a certain amount of deionized water, add 6.5nmol of citric acid as a reducing agent and complexing agent, heat and stir at 70°C, then add 4.5nmol of sodium hydroxide, 4.5nmol of ammonium dihydrogen phosphate and 15% of rhodamine, stir and mix thoroughly until gel, and obtain a sodium vanadium phosphate precursor. The obtained precursor is dried at 100°C for 15h. After grinding, pre-treat at 350°C / 5h in an argon atmosphere, and then sinter at 780°C for 10h to obtain a carbon-coated sodium vanadium phosphate positive electrode material.

[0042] Comparative Example According to the stoichiometric ratio of sodium vanadium phosphate positive electrode material, the required raw materials are weighed. The sodium source is sodium hydroxide, the vanadium source is ammonium metavanadate, and the phosphorus source is ammonium dihydrogen phosphate. Dissolve 3nmol of ammonium metavanadate in a certain amount of deionized water, add 6.5nmol of citric acid as a reducing agent and complexing agent, heat and stir at 70°C, then add 4.5nmol of sodium hydroxide and ammonium dihydrogen phosphate, without adding rhodamine, stir and mix thoroughly until gelled, and obtain a sodium vanadium phosphate precursor, and dry the obtained precursor at 100°C for 15h. After grinding, pre-treat at 350°C / 5h in an argon atmosphere, and then sinter at 780°C for 10h to obtain a carbon-coated sodium vanadium phosphate positive electrode material.

[0043] Experimental Group The carbon-coated sodium vanadium phosphate positive electrode material samples prepared in Example 1, Example 2, Example 3 and the comparative example were selected respectively. The experimental results are as follows Figure 2-Figure 7 .

[0044] Figure 2 In the embodiment 1, the diffraction peaks of the sample obtained all belong to the typical sodium superionic structure with R-3 space group (referring to the space group of the crystal), and the diffraction peaks are sharp, which indicates that the purity and crystallinity of the modified NVP (ie, sodium vanadium phosphate) are high.

[0045] Figure 3 In the embodiment 1, the sample obtained can achieve excellent cycle stability. After 100 cycles at 0.2C (referring to the charge and discharge rate), the capacity retention rate is 98% and the coulombic efficiency is close to 100%.

[0046] Figure 4 In the embodiment 2, the diffraction peaks of the sample obtained belong to the typical sodium superion structure with R-3 space group, and the diffraction peaks are sharp, which indicates that the purity and crystallinity of the modified NVP are high.

[0047] Figure 5 In the embodiment 2, the sample obtained can achieve excellent high rate performance, which is convenient for fast charging. The discharge capacity of the uncoated sample is greater than that of the coated sample at 0.5C, but when the current density exceeds 1C, the discharge capacity of the coated sample is much greater than that of the uncoated sample, and the discharge capacity at 20C is still 80mAhg -1 , while the discharge capacity of the uncoated sample is only 5 mAhg -1 about.

[0048] Figure 6 The sample obtained in Example 2 can achieve better cycle stability. After 500 cycles at 20C, the discharge capacity is 70.7 mAh g -1 , the capacity retention rate is 88% and the coulombic efficiency is close to 100%.

[0049] Figure 7In the embodiment 3, the diffraction peaks of the sample obtained belong to the typical sodium superionic structure with R-3 space group, and the diffraction peaks are sharp, which indicates that the purity and crystallinity of the modified NVP are high.

[0050] also, Figure 2 , Figure 4 and Figure 7 PDF#53-0018 in the table is the X-ray diffraction standard card number of sodium vanadium phosphate.

[0051] In summary, if Figure 8-Figure 11 As shown, coating with rhodamine can improve the particle morphology of NVP, and the cycle stability and high rate performance of the coated material are significantly improved, among which, Example 2 has the best comprehensiveness.

[0052] The present invention utilizes rhodamine to carbon-coat sodium vanadium phosphate, and the preparation method adopted is a sol-gel method. The prepared sodium vanadium phosphate / C positive electrode material has a small particle size, uniform distribution, good crystallinity, and significantly improved electronic conductivity of the material, so that the battery has high rate performance, good cycle stability, and long life. The present invention is simple, low-cost, high-efficiency, and excellent product comprehensive performance. The preparation method of the high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries provided by the present invention is simple and easy to operate, and has simple equipment requirements. Only stirring, drying, and calcining are required to obtain a carbon-coated sodium vanadium phosphate positive electrode material with excellent performance, and the preparation method is easy to promote and apply. The coated material has a small particle size, which can increase the contact with the electrolyte, improve the electronic conductivity of the material, and thus significantly improve the rate performance, cycle performance, and service life of the material.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries, characterized in that: The preparation method of the high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries comprises: According to the stoichiometric ratio of the sodium vanadium phosphate positive electrode material, raw materials for preparation are weighed, and the raw materials for preparation include a sodium source, a vanadium source and a phosphorus source; According to a preset order of addition, a vanadium source, a reaction auxiliary agent, a sodium source, a phosphorus source and rhodamine are added as additives to deionized water, and the mixing process of the additives and the deionized water is accelerated to obtain a sodium vanadium phosphate precursor, wherein the reaction auxiliary agent includes a reducing agent and a complexing agent; The sodium vanadium phosphate precursor is processed by drying technology and grinding technology, and the ground sodium vanadium phosphate precursor is placed in an inert atmosphere, and is heated and sintered in sequence to obtain the sodium vanadium phosphate positive electrode material for sodium ion batteries.

2. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 1, characterized in that: The sodium source includes at least one of sodium carbonate, sodium acetate, sodium hydroxide, sodium phosphate and sodium dihydrogen phosphate.

3. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 1, characterized in that: The vanadium source includes at least one of vanadium pentoxide and ammonium metavanadate.

4. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 1, characterized in that: The phosphorus source includes at least one of ammonium dihydrogen phosphate, phosphoric acid, sodium dihydrogen phosphate and ammonium hydrogen phosphate.

5. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 1, characterized in that: The reducing agent and the complexing agent are both citric acid, and the ratio of citric acid to vanadium source is 1.8-2.5:

1.

6. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 1, characterized in that: The method of adding a vanadium source, a reaction auxiliary agent, a sodium source, a phosphorus source and rhodamine as additives to deionized water according to a preset order of addition, and accelerating the mixing process of the additives and the deionized water to obtain a sodium vanadium phosphate precursor comprises: Dissolve the vanadium source in deionized water and add a preset proportion of citric acid; heat and stir the deionized water until it is evenly mixed; A sodium source, a phosphorus source and rhodamine are added to deionized water, and the deionized water is stirred until the mixture is mixed into a gel, thereby obtaining a sodium vanadium phosphate precursor.

7. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 6, characterized in that: When the deionized water is heated and stirred, the heating temperature is 60-80°C.

8. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 6, characterized in that: After the sodium source, the phosphorus source and rhodamine are added into deionized water, the mass percentage concentration of rhodamine is 5-15%.

9. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 1, characterized in that: The method of treating the sodium vanadium phosphate precursor by drying technology and grinding technology, placing the ground sodium vanadium phosphate precursor in an inert atmosphere, and sequentially performing heating treatment and sintering treatment to obtain the sodium vanadium phosphate positive electrode material for sodium ion batteries includes: According to preset conditions, the sodium vanadium phosphate precursor is dried and ground in sequence, and the sodium vanadium phosphate precursor is heated in an inert atmosphere; The heated sodium vanadium phosphate precursor is treated in a sintering environment to obtain a carbon-coated sodium vanadium phosphate positive electrode material after a predetermined time; Wherein, the inert atmosphere includes argon, nitrogen and argon-hydrogen mixture; The sintering environment includes a sintering temperature of 720-850°C and a sintering time of 6-12h.

10. The method for preparing a high-performance sodium vanadium phosphate positive electrode material for sodium ion batteries according to claim 9, characterized in that: The pre-conditions include: The drying temperature is 80-120℃ and the drying time is 12-18h; The heating temperature is 300-400°C and the heating time is 3-5h.

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