Electrode material of sodium-ion battery and preparation method therefor, and device

Abstract

A preparation method for an electrode material of a sodium-ion battery, the method comprising the following steps: S1, raw material preparation, involving: selecting manganese acetate, tetrapropyl chlorotitanate, sodium acetate, ammonium dihydrogen phosphate, citric acid and carbon nanotubes as raw materials, preparing tetrapropyl chlorotitanate into a tetrapropyl chlorotitanate solution, and preparing the carbon nanotubes into a carbon nanotube slurry; S2, raw material mixing, involving: firstly, dispersing citric acid and the carbon nanotube slurry into distilled water, and then adding sodium acetate, manganese acetate and ammonium dihydrogen phosphate thereto, so as to obtain a mixture; S3, sol preparation, involving: adding the tetrapropyl chlorotitanate solution into the mixture obtained in S2, and stirring same until a sol is obtained; S4, gel precursor preparation, involving: drying the sol obtained in S3 at 75ºC, so as to obtain a gel precursor; and S5, gel precursor drying, involving: drying the gel precursor under anaerobic conditions, so as to obtain a CNTs-NMTPO@C product, wherein the product can significantly improve the high-speed performance of an NMTPO electrode and significantly prolong the cycle life thereof.

Description

Electrode material for sodium ion battery and preparation method and device thereof Technical Field

[0001] The present invention relates to the technical field of battery electrode preparation, and in particular to an electrode material for a sodium ion battery and a preparation method and device thereof. Background Art

[0002] Sodium-ion batteries have attracted widespread attention due to their good safety, low price, abundant sodium resources and excellent electrochemical performance. However, the practical application of sodium-ion batteries in various fields remains a huge challenge. In recent years, many methods have been adopted to improve the power density and cycle life of sodium energy storage. Cathode materials are very important components in sodium-ion storage. To date, different studies have been conducted to study cathodes, such as NaxNi1 / 3Fe1 / 3Mn1 / 3O2, Na3V2(PO4)2F3, Na3V2(PO 4)3, Na0.67Mn0.7Cu0.15Ni0.15O2, Na2FeP2O7, NaVPO4F, NMTPO and Na2FePO4F.

[0003] Pure NMTPO, namely nose-type Na3MnTi(PO4)3 (NMTPO), has been proposed as a new sodium energy storage electrode due to its high plateau capacity, high theoretical capacity, low toxicity, low cost, and low price. However, due to unsatisfactory electrical conductivity, the original NMTPO electrode exhibits poor high-rate performance and poor cycle life.

[0004] In summary, it is very necessary to develop an electrode material that can improve the high-rate performance and cycle life of NMTPO electrodes.

[0005] Summary of the Invention

[0006] In order to solve the above-mentioned problems, the present invention provides an electrode material for a sodium ion battery and a preparation method and device thereof. The electrode material prepared by the preparation method and device disclosed in the present invention can significantly improve the high-rate performance and cycle life of the NMTPO electrode.

[0007] The first technical solution disclosed in the present invention is as follows:

[0008] A method for preparing an electrode material for a sodium ion battery comprises the following steps:

[0009] S1. Raw material preparation: manganese acetate, tetrapropyl chlorotitanate, the sodium acetate, ammonium dihydrogen phosphate, citric acid and carbon nanotubes are selected as raw materials, and the tetrapropyl chlorotitanate is prepared into a tetrapropyl chlorotitanate solution, and the carbon nanotubes are prepared into a carbon nanotube slurry;

[0010] S2. Mixing raw materials: first, dispersing citric acid and carbon nanotube slurry into distilled water, and then adding the sodium acetate, manganese acetate and ammonium dihydrogen phosphate to obtain a mixture;

[0011] S3, sol preparation: adding tetrapropyl chlorotitanate solution to the mixture obtained in S2 and stirring until a sol is obtained;

[0012] S4, preparation of gel precursor: drying the sol obtained in S3 at 75°C to obtain a gel precursor;

[0013] S5. Drying the gel precursor: Drying the gel precursor under anaerobic conditions to obtain a CNTs-NMTPO@C product.

[0014] Furthermore, the preparation process of the tetrapropyl chlorotitanate solution in S1 is to add tetrapropyl chlorotitanate to ethanol, specifically, to add tetrapropyl chlorotitanate to 100 ml of ethanol at a rate of 1 g / s, set the stirring speed to 500 rpm, and stir for 30 minutes until it is completely dissolved. The preparation process of the carbon nanotube slurry is to add carbon nanotubes to ethanol, specifically, to add carbon nanotubes to ethanol at a rate of 2 g / s, perform ultrasonic treatment, set the frequency to 20 kHz, and continue the treatment for 15 minutes until the carbon nanotubes are fully dispersed.

[0015] Furthermore, the process of dispersing the citric acid and carbon nanotube slurry in distilled water in S2 is as follows: placing distilled water in a container; adding citric acid to the distilled water and stirring at a speed of 500 rpm to dissolve it for 15 minutes; slowly adding 20 ml of the carbon nanotube slurry to the distilled water containing citric acid at a speed of 2 ml / s; continuing to stir and mix at a speed of 300 rpm for 30 minutes until the citric acid and carbon nanotubes are fully dispersed in the distilled water to obtain a final mixture;

[0016] The process of adding sodium acetate, manganese acetate and ammonium dihydrogen phosphate is as follows: sodium acetate is gradually added to the mixture at a rate of 2 ml / s; manganese acetate is added and mixed thoroughly at a speed of 500 rpm for 20 minutes; and finally ammonium dihydrogen phosphate is added and stirred to ensure uniform mixing.

[0017] Furthermore, the process of adding the tetrapropyl chlorotitanate solution in S3 is to slowly add the tetrapropyl chlorotitanate solution to the mixture obtained in S2 at a rate of 2 ml / s, while stirring and mixing. The stirring speed is set to 300 rpm, and the stirring and mixing is continued to ensure that the tetrapropyl chlorotitanate solution is evenly mixed with other ingredients. The stirring time is 30 minutes.

[0018] Furthermore, the process of the preparation in S4 is to stand at 75° C. for 6 hours.

[0019] Furthermore, the drying process in S5 is to stand at 660° C. for 10 hours.

[0020] The second technical solution disclosed in the present invention is as follows:

[0021] A sodium ion battery electrode material is prepared according to any of the above preparation methods.

[0022] The third technical solution disclosed in the present invention is as follows:

[0023] A device for preparing an electrode material for a sodium ion battery according to any of the above methods, the device comprising an agitator, a first connecting pipe, a solvent reflux device, a second connecting pipe, a vacuum dryer, a third connecting pipe, an argon gas source, a fourth connecting pipe, and a heat treatment furnace, wherein the agitator is connected to the solvent reflux device via the first connecting pipe, the vacuum dryer is connected to the solvent reflux device via the second connecting pipe, the third connecting pipe is connected to the argon gas source, and the fourth connecting pipe is connected to the heat treatment furnace.

[0024] Furthermore, the stirrer includes a container, a stirring paddle and a motor. The stirring paddle is built into the middle position of the container, one end of the stirring paddle is connected to the motor, and the container is connected to the solvent reflux device through a first connecting pipe.

[0025] Furthermore, the solvent reflux device includes a reflux pipe, a reflux pump, a recovery bottle, a heating device and a cooling device. The reflux pump, the recovery bottle, the heating device and the cooling device are all connected to the reflux pipe. The recovery bottle is used to store the recovered solvent. The heating device and the cooling device are used to control the temperature of the solvent reflux. The recovery bottle is connected to the vacuum dryer through a first connecting pipe.

[0026] Furthermore, the vacuum dryer includes a vacuum pump and a drying and heating box, and the vacuum pump is used for vacuuming and assisting drying.

[0027] Furthermore, the argon gas source includes an argon gas cylinder, a pressure reducing valve, a control valve and a flow meter, the argon gas cylinder is used to provide argon gas; the pressure reducing valve is connected to the argon gas cylinder to reduce the gas pressure, the flow meter is connected to the outlet of the argon gas cylinder to monitor the gas flow, and the control valve is connected to the outlet of the argon gas cylinder to adjust the flow of argon gas.

[0028] Furthermore, the heat treatment furnace includes a furnace body and a temperature controller, and the temperature controller is used to accurately control the temperature in the heating furnace.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] In the material designed by the present invention, the nose-structured NMTPO particles are covered with a carbon coating, and carbon nanotubes are uniformly dispersed between the NMTPO@C particles. Due to the synergistic effect of nano-NMTPO, thin carbon coating, and carbon nanotubes, the prepared CNTs-NMTPO@C electrode can provide a reversible capacity of 136.8 mAh g-1 at 2.0C and retain approximately 92.2% after 300 cycles at 10.0C. It has good rate performance and excellent cycling stability, and has very broad application prospects. The excellent battery performance of CNTs-NMTPO@C can be attributed to the following aspects: ① The conductive network formed by the carbon film and CNTs can greatly promote the conductivity of NMTPO, which is conducive to changing the transport of electrons and Na+ during the electrochemical reaction; ② During the charge and discharge process, the small NMTPO particles reduce the transport path of Na+; BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG1 is a schematic diagram of a simplified process of a method for preparing an electrode material for a sodium ion battery in Example 1;

[0032] FIG2 is a schematic diagram of the structure of a device for preparing electrode materials for a sodium ion battery in Example 2;

[0033] FIG3 shows the XRD patterns (a) and Raman spectra (b) of NMTPO@C and CNTs-NMTPO@C powders prepared in the present invention; and the XPS spectra (ce) of the CNTs-NMTPO@C composite material.

[0034] Figure 4 shows the SEM images of NMTPO@C (a, b) and CNTs-NMTPO@C (c, d) particles in Example 2; EDS point mapping images of CNTs-NMTPO@C particles (ej);

[0035] Figure 5 shows the TEM images of NMTPO@C (a, b) and CNTs-NMTPO@C (c, d) particles in Example 2;

[0036] Figure 6 shows the EIS curves of the NMTPO@C and CNTs-NMTPO@C cathodes prepared in Example 2. DETAILED DESCRIPTION

[0037] In order to make the purposes, features, and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0038] Example 1

[0039] A method for preparing an electrode material for a sodium ion battery comprises the following steps: preparing a CNTs-NMTPO@C composite material by a sol-gel approach;

[0040] S1. Raw material preparation: manganese acetate, tetrapropyl chlorotitanate, sodium acetate, ammonium dihydrogen phosphate, citric acid and carbon nanotubes are selected as raw materials, and tetrapropyl chlorotitanate is prepared into a tetrapropyl chlorotitanate solution, and carbon nanotubes are prepared into a carbon nanotube slurry;

[0041] S2. Mixing raw materials: First, citric acid and carbon nanotube slurry are dispersed in distilled water, and then sodium acetate, manganese acetate and ammonium dihydrogen phosphate are added to obtain a mixture;

[0042] S3, sol preparation: adding tetrapropyl chlorotitanate solution to the mixture obtained in S2 and stirring until a sol is obtained;

[0043] S4, preparation of gel precursor: drying the sol obtained in S3 at 75°C to obtain a gel precursor;

[0044] S5, drying the gel precursor: drying the gel precursor under anaerobic conditions to obtain a CNTs-NMTPO@C product;

[0045] Furthermore, the preparation process of the tetrapropyl chlorotitanate solution in S1 is to add tetrapropyl chlorotitanate to ethanol, specifically, to add tetrapropyl chlorotitanate to 100 ml of ethanol at a rate of 1 g / s, set the stirring speed to 500 rpm, and stir for 30 minutes until it is completely dissolved. The preparation process of the carbon nanotube slurry is to add carbon nanotubes to ethanol, specifically, to add carbon nanotubes to ethanol at a rate of 2 g / s, perform ultrasonic treatment, set the frequency to 20 kHz, and continue the treatment for 15 minutes until the carbon nanotubes are fully dispersed.

[0046] Furthermore, the process of dispersing the citric acid and carbon nanotube slurry in distilled water in S2 is as follows: placing distilled water in a container; adding citric acid to the distilled water and stirring at a speed of 500 rpm to dissolve it for 15 minutes; slowly adding 20 ml of the carbon nanotube slurry to the distilled water containing citric acid at a speed of 2 ml / s; continuing to stir and mix at a speed of 300 rpm for 30 minutes until the citric acid and carbon nanotubes are fully dispersed in the distilled water to obtain a final mixture;

[0047] The process of adding sodium acetate, manganese acetate and ammonium dihydrogen phosphate is as follows: sodium acetate is gradually added to the mixture at a rate of 2 ml / s; manganese acetate is added and mixed thoroughly at a speed of 500 rpm for 20 minutes; and finally ammonium dihydrogen phosphate is added and stirred to ensure uniform mixing.

[0048] Furthermore, the process of adding the tetrapropyl chlorotitanate solution in S3 is to slowly add the tetrapropyl chlorotitanate solution to the mixture obtained in S2 at a rate of 2 ml / s, while stirring and mixing. The stirring speed is set to 300 rpm, and the stirring and mixing is continued to ensure that the tetrapropyl chlorotitanate solution is evenly mixed with other ingredients. The stirring time is 30 minutes.

[0049] Based on the preparation steps S1 to S5 of this embodiment, if the carbon nanotube slurry in S2 is removed, a carbon-coated NMTPO (NMTPO@C) material can be obtained.

[0050] In this embodiment, for steps S1-S3, a stirrer is used to mix the citric acid and carbon nanotube slurry with other raw materials in distilled water to ensure sufficient stirring and dissolution. A solvent reflux device is used to recover and reflux the distilled water and solvent to maintain suitable conditions for sol formation, forming a sol containing C12H28O4Ti, thereby preparing for subsequent gel formation.

[0051] In this embodiment, for steps S4-S5, a drying oven / vacuum dryer is used to form a gel precursor at 75°C. An argon gas source and control system are connected to a heat treatment furnace to provide an inert atmosphere. The precursor is heat treated at 660°C for 10 hours to obtain a CNTs-NMTPO@C product.

[0052] In this embodiment, a simple method is used to prepare CNTs-NMTPO@C particles as an electrode material for sodium ion storage. The designed CNTs-NMTPO@C composite material is prepared by a sol-gel route. It is worth noting that manganese acetate (Mn(CH3COO)2·4H2O), tetrapropylchlorotitanate (C12H28O4Ti), sodium acetate (CH3COONa), ammonium dihydrogen phosphate (NH4H2PO4), citric acid (citric acid) and carbon nanotubes are used as raw materials. First, an appropriate amount of citric acid and carbon nanotube slurry are dispersed in distilled water under stirring at 30°C. Then, CH3COONa, Mn(CH3COO)2·4H2O and NH4H2PO4 are added to the mixture in a stoichiometric ratio. Third, an ethanol solution containing C12H28O4Ti is slowly added to the above mixture and stirred until a sol is obtained. Subsequently, it is dried at 75°C. The precursor was dried to obtain a gel precursor. Finally, the precursor was placed under argon conditions and heated at 660°C for 10 hours to obtain a CNTs-NMTPO@C product. In addition, without adding a conductive carbon nanotube slurry, a carbon-coated NMTPO (NMTPO@C) material was successfully prepared. The electrochemical and physical properties of CNTs-NMTPO@C were further analyzed. XRD results showed that the added carbon nanotubes and the formed carbon coating had no effect on the phase structure of NMTPO. Transmission electron microscopy images showed that the carbon nanotubes were uniformly dispersed in the NMTPO@C particles. Electrochemical measurement results showed that the CNTs-NMTPO@C electrode had good high-speed performance (114.1 mAh at 5.0C) and good cycle stability (92.2% after 300 cycles at 10.0C). Therefore, it can be seen that the CNTs-NMTPO@C prepared in this example is a high-performance sodium ion storage material.

[0053] Example 2

[0054] Based on the above-mentioned embodiment 1, this embodiment provides a device for preparing an electrode material for a sodium ion battery, so as to implement the above-mentioned method for preparing an electrode material for a sodium ion battery.

[0055] A device for preparing electrode materials for a sodium ion battery, comprising:

[0056] The agitator includes a container and a stirring paddle. The stirring paddle is built into the middle position of the container. One end of the stirring paddle is connected to a motor. The container is connected to a solvent reflux device through a pipeline so that the solvent and distilled water can be recovered and refluxed to an appropriate location.

[0057] The solvent reflux device includes a reflux pipe, a pump, a recovery bottle, a heating device and a cooling device. The reflux pipe is equipped with a pump and is connected to the recovery bottle. The recovery bottle is used to store the recovered solvent. The heating device and the cooling device are used to control the temperature of the solvent reflux. The recovery bottle is also connected to a vacuum dryer.

[0058] The vacuum dryer includes a vacuum pump and a drying and heating box. The vacuum pump is used for vacuuming and assisting drying. The drying and heating box is used to send the recovered solvent to the drying box for processing.

[0059] An argon gas source includes an argon gas cylinder, a pressure reducing valve, a control valve and a flow meter. The argon gas cylinder is used to provide argon gas; the pressure reducing valve is connected to the argon gas cylinder to reduce the gas pressure, the flow meter is connected to the outlet of the argon gas cylinder to monitor the gas flow, and the control valve is connected to the outlet of the argon gas cylinder to adjust the flow of argon gas.

[0060] The heat treatment furnace comprises a furnace body and a temperature controller, wherein the temperature controller is used to accurately control the temperature in the heating furnace.

[0061] Performance verification experiment

[0062] Experiment 1: Identification of the crystal purity of NMTPO@C and CNTs-NMTPO@C materials using XRD

[0063] The morphology of NMTPO@C and CNTs-NMTPO@C nanoparticles was investigated by scanning electron microscopy and EDS, while the microstructure of the resulting NMTPO@C and CNTs-NMTPO@C particles was examined by transmission electron microscopy. Elemental analysis was used to determine the carbon content in the NMTPO@C and CNTs-NMTPO@C samples, and the ID / IG ratio was used to investigate the carbon crystallinity. As shown in Figure 3(b), the ID / IG ratio for the CNTs-NMTPO@C sample (0.97) is lower than that for the NMTPO@C sample (1.01), demonstrating that the CNTs-NMTPO@C material exhibits a relatively high degree of graphitization. XPS was used to investigate the chemical composition of the CNTs-NMTPO@C composites. Raman spectroscopy of the two composites confirmed the presence of carbon in the prepared samples. As shown in Figure 3(c), the Mn2p peak shows two broad patterns at 653.5 eV and 640.8 eV, representing Mn2p1 / 2 and Mn2p3 / 2, respectively. As can be seen from Figure 3d, the two peaks of Ti2p3 / 2 and Ti2p1 / 2 are located at about 459.7 and 465.5 eV, respectively. As shown in the graph in Figure 3e, a broad peak centered at 284.8 eV belongs to C1s;

[0064] Experiment 2: Study on the sodium storage performance of NMTPO@C and CNTs-NMTPO@C using CR2016 cells

[0065] The research methods are as follows:

[0066] Sa1. Preparation of working slurry: NMTPO@C or CNTs-NMTPO@C, super P in NMP (70:20:10) and PVDF were mixed and stirred to form a slurry;

[0067] Sa2, slurry coating: The prepared slurry is applied on a clean aluminum coil to form a working electrode;

[0068] Sa3, heating treatment: heating the slurry on the aluminum coil at 100°C to solidify the working electrode;

[0069] Sa4. Use of glass microfiber as separator: Use glass microfiber as separator in the working battery to support and isolate the working cathode;

[0070] Sa5. Select reference electrode and electrolyte: Use Na film as reference electrode and 1 m NaClO4 dissolved in PC / EC (50:50) as electrolyte;

[0071] Sa6. Perform electrochemical tests: Use the LAND battery test system to test the rate performance of NMTPO@C and CNTs-NMTPO@C, including EIS and CV measurements.

[0072] As shown in Figure 4, the NMTPO@C composite material with a size range of 100-200 nm has an irregular morphology. Nanoscale crystals help shorten the transport distance of Na+ during the electrochemical reaction. For the CNTs-NMTPO@C composite material (Figures c and d in Figure 4), the added CNTs are uniformly dispersed in the NMTPO@C particles. The EDS dot pattern of Figures ej in Figure 4 shows that carbon, oxygen, sodium, manganese, phosphorus, and titanium are all present in the CNTs-NMTPO@C composite material. The nanostructure of NMTPO@C and CNTs-NMTPO@C particles was deeply studied by TEM. As shown in Figure 5, the average particle size of NMTPO@C in Figures a and b in Figure 5 is about 165 nm, and its particle surface is covered by a carbon film with a thickness of 7 nm. As shown in Figures c and d, CNTs with a diameter of about 20 nm can be observed. The NMTPO@C particles are interconnected by CNTs. The formed carbon coating and CNTs can construct a conductive network, providing an effective pathway for the transfer of electrons and Na+. Therefore, the sodium ion storage rate capability of the obtained CNTs-NMTPO@C cathode can be greatly improved.

[0073] The XRD instrument is used to perform X-ray diffraction analysis on the product to identify the crystal purity of the material; the scanning electron microscope and energy dispersive spectrometer are used to observe and analyze the morphology and microstructure of the product; the transmission electron microscope is used to observe and analyze the microstructure of the product in more detail; the elemental analyzer is used to detect the content of carbon substances in the product; the XPS instrument is used to study the surface chemical composition of the CNTs-NMTPO@C composite material; and the Raman spectrometer is used to prove the presence of carbon in the prepared sample.

[0074] To evaluate the electrochemical behavior of the NMTPO@C and CNTs-NMTPO@C cathodes, EIS measurements were performed after 300 cycles at 10.0°C. The results are shown in Figure 6. Both the NMTPO@C and CNTs-NMTPO@C electrodes display a line at low frequencies and a semicircle at high frequencies. The straight line represents the Na+ diffusion impedance, while the concave semicircle represents the charge transfer impedance. The charge transfer impedance of CNTs-NMTPO@C is lower than that of NMTPO@C. This low charge transfer impedance favors the transport of Na+ and electrons during the electrochemical reaction. Therefore, the prepared CNTs-NMTPO@C exhibits excellent electrochemical performance in sodium-ion batteries.

[0075] The excellent battery performance of CNTs-NMTPO@C can be attributed to the following aspects: the conductive network formed by the carbon film and CNTs can greatly promote the conductivity of NMTPO, which is beneficial to changing the transport of electrons and Na+ during the electrochemical reaction; during the charge and discharge process, small NMTPO particles will reduce the transport path of Na+.

[0076] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing an electrode material for a sodium ion battery, characterized in that: The following steps are involved: S1. Raw material preparation: manganese acetate, tetrapropyl chlorotitanate, sodium acetate, ammonium dihydrogen phosphate, citric acid and carbon nanotubes are selected as raw materials, and the tetrapropyl chlorotitanate is prepared into a tetrapropyl chlorotitanate solution, and the carbon nanotubes are prepared into a carbon nanotube slurry; S2. Mixing raw materials: first, dispersing the citric acid and carbon nanotube slurry into distilled water, and then adding the sodium acetate, manganese acetate and ammonium dihydrogen phosphate to obtain a mixture; S3, sol preparation: adding the tetrapropyl chlorotitanate solution to the mixture obtained in S2, and stirring until a sol is obtained; S4, preparation of gel precursor: drying the sol obtained in S3 at 75°C to obtain a gel precursor; S5. Drying the gel precursor: drying the gel precursor under anaerobic conditions to obtain a CNTs-NMTPO@C product.

2. The method for preparing an electrode material for a sodium ion battery according to claim 1, wherein: The preparation process of the tetrapropyl chlorotitanate solution in S1 is to add the tetrapropyl chlorotitanate to ethanol at a rate of 1 g / s and stir at a speed of 500 rpm for 30 minutes. The preparation process of the carbon nanotube slurry is to add carbon nanotubes to ethanol at a rate of 2 g / s and then ultrasonicate at 20 kHz for 15 minutes.

3. The method for preparing an electrode material for a sodium ion battery according to claim 1, wherein: The process of dispersing the citric acid and carbon nanotube slurry into distilled water in S2 is as follows: first, the citric acid is added to the distilled water, and then stirred at a speed of 500 rpm for 15 minutes to obtain the aqueous solution of the citric acid, then the carbon nanotube slurry is added to the aqueous solution of the citric acid at a speed of 2 ml / s and stirred at a speed of 300 rpm for 30 minutes. The process of adding the sodium acetate, manganese acetate and ammonium dihydrogen phosphate in S2 is as follows: first, the sodium acetate is gradually added to the mixture slowly at a speed of 2 ml / s, then manganese acetate is added, and finally ammonium dihydrogen phosphate is added and stirred at a speed of 500 rpm for 20 minutes to obtain a mixture.

4. The method for preparing an electrode material for a sodium ion battery according to claim 1, wherein: The process of adding the tetrapropyl chlorotitanate solution in S3 is to add the tetrapropyl chlorotitanate solution to the mixture obtained in S2 at a speed of 2 ml / s and stir at a speed of 300 rpm for 30 minutes.

5. The method for preparing an electrode material for a sodium ion battery according to claim 1, wherein: The process of the preparation in S4 is to stand at 75° C. for 6 hours.

6. The method for preparing an electrode material for a sodium ion battery according to claim 1, wherein: The drying process in S5 is to stand at 660° C. for 10 hours.

7. An electrode material for a sodium ion battery, characterized in that: The electrode material of the sodium ion battery is prepared according to the preparation method according to any one of claims 1 to 6.

8. A device for preparing electrode materials for sodium ion batteries, characterized in that: The device includes an agitator, a first connecting pipe, a solvent reflux device, a second connecting pipe, a vacuum dryer, a third connecting pipe, an argon gas source, a fourth connecting pipe and a heat treatment furnace. The agitator is connected to the solvent reflux device through the first connecting pipe, the vacuum dryer is connected to the solvent reflux device through the second connecting pipe, the third connecting pipe is connected to the argon gas source, and the fourth connecting pipe is connected to the heat treatment furnace.

9. The device for preparing an electrode material for a sodium ion battery according to claim 8, wherein: The stirrer includes a container, a stirring paddle and a motor. The stirring paddle is built into the middle position of the container, one end of the stirring paddle is connected to the motor, and the container is connected to the solvent reflux device through a first connecting pipe.

10. The device for preparing an electrode material for a sodium ion battery according to claim 9, wherein: The solvent reflux device includes a reflux pipe, a reflux pump, a recovery bottle, a heating device and a cooling device. The reflux pump, the recovery bottle, the heating device and the cooling device are all connected to the reflux pipe. The recovery bottle is used to store the recovered solvent. The heating device and the cooling device are used to control the temperature of the solvent reflux. The recovery bottle is connected to the vacuum dryer through a first connecting pipe.

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