A high-alloy material for the negative electrode of a sodium-ion battery, its preparation method, and application

Abstract

The present invention discloses a high-alloy material for the negative electrode of a sodium-ion battery, its preparation method and application. The high-alloy material is prepared by a simple process to form a material by mixing one metal with another or multiple metal elements. Among them, the high-alloy material of the present invention has a large specific surface area and has many mesoporous structures, which can significantly improve the conductivity and cycle stability. At the same time, the raw material resources of the alloy material are rich, reducing the manufacturing cost of the sodium-ion battery.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and relates to a high-alloy material for the negative electrode of a sodium-ion battery, a preparation method thereof, and an application thereof.

Background Art

[0002] With the acceleration of the global energy transformation, sodium-ion batteries, as a new type of green energy technology, are gradually showing their great potential and market prospects. Compared with traditional lithium-ion batteries, sodium-ion batteries have the advantages of low cost, rich resources, high safety performance, etc., and thus have broad application prospects in the future green energy field. The application fields of sodium-ion batteries are very wide, including electric vehicles, mobile devices, energy storage systems, power grids and other fields.

[0003] Sodium-ion negative electrode materials include graphite, alloy composite materials, etc. The application of alloy materials in sodium-ion batteries has multiple advantages, which helps to improve the performance of the batteries. By optimizing the internal structure and stability of the batteries, alloy materials reduce the structural changes and losses during the charge and discharge processes of the batteries. The application of alloy materials to the negative electrode of sodium-ion batteries effectively improves the cycle life of the batteries. The application of alloy materials can also improve the energy density of sodium-ion batteries. By optimizing the composition and structure of the electrode materials, alloy materials improve the sodium storage capacity and energy conversion efficiency of the electrode materials, thereby enhancing the energy density of the batteries.

[0004] In addition, alloy materials also have the characteristics of low cost and rich resources. The raw material resources of alloy materials are rich, which can reduce the manufacturing cost of sodium-ion batteries. At the same time, the rich resources of alloy materials also ensure their sustainable supply in the future, providing strong support for the large-scale application of sodium-ion batteries. The application of alloy materials in sodium-ion batteries has significant advantages and potential. Alloy materials will play a more important role in improving the performance and reducing the cost of sodium-ion batteries in the future, and promoting the wide application of sodium-ion batteries in the energy field.

Summary of the Invention

[0005] Aiming at the problems of low performance and high cost in existing sodium-ion batteries, the present invention provides a high-alloy material for the negative electrode of a sodium-ion battery, a preparation method thereof, and an application thereof, and prepares a new type of high-alloy negative electrode material for sodium-ion batteries through a simple process.

[0006] In order to achieve the above-mentioned invention purpose, the technical solution adopted by the present invention is as follows:

[0007] A preparation method of a high-alloy material for the negative electrode of a sodium-ion battery, comprising the following steps:

[0008] 1) Prepare cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, copper acetate anhydrous, and a mixed solution in a mass-volume ratio of (3 - 8) g : (3 - 8) g : (6 - 11) g : (6 - 11) g : 1 g : 150 mL;

[0009] Mix cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, and copper acetate anhydrous evenly to obtain a mixed powder precursor;

[0010] 2) Preparation of the mixed solution: Mix N,N-dimethylformamide, ethanol, and water in a ratio of (14 - 16) g : 1 g : 1 g, stir evenly for 1 - 3 h, add 0.2 - 0.4 g of purified terephthalic acid, and ultrasonically mix evenly to obtain a mixed solution;

[0011] Add the mixed precursor powder obtained in the above step to the mixed solution to obtain dispersion liquid I;

[0012] 3) Transfer the dispersion liquid I obtained in the above step into a reaction kettle, carry out a hydrothermal reaction at 100 - 200 °C for 12 - 24 h, cool to room temperature, wash with water, wash with alcohol, wash with N,N-dimethylformamide, centrifuge, dry the precipitate, and calcine at 500 - 900 °C for 1 - 5 h in a hydrogen-argon mixed atmosphere to obtain a high-alloy material for the negative electrode of a sodium-ion battery.

[0013] Furthermore, among the raw materials for synthesizing the high-alloy material in step 1), at least two of cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, and copper acetate anhydrous are selected.

[0014] Furthermore, in step 2), N,N-dimethylformamide, ethanol, and water are mixed in a ratio of 15 g : 1 g : 1 g; the uniform stirring is for 1 h.

[0015] Furthermore, in step 3), it is calcined at 700 °C for 2 h in a hydrogen-argon mixed atmosphere.

[0016] Furthermore, in step 3), the equipment used for calcination is a tube furnace or a box furnace, and the heating rate is 2 - 15 °C·min -1 。

[0017] Furthermore, in step 3), the hydrogen-argon mixed gas used for calcination is a mixed gas with 5% hydrogen.

[0018] Furthermore, in step 3), the alcohol washing is carried out using ethanol.

[0019] The present invention also relates to a high-alloy material for the negative electrode of a sodium-ion battery, which is obtained by using the preparation method of the above-mentioned high-alloy material for the negative electrode of a sodium-ion battery and has the following technical indicators:

[0020] High-alloy raw materials with high electrochemical activity, low cost and stability, such as alloy powders containing elements such as nickel, cobalt, manganese, etc.; the high-alloy materials can remain stable under harsh conditions such as high temperature above 600 °C and high humidity, without structural changes or phase transitions; at the same time, the high-alloy materials used for the negative electrode of sodium-ion batteries have a large specific surface area, 50-100m 2 / g, and there are many mesoporous structures of 2-50 nm, which can significantly improve the conductivity and cycle stability.

[0021] The present invention also relates to the application of the above-mentioned high-alloy material for the negative electrode of sodium-ion batteries, which is applied to the negative electrode material of sodium-ion batteries.

[0022] Furthermore, when applied to the negative electrode material of sodium-ion batteries, it is prepared into a button battery, including the following steps:

[0023] 1) Mix the negative electrode active material, conductive agent, binder and solvent according to the mass-volume ratio of (8-9) g: (0.5-1) g: (0.5-1) g: (5-8) mL, and after mixing evenly, obtain the negative electrode paste. Use an automatic coater to coat it on a metal aluminum foil, and the average coating mass is 2.5-3 mg / cm 2 , perform vacuum drying treatment at 60-200 °C, and then cut it into circular electrode sheets with a diameter of 11-14 mm;

[0024] The conductive agent is conductive carbon black (Super P); the binder is polyvinylidene fluoride (PVDF); the solvent is N-methylpyrrolidone (NMP);

[0025] 2) Use the obtained circular electrode sheet as the counter electrode with a sodium sheet in a glove box, sodium perchlorate (NaClO 4 ) as the electrolyte, and cellulose GF / D as the separator to assemble a half-cell, and test its rate performance and cycle performance at different current densities under a potential window of 0.01-2.5 V.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. The preparation method of the high-alloy material for the negative electrode of sodium-ion batteries described in the present invention is separated from the traditional cumbersome multiple technologies and processes. The simple and convenient preparation method can design and optimize the existing process flow, and while ensuring the performance of the alloy material, simplify the preparation process.

[0028] 2. A high-alloy material for the negative electrode of a sodium-ion battery prepared by the present invention. The specific surface area distribution and pore size distribution of the high-alloy material of the present invention are tested by nitrogen isothermal adsorption and desorption. There are a large number of mesoporous structures in the high-alloy negative electrode material of the present invention, which has a large specific surface area. The porous structure effectively helps sodium ions to transport in the channels, improves the ion transport rate, and the large specific surface area provides more active sites for sodium ions.

[0029] 3. When the high-alloy material of the present invention is applied to sodium batteries, the specific capacity of the button battery can reach up to 80 mAh / g after 5 cycles under the condition of 25 mA / g. When the cycle reaches 50 cycles, the cycle life shows excellent cycle stability and has more excellent electrochemical performance.

Description of the Drawings

[0030] Figure 1 It is the X-ray diffraction pattern of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 of the present invention;

[0031] Figure 2 It is the figure of the scanning electron microscope photograph of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 of the present invention;

[0032] Figure 3 It is the figure of the transmission electron microscope photograph of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 of the present invention;

[0033] Figure 4 It is the figure of the BET surface area and pore size distribution of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 of the present invention;

[0034] Figure 5 It is the figure of the GCD curve of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 of the present invention applied to a button battery;

[0035] Figure 6 It is the figure of the long cycle curve of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 of the present invention applied to a button battery;

[0036] Figure 7 It is the X-ray diffraction pattern of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 2 of the present invention;

[0037] Figure 8 It is the figure of the scanning electron microscope photograph of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 of the present invention;

[0038] Figure 9 It is the figure of the GCD curve of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 2 of the present invention applied to a button battery;

[0039] Figure 10 The figure of the long cycle curve of a high alloy material for the negative electrode of a sodium ion battery prepared in Example 2 of the present invention applied to a button battery;

[0040] Figure 11 The figure of the GCD curve of a high alloy material for the negative electrode of a sodium ion battery prepared in Comparative Example 1 of the present invention applied to a button battery;

[0041] Figure 12 The figure of the long cycle curve of a high alloy material for the negative electrode of a sodium ion battery prepared in Comparative Example 1 of the present invention applied to a button battery.

Specific Embodiments

[0042] The following specific embodiments are used to further illustrate the present invention in detail, but the embodiments do not limit the present invention in any form. In addition, after reading the content described in the present invention, those skilled in the art can make various forms of changes or modifications to the present invention, and these equivalent forms also belong to the scope defined by the appended claims of the present application.

[0043] The present invention is further described below with reference to the accompanying drawings.

[0044] In the following embodiments, all chemical reagents used are commercially available products without special purification treatment. The thickness of the aluminum foil is 0.02 mm, and the conductive carbon black Surper P and polyvinylidene fluoride PVDF are all purchased from Kelude.

[0045] Example 1:

[0046] A preparation method of a high alloy material for the negative electrode of a sodium ion battery, comprising the following steps:

[0047] S01. Cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, and copper acetate anhydrous are respectively prepared according to a mass ratio of 7:6:9:9:1, and the total mass is 45 g to obtain the precursor in the synthetic high alloy negative electrode material;

[0048] S02. After uniformly mixing the high alloy material precursor, 150 mL of a mixed solution is added. The mixed solution is prepared by mixing N,N-dimethylformamide, ethanol, and water in a ratio of 15:1:1. After uniformly stirring for 1 h, 0.3 g of purified terephthalic acid is added and ultrasonically homogenized to obtain a mixed solution;

[0049] S03. Transfer the mixed solution into a reaction kettle, carry out a hydrothermal reaction at 200 °C for 24 h, cool to room temperature, wash with water, alcohol, and N,N-dimethylformamide three times, centrifuge, dry the precipitate, and calcine in a hydrogen-argon mixed atmosphere from room temperature to 700 °C for 2 h to obtain a high alloy negative electrode material.

[0050] A high-alloy material for the negative electrode of a sodium-ion battery obtained has the following technical indicators:

[0051] A high-alloy raw material with high electrochemical activity, low cost and stability, such as alloy powder containing elements such as nickel, cobalt, manganese, etc.; the high-alloy material can still remain stable under harsh conditions such as high temperature, high humidity, high voltage, etc., without structural changes or phase transitions; at the same time, the high-alloy material for the negative electrode of a sodium-ion battery has a large specific surface area and there are many mesoporous structures, which can significantly improve the conductivity and cycle stability.

[0052] Figure 1 It is an X-ray diffraction pattern of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1;

[0053] Four peak signals appear at 26°, 44.5°, 51.8° and 76.3° respectively in the figure. The carbon peak at 26° corresponds to the (002) diffraction crystal plane of graphite, and the diffraction peaks at 44.5°, 51.8° and 76.3° correspond to the face-centered cubic (FCC) crystal structure of the (111), (020), (022) planes.

[0054] Figure 2 It is a figure of a scanning electron microscope photograph of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1;

[0055] A hard carbon material with an irregular block-shaped macroscopic morphology and a nanoscale microporous structure inside; among them, the typical size of the irregular block is 10 - 200 μm; the pore diameter of the nanoscale microporous structure is less than 2 nm.

[0056] Figure 3 It is a figure of a transmission electron microscope photograph of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1;

[0057] The high-resolution image shows high crystallinity, and the atomic arrangement is relatively clear. The vertical lattice fringes can be clearly distinguished. A set of crystal planes with the largest interplanar spacing and perpendicular to each other are the (024) and (024) crystal planes respectively. The hard carbon material has the microscopic structural characteristics of short-range order and long-range disorder.

[0058] Figure 4 It is the BET surface area and pore size distribution of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1;

[0059] Through N 2 The adsorption isotherm measures that its pore size distribution is mainly in the mesoporous distribution of 2 - 10 nm, and its specific surface area is as high as 66.49 m 2 ·g -1 .

[0060] Example 2:

[0061] A preparation method of a high alloy material for the negative electrode of a sodium ion battery, comprising the following steps:

[0062] S01. Cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, and copper acetate anhydrous are respectively prepared according to a mass ratio of 7:6:9:9:1, with a total mass of 45 g, to obtain a precursor in the synthetic high alloy negative electrode material;

[0063] S02. After uniformly mixing the high alloy material precursor, 150 mL of a mixed solution is added. The mixed solution is prepared by mixing N-N dimethylformamide, ethanol, and water in a ratio of 15:1:1. After uniformly stirring for 1 h, 0.3 g of purified terephthalic acid is added, and ultrasonic treatment is performed to obtain a uniform mixed solution;

[0064] S03. Transfer the mixed solution into a reaction kettle, perform hydrothermal reaction at 150 °C for 12 h, cool to room temperature, wash with water, wash with alcohol, and wash with N-N dimethylformamide three times, then centrifuge, dry the precipitate, and calcine at 700 °C from room temperature in a hydrogen-argon mixed atmosphere for 2 h to obtain a high alloy negative electrode material.

[0065] Figure 7 X-ray diffraction pattern of a high alloy material for the negative electrode of a sodium ion battery prepared in Example 2;

[0066] Four peak signals appear at 26°, 44.5°, 51.8°, and 76.3° respectively in the figure. The carbon peak at 26° corresponds to the (002) diffraction crystal plane of graphite, and the diffraction peaks at 44.5°, 51.8°, and 76.3° correspond to the face-centered cubic (FCC) crystal structure of the (111), (020), and (022) planes.

[0067] Figure 8 Figure of the scanning electron microscope photograph of a high alloy material for the negative electrode of a sodium ion battery prepared in Example 1;

[0068] Hard carbon material with a macroscopic morphology of irregular blocks and a nanoscale microporous structure inside; among them, the typical size of the irregular blocks is 10 - 200 μm; the pore diameter of the nanoscale microporous structure is less than 2 nm.

[0069] Example 3:

[0070] A preparation method of a high alloy material for the negative electrode of a sodium ion battery, comprising the following steps:

[0071] S01. Cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, and copper acetate anhydrous are respectively prepared according to a mass ratio of 3:3:9:9:1, with a total mass of 45 g, to obtain a precursor in the synthetic high alloy negative electrode material;

[0072] S02. After uniformly mixing the high-alloy material precursor, add 150 mL of a mixed solution prepared by mixing N-N dimethylformamide, ethanol, and water in a ratio of 15:1:1. After uniformly stirring for 1 h, add 0.3 g of purified terephthalic acid and ultrasonically mix to obtain a mixed solution;

[0073] S03. Transfer the mixed solution to a reaction kettle, carry out hydrothermal reaction at 200 °C for 24 h, cool to room temperature, wash with water, wash with alcohol, wash three times with N-N dimethylformamide, centrifuge, dry the precipitate, and calcine at 800 °C for 2 h in a hydrogen-argon mixed atmosphere to obtain a high-alloy anode material.

[0074] Comparative example:

[0075] The existing preparation method of the high-alloy material for the anode of sodium-ion batteries includes the following steps:

[0076] S01. Use 45 g of manganese acetate tetrahydrate to prepare the precursor in the synthesis of the high-alloy anode material;

[0077] S02. After uniformly mixing the high-alloy material precursor, add 150 mL of a mixed solution prepared by mixing N-N dimethylformamide, ethanol, and water in a ratio of 15:1:1. After uniformly stirring for 1 h, add 0.3 g of purified terephthalic acid and ultrasonically mix to obtain a mixed solution;

[0078] S03. Transfer the mixed solution to a reaction kettle, carry out hydrothermal reaction at 200 °C for 24 h, cool to room temperature, wash with water, wash with alcohol, wash three times with N-N dimethylformamide, centrifuge, dry the precipitate, and calcine at 700 °C for 2 h in a hydrogen-argon mixed atmosphere to obtain a high-alloy anode material.

[0079] Experimental example:

[0080] Apply the high-alloy composite materials prepared in Example 1, Example 2, Example 3 and the comparative example as the anode materials of sodium-ion batteries, including the following steps:

[0081] 1) Prepare a negative electrode slurry by mixing the negative electrode active material, conductive agent, and binder in a mass ratio of 8:1:1 with a solvent;

[0082] 2) Use an automatic coater to uniformly coat the slurry on a metal aluminum foil, with an average coating mass of 2.5 mg / cm 2 , carry out vacuum drying treatment at 80 °C, and then cut it into circular electrode sheets with a diameter of 14 mm;

[0083] 3) Use the electrode sheet as the working electrode, a metal sodium sheet as the counter electrode / reference electrode, a Whatman glass fiber filter paper as the diaphragm, and use 1 M NaClO as the electrolyte 4Dissolved in ethylene carbonate and propylene carbonate with a volume ratio of 0.1:1, and assembled into a button cell in a glove box filled with argon gas.

[0084] 4) According to the above method, 10 button cells were prepared in parallel, and the weight test specific capacity was measured after 5 cycles.

[0085] Figure 5 It is a graph of the GCD curve of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 applied to a button cell;

[0086] As can be seen from the figure, in the first cycle, the constant-current discharge (top) and charge (bottom) curves divide the GCD region into four regions. Region I is from 0 to 0.2 V, Region II is from 0.2 to 0.5 V, Region III is from 0.5 to 1.0 V, and Region IV is from 1.0 to 3.0 V (discharge data is 3.0 V). The initial charge and discharge capacities are 271.39 / 85.33 mAh g -1 , 25 mA g -1 The initial Coulomb efficiency is 31.4%. From the 2nd cycle to the 10th cycle, their constant-current charge and discharge (GCD) curves are exactly the same.

[0087] Figure 6 It is a graph of the long cycle curve of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 1 applied to a button cell;

[0088] Example 1 shows the best electrochemical performance, with the first efficiency reaching 31.4%, the initial reversible specific capacity reaching 271 mAh g-1 (at a current density of 25 mA g -1 ). After 20 cycles, the reversible specific capacity of the material can reach 74 mA g -1 , and the Coulomb efficiency is 96%.

[0089] Figure 9 It is a graph of the GCD curve of a high-alloy material for the negative electrode of a sodium-ion battery prepared in Example 2 applied to a button cell. As can be seen from the figure, in the first cycle, the constant-current discharge (top) and charge (bottom) curves divide the GCD region into four regions. Region I is from 0 to 0.2 V, Region II is from 0.2 to 0.5 V, Region III is from 0.5 to 1.0 V, and Region IV is from 1.0 to 3.0 V (discharge data is 3.0 V). The initial charge and discharge capacities are 260.07 / 79.71 mAh g -1 , 25 mA g -1 The initial Coulomb efficiency is 31.4%. From the 2nd cycle to the 10th cycle, their constant-current charge and discharge (GCD) curves are exactly the same.

[0090] Figure 10Graph of the long cycle curve of a high alloy material for the negative electrode of a sodium-ion battery prepared in Example 2 applied to a button battery;

[0091] Example 2 exhibits the best electrochemical performance. The first efficiency can reach 30%, and the initial reversible specific capacity can reach 260 mAh g -1 (at a current density of 25 mA g -1 . After 20 cycles, the reversible specific capacity of the material can reach 71 mA g -1 , and the Coulombic efficiency is 96%.

[0092] Figure 11 Graph of the GCD curve of a high alloy material for the negative electrode of a sodium-ion battery prepared in Comparative Example 1 applied to a button battery;

[0093] As can be seen from the graph, in the first cycle, the constant current discharge (top) and charge (bottom) curves divide the GCD region into two regions. Region I is from 0 to 0.7 V, and Region II is from 0.7 to 3.0 V (discharge data is 3.0 V)

[0094] Figure 12 Graph of the long cycle curve of a high alloy material for the negative electrode of a sodium-ion battery prepared in Comparative Example 1 applied to a button battery;

[0095] Comparative Example 1 exhibits poor long cycle performance and poor stability. The initial reversible specific capacity can reach 79 mAh g -1 (at a current density of 25 mA g -1 . After 20 cycles, the reversible specific capacity of the material is 9.32 mA g -1 , and the Coulombic efficiency is 96%.

[0096] Summary and discussion:

[0097] From Figure 5 , Figure 9 and Figure 11 , it can be seen that, by comparison, Application Example 1 using the high alloy material prepared in Example 1 as the negative electrode material of the sodium-ion battery has a higher capacity, and the capacity values of both decrease with the increase of the initial potential value. In addition, there is no significant capacity in the voltage range of 2.0 - 3.0 V for the button batteries of Application Example 1 and Application Example 2, thus confirming that this substance of the high alloy material has low voltage behavior.

[0098] From Figure 6 , Figure 10 and Figure 12It can be seen that, in contrast, Application Example 1 using the high-alloy material prepared in Example 1 as the negative electrode material of the sodium-ion battery has higher reversibility. After the second cycle, there is a plateau voltage when discharging at 0.7V compared with Comparative Example 1, and there is a plateau voltage when applying Example 1 and Application Example 2. The high-alloy material of the present application has more excellent electrochemical performance when used as the negative electrode material of the sodium-ion battery.

[0099] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. Any equivalent changes or modifications made under the technical spirit disclosed by the present invention shall fall within the scope of the patent covered by the present invention.

Claims

1. A method for preparing a high alloy material for a negative electrode of a sodium ion battery, characterized in that: The steps include: 1) Prepare a mixed solution of cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, and anhydrous copper acetate in a mass volume ratio of (3-8) g:(3-8) g:(6-11) g:(6-11) g:1 g:150 mL; Cobalt acetate tetrahydrate, manganese acetate tetrahydrate, aluminum acetate, nickel acetate tetrahydrate, and anhydrous copper acetate are mixed uniformly to obtain a mixed powder precursor; 2) Preparation of mixed solution: N-N-dimethylamide, ethanol and water are mixed in a ratio of (14-16) g:1 g:1 g, stirred evenly for 1-3 h, and 0.2-0.4 g of purified terephthalic acid is added, and ultrasonically homogenized to obtain a mixed solution; The mixed powder precursor obtained in the above step is added to the mixed solution to obtain dispersion I; 3) The dispersion I obtained in the above step is transferred into a reactor, subjected to a hydrothermal reaction at 100-200° C. for 12-24 hours, cooled to room temperature, washed with water, alcohol, and NN dimethylamide, centrifuged, precipitated and dried, and heated from room temperature to 500-900° C. in a hydrogen-argon mixed atmosphere for calcination for 1-5 hours to obtain a high alloy material for the negative electrode of a sodium ion battery.

2. The method for preparing a high alloy material for a negative electrode of a sodium ion battery according to claim 1, characterized in that: In step 2), N-N-dimethylamide, ethanol and water are mixed in a ratio of 15 g:1 g:1 g; the uniform stirring is performed for 1 hour.

3. The method for preparing a high alloy material for a negative electrode of a sodium ion battery according to claim 1, characterized in that: In step 3), the temperature is raised from room temperature to 700° C. in a hydrogen-argon mixed atmosphere and calcined for 2 h.

4. The method for preparing a high alloy material for a negative electrode of a sodium ion battery according to claim 1, characterized in that: In step 3), the calcination equipment is a tube furnace or a box furnace, and the heating rate is 2-15℃·min -1 .

5. The method for preparing a high alloy material for a negative electrode of a sodium ion battery according to claim 1, characterized in that: In step 3), the hydrogen-argon mixed gas used for calcination is a mixed gas containing 5% hydrogen.

6. The method for preparing a high alloy material for a negative electrode of a sodium ion battery according to claim 1, characterized in that: In step 3), the alcohol washing is performed using ethanol.

7. A high alloy material for a negative electrode of a sodium ion battery, characterized in that: The high alloy material for the negative electrode of a sodium ion battery is prepared by the method for preparing the high alloy material for the negative electrode of a sodium ion battery according to any one of claims 1 to 6, and has the following technical indicators: a high alloy raw material with high electrochemical activity, low cost and stability, and alloy powder containing nickel, cobalt, manganese, copper and aluminum elements; the high alloy material can remain stable under harsh conditions of high temperature and high humidity above 600°C without structural change or phase change; at the same time, the high alloy material for the negative electrode of a sodium ion battery has 50-100m 2 / g has a large specific surface area and a mesoporous structure of 2~50nm, which can significantly improve the conductivity and cycle stability.

8. The use of a high alloy material for a negative electrode of a sodium ion battery according to claim 7, characterized in that: Used in negative electrode materials for sodium ion batteries.

9. The use of a high alloy material for a negative electrode of a sodium ion battery according to claim 8, characterized in that: It is used in the negative electrode material of sodium ion battery and prepared into button battery, including the following steps: 1) The negative electrode active material, conductive agent, binder and solvent are mixed evenly according to the mass volume ratio of (8-9) g: (0.5-1) g: (0.5-1) g: (5-8) mL to obtain the negative electrode slurry, which is coated on the metal aluminum foil by an automatic coating machine with an average coating mass of 2.5-3 mg / cm 2 , vacuum drying at 60-200°C, and then cutting into circular electrode sheets with a diameter of 11-14 mm; The conductive agent is conductive carbon black; the binder is polyvinylidene fluoride; and the solvent is N-methylpyrrolidone; 2) The obtained circular electrode sheet was assembled into a half-cell in a glove box with a sodium sheet as the counter electrode, sodium perchlorate as the electrolyte, and cellulose GF / D as the separator. The rate performance and cycle performance were tested at different current densities in the potential window of 0.01-2.5 V.

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