A self-supporting bimetallic telluride sodium-ion battery electrode material and preparation method

Abstract

The present invention discloses a self-supporting bimetallic telluride sodium-ion battery electrode material and a preparation method thereof. In the present invention, urea is used as a precipitating agent to precipitate Ni<supgt;2+< / supgt; and Co<supgt;2+< / supgt; in a solution on a conductive substrate to form nickel-cobalt bimetallic hydroxide, and then it is placed in a tube furnace for high-temperature annealing to obtain nickel-cobalt bimetallic oxide; thereafter, the conductive substrate with nickel-cobalt bimetallic oxide and an aqueous solution containing tellurium powder and hydrazine hydrate are put into a hydrothermal autoclave for high-temperature tellurization. Through the reduction effect of hydrazine hydrate, the tellurium powder is reduced to an ionic state and exchanges with oxygen ions in the conductive substrate to obtain nickel-cobalt bimetallic telluride. The electrode material of the present invention has excellent electrochemical performance and long cycle life, and the cost is relatively low.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of sodium-ion battery electrode materials, and particularly provides a self-supporting bimetallic telluride sodium-ion battery electrode material and a preparation method thereof. Background Art

[0002] Lithium is an important element required in the production of lithium-ion batteries. However, the limited lithium resources and the continuously growing demand for lithium-ion batteries have led to its high price and restricted its large-scale application. Compared with elements in the same group, sodium is abundant in the earth's crust and inexpensive. Sodium-ion batteries have a similar structure and operating mechanism to lithium-ion batteries, so they have become an alternative system in energy storage devices and have been widely studied.

[0003] In recent years, transition metal chalcogenides have become a key research area for anode materials of sodium-ion batteries. Compared with S and Se, Te has the weakest bonding with metals, and Te has a lower electronegativity and higher electronic conductivity, which is kinetically beneficial for the conversion reaction of sodium ions, improving the conductivity and sodium insertion / extraction reversibility of the electrode material. Traditional electrodes mostly use nano-powders as active substances, and the volume expansion occurring during charge and discharge will accelerate the agglomeration and pulverization of the electrode material, thus affecting the rate performance and cycle performance of the battery. Moreover, the use of conductive agents and binders easily separates the active material from the current collector, reducing the cycle life of the battery. Summary of the Invention

[0004] To solve the problems existing in the prior art, the purpose of the present invention is to provide a self-supporting bimetallic telluride sodium-ion battery electrode material and a preparation method thereof. The electrode material of the present invention has excellent electrochemical performance and long cycle life, and is of low cost.

[0005] The technical solution of the present invention is as follows:

[0006] A preparation method of a self-supporting bimetallic telluride sodium-ion battery electrode material, comprising the following process:

[0007] Using a hydrothermal reaction, Ni 2+ and Co 2+ in an aqueous solution of urea, nickel nitrate hexahydrate and cobalt nitrate hexahydrate are precipitated on a conductive substrate to form nickel-cobalt bimetallic hydroxide on the conductive substrate, and then the conductive substrate loaded with nickel-cobalt bimetallic hydroxide is washed and vacuum dried;

[0008] The dried conductive substrate loaded with nickel-cobalt bimetallic hydroxide is oxidized to convert the nickel-cobalt bimetallic hydroxide into nickel-cobalt bimetallic oxide;

[0009] The conductive substrate loaded with nickel-cobalt bimetallic oxide is tellurized with an aqueous solution containing tellurium powder and hydrazine hydrate. During the tellurization process, the tellurium powder is reduced to an ionic state and exchanges with the oxygen ions in the nickel-cobalt bimetallic oxide, converting the nickel-cobalt bimetallic oxide into nickel-cobalt bimetallic telluride;

[0010] The conductive substrate loaded with nickel-cobalt bimetallic telluride is washed and vacuum dried to obtain the self-supporting bimetallic telluride sodium-ion battery electrode material.

[0011] Preferably, 1-4 mmol of nickel nitrate hexahydrate, 2-8 mmol of cobalt nitrate hydrate, and 6-24 mmol of urea are added to every 30-60 ml of water to form the aqueous solution of urea, nickel nitrate hexahydrate, and cobalt nitrate hydrate.

[0012] Preferably, the hydrothermal reaction temperature is 120-180 °C, the heat preservation time is 4-8 h, and after the heat preservation ends, it is naturally cooled to room temperature.

[0013] Preferably, when washing the conductive substrate loaded with nickel-cobalt bimetallic hydroxide, it is repeatedly washed alternately with deionized water and alcohol until the pH of the conductive substrate loaded with nickel-cobalt bimetallic hydroxide is neutral, and the washing ends;

[0014] When drying the washed conductive substrate loaded with nickel-cobalt bimetallic hydroxide, vacuum drying is carried out, the drying temperature is 60-100 °C, and the drying time is 8-12 h.

[0015] Preferably, when oxidizing the dried conductive substrate loaded with nickel-cobalt bimetallic hydroxide, it is oxidized at 300-400 °C in an oxygen atmosphere, the heat preservation time for oxidation is 2 h-4 h, and the heating rate during heating is 3-5 °C / min.

[0016] Preferably, 5-10 ml of hydrazine hydrate and 60-100 mg of tellurium powder are added to every 30-60 ml of aqueous solution to form the aqueous solution containing tellurium powder and hydrazine hydrate.

[0017] Preferably, during the tellurization process, the reaction temperature is 120-180 °C, the heat preservation time is 12-18 h, and after the heat preservation ends, it is naturally cooled to room temperature.

[0018] Preferably, when washing the conductive substrate loaded with nickel-cobalt bimetallic telluride, it is repeatedly washed alternately with deionized water and alcohol until the pH of the conductive substrate loaded with nickel-cobalt bimetallic telluride is neutral, and the washing ends;

[0019] When vacuum drying the washed conductive substrate loaded with nickel-cobalt bimetallic telluride, the drying temperature is 80-120 °C, and the drying time is 8-12 h.

[0020] The present invention also provides a self-supporting bimetallic telluride sodium-ion battery electrode material, which is prepared by the preparation method of the present invention as described above.

[0021] The self-supporting bimetallic telluride sodium-ion battery electrode material of the present invention as described above is used as a negative electrode material for a sodium-ion battery.

[0022] The present invention has the following beneficial effects:

[0023] The preparation method of the self-supporting bimetallic telluride sodium-ion battery electrode material of the present invention is to in-situ synthesize a bimetallic telluride nanocomposite on a conductive substrate, replacing the preparation of the active material by coating with chemical bonding between the active material and the conductive substrate, greatly enhancing the structural stability of the composite material. Preparing an orderly grown electrode with the help of a conductive substrate can solve the volume expansion of the electrode material and achieve a long cycle life of the sodium-ion battery. The remarkable advantages of the present invention are: (1) The present invention prepares a self-supporting bimetallic telluride sodium-ion battery electrode material by a hydrothermal method and a high-temperature calcination process, with simple operation and easy large-scale preparation. (2) Using nickel-cobalt bimetallic telluride as the electrode material because of its multi-electron reaction characteristics, high electron conductivity and rich redox active sites, can achieve the purpose of high specific capacity, cycle performance and rate performance of the battery. (3) Growing the active material in-situ on the conductive substrate and directly using it as the electrode material without the aid of a conductive agent and a binder can effectively improve the structural stability of the material, reduce the interfacial resistance between the electrode / electrolyte, and is conducive to the rapid insertion / extraction of ions. Description of the Drawings

[0024] Figure 1 SEM image of nickel-cobalt hydroxide supported on a conductive substrate prepared in Example 1.

[0025] Figure 2 EDS image of nickel-cobalt oxide supported on a conductive substrate prepared in Example 2.

[0026] Figure 3 SEM image of nickel-cobalt telluride supported on a conductive substrate prepared in Example 3.

[0027] Figure 4 SEM image of nickel-cobalt telluride supported on a conductive substrate prepared in Example 4.

[0028] Figure 5 SEM image of nickel-cobalt hydroxide supported on a conductive substrate prepared in Example 5.

[0029] Figure 6 SEM image of nickel-cobalt telluride supported on a conductive substrate prepared in Example 5.

[0030] Figure 7 It is the cyclic voltammetry curve of the sodium-ion battery prepared in Example 4.

[0031] Figure 8 It is the charge-discharge curves of the first three cycles of the sodium-ion battery prepared in Example 4 at 1 A / g. Detailed implementation manners

[0032] The present invention is further illustrated by the following examples, but the protection scope of the present invention is not limited to the following examples.

[0033] In the preparation method of the present invention, urea is used as a precipitating agent to precipitate Ni 2+ and Co 2+ on the conductive substrate to form nickel-cobalt bimetallic hydroxide, and then it is placed in a tube furnace for high-temperature annealing to obtain nickel-cobalt bimetallic oxide; then the conductive substrate with nickel-cobalt bimetallic oxide and an aqueous solution containing tellurium powder and hydrazine hydrate are put into a hydrothermal autoclave for high-temperature tellurization. Through the reduction effect of hydrazine hydrate, the tellurium powder is reduced to an ionic state and exchanges with the oxygen ions in the conductive substrate to obtain nickel-cobalt bimetallic telluride.

[0034] The preparation method of the self-supporting bimetallic telluride sodium-ion battery electrode material of the present invention includes the following steps:

[0035] S1, Add 1-4 mmol of nickel nitrate hexahydrate and 2-8 mmol of cobalt nitrate hexahydrate to 30-60 ml of water, and then add 6-24 mmol of urea as a precipitating agent, and stir magnetically to form a uniform solution; then put the pre-cleaned conductive substrate and the solution into a high-pressure hydrothermal autoclave for heating, carry out hydrothermal reaction at 120-180 °C for 4-8 h, take out the conductive substrate after natural cooling, and wash it repeatedly with deionized water and alcohol alternately to make the conductive substrate neutral, and dry it in a vacuum drying oven at 60-100 °C for 8-12 h.

[0036] S2, Take out the dried conductive substrate and place it in a porcelain boat, and then put the porcelain boat into a tube furnace. Under an oxygen atmosphere, heat it to 300-400 °C at a heating rate of 3-5 °C / min for high-temperature oxidation. The heat preservation time of the high-temperature oxidation is 2 h-4 h, and the nickel-cobalt hydroxide loaded on the conductive substrate is transformed into a nickel-cobalt oxide composite material.

[0037] S3. Place the nickel-cobalt conductive matrix obtained in S2 and an aqueous solution containing tellurium powder and hydrazine hydrate in a hydrothermal autoclave and heat them. Carry out hydrothermal reaction at 120 - 180 °C for 12 - 18 h. After natural cooling, take out the conductive matrix, and wash it alternately with deionized water and alcohol for multiple times until the matrix is neutral. Then dry the matrix in a vacuum drying oven at 80 - 120 °C for 8 - 12 h to obtain the self-supporting bimetallic telluride sodium-ion battery electrode material. In the aqueous solution containing tellurium powder and hydrazine hydrate, there are 5 - 10 ml of hydrazine hydrate, 60 - 100 mg of tellurium powder, and 30 - 60 ml of water.

[0038] With the aid of a conductive matrix, the present invention constructs a multi-level self-supporting nanostructure and an orderly growing electrode, which can solve the volume expansion of the negative electrode material and achieve the structural stability of the electrode material. The prepared electrode material does not need to add a conductive agent and a binder, can be directly used as a sodium-ion battery electrode material, effectively reduces the cost, simplifies the preparation process, and at the same time has rich ion diffusion channels and good cycle capacity.

[0039] Example 1

[0040] The preparation method of the self-supporting bimetallic telluride sodium-ion battery electrode material in this example includes the following steps:

[0041] (1) Add 2 mmol of nickel nitrate and 4 mmol of cobalt nitrate to 40 ml of deionized water, add 12 mmol of urea, and stir magnetically to form a uniform solution. Then put the pre-cleaned conductive matrix and the above solution into a high-pressure hydrothermal autoclave and heat at 120 °C for 4 h. After natural cooling, take out the conductive matrix, and wash it alternately with deionized water and alcohol three times until the matrix is neutral. Dry it in a vacuum drying oven at 60 °C for 12 h to obtain nickel-cobalt hydroxide supported on the conductive matrix. The SEM of the nickel-cobalt hydroxide composite material supported on the conductive matrix prepared in this example is as Figure 1 shown. It can be seen from Figure 1 that the nickel-cobalt hydroxide grown on the conductive matrix is arranged in a flower-like structure, which is a typical array structure and is relatively evenly distributed on the matrix.

[0042] (2) Take out the dried matrix and place it in a porcelain boat, put it into a tube furnace, and oxidize it at 350 °C for 2 h in an air atmosphere to convert the nickel-cobalt hydroxide supported on the conductive matrix into a nickel-cobalt oxide composite material.

[0043] (3) Add 60 mg of tellurium powder and 5 ml of hydrazine hydrate to 40 ml of deionized water and stir magnetically. Then, place the conductive substrate and the mixed solution containing tellurium powder and hydrazine hydrate in a hydrothermal autoclave and heat at 160 °C for 12 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol until the substrate is neutral, and dry it in a vacuum drying oven at 80 °C for 12 h to obtain a self-supported bimetallic telluride composite material.

[0044] Example 2

[0045] The preparation method of the self-supported bimetallic telluride sodium-ion battery electrode material in this example includes the following steps:

[0046] (1) Add 1 mmol of nickel nitrate and 2 mmol of cobalt nitrate to 40 ml of deionized water, add 6 mmol of urea, and stir magnetically to form a homogeneous solution. Then, place the pre-cleaned conductive substrate and the above solution together in a high-pressure hydrothermal autoclave and heat at 120 °C for 4 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol until the substrate is neutral, and dry it in a vacuum drying oven at 80 °C for 8 h.

[0047] (2) Take out the dried substrate and place it in a porcelain boat, put it in a tube furnace, and oxidize it at 400 °C for 2 h in an air atmosphere to convert the nickel-cobalt hydroxide loaded on the conductive substrate into a nickel-cobalt oxide composite material. The EDS of the nickel-cobalt oxide composite material loaded on the conductive substrate prepared in this example is as Figure 2 shown. It can be clearly seen from the figure the diffraction peaks of the three elements Ni, Co, and O, indicating that the nickel-cobalt oxide composite material has been successfully synthesized on the conductive substrate.

[0048] (3) Add 100 mg of tellurium powder and 10 ml of hydrazine hydrate to 40 ml of deionized water and stir magnetically. Then, place the conductive substrate and the mixed solution containing tellurium powder and hydrazine hydrate in a hydrothermal autoclave and heat at 120 °C for 12 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol until the substrate is neutral, and dry it in a vacuum drying oven at 60 °C for 12 h to obtain a self-supported bimetallic telluride composite material.

[0049] Example 3

[0050] The preparation method of the self-supported bimetallic telluride sodium-ion battery electrode material in this example includes the following steps:

[0051] (1) Add 3 mmol of nickel nitrate and 6 mmol of cobalt nitrate to 60 ml of deionized water. Add 18 mmol of urea and stir magnetically to form a homogeneous solution. Then, put the pre-cleaned conductive substrate and the solution of Chinese fir into a high-pressure hydrothermal reactor and heat at 140 °C for 4 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol to make the substrate neutral, and dry it in a vacuum drying oven at 80 °C for 12 h.

[0052] (2) Take out the dried substrate and place it in a porcelain boat. Put it into a tube furnace and oxidize it at 350 °C for 4 h in an air atmosphere to convert the nickel-cobalt hydroxide supported on the conductive substrate into a nickel-cobalt oxide composite material.

[0053] (3) Add 80 mg of tellurium powder and 8 ml of hydrazine hydrate to 40 ml of deionized water and stir magnetically. Then, place the conductive substrate and the mixed solution containing tellurium powder and hydrazine hydrate in a hydrothermal reactor at the same time and heat at 140 °C for 12 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol to make the substrate neutral, and dry it in a vacuum drying oven at 60 °C for 12 h to obtain a self-supported bimetallic telluride composite material. The SEM of the nickel-cobalt telluride composite material supported on the conductive substrate prepared in this example is as Figure 3 shown. From Figure 3 it can be seen that nickel-cobalt telluride nanoparticles are successfully prepared on the conductive substrate, and the particle size of the particles is uniform, with good crystallinity and periodic distribution.

[0054] Example 4

[0055] The preparation method of the self-supported bimetallic telluride sodium-ion battery electrode material in this example includes the following steps:

[0056] (1) Add 3 mmol of nickel nitrate and 6 mmol of cobalt nitrate to 60 ml of deionized water. Add 24 mmol of urea and stir magnetically to form a homogeneous solution. Then, put the pre-cleaned conductive substrate and the above solution into a high-pressure hydrothermal reactor and heat at 140 °C for 4 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol to make the substrate neutral, and dry it in a vacuum drying oven at 70 °C for 12 h.

[0057] (2) Take out the dried substrate and place it in a porcelain boat. Put it into a tube furnace and oxidize it at 350 °C for 2 h in an air atmosphere to convert the nickel-cobalt hydroxide supported on the conductive substrate into a nickel-cobalt oxide composite material.

[0058] (3) Add 80 mg of tellurium powder and 10 ml of hydrazine hydrate to 40 ml of deionized water and stir magnetically. Then, place the conductive substrate and the mixed solution containing tellurium powder and hydrazine hydrate into a hydrothermal autoclave and heat at 160 °C for 12 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol until the substrate is neutral, and dry it in a vacuum drying oven at 100 °C for 12 h to obtain a self-supported bimetallic telluride composite material. The SEM of the bimetallic telluride composite material prepared in this example is as shown in Figure 4 shown. It can be seen from Figure 4 that the composite material has grown on the conductive substrate skeleton and uniformly covered the substrate.

[0059] Example 5

[0060] The preparation method of the self-supported bimetallic telluride sodium-ion battery electrode material in this example includes the following steps:

[0061] (1) Add 4 mmol of nickel nitrate and 8 mmol of cobalt nitrate to 60 ml of deionized water, add 24 mmol of urea, and stir magnetically to form a homogeneous solution. Then, place the pre-cleaned conductive substrate and the above solution into a high-pressure hydrothermal autoclave and heat at 180 °C for 8 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol until the substrate is neutral, and dry it in a vacuum drying oven at 80 °C for 12 h. The SEM of the nickel-cobalt hydroxide composite material supported on the conductive substrate prepared in this example is as shown in Figure 5 shown. It can be seen from Figure 5 that a layer of nickel-cobalt hydroxide covers the conductive substrate skeleton.

[0062] (2) Take out the dried substrate and place it in a porcelain boat, then put it into a tube furnace and oxidize it at 350 °C for 4 h in an air atmosphere to convert the nickel-cobalt hydroxide supported on the conductive substrate into a nickel-cobalt oxide composite material.

[0063] (3) Add 100 mg of tellurium powder and 10 ml of hydrazine hydrate to 40 ml of deionized water and stir magnetically. Then, place the conductive substrate and the mixed solution containing tellurium powder and hydrazine hydrate into a hydrothermal autoclave and heat at 180 °C for 18 h. After natural cooling, take out the conductive substrate, wash it alternately three times with deionized water and alcohol until the substrate is neutral, and dry it in a vacuum drying oven at 120 °C for 12 h to obtain a self-supported bimetallic telluride composite material. The SEM of the bimetallic telluride composite material prepared in this example is as shown in Figure 6 shown. It can be seen from the figure that spherical nickel-cobalt telluride materials have grown in-situ on the substrate skeleton.

[0064] The sodium-ion battery electrode material prepared in Example 4 was cut into circular wafers with a diameter of 12 mm, and coin cells were assembled in a glove box filled with an argon atmosphere. A metal sodium sheet was used as the counter electrode, the separator was Celgard 2700, and the electrolyte was 1 M NaClO4 / EC:DEC (1:1, v).

[0065] The impedance test was carried out on the prepared sodium-ion battery. Figure 7 It is the Nyquist curve diagram of the negative electrode material of the sodium-ion battery in Example 4. As Figure 7 shown, the prepared sodium-ion battery material shows a low charge transfer resistance, indicating that the self-supported bimetallic telluride electrode material has high conductivity. Therefore, the sodium-ion battery exhibits remarkable electrochemical performance, which can be attributed to the reasonable structural design

[0066] The charge-discharge test was carried out on the battery in the voltage range of 0.01 - 3.0 V. Figure 8 It is the charge-discharge curve diagram of the negative electrode material of the sodium-ion battery prepared in Example 4 at a current density of 1 A / g. The first-cycle discharge capacity of the negative electrode material of the sodium-ion battery reaches 450 mAh / g, showing excellent high-current discharge ability. Second, the charge-discharge curves of the third cycle basically coincide, proving that the battery has stable cycle reversibility and a high capacity retention rate.

[0067] In summary, it can be seen that the preparation method of the present invention is simple to operate. The prepared electrode material does not require additional conductive agents and binders, effectively reducing the production cost. The prepared electrode material has excellent electrochemical performance and long cycle life. Constructing a self-supported nanostructure with a conductive substrate can effectively avoid the use of conductive agents and binders. The chemical bonding between the active substance and the substrate, as well as the rich active sites and ion diffusion channels of the conductive substrate, make it outstanding in terms of structural stability and conductivity, which is beneficial to alleviating the deformation stress caused by volume expansion and improving the energy density of the sodium-ion battery.

Claims

1. A preparation method of a self-supporting bimetallic telluride sodium-ion battery electrode material, characterized in that, It includes the following processes: Using a hydrothermal reaction, Ni in an aqueous solution of urea, nickel nitrate hexahydrate, and cobalt nitrate hexahydrate 2+ and Co 2+ are precipitated on a conductive substrate to form nickel-cobalt bimetallic hydroxide on the conductive substrate, and then the conductive substrate loaded with nickel-cobalt bimetallic hydroxide is washed and vacuum dried; Oxidize the dried conductive substrate loaded with nickel-cobalt bimetallic hydroxide to convert the nickel-cobalt bimetallic hydroxide into nickel-cobalt bimetallic oxide; Carry out tellurization on the conductive substrate loaded with nickel-cobalt bimetallic oxide and an aqueous solution containing tellurium powder and hydrazine hydrate. During the tellurization process, the tellurium powder is reduced to an ionic state and exchanges with the oxygen ions in the nickel-cobalt bimetallic oxide, converting the nickel-cobalt bimetallic oxide into nickel-cobalt bimetallic telluride; Wash and vacuum dry the conductive substrate loaded with nickel-cobalt bimetallic telluride to obtain the self-supporting bimetallic telluride sodium-ion battery electrode material; Add 1-4 mmol of nickel nitrate hexahydrate, 2-8 mmol of cobalt nitrate hexahydrate, and 6-24 mmol of urea to every 30-60 ml of water to form an aqueous solution of urea, nickel nitrate hexahydrate, and cobalt nitrate hexahydrate; Correspondingly add 5-10 ml of hydrazine hydrate and 60-100 mg of tellurium powder to every 30-60 ml of the aqueous solution to form the aqueous solution containing tellurium powder and hydrazine hydrate; During the tellurization process, the reaction temperature is 120-180 °C, the heat preservation time is 12-18 h, and after the heat preservation ends, it is naturally cooled to room temperature.

2. The preparation method of a self-supporting bimetallic telluride sodium-ion battery electrode material according to claim 1, characterized in that, The temperature of the hydrothermal reaction is 120-180 °C, the heat preservation time is 4-8 h, and after the heat preservation ends, it is naturally cooled to room temperature.

3. The preparation method of a self-supporting bimetallic telluride sodium-ion battery electrode material according to claim 1, characterized in that, When washing the conductive substrate loaded with nickel-cobalt bimetallic hydroxide, wash it repeatedly with deionized water and alcohol alternately until the pH of the conductive substrate loaded with nickel-cobalt bimetallic hydroxide is neutral, and the washing ends; When drying the washed conductive substrate loaded with nickel-cobalt bimetallic hydroxide, carry out vacuum drying. The drying temperature is 60-100 °C, and the drying time is 8-12 h.

4. The preparation method of a self-supporting bimetallic telluride sodium-ion battery electrode material according to claim 1, characterized in that, When oxidizing the dried conductive substrate loaded with nickel-cobalt bimetallic hydroxide, oxidize it in an oxygen atmosphere at 300-400 °C. The heat preservation time for oxidation is 2 h-4 h, and the heating rate during heating is 3-5 °C / min.

5. The preparation method of a self-supporting bimetallic telluride sodium-ion battery electrode material according to claim 1, characterized in that, When washing the conductive substrate loaded with nickel-cobalt bimetallic telluride, wash it repeatedly with deionized water and alcohol alternately until the pH of the conductive substrate loaded with nickel-cobalt bimetallic telluride is neutral, and the washing ends; When vacuum drying the washed conductive substrate loaded with nickel-cobalt bimetallic telluride, the drying temperature is 80-120 °C, and the drying time is 8-12 h.

6. A self-supporting bimetallic telluride sodium-ion battery electrode material, characterized in that, The self-supporting bimetallic telluride sodium-ion battery electrode material is prepared by the preparation method of the self-supporting bimetallic telluride sodium-ion battery electrode material according to any one of claims 1-5.

7. Use of the self-supporting bimetallic telluride sodium-ion battery electrode material according to claim 6, characterized in that, The self-supporting bimetallic telluride sodium-ion battery electrode material is used as the negative electrode material of the sodium-ion battery.

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