CN108649191B

CN108649191B - Preparation method of antimony/nitrogen-doped graphene composite for sodium ion battery, and obtained material and application thereof

Info

Publication number: CN108649191B
Application number: CN201810297192.5A
Authority: CN
Inventors: 周小四; 许欣
Original assignee: Nanjing Normal University
Current assignee: Nanjing Normal University
Priority date: 2018-03-30
Filing date: 2018-03-30
Publication date: 2020-09-18
Anticipated expiration: 2038-03-30
Also published as: CN108649191A

Abstract

The invention provides a preparation method of an antimony/nitrogen doped graphene composite for a sodium ion battery, an obtained composite material and application of the composite material as a sodium ion battery cathode material, wherein the preparation method comprises the following steps: 1) ball-milling and mixing graphene oxide, 1-ethyl-3-methylimidazole dicyandiamide and antimony powder; 2) taking out the ball-milled mixture, dispersing the ball-milled mixture in distilled water, performing ultrasonic dispersion uniformly, and performing freeze drying; 3) subjecting the product obtained in step 2) to reaction in H₂And carbonizing in an Ar atmosphere to obtain the antimony/nitrogen doped graphene compound. Compared with the prior art, the method has the advantages that the process is simple, the used raw materials are environment-friendly and suitable for batch production, and the prepared antimony/nitrogen doped graphene composite has excellent electrochemical performance, can be used as an ideal sodium ion battery cathode material to replace pure antimony with low reversible capacity to be applied to a sodium ion battery, and is a sodium ion battery cathode material with a prospect.

Description

Preparation method of antimony/nitrogen-doped graphene composite for sodium ion battery, and obtained material and application thereof

Technical Field

The invention relates to a preparation method of an antimony/nitrogen doped graphene composite for a sodium ion battery, and an obtained material and application thereof, and belongs to the technical field of electrode materials.

Background

Lithium ion batteries, which are the most widely used energy storage systems, have a dominant market for power supplies for electric vehicles and portable electronic devices due to their high energy density and long life cycle. However, the scarcity and uneven geographical distribution of lithium resources severely hamper the large-scale application of lithium ion batteries in energy storage. The sodium ion battery has physical and chemical characteristics equivalent to those of lithium, is rich in sodium resource and low in price, and is considered to be applicable to large-scale stationary energy storage. Recently, a large number of layered oxides and polyanionic compounds have been demonstrated as highly efficient positive electrode materials for sodium-ion batteries. Although a variety of lithium ion battery negative electrode materials have been used in sodium ion battery research, most attempts have been unsatisfactory. Therefore, developing new anode materials with high specific capacity and suitable redox potential is a significant challenge in the field of sodium ion batteries.

Antimony has higher theoretical specific capacity (660mAh g)^-1) Has received wide attention from researchers. Na can be formed between antimony and sodium₃Sb alloys, but antimony-based materials undergo severe volume expansion (-390%) during sodium and sodium deliquescence, causing the active species to lose electrical contact with the conductive additive, resulting in rapid capacity fade. In the circulation process, a thick, unstable and electronic insulating solid electrolyte membrane is formed on the surface of the antimony particles to hinder the reaction process, and the coulomb efficiency of the first circle is reduced, so that the circulation stability is poor.

Disclosure of Invention

The purpose of the invention is as follows: aiming at the problems in the prior art, the invention aims to provide a preparation method of an antimony/nitrogen doped graphene composite for a sodium ion battery, and an obtained material and application thereof.

The technical scheme is as follows: in order to solve the problems, the technical scheme adopted by the invention is as follows:

a preparation method of an antimony/nitrogen-doped graphene composite for a sodium-ion battery comprises the following steps:

1) ball-milling and mixing graphene oxide, 1-ethyl-3-methylimidazole dicyandiamide and antimony powder;

2) taking out the ball-milled mixture, dispersing the ball-milled mixture in distilled water, performing ultrasonic dispersion uniformly, and performing freeze drying;

3) subjecting the product obtained in step 2) to reaction in H₂And carbonizing in an Ar atmosphere to obtain the antimony/nitrogen doped graphene compound.

In the step 1), the mass ratio of the added 1-ethyl-3-methylimidazole dicyandiamide to the added graphene oxide to antimony is 1:2 (4-7).

In the step 1), the rotation speed and the time of ball milling are respectively 600-800 rpm and 20-24 h.

In the step 2), the freeze drying time is 2-4 days.

In the step 3), the carbonization method comprises the following steps: placing the product obtained in the step 2) in a tubular furnace, and enabling the tubular furnace to be at 4-10 ℃ for min^-1The temperature is raised to 550-650 ℃ at the rate of (A) and then kept for 2-4 h.

In step 3), the H₂And Ar mixed atmosphere, H₂The volume percentage of (A) is 5-10%.

The antimony/nitrogen-doped graphene composite prepared by the preparation method.

The antimony/nitrogen doped graphene composite is applied as a negative electrode material of a sodium-ion battery.

The cathode material of the sodium-ion battery comprises the antimony/nitrogen-doped graphene composite.

According to the method, the graphene oxide, the 1-ethyl-3-methylimidazole dicyandiamide and the antimony are mixed and ball-milled, ultrasonically dispersed, freeze-dried, carbonized and the like to obtain the antimony/nitrogen-doped graphene compound, and the 1-ethyl-3-methylimidazole dicyandiamide is decomposed and nitrogen doping of the graphene oxide is realized in the carbonization process. Therefore, the invention provides an antimony/nitrogen-doped graphene composite, which is prepared by the method. Testing the components of the obtained antimony/nitrogen doped graphene composite by adopting an X-ray powder diffractometer (XRD) and an X-ray photoelectron spectroscopy (XPS); the size, morphology, microstructure, and the like of the obtained antimony/nitrogen-doped graphene composite were analyzed using a Scanning Electron Microscope (SEM), a Transmission Electron Microscope (TEM), Selective Area Electron Diffraction (SAED), and a high-resolution transmission electron microscope (HRTEM). The result shows that the surface of the antimony/nitrogen-doped graphene is smooth, the visible reduced graphene oxide is in a wrinkle shape, and antimony nanoparticles are uniformly distributed in a nitrogen-doped graphene matrix.

In the prior art, 1-ethyl-3-methylimidazole dicyanamide is used as a carbon source to prepare an antimony/nitrogen-doped carbon compound, and the preparation method comprises the steps of forming a complex by using 1-ethyl-3-methylimidazole dicyanamide and antimony trichloride, and enabling the complex to have high carbon formation rate after pyrolysis and exist in a carbon matrix form; since 1-ethyl-3-methylimidazolium dicyanamide contains nitrogen, the resulting carbon matrix is nitrogen-doped. In the method, 1-ethyl-3-methylimidazole dicyanamide does not form a complex with antimony powder or graphene oxide, the dosage of 1-ethyl-3-methylimidazole dicyanamide is less, 1-ethyl-3-methylimidazole dicyanamide is completely decomposed in the pyrolysis process, nitrogen doping of graphene oxide is realized, and the nitrogen exists in the form of a nitrogen source in the whole material preparation process.

The invention uses the antimony/nitrogen doped graphene compound as the cathode material of the sodium ion battery to test the electrochemical performance of the sodium ion battery, and the result shows that the antimony/nitrogen doped graphene compound has excellent electrochemical performance, and the charge and discharge capacities of the first circle are 521.9mAh g respectively^-1Left and right sum 715.5mAh g^-1About, the first turn coulombic efficiency is about 72.9%, and the rate capability is excellent. On the other hand, the invention provides application of the antimony/nitrogen-doped graphene composite as a negative electrode material of a sodium-ion battery.

The technical effects are as follows: compared with the prior art, the method has the advantages that the process is simple, the used raw materials are environment-friendly and suitable for batch production, and the prepared antimony/nitrogen doped graphene composite has excellent electrochemical performance, can be used as an ideal sodium ion battery cathode material to replace pure antimony with low reversible capacity to be applied to a sodium ion battery, and is a sodium ion battery cathode material with a prospect.

Drawings

FIG. 1: wherein a is an SEM image of an antimony/nitrogen-doped graphene composite (Sb/N-rGO), and the image shows that the composite obtained by pyrolysis has a smooth surface, which indicates that antimony is coated by graphene; b is a TEM image of the antimony/nitrogen doped graphene composite showing that the average size of antimony in the composite is about 100nm and is uniformly distributed in the carbon substrate; c is the SAED diagram of the antimony/nitrogen doped graphene composite showing that the antimony nanoparticles belong to the hexagonal system; d is an HRTEM of the antimony/nitrogen doped graphene composite, further demonstrating that the antimony nanoparticles are coated with nitrogen doped graphene.

FIG. 2: where a is the XRD pattern of the Sb/N-rGO complex, which shows that the characteristic peak (012) of antimony appears at 28.7 deg., corresponding to the interplanar spacing of 0.31nm, which is consistent with the results observed in HRTEM images; b isRaman (Raman) patterns of Sb/N-rGO compound and nitrogen-doped graphene (N-rGO), wherein two characteristic peaks of amorphous carbon in the Raman pattern of the Sb/N-rGO appear at 1351cm^-1And 1585cm^-1To (3). Peak intensity ratio of D band and G band in Sb/N-rGO sample (I)_D/I_G1.25) greater than antimony/graphene (Sb/rGO) (I)_D/I_G1.23), which may further enhance its disordered structure due to nitrogen doping; c is the N1s XPS plot of Sb/N-rGO complex and N-rGO, fitted with three N1s peaks at 397.9e V, 399.2e V and 400.8e V, corresponding to pyridine nitrogen, pyrrole nitrogen and graphite nitrogen, respectively. The shift in pyridine nitrogen position from 399.2eV to 399.8eV in Sb/N-rGO compared to N-rGO, i.e., towards a high binding energy, indicates a stronger interaction between the pyridine nitrogens of the antimony and/or nitrogen doped graphene oxide, which may be associated with the generation of Sb-N-C bonds during pyrolysis of the three feedstocks.

FIG. 3: wherein a is Sb/N-rGO compound electrode at 0.01-2.0V (vs. Na/Na)⁺) Voltage interval, scan rate 0.1mV s^-1Cyclic voltammetry curves of the first four rings; b is the charge/discharge curve of the Sb/N-rGO compound. It can be seen that the slope of the first round of charge-discharge curve around 0.98V is due to the formation of the SEI film; the discharging platform is at 0.55V and the charging platform is at about 0.78V, which correspond to the insertion and extraction of sodium ions respectively. This is consistent with the peaks observed in the CV curve; c is Sb, Sb/rGO compound and Sb/N-rGO compound in the voltage range of 0.01-2V vs Na/Na⁺Current density of 0.1A g^-1Under the conditions of (1), the cycle performance diagram of 3 materials shows that the first-turn charging and discharging specific capacities of the Sb/N-rGO electrode material are 521.9 and 715.7mAh g respectively^-1The coulombic efficiency of the first cycle is 72.9%, and the specific loss rate during the charge and discharge of the first cycle is about 27.1%, which may be caused by the formation of a solid electrolyte film (SEI), the decomposition of the electrolyte and the irreversible intercalation of sodium ions. After the three electrodes circulate for 150 circles, the capacities are 16.6, 323.5 and 472.4mAh g in sequence^-1The capacity retention rates were 3.14%, 61.9 and 90.5%, respectively. It is clear that the cycling stability of Sb and Sb/rGO composites is far behind that of Sb/N-rGO composites; d is a multiplying power performance diagram of Sb, Sb/rGO and Sb/N-rGO. Sb/N-rGO even at high current densities, e.g. 2 or 5A g^-1The capacity can still be maintained at 403 or 360mAh g^-1The capacity of (c).

Detailed Description

The invention is further described with reference to specific examples.

Example 1

(1) Preparation of Sb/N-rGO compound

10mL of the graphene oxide dispersion prepared by the Hummers method (10mg mL)^-1) 300mg of commercial antimony powder purchased and 50mg of 1-ethyl-3-methylimidazolium dicyanamide were charged into a ball mill jar and ball milled at 800rpm for 24 hours. And adding 10mL of water into the ball-milled dispersion liquid for dilution, taking out the diluted mixture, and carrying out ultrasonic treatment in a numerical control ultrasonic cleaner for 5min to form uniform dispersion liquid. Quickly freezing the obtained solution with liquid nitrogen, freeze-drying for 2 days, placing the obtained powder in a single-temperature-zone tube furnace, and performing vacuum distillation in Ar and H₂Under mixed atmosphere (wherein H₂Volume percent of 5%) at 5 ℃ for min^-1Heated to 600 c and held at this temperature for 2 hours to give the Sb/N-rGO composite.

(2) Characterization of antimony/nitrogen-doped graphene composites

The size, morphology and microstructure of the resulting Sb/N-rGO composites were analyzed using SEM, TEM, SAED and HRTEM images. FIG. 1a is an SEM image of an Sb/N-rGO composite showing that the composite obtained by pyrolysis has a smooth surface, indicating that antimony is coated with nitrogen-doped carbon. FIG. 1b is a TEM image of Sb/N-rGO composite, from which it can be seen that antimony has an average size of about 100nm in the composite and is uniformly distributed in the nitrogen-doped graphene matrix. FIG. 1c is a SAED plot of Sb/N-rGO complexes indicating that the antimony nanoparticles are hexagonal. FIG. 1d is a HRTEM image of Sb/N-rGO complex, further illustrating the coating of antimony nanoparticles with nitrogen-doped graphene.

FIG. 2a is an XRD pattern of the Sb/N-rGO complex showing that the (012) characteristic peak of antimony appears at 28.7 deg., corresponding to a interplanar spacing of 0.31nm, which is consistent with the results observed with HRTEM. FIG. 2b is a Raman plot of Sb/N-rGO complex and N-rGO, where two characteristic peaks of amorphous carbon appear at 1351cm^-1And 1585cm^-1To (3). Peak intensity ratio of D band and G band in Sb/N-rGO sample (I)_D/I_G1.25) greater than Sb/rGO (I)_D/I_G1.23), which may further enhance its disordered structure due to nitrogen doping. FIG. 2c is a N1s XPS plot of Sb/N-rGO complex and N-rGO, fitted with three N1s peaks at 397.9e V, 399.2e V and 400.8e V, corresponding to pyridine nitrogen, pyrrole nitrogen and graphite nitrogen, respectively. The shift in pyridine nitrogen position from 399.2eV to 399.8eV in Sb/N-rGO compared to N-rGO, i.e., towards a high binding energy, indicates a stronger interaction between the pyridine nitrogens of the antimony and/or nitrogen doped graphene oxide, which may be associated with the generation of Sb-N-C bonds during pyrolysis of the three feedstocks.

(3) Electrochemical performance test

Using deionized water as a solvent, grinding and uniformly mixing the Sb/N-rGO compound prepared in the embodiment, carbon black and sodium carboxymethylcellulose in a mass ratio of 7:2:1, coating the obtained uniform slurry on a Cu foil, and drying the Cu foil in vacuum at40 ℃ for 12 hours to obtain a supported amount of 0.8-1.2mg cm^-2The electrode sheet of (1). Using 1mol of L^-1NaClO₄The solution of propylene carbonate/fluoroethylene carbonate (volume ratio is 1:0.05) is used as the electrolyte of the sodium ion battery, and the glass fiber and the pure sodium metal foil are respectively used as the diaphragm and the counter electrode of the sodium ion battery. The electrochemical performance was tested using a CR2032 cell. The cell assembly was carried out in a glove box filled with argon atmosphere.

Constant current charge and discharge test of the cell at room temperature, using a blue CT2001A multichannel cell test system at 0.01-2V vs Na/Na⁺Within a fixed voltage range. Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) were tested using the parsta 4000 electrochemical workstation. CV at 0.1mV s^-1At a sweep rate of (2), EIS is performed at a sine wave frequency in the range of 100kHz to 10mHz with an amplitude of 10.0 mV. The specific properties are shown in figure 3. FIG. 3a shows Sb/N-rGO composite electrodes at 0.01-2.0V (vs. Na/Na)⁺) Voltage interval, scan rate 0.1mV s^-1Cyclic voltammograms of the first four cycles. FIG. 3b is a charge/discharge graph of Sb/N-rGO composite. It can be seen that the first circle of charging and discharging curve is inclined at about 0.98VThe slopes are due to the formation of the SEI film; the 0.55V discharge platform and the 0.78V charging platform correspond to the intercalation and deintercalation of sodium ions respectively. This is consistent with the peak exhibited on the CV curve. FIG. 3c shows Sb, Sb/rGO complexes, Sb/N-rGO complexes in the voltage range of 0.01-2V vs Na/Na⁺Current density of 0.1Ag^-1Under the conditions of (1), the cycle performance diagram of 3 materials shows that the first-turn charging and discharging specific capacities of the Sb/N-rGO electrode material are 521.9 and 715.7mAh g respectively^-1The coulombic efficiency of the first cycle is 72.9%, and the specific loss rate during the charge and discharge of the first cycle is about 27.1%, which is probably caused by the formation of a solid electrolyte film (SEI), the reductive decomposition of the electrolyte and the irreversible intercalation of sodium ions. After the three electrodes circulate for 150 circles, the capacities are 16.6, 323.5 and 472.4mAh g in sequence^-1The capacity retention rates were 3.14%, 61.9 and 90.5%, respectively. It is clear that the cycling stability of Sb and Sb/rGO composites lags far behind that of Sb/N-rGO composites. FIG. 3d is a graph of the rate capability of Sb, Sb/rGO, Sb/N-rGO. Sb/N-rGO even at high current densities, e.g. 2 or 5Ag^-1The capacity can still be maintained at 403 or 360mAhg^-1The capacity of (c).

Comparative example 1

(1) Purchasing commercial antimony powder

(2) Electrochemical performance test

Grinding and mixing antimony powder, carbon black and sodium carboxymethylcellulose in water at a mass ratio of 7:2:1, coating the obtained uniform slurry on a Cu foil, and vacuum drying at40 deg.C for 12h to obtain a material with a loading capacity of 0.8-1.2mg cm^-2The electrode sheet of (1). Using 1mol of L^-1NaClO₄The solution of propylene carbonate/ethylene fluorocarbonate (volume ratio is 1:0.05) is used as the electrolyte of the sodium ion battery, and the glass fiber and the pure sodium metal foil are respectively used as a diaphragm and a counter electrode of the sodium ion battery. The electrochemical performance was tested using a CR2032 cell. The cell assembly was carried out in a glove box filled with argon atmosphere.

The sodium ion battery performance test is carried out on pure antimony, the specific process and condition parameters are the same as those of the example 1, and the specific test result is shown in figure 3. As shown in FIG. 3, the cycle performance diagram (FIG. 3c) shows the first cycle charge/discharge capacity of the material527.4/700.4mAh g^-1(ii) a After 150 cycles of circulation, the discharge capacity is reduced to 16.6mAh g^-1The capacity retention rate is 3.14 percent and is obviously lower than the cycle performance of Sb/N-rGO.

Comparative example 2

(1) Preparation of Sb/rGO

10mL of the graphene oxide dispersion prepared by the Hummers method (10mg mL)^-1) Charged into a ball mill jar with 300mg of commercial antimony powder purchased and ball milled at 800rpm for 24 hours. And adding 10mL of water into the ball-milled dispersion liquid for dilution, taking out the diluted mixture, and carrying out ultrasonic treatment in a numerical control ultrasonic cleaner for 5min to form uniform dispersion liquid. Quickly freezing the obtained solution with liquid nitrogen, freeze-drying for 2 days, placing the obtained powder in a single-temperature-zone tube furnace, and performing vacuum distillation in Ar and H₂Under mixed atmosphere (wherein H₂Volume percent of 5%) at 5 ℃ for min^-1Heated to 600 c and held at this temperature for 2 hours to give the Sb/rGO composite.

(2) Electrochemical performance test

Grinding and uniformly mixing the Sb/rGO compound in the step (1), carbon black and sodium carboxymethylcellulose in a mass ratio of 7:2:1 by taking deionized water as a solvent, coating the obtained uniform slurry on a Cu foil, and drying the Cu foil in vacuum at40 ℃ for 12 hours to obtain the supported amount of 0.8-1.2mg cm^-2The electrode sheet of (1). Using 1mol of L^-1NaClO₄The solution of propylene carbonate/ethylene fluorocarbonate (volume ratio is 1:0.05) is used as the electrolyte of the sodium ion battery, and the glass fiber and the pure sodium metal foil are respectively used as a diaphragm and a counter electrode of the sodium ion battery. The electrochemical performance was tested using a CR2032 cell. All the operations related to the cell were carried out in a glove box filled with an argon atmosphere.

As shown in FIG. 3, the cycle performance diagram (FIG. 3c) shows the first cycle charge/discharge capacity of the material 503.4/681.7mAhg^-1(ii) a After circulating for 150 circles, the specific discharge capacity is reduced to 323.5mAh g^-1The capacity retention rate was 64.2%. The capacity retention, although not low, is significantly lower than the Sb/N-rGO composite.

Example 2

10mL of the graphene oxide dispersion prepared by the Hummers method (10mg mL)^-1) 250mg of commercial antimony powder purchased and 50mg of 1-ethyl-3-methylimidazolium dicyanamide were charged into a ball mill jar and ball milled at 800rpm for 24 hours. And adding 10mL of water into the ball-milled dispersion liquid for dilution, taking out the diluted mixture, and carrying out ultrasonic treatment in a numerical control ultrasonic cleaner for 5min to form uniform dispersion liquid. Quickly freezing the obtained solution with liquid nitrogen, freeze-drying for 2 days, placing the obtained powder in a single-temperature-zone tube furnace, and performing vacuum distillation in Ar and H₂Under mixed atmosphere (wherein H₂Volume percent of 5%) at4 ℃ for min^-1Heated to 600 c and held at this temperature for 2 hours to give the Sb/N-rGO-2 composite.

The prepared Sb/N-rGO-2 composite is subjected to structural characterization and electrochemical performance test according to the same method as the embodiment 1, and the result is basically the same as the embodiment 1.

Example 3

10mL of the graphene oxide dispersion prepared by the Hummers method (10mg mL)^-1) 350mg of commercial antimony powder purchased and 50mg of 1-ethyl-3-methylimidazolium dicyanamide were charged into a ball mill pot and ball milled at 800rpm for 24 hours. And adding 10mL of water into the ball-milled dispersion liquid for dilution, taking out the diluted mixture, and carrying out ultrasonic treatment in a numerical control ultrasonic cleaner for 5min to form uniform dispersion liquid. Quickly freezing the obtained solution with liquid nitrogen, freeze-drying for 2 days, placing the obtained powder in a single-temperature-zone tube furnace, and performing vacuum distillation in Ar and H₂Under mixed atmosphere (wherein H ₂10% by volume) at 5 ℃ for min^-1Heated to 600 c and held at this temperature for 3 hours to give the Sb/N-rGO-3 composite.

The obtained Sb/N-rGO compound is subjected to structural characterization and electrochemical performance test according to the same method as the example 1, and the result is basically the same as the example 1.

Example 4

10mL of the graphene oxide dispersion prepared by the Hummers method (10mg mL)^-1) 300mg of commercial antimony powder purchased and 50mg of 1-ethyl-3-methylimidazolium dicyanamide were charged into a ball mill jar and ball milled at 600rpm for 24 hours. Diluting the ball-milled dispersion with 10mL of water, taking out the diluted mixture, and subjecting the mixture to ultrasonic treatment in a numerical control ultrasonic cleaner for 5min to obtain the final productTo form a uniform dispersion liquid. Quickly freezing the obtained solution with liquid nitrogen, freeze-drying for 2 days, placing the obtained powder in a single-temperature-zone tube furnace, and performing vacuum distillation in Ar and H₂Under mixed atmosphere (wherein H ₂10% by volume) at 5 ℃ for min^-1Heated to 650 ℃ and held at this temperature for 3h to give the Sb/N-rGO-4 composite.

The prepared Sb/N-rGO-4 composite is subjected to structural characterization and electrochemical performance test according to the same method as the embodiment 1, and the result is basically the same as the embodiment 1.

Example 5

10mL of the graphene oxide dispersion prepared by the Hummers method (10mg mL)^-1) 300mg of commercial antimony powder purchased and 50mg of 1-ethyl-3-methylimidazolium dicyanamide were charged into a ball mill jar and ball milled at 600rpm for 20 hours. And adding 10mL of water into the ball-milled dispersion liquid for dilution, taking out the diluted mixture, and carrying out ultrasonic treatment in a numerical control ultrasonic cleaner for 5min to form uniform dispersion liquid. Quickly freezing the obtained solution with liquid nitrogen, freeze drying for 4 days, placing the obtained powder in a single-temperature-zone tube furnace, and performing vacuum distillation in Ar and H₂Under mixed atmosphere (wherein H ₂10% by volume) at 10 ℃ for min^-1Heated to 550 c and held at this temperature for 4 hours to give the Sb/N-rGO-4 composite.

Claims

1. A preparation method of an antimony/nitrogen-doped graphene composite for a sodium-ion battery is characterized by comprising the following steps:

1) ball-milling and mixing graphene oxide, 1-ethyl-3-methylimidazole dicyanamide and antimony powder, wherein the mass ratio of the added 1-ethyl-3-methylimidazole dicyanamide to the graphene oxide to the antimony is 1:2 (4-7);

3) subjecting the product obtained in step 2) to reaction in H₂And Ar mixed atmosphereAnd (3) performing carbonization, namely decomposing the 1-ethyl-3-methylimidazole dicyandiamide by self and realizing nitrogen doping on the graphene oxide to obtain the antimony/nitrogen doped graphene composite.

2. The preparation method of the antimony/nitrogen-doped graphene composite for the sodium-ion battery according to claim 1, wherein in the step 1), the rotation speed and the time of ball milling are 600-800 rpm and 20-24 h respectively.

3. The method for preparing the antimony/nitrogen-doped graphene composite for the sodium-ion battery according to claim 1, wherein in the step 2), the freeze-drying time is 2-4 days.

4. The method for preparing the antimony/nitrogen-doped graphene composite for the sodium-ion battery according to claim 1, wherein in the step 3), the carbonization method comprises: placing the product obtained in the step 2) into a tube furnace, and enabling the tube furnace to be 4-10%^oC min⁻¹Heating to 550-650 deg.C^oAnd keeping for 2-4 h after C.

5. The method for preparing the antimony/nitrogen-doped graphene composite for the sodium-ion battery according to claim 1, wherein in the step 3), the H is₂And Ar mixed atmosphere, H₂The volume percentage of (A) is 5-10%.

6. The antimony/nitrogen doped graphene composite prepared by the preparation method of any one of claims 1 to 5.

7. The use of the antimony/nitrogen doped graphene composite for a sodium-ion battery as claimed in claim 6 as a negative electrode material for a sodium-ion battery.

8. A sodium-ion battery negative electrode material, characterized in that the sodium-ion battery negative electrode material comprises the antimony/nitrogen-doped graphene composite according to claim 7.