CN108963237B

CN108963237B - Preparation method of sodium ion battery negative electrode material

Info

Publication number: CN108963237B
Application number: CN201810889045.7A
Authority: CN
Inventors: 张永光; 杨爽
Original assignee: Synergy Innovation Institute Of Gdut Heyuan; Hebei University of Technology
Current assignee: Synergy Innovation Institute Of Gdut Heyuan; Hebei University of Technology
Priority date: 2018-08-07
Filing date: 2018-08-07
Publication date: 2021-03-16
Anticipated expiration: 2038-08-07
Also published as: CN108963237A

Abstract

The invention relates to a preparation method of a sodium-ion battery cathode material. The method comprises the steps of taking antimony trichloride, selenium powder and triethylene glycol as raw materials, preparing rod-shaped antimony selenide by a polyol method, taking antimony selenide and carbon nano tubes as main materials, and carrying out steam etching and spray drying to obtain microspheres with antimony selenide nano rods and carbon nano tubes uniformly distributed. The spherical structure of the material can effectively solve the problem of large-scale change of the volume generated when the antimony selenide is used as the anode material in the sodium ion battery, and the more defects are formed on the surface of the antimony selenide/carbon nano tube composite material through water etching, so that the transmission speed of electrons and ions is improved, and the electrochemical performance and the cycling stability of the lithium sulfur battery are integrally improved.

Description

Preparation method of sodium ion battery negative electrode material

Technical Field

The invention relates to the technical field of cathode materials of sodium-ion batteries, in particular to a preparation method of an antimony selenide/carbon nanotube composite material for a cathode of a sodium-ion battery.

Background

Energy is one of the important factors driving the progress of human civilization. With the development of modern industrialization and emerging technologies, the consumption of traditional energy sources such as fossil, coal, oil and natural gas is accelerating. The global energy crisis brought with the global energy crisis not only brings serious influence to the basic life of people. In addition, environmental problems associated with excessive use of conventional energy sources are also not negligible. In order to cope with the above problems, clean energy sources such as wind energy, solar energy, tidal energy, biological energy, and geothermal energy are being developed and used gradually. The total amount of the renewable clean energy sources is large, but the energy density is small, and the energy supply is random and discontinuous in time and space. Therefore, in order to meet the requirement of people on convenient use of the clean energy in life, various energy storage devices capable of meeting the actual requirements are widely developed and applied.

At present, lithium ion batteries are widely applied to portable electronic devices, and with the large-scale development and application of power automobiles and electronic portable devices, the cost of the lithium ion batteries is likely to be increased due to the limited lithium resources on the earth, and the lithium ion batteries are eventually consumed up quickly. Therefore, sodium ion secondary batteries with electrochemical performance similar to that of lithium ion batteries become the most suitable substitute. Although sodium ions are heavier than lithium ions, small-sized energy storage devices (such as mobile phone batteries, notebook batteries and the like) have small mobility except for the need of considering the energy and the volume density of the batteries of the power automobiles, so that the sodium ion batteries have great possibility in practical application. The properties of the sodium and lithium elements, which are both in group i of the periodic table, share many similarities, and so sodium-ion batteries constructed in many ways resemble lithium-ion batteries. The basic working principle of the battery is the same as that of a rocking chair type battery of a lithium ion battery, and a simple substance or a compound capable of reversibly embedding and releasing sodium ions is used as the positive electrode and the negative electrode of a battery system. The sodium element has abundant resources and is easy to obtain, and sodium has higher half-cell potential compared with lithium, so that electrolyte with low decomposition voltage can be used, and the safety performance is hopeful to be superior to that of a lithium ion battery. Therefore, in order to realize sustainable development of the battery industry, development of novel energy storage batteries without environmental pollution is in great tendency, and sodium ion batteries are one member of the novel high-energy green batteries.

Although the sodium ion battery has the above advantages, when the interlayer distance of the negative electrode is smaller than the diameter of the sodium ion due to the large radius of the sodium ion, it is difficult for the sodium ion to be intercalated into the negative electrode and thus the intercalation amount of the sodium ion is very small, resulting in an extremely low specific capacity of the sodium ion battery. In addition, sodium can be intercalated into the negative electrode material to form a compound, but the volume expansion of the material is very serious when the compound is formed, and even the electrode is broken and pulverized, so that the electrochemical performance is rapidly reduced, and the cycling stability is difficult to solve. In general, sodium ion batteries, which can replace lithium ion batteries, are attracting attention of global scientists, but there are a lot of problems in sodium ion batteries, which are to be solved by further research.

Antimony-based materials are promising sodium-ion battery negative electrode materials due to the high deintercalation capacity of sodium ions. Antimony selenide is a typical V-VI compound, is a direct band gap P-type semiconductor with a layered structure, and is widely applied to the fields of hydrogen storage, photocatalysis, electrochemical energy storage and the like. Moreover, 1mol of antimony selenide can be intercalated into 12mol of sodium ions, and the generated reaction is reversible, so that 678mAh g can be finally obtained^-1The theoretical specific capacity of (a). However, antimony selenide as a cathode material of a sodium ion battery has a large volume expansion and shrinkage in a reversible reaction process, and the increase of the cycle number may cause cracking and pulverization of an electrode, so that the cycle stability is poor, and the defect of the antimony selenide greatly limits the wide application. Therefore, it is required to improve the reactivity of the battery by controlling the morphology of the product, and to reduce the volume change during the charge and discharge process by reducing the size of the material or compounding with other materials, thereby improving the cycle performance. CN 107140609A discloses a method for preparing a beam-packed antimony selenide electrode material for a sodium ion battery cathode by microwave oven hydrothermal. The size of the antimony selenide nano-beam prepared by the material is large, the length can reach 6-7 mu m, and the top end of the nano-beam is formed by agglomerating antimony selenide nano-wires, which is extremely unfavorable for volume expansion and contraction in the charging and discharging process when the antimony selenide nano-beam is used as a cathode material of a sodium ion battery, and is easy to cause cracking and crushing of an electrode, which is unfavorable for the cycle stability of the lithium sulfur battery. Therefore, the development of novel antimony selenide sodium ion battery cathode materials becomes a focus of attention.

Disclosure of Invention

The technical problem to be solved by the patent is to provide a preparation method of a sodium ion battery cathode material aiming at the defects existing in the current technical center. The method comprises the steps of taking antimony trichloride, selenium powder and triethylene glycol as raw materials, preparing rod-shaped antimony selenide by a polyol method, taking antimony selenide and carbon nano tubes as main materials, and carrying out steam etching and spray drying to obtain microspheres with antimony selenide nano rods and carbon nano tubes uniformly distributed. The spherical structure of the material can effectively solve the problem of large-scale change of the volume generated when the antimony selenide is used as the anode material in the sodium ion battery, and the more defects are formed on the surface of the antimony selenide/carbon nano tube composite material through water etching, so that the transmission speed of electrons and ions is improved, and the electrochemical performance and the cycling stability of the lithium sulfur battery are integrally improved.

The technical scheme of the invention is as follows:

a preparation method of a sodium-ion battery negative electrode material comprises the following steps:

the method comprises the following steps: preparing an antimony trichloride solution; wherein the solvent is triethylene glycol, and 0.5-2 g of antimony trichloride is added into every 20-50 mL of triethylene glycol;

step two: preparing selenium solution with the concentration of 0.2-2 mmol/mL; wherein the solvent is ethanolamine and hydrazine hydrate, and the volume ratio of ethanolamine to hydrazine hydrate is 1-5: 1;

step three: preparing an antimony selenide dispersion liquid:

adding the selenium liquid prepared in the step two, polyvinylpyrrolidone and triethylene glycol into a closed container, vacuumizing, introducing argon, heating to 200-250 ℃, injecting the antimony trichloride solution obtained in the step one into an injector, stirring at 200-250 ℃, and reacting for 20-50 min; cooling to normal temperature, centrifuging to obtain antimony selenide, adding the antimony selenide into deionized water, and performing ultrasonic dispersion to obtain an antimony selenide aqueous suspension;

wherein, 0.2-2 g of polyvinylpyrrolidone, 10-50 mL of triethylene glycol and 20-200 mL of antimony trichloride solution are added into every 7-20 mL of the selenium solution prepared in the second step; adding 10-20 mL of deionized water into every 1g of antimony selenide;

step four: spray preparation of powder: diluting the antimony selenide aqueous suspension into 10-100 times of the original volume, and carrying out ultrasonic treatment for 0.5-1.5 h; adding carbon nanotube powder, and continuing to perform ultrasonic treatment for 0.5-1.5 h; spraying to obtain antimony selenide/carbon nanotube powder;

wherein the mass ratio of the antimony selenide to the carbon nano tube is 1: 0.2-1.5, and the parameters of a spray drying instrument are as follows: the air intake is 100%, and the feeding speed is 3-10 mLmin^-1The air inlet temperature is 150-200 ℃;

step five: water vapor etching:

placing antimony selenide/carbon nanotube powder in a tube furnace, and sealing the tube furnace in an argon atmosphere; then heating the tube furnace to 200-400 ℃; then introducing mixed gas for 3-10 min, turning off the tubular furnace, and cooling to room temperature to obtain the antimony selenide/carbon nanotube composite material, namely the preparation method of the sodium ion battery cathode material; wherein the mixed gas consists of water vapor and argon, and the volume of the water vapor is 10-30% of the volume of the mixed gas.

The temperature rise rate in the fifth step is 5-10 ℃ min^-1。

The above method for preparing the antimony selenide/carbon nanotube composite material for the cathode of the sodium-ion battery uses commercially available raw materials, and the equipment and process used are well known to those skilled in the art.

Compared with the prior art, the method has the prominent substantive characteristics as follows:

1. the interlayer spacing of antimony selenide is large, 1mol of antimony selenide can be embedded with 12mol of sodium ions, and the generated reaction is reversible, so that higher specific capacity can be obtained.

2. The preparation process of the antimony selenide/carbon nanotube composite material is simple, the process is intuitive, and the cost is low.

3. The antimony selenide/carbon nanotube composite material is prepared by a spray drying method, the carbon nanotubes form a three-dimensional net structure, and the rod-shaped antimony selenide is uniformly inserted in the three-dimensional net structure, so that the structure greatly shortens the transmission path of ions and electrons in the reaction process, and the carbon nanotubes have strong flexibility, so that the volume change of electrodes in the charging and discharging process can be effectively relieved, and the electrochemical performance of the lithium-sulfur battery is improved.

4. Through the water vapor etching, more atom defects are generated on the surface of the antimony selenide/carbon nano tube composite material, which is beneficial to the transmission of electrons and ions in the reaction process, and the holes etched on the surface of the antimony selenide/carbon nano tube composite material are beneficial to relieving the volume change generated by the electrode in the charging and discharging process, so that the integrity of the electrode is maintained, and the cycle performance of the electrode is improved.

Compared with the prior art, the method provided by the invention has the following remarkable improvements:

1. compared with the prior art CN 107256967A, the antimony selenide rod with a nano structure and uniform distribution and the carbon nano tube with excellent conductivity and flexibility are compounded together through spray drying, so that the volume change of the antimony selenide rod as a cathode material of a sodium ion battery can be effectively buffered, and the volume change generated in the charging and discharging process can be buffered due to the fact that the rod-shaped antimony selenide inside the spherical antimony selenide/carbon nano tube composite material is crossed to generate a large number of pores, so that the performance of the battery is improved. The spherical antimony selenide prepared in the prior art CN 107256967A is extremely easy to agglomerate, so that when the spherical antimony selenide is used as a negative electrode material of a sodium ion battery, the spherical antimony selenide is easy to generate large volume change to cause pole piece cracking and active substance falling, and the cycle performance is poor. And the surface of the antimony selenide ball prepared in the prior art CN 107256967A is smooth, but the surface etched by the water vapor has a large number of defects, so that the prior art CN 107256967A has fewer defects compared with the invention, is not beneficial to the transmission of electrons and ions in the reaction process, leads to low utilization rate of active substances, and can be represented by the specific capacity of electrochemical charge and discharge. The specific discharge capacity of the antimony selenide/carbon nano tube composite material as the cathode of the sodium ion battery for the second time is 657mAh g^-1495mAh g which is far higher than the second discharge capacity of CN 107256967A in the prior art^-1。

2. Compared with CN 107140608A in the prior art, the invention has short reaction time and short experimental period, does not need freeze drying, achieves drying in one step and uniform composition with the carbon nano tube in one step by spray drying, takes part in the reaction of hydrazine hydrate in a closed reaction instrument, and has little air pollution. In the prior art, the CN 107140608A experiment has long reaction period, and hydrazine hydrate and selenium powder are required to be prepared into solution to be subjected to ultrasonic treatment in the air, so that the environmental pollution is great. The size of the spheres formed by the antimony selenide/carbon nano tube composite material obtained by spray drying is smaller and is uniformly distributed between 3 and 3.5 mu m, while the antimony selenide negative electrode material prepared in the prior art CN 107140608A is seriously agglomerated and has diameter distribution20-30 μm, so when the material obtained in the invention is used as a sodium ion battery cathode, the contact area with the electrolyte is larger, and the utilization rate of active substances is favorably improved. In addition, the three-dimensional network carbon nano tube obtained by spray drying and the defects generated by steam etching further provide an ion transmission channel, the flexibility of the carbon nano tube and more holes etched by the steam further relieve the problem of volume expansion generated by taking antimony selenide as a battery cathode, while in the prior art, CN 107140608A is a single-phase antimony selenide nanorod which is agglomerated to form an irregular spherical structure with the diameter of 20-30 mu m, and the antimony selenide nanorod is used as a sodium ion battery cathode material and can generate great volume change in the charging and discharging processes, and the buffer space is extremely small, so that the pole piece is easy to crack, and the cycle performance is not added. In addition, the carbon nano tube is added in the invention, so that the transmission path of electrons and ions can be further shortened, the utilization rate of active substances is improved, but the carbon nano tube is not added in the prior art CN 107140608A, so that the electrochemical result is poor, and the secondary discharge capacity of the invention is 657mAh g^-1Coulombic efficiencies as high as 99.7%, while the electrochemical results of the prior art CN 107140608A gave a capacity of 608mAh g on the second discharge^-1About, far lower than the specific discharge capacity of the invention.

In a word, the antimony selenide/carbon nanotube composite material prepared by the invention solves the problems of low capacity and poor cycle of the existing antimony selenide material as a sodium ion battery, the carbon nanotubes and the antimony selenide are compounded by spray drying to form a three-dimensional network structure, rod-shaped antimony selenide is uniformly inserted between the carbon nanotubes and the antimony selenide, and the rod-shaped antimony selenide is mutually staggered and generates a large number of pores in a spherical structure, so that the defects of volume expansion and poor cycle performance of the antimony selenide as a battery cathode material are overcome. And through water vapor etching, the surface of the spherical antimony selenide/carbon nano tube composite material generates more surface defects, which is beneficial to the transmission in the reaction process of ions and electrons, so that the utilization rate of active substances is improved, and therefore, the sodium ion battery using the antimony selenide/carbon nano tube composite material as a cathode has excellent rate capability and cycle performance, and is a battery with great market prospect.

Drawings

Fig. 1 is an X-ray diffraction pattern of the antimony selenide/carbon nanotube composite prepared in example 2.

Fig. 2 is a scanning electron microscope image of the antimony selenide/carbon nanotube composite material prepared in example 2.

Fig. 3 is a second charge-discharge curve of the antimony selenide/carbon nanotube composite material prepared in example 2 at a current density of 0.1C when used as a negative electrode of a sodium ion battery.

Detailed Description

Example 1

First, preparing a solution:

1g of antimony trichloride was weighed into 20mL of triethylene glycol and placed on a magnetic stirrer to be stirred so that the antimony trichloride was completely dissolved and set aside for use.

Step two, preparing selenium liquid:

ethanolamine and hydrazine hydrate were mixed according to a 4: 1, adding selenium powder to prepare a selenium solution with the concentration of 1mmol/mL, and placing aside for later use.

Step three, preparing an antimony selenide dispersion liquid:

and (3) taking a three-neck flask, adding 7mL of selenium liquid prepared in the step two, 1g of polyvinylpyrrolidone and 20mL of triethylene glycol into the three-neck flask, plugging the left bottle mouth by using a bottle stopper with a needle, connecting the middle bottle mouth with a condensing tube, inserting a thermometer into the right bottle mouth, confirming that the instrument is sealed, starting vacuumizing, introducing argon after the inside of the experimental instrument is vacuumized, and repeating for 3 times. Inserting a syringe containing 20mL of the mixed solution prepared in the first step into a three-mouth bottle, turning on a stirring heater to start stirring and heating, raising the temperature to 210 ℃, injecting all the liquid in the syringe, controlling the temperature at 210 ℃, and reacting for 20 min. After the three-necked flask is cooled to normal temperature, 1.05g of Sb is obtained by centrifugation₂Se₃Adding 15mL of deionized water, and performing ultrasonic homogenization to obtain Sb₂Se₃An aqueous suspension.

Fourthly, spraying to prepare powder:

diluting the aqueous suspension of antimony selenide to 350mL, and putting the aqueous suspension into an ultrasonic machine for ultrasonic treatment for 0.5 h. Adding 0.5g of carbon nanotube powder into the antimony selenide dispersion liquid, and continuously putting the antimony selenide dispersion liquid into an ultrasonic machine for ultrasonic treatment for 0.5 h. Then spraying to obtain antimony selenide/carbon nanotube powder, wherein the parameters of a spray drying instrument are as follows: the air intake is 100 percent, the feeding speed is 5mL/min, and the air intake temperature is 180 ℃.

Step five, water vapor etching:

and (3) placing the antimony selenide/carbon nanotube powder into a tube furnace, and sealing two ends of the tube furnace. A conical bottle is prepared and sealed by a rubber plug with three vent pipes, and the three vent pipes are respectively connected with a water bottle, an argon bottle and a tube furnace through rubber pipes. Firstly, tightly closing a rubber tube connected with a water bottle, introducing argon into a conical flask, leading the argon to enter a tube furnace through the conical flask, exhausting air after continuously keeping for 1h, opening a heating switch of the tube furnace, and keeping the temperature for 10 ℃ min^-1The temperature rise rate of (2) is increased to 200 ℃. At the same time, 20mL of deionized water was added to the flask and the water bath was opened to heat the water in the flask to 85 ℃. And then introducing deionized water with the temperature of 85 ℃ into argon, then introducing into the tube furnace, so that the argon introduced into the tube furnace contains water vapor, the content of the water vapor is controlled by the flow rate of the introduced argon, the flow rate of the introduced argon is controlled at 2L/min, the content of the water vapor in the argon is 25%, introducing for 5min, then closing the tube furnace, and cooling to room temperature to obtain a sample, namely the water vapor etched antimony selenide/carbon nanotube composite material.

Sixthly, preparing a battery negative plate and assembling a battery:

and (3) putting the prepared antimony selenide/carbon nanotube composite material, a conductive agent and a binder into a mortar according to the mass ratio of 8: 1, grinding and mixing to obtain slurry, uniformly scraping and coating the slurry on a copper foil, drying at 55 ℃ for 24 hours, and pressing into a thin sheet by using a tablet press under the pressure of 5MPa to obtain the negative plate. And (3) adding electrolyte into the antimony selenide/carbon nano tube serving as a cathode and the metal Li sheet serving as an anode, and assembling the battery in a glove box to obtain the button type CR2025 half-battery.

The prepared samples were subjected to electrochemical performance analysis (BTS-5V5mA, Newway).

Example 1 preparationThe prepared rod-like antimony selenide has the length of 1-1.5 mu m and the width of 50-100 nm, and the diameter of the antimony selenide/carbon nano tube composite material nano microspheres prepared by spraying is evenly distributed between 3.5-4.1 mu m. And because of the water vapor etching, a more porous structure is generated on the surface. The electrochemical result shows that the second discharge capacity is 628mAh g^-1。

Example 2

The process is otherwise the same as example 1, except that in the fourth step, the aqueous suspension of antimony selenide is diluted to 500mL, and in the fifth step, the temperature of the tube furnace is raised to 300 ℃.

Fig. 1 is an X-ray diffraction pattern of the antimony selenide/carbon nanotube composite prepared in example 2. As can be seen from the figure, there is a relatively broad peak at 26 °, which is the carbon peak of the carbon nanotube. And the other peaks correspond to the peaks of antimony selenide, thus proving the successful synthesis of the antimony selenide/carbon nanotube composite material.

Fig. 2 is a scanning electron microscope image of the antimony selenide/carbon nanotube composite material prepared in example 2. The length of the rod-shaped antimony selenide is 1-1.5 mu m, the width of the rod-shaped antimony selenide is 50-100 nm, the antimony selenide/carbon nano tube obtained by spraying is of a uniformly distributed spheroidal structure with the diameter of 3-3.5 mu m, and the rod-shaped antimony selenide is uniformly wound by the carbon nano tube. And a large number of hole structures exist on the surface of the spherical structure.

Fig. 3 is a second charge-discharge curve of the antimony selenide/carbon nanotube composite material prepared in example 2 at a current density of 0.1C when used as a negative electrode of a sodium ion battery. The secondary discharge capacity of the sodium ion battery taking antimony selenide/carbon nano tube as the cathode is 657mAh g^-1The coulombic efficiency is as high as 99.7%.

Example 3

The process is otherwise the same as example 1, except that in the fourth step, the aqueous suspension of antimony selenide is diluted to 650mL and in the fifth step, the temperature in the tube furnace is raised to 400 ℃.

The length of the rod-shaped antimony selenide prepared in the embodiment 3 is 1-1.5 mu m, the width of the rod-shaped antimony selenide is 50-100 nm, and the precursor solution prepared before spray drying is low in concentration, so that the antimony selenide/carbon nano tube composite material prepared by spraying is low in concentrationThe rice-tube composite material has a small nano-structure size, the diameters of the nano-structure are evenly distributed between 2 and 2.8 mu m, and the surface holes are obviously increased due to the high water vapor etching temperature. The electrochemical result shows that the second discharge capacity is 649mAh g^-1。

Example 4

The process is otherwise the same as in example 1, except that 1.5g of antimony selenide is added to 20mL of triethylene glycol in the first step and the concentration of the selenium solution prepared in the second step is 1.5 mmol/mL.

The length of the rod-shaped antimony selenide prepared in the embodiment 4 is 1.2-1.6 mu m, the width of the rod-shaped antimony selenide is 80-120 nm, the diameter of the antimony selenide/carbon nano tube composite material obtained by spraying is 3.1-3.5 mu m, and more holes generated by steam etching exist on the surface of the antimony selenide/carbon nano tube composite material. The electrochemical result shows that the second discharge capacity is 622mAh g^-1。

Example 5

The process is otherwise the same as in example 1, except that 2g of antimony selenide is added to 20mL of triethylene glycol in the first step, and the concentration of the selenium solution prepared in the second step is 2 mmol/mL.

The length of the rod-shaped antimony selenide prepared in the embodiment 5 is 1.5-1.9 mu m, the width of the rod-shaped antimony selenide is 90-135 nm, the diameter of the antimony selenide/carbon nano tube composite material obtained by spraying is 3.2-3.6 mu m, and more holes generated by steam etching exist on the surface of the antimony selenide/carbon nano tube composite material. The electrochemical result shows that the second discharge capacity is 628mAh g^-1。

Example 6

The procedure is otherwise as in example 1, except that in the third step the reaction temperature is increased to 230 ℃ and the reaction time is prolonged to 35 min.

The length of the rod-shaped antimony selenide prepared in the embodiment 6 is 1.8-1.9 mu m, the width of the rod-shaped antimony selenide is 70-105 nm, the diameter of the antimony selenide/carbon nano tube composite material obtained by spraying is 3.1-3.3 mu m, and more holes generated by steam etching exist on the surface of the antimony selenide/carbon nano tube composite material. The electrochemical result shows that the second discharge capacity is 638mAh g^-1。

Example 7

The procedure is otherwise as in example 1, except that in the third step the reaction temperature is raised to 250 ℃ and the reaction time is prolonged to 50 min.

The length of the rod-shaped antimony selenide prepared in the embodiment 7 is 1.85-2 mu m, the width of the rod-shaped antimony selenide is 90-110 nm, the diameter of the antimony selenide/carbon nano tube composite material obtained by spraying is 3.2-3.5 mu m, and more holes generated by water vapor etching exist on the surface of the antimony selenide/carbon nano tube composite material. The electrochemical result shows that the second discharge capacity is 630mAh g^-1。

In order to solve the problem generated when the antimony selenide is applied to the cathode of a sodium ion battery, the antimony selenide/carbon nano tube composite material is processed by a water vapor etching technology, so that a large number of atom defects are generated on the surface of the antimony selenide/carbon nano tube composite material, and the transmission of ions and electrons in the charging and discharging process is facilitated, so that the charging and discharging efficiency is improved. And the surface of the material generates holes, which is beneficial to relieving the volume effect in the charging and discharging process and keeping the structural integrity. In addition, the antimony selenide/carbon nanotube composite material is prepared by a spray drying method and used as a negative electrode material of the sodium ion battery. Because the carbon nanotube material has some excellent characteristics, the composition of the carbon nanotube material and antimony selenide can solve the problems of antimony selenide, such as further improving the conductivity of the carbon nanotube material, shortening the transmission path of electrons and ions, and further improving the electrochemical performance of the carbon nanotube material. And the carbon nano tube has higher flexibility, and the volume change of the antimony selenide in the charging and discharging process is effectively buffered by forming a three-dimensional network structure through mutual staggering, so that the cycle performance of the battery is improved.

The invention is not the best known technology.

Claims

1. A preparation method of a negative electrode material of a sodium-ion battery is characterized by comprising the following steps:

step three: preparing an antimony selenide dispersion liquid:

adding the selenium liquid prepared in the second step, polyvinylpyrrolidone and triethylene glycol into a closed container, vacuumizing, introducing argon, heating to 200-250 ℃, injecting the antimony trichloride solution obtained in the first step through an injector, stirring at 200-250 ℃, and reacting for 20-50 min; cooling to normal temperature, centrifuging to obtain antimony selenide, adding the antimony selenide into deionized water, and performing ultrasonic dispersion to obtain an antimony selenide aqueous suspension;

step five: water vapor etching:

2. The method for preparing the negative electrode material of the sodium-ion battery according to claim 1, wherein the temperature rise rate in the fifth step is 5-10 ℃ for min^-1。