阅读说明：本技术 一种硒化铋/硒化钼异质结构电极材料的制备方法及其应用 (Preparation method and application of bismuth selenide/molybdenum selenide heterostructure electrode material ) 是由 韩曼舒 李誉 周志浩 陈明华 陈庆国 于 2020-12-03 设计创作，主要内容包括：一种硒化铋/硒化钼异质结构电极材料的制备方法及其应用,它涉及一种硒化铋/硒化钼异质结构电极材料的制备方法。本发明的目的是要解决现有钠离子电池的循环性能和倍率性能差的问题。方法：一、合成Bi-2Se-3；二、制备Bi-2Se-3/MoSe-2异质结构,得到硒化铋/硒化钼异质结构电极材料。本发明对制备的硒化铋/硒化钼异质结构电极材料的电化学性能进行测试,循环伏安和恒流充放电实验表明,该电极材料具有较好的倍率性能,在0.1A g～(-1)的电流密度下,可获得约360mAhg～(-1)的质量比容量,在50次循环后没有明显的衰减。本发明可获得一种硒化铋/硒化钼异质结构电极材料。(A preparation method and application of a bismuth selenide/molybdenum selenide heterostructure electrode material relate to a preparation method of a bismuth selenide/molybdenum selenide heterostructure electrode material. The invention aims to solve the problem that the existing sodium ion battery is poor in cycle performance and rate capability. The method comprises the following steps: synthesis of Bi 2 Se 3 (ii) a II, preparing Bi 2 Se 3 /MoSe 2 And obtaining the bismuth selenide/molybdenum selenide heterostructure electrode material by adopting the heterostructure. The electrochemical performance of the prepared bismuth selenide/molybdenum selenide heterostructure electrode material is tested, and cyclic voltammetry and constant current charge and discharge experiments show that the electrode material has better rate capability which is 0.1A g ‑1 At a current density of about 360mAhg ‑1 The mass to capacity ratio of (a) was not significantly attenuated after 50 cycles. The invention can obtain a bismuth selenide/molybdenum selenide heterostructure electrode material.)

1. A preparation method of a bismuth selenide/molybdenum selenide heterostructure electrode material is characterized in that the preparation method of the bismuth selenide/molybdenum selenide heterostructure electrode material is completed according to the following steps:

synthesis of Bi₂Se₃：

Firstly, Na is added₂SO₃Adding Se powder into deionized water, and stirring to obtain a solution A;

② first, Bi (NO) is added₃)₃·5H₂Uniformly mixing the solution O and the ethylene diamine tetraacetic acid solution, then dropwise adding the ascorbic acid solution, stirring again to obtain a mixed solution, and dropwise adding the ammonia water solution into the mixed solution until the mixed solution is completely transparent to obtain a solution B;

thirdly, dropwise adding the solution A into the solution B, and stirring to obtain a clear solution; transferring the clear solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction to obtain a reaction product I;

fourthly, centrifugally cleaning the reaction product I by using deionized water until the solution is clear, performing vacuum filtration, and drying solid substances obtained after the filtration in vacuum to obtain Bi₂Se₃：

II, preparing Bi₂Se₃/MoSe₂Heterostructure:

under the condition of ultrasound, Bi is reacted₂Se₃Dispersing in deionized water to obtain Bi₂Se₃A solution;

② mixing Na₂MoO₄·2H₂Dissolving O in deionized water, and stirring to obtain Na₂MoO₄A solution;

dissolving Se powder into hydrazine hydrate, and stirring to obtain Se powder dispersion liquid;

fourthly, mixing Bi₂Se₃Solution, Na₂MoO₄Mixing the solution and the Se powder dispersion liquid, and stirring to obtain a mixed solution; transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction to obtain a reaction product II;

fifthly, centrifugally cleaning the reaction product II by using deionized water as a cleaning agent, and then performing vacuum drying to obtain a dried reaction product II;

and sixthly, annealing the dried reaction product II under the protection of argon to obtain the bismuth selenide/molybdenum selenide heterostructure electrode material.

2. The method for preparing the bismuth selenide/molybdenum selenide heterostructure electrode material as claimed in claim 1, wherein Na is used in the first step₂SO₃The volume ratio of the substance(s) to the deionized water is (1 mmol-3 mmol): 5 mL-10 mL; the volume ratio of the Se powder to the deionized water in the first step is (0.5 mmol-1 mmol): 5 mL-10 mL; the stirring temperature in the first step is 75-85 ℃, the stirring speed is 200-300 r/min, and the stirring time is 6-8 h.

3. The method for preparing bismuth selenide/molybdenum selenide heterostructure electrode material according to claim 1, wherein the step one is Bi (NO)₃)₃·5H₂The concentration of the O solution is 0.05mol/L to0.15 mol/L; the concentration of the ethylene diamine tetraacetic acid solution in the first step is 0.05-0.15 mol/L; the concentration of the ascorbic acid solution in the first step is 0.3-0.8 mol/L.

4. The method for preparing the bismuth selenide/molybdenum selenide heterostructure electrode material according to claim 1, wherein the mass fraction of the ammonia water in the first step is 28 wt%; bi (NO) described in step one₃)₃·5H₂The volume ratio of the O solution to the EDTA solution is (2-6) to (60-100).

5. The method for preparing bismuth selenide/molybdenum selenide heterostructure electrode material according to claim 1, wherein the step one is Bi (NO)₃)₃·5H₂The volume ratio of the O solution to the ascorbic acid solution is 1: 1; the stirring speed in the first step is 500 r/min-700 r/min, and the stirring time is 0.5 h-1 h.

6. The method for preparing a bismuth selenide/molybdenum selenide heterostructure electrode material as claimed in claim 1, wherein the volume ratio of the solution A to the solution B in the step one is (8-16): (70-120); stirring speed is 500 r/min-700 r/min, and stirring time is 20 min-40 min; the hydrothermal reaction temperature in the step one is 170-180 ℃, and the hydrothermal reaction time is 20-24 h; the drying temperature in the first step and the drying time in the second step are 60 ℃ and 10-12 h.

7. The method for preparing the bismuth selenide/molybdenum selenide heterostructure electrode material as claimed in claim 1, wherein the Bi in the second step₂Se₃The mass ratio of the deionized water to the deionized water is (30 mg-80 mg) to 10 mL; the power of the ultrasound in the second step is 100W-200W; na in step two₂MoO₄·2H₂The volume ratio of the mass of O to the deionized water is (8 mg-12 mg) to 10 mL; stirring as described in step two-The speed is 300r/min to 600r/min, and the stirring time is 20min to 40 min.

8. The preparation method of the bismuth selenide/molybdenum selenide heterostructure electrode material according to claim 1, wherein the volume ratio of the Se powder to the hydrazine hydrate in the second step (10 mg-15 mg):10 mL; the stirring speed in the second step is 400 r/min-600 r/min, and the stirring time is 20 min-40 min.

9. The method for preparing the bismuth selenide/molybdenum selenide heterostructure electrode material according to claim 1, wherein the Bi in the step II and II₂Se₃Solution with Na₂MoO₄The volume ratio of the solution is 1: 1; bi described in the second to fourth step₂Se₃The volume ratio of the solution to the Se powder dispersion liquid is 1: 1; the hydrothermal reaction temperature in the second step and the hydrothermal reaction time is 190-210 ℃ and 20-24 h; the stirring speed in the second step is 400 r/min-700 r/min, and the stirring time is 20 min-40 min; the centrifugal cleaning frequency in the second step is 5-7 times, the vacuum drying temperature is 60-65 ℃, and the vacuum drying time is 10-12 hours; in the step two, the annealing temperature is 380-420 ℃, and the annealing time is 20-40 min.

10. The application of the bismuth selenide/molybdenum selenide heterostructure electrode material prepared by the preparation method of claim 1, which is characterized in that the bismuth selenide/molybdenum selenide heterostructure electrode material is used as a cathode material of a sodium-ion battery.

Technical Field

The invention relates to a preparation method of a bismuth selenide/molybdenum selenide heterostructure electrode material.

Background

With the increasing influence of greenhouse gases on the environment, solving environmental problems is one of the most urgent problems to be solved at present. Fossil fuel energy is considered one of the major sources of greenhouse gases. In order to reduce greenhouse gas emissions, the amount of clean energy used must be increased. However, since the clean energy has intermittency, it is difficult to continuously supply power to the power system. Therefore, increasing the proportion of clean energy in the total power supply necessitates the use of energy storage or conversion devices as relays to ensure the continuity of the power supply. In addition, the exhaust emissions of internal combustion engine automobiles are also one of the main sources of greenhouse gases. The development of hybrid electric vehicles and electric vehicles can effectively reduce the emission of the greenhouse gases. However, the high specific energy density lithium ion batteries that are currently commercialized have high cost that makes them difficult to use in large-scale energy storage systems due to limited lithium resources and the continuing increase in cobalt prices. In addition, the power density of the lithium ion battery is low, and the lithium ion battery is difficult to cope with the scene of the electric automobile when high-power output is required. Under such a background, development of an electrode material that can achieve both low cost, high energy density, and high power density is one of the most important issues in the energy storage field. Because sodium has similar physicochemical properties to lithium and abundant sodium resources in nature, sodium ion batteries are considered to be one of the most promising energy storage technologies to replace lithium ion batteries and realize large-scale application of clean energy. Unfortunately, the commercialization of sodium ion batteries is greatly limited because the graphite negative electrode is difficult to incorporate into the sodium ion battery because the sodium ions cannot form high-capacity intercalation compounds between graphite layers. Therefore, the development of low-cost, high-capacity electrode materials is one of the keys to achieving this technology floor.

Transition metal dichalcogenides, for example: MoS₂、MoSe₂、WS₂Etc., in their rich valence state and uniqueLayered structures are receiving a great deal of attention in the field of electrochemical energy storage. The layers of the layered material are connected through weak van der Waals force, and a few-layer nanosheet structure can be prepared through a simple stripping method, so that ion diffusion is facilitated, and the number of active sites is increased. Meanwhile, the interlayer spacing of the molybdenum-based dichalcogenide is more than 0.63nm, and can be further expanded to be more than 0.9nm through subsequent treatment, which is enough to meet the diffusion requirement of large-size ions. These materials are reported to store energy through intercalation and transformation reactions, with higher specific capacities than carbon electrode materials. Generally, transition metal selenides are more conductive than transition metal sulfides and are less toxic during processing. In this regard, transition metal selenides have a greater potential than sulfides in energy storage applications. However, the intrinsic conductivity of transition metal dichalcogenides is insufficient to cope with the case of large current charge and discharge, and these materials may undergo a large volume change during charge and discharge, resulting in pulverization of the electrode material and detachment from the surface of the current collector. And the two-dimensional materials can generate a phenomenon of re-stacking in the continuous charging and discharging process, the number of active sites is reduced, and poor cycle stability is shown. In order to solve the problem, the modification thought of the prior art is mainly to limit the transition metal chalcogenide in the carbon-based material with high mechanical strength, or improve the interaction of the rest carbon-based materials through chemical bond action, so that the volume expansion of the transition metal chalcogenide is limited while the fast electron transfer channel is improved, the loss of active substances is reduced, and therefore more excellent cycle and rate performance is obtained. However, as mentioned above, sodium ions are difficult to form high specific capacity intercalation compounds, and thus these carbon materials have little capacity contribution.

Disclosure of Invention

The invention aims to solve the problem of poor cycle performance and rate capability of the existing sodium ion battery, and provides a preparation method and application of a bismuth selenide/molybdenum selenide heterostructure electrode material.

A preparation method of a bismuth selenide/molybdenum selenide heterostructure electrode material is completed according to the following steps:

synthesis of Bi₂Se₃：

Firstly, Na is added₂SO₃Adding Se powder into deionized water, and stirring to obtain a solution A;

② first, Bi (NO) is added₃)₃·5H₂Uniformly mixing the solution O and the ethylene diamine tetraacetic acid solution, then dropwise adding the ascorbic acid solution, stirring again to obtain a mixed solution, and dropwise adding the ammonia water solution into the mixed solution until the mixed solution is completely transparent to obtain a solution B;

thirdly, dropwise adding the solution A into the solution B, and stirring to obtain a clear solution; transferring the clear solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction to obtain a reaction product I;

fourthly, centrifugally cleaning the reaction product I by using deionized water until the solution is clear, performing vacuum filtration, and drying solid substances obtained after the filtration in vacuum to obtain Bi₂Se₃：

II, preparing Bi₂Se₃/MoSe₂Heterostructure:

under the condition of ultrasound, Bi is reacted₂Se₃Dispersing in deionized water to obtain Bi₂Se₃A solution;

② mixing Na₂MoO₄·2H₂Dissolving O in deionized water, and stirring to obtain Na₂MoO₄A solution;

dissolving Se powder into hydrazine hydrate, and stirring to obtain Se powder dispersion liquid;

fourthly, mixing Bi₂Se₃Solution, Na₂MoO₄Mixing the solution and the Se powder dispersion liquid, and stirring to obtain a mixed solution; transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction to obtain a reaction product II;

fifthly, centrifugally cleaning the reaction product II by using deionized water as a cleaning agent, and then performing vacuum drying to obtain a dried reaction product II;

and sixthly, annealing the dried reaction product II under the protection of argon to obtain the bismuth selenide/molybdenum selenide heterostructure electrode material.

The principle and the advantages of the invention are as follows:

the invention provides a bismuth selenide/molybdenum selenide heterostructure electrode material (Bi)₂Se₃/MoSe₂) The preparation method is applied to the negative electrode of the sodium ion battery, and the nano powder material with a flower-shaped structure is prepared by a hydrothermal synthesis method and a subsequent low-temperature calcination method; in the design, bismuth selenide is taken as a typical topological insulator, the excellent electron transfer capacity of the surface of the bismuth selenide is the excellent dynamic characteristic of an electrode material, the shape of the nano-sheet can reduce a sodium ion diffusion barrier and assist ion diffusion, and molybdenum selenide can be anchored on the surface of the bismuth selenide nano-sheet to form a heterostructure due to the small size of the nano-sheet; meanwhile, bismuth selenide and molybdenum selenide can provide higher specific capacity, so that the introduction of inactive substances can be reduced, and the specific capacity of the whole battery is improved; the excellent specific mass capacity and the excellent specific volume capacity can reduce the use of electrolyte in the actual battery and reduce the cost of the electrolyte; by combining the excellent rate characteristic, the material can give consideration to high quality, volume energy density and high power density, provides a new idea for the design of other electrode materials, and can be further expanded to the application of other energy storage devices;

secondly, the electrochemical performance of the prepared bismuth selenide/molybdenum selenide heterostructure electrode material is tested, and cyclic voltammetry and constant current charge and discharge experiments show that the electrode material has better rate capability which is 0.1A g^-1At a current density of about 360mAhg^-1The specific capacity of the material is not obviously attenuated after 50 cycles; even at 10A g^-1The heterostructure can still obtain 260mAhg at high current density^-1The mass to capacity ratio of (d); the negative electrode material provided by the invention has better energy storage performance of the sodium ion battery.

The invention can obtain a bismuth selenide/molybdenum selenide heterostructure electrode material.

Drawings

FIG. 1 shows Bi prepared in one step I of the example₂Se₃SEM picture of (1);

FIG. 2 shows Bi prepared in one step two of the example₂Se₃/MoSe₂SEM images of heterostructure electrode materials;

FIG. 3 shows Bi prepared in one step two of the example₂Se₃/MoSe₂An X-ray diffraction pattern of the heterostructure electrode material;

FIG. 4 is an XRD diagram, in which 1 is Bi prepared by one step I of the example₂Se₃And 2 is Bi prepared in the second step of the example₂Se₃/MoSe₂A heterostructure electrode material;

FIG. 5 shows Bi prepared in one step two of the example₂Se₃/MoSe₂Capacity of heterostructure electrode materials at different current densities;

FIG. 6 shows Bi prepared in one step two of the example₂Se₃/MoSe₂A cycle performance map of the heterostructure electrode material;

FIG. 7 is a Raman spectrum, in which 1 is Bi prepared in one step I of the example₂Se₃And 2 is Bi prepared in the second step of the example₂Se₃/MoSe₂A heterostructure electrode material.

Detailed Description

The following examples further illustrate the present invention but are not to be construed as limiting the invention. Modifications and substitutions to methods, procedures, or conditions of the invention may be made without departing from the spirit of the invention.

The first embodiment is as follows: the preparation method of the bismuth selenide/molybdenum selenide heterostructure electrode material is completed according to the following steps:

synthesis of Bi₂Se₃：

Firstly, Na is added₂SO₃Adding Se powder into deionized water, and stirring to obtain a solution A;

② first, Bi (NO) is added₃)₃·5H₂O solution and ethylenediamineUniformly mixing the tetraacetic acid solution, then dropwise adding the ascorbic acid solution, stirring again to obtain a mixed solution, and dropwise adding an ammonia water solution into the mixed solution until the mixed solution is completely transparent to obtain a solution B;

thirdly, dropwise adding the solution A into the solution B, and stirring to obtain a clear solution; transferring the clear solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction to obtain a reaction product I;

fourthly, centrifugally cleaning the reaction product I by using deionized water until the solution is clear, performing vacuum filtration, and drying solid substances obtained after the filtration in vacuum to obtain Bi₂Se₃：

II, preparing Bi₂Se₃/MoSe₂Heterostructure:

under the condition of ultrasound, Bi is reacted₂Se₃Dispersing in deionized water to obtain Bi₂Se₃A solution;

② mixing Na₂MoO₄·2H₂Dissolving O in deionized water, and stirring to obtain Na₂MoO₄A solution;

dissolving Se powder into hydrazine hydrate, and stirring to obtain Se powder dispersion liquid;

fourthly, mixing Bi₂Se₃Solution, Na₂MoO₄Mixing the solution and the Se powder dispersion liquid, and stirring to obtain a mixed solution; transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction to obtain a reaction product II;

fifthly, centrifugally cleaning the reaction product II by using deionized water as a cleaning agent, and then performing vacuum drying to obtain a dried reaction product II;

and sixthly, annealing the dried reaction product II under the protection of argon to obtain the bismuth selenide/molybdenum selenide heterostructure electrode material.

The principle and advantages of the embodiment are as follows:

one embodiment provides a bismuth selenide/molybdenum selenide heterojunctionElectrode material (Bi)₂Se₃/MoSe₂) The preparation method is applied to the negative electrode of the sodium ion battery, and the nano powder material with a flower-shaped structure is prepared by a hydrothermal synthesis method and a subsequent low-temperature calcination method; in the design, bismuth selenide is taken as a typical topological insulator, the excellent electron transfer capacity of the surface of the bismuth selenide is the excellent dynamic characteristic of an electrode material, the shape of the nano-sheet can reduce a sodium ion diffusion barrier and assist ion diffusion, and molybdenum selenide can be anchored on the surface of the bismuth selenide nano-sheet to form a heterostructure due to the small size of the nano-sheet; meanwhile, bismuth selenide and molybdenum selenide can provide higher specific capacity, so that the introduction of inactive substances can be reduced, and the specific capacity of the whole battery is improved; the excellent specific mass capacity and the excellent specific volume capacity can reduce the use of electrolyte in the actual battery and reduce the cost of the electrolyte; by combining the excellent rate characteristic, the material can give consideration to high quality, volume energy density and high power density, provides a new idea for the design of other electrode materials, and can be further expanded to the application of other energy storage devices;

secondly, the electrochemical performance of the prepared bismuth selenide/molybdenum selenide heterostructure electrode material is tested, and cyclic voltammetry and constant current charge and discharge experiments show that the electrode material has good rate capability which is 0.1A g^-1At a current density of about 360mAhg^-1The specific capacity of the material is not obviously attenuated after 50 cycles; even at 10A g^-1The heterostructure can still obtain 260mAhg at high current density^-1The mass to capacity ratio of (d); the negative electrode material provided by the embodiment has better energy storage performance of the sodium-ion battery.

The embodiment can obtain the bismuth selenide/molybdenum selenide heterostructure electrode material.

The second embodiment is as follows: the present embodiment differs from the present embodiment in that: na as described in step one₂SO₃The volume ratio of the substance(s) to the deionized water is (1 mmol-3 mmol): 5 mL-10 mL; the volume ratio of Se powder to deionized water in the first step is (0.5 mmol-1 mmol): 5 mL-10 mL) (ii) a The stirring temperature in the first step is 75-85 ℃, the stirring speed is 200-300 r/min, and the stirring time is 6-8 h. Other steps are the same as in the first embodiment.

The third concrete implementation mode: the present embodiment differs from the first or second embodiment in that: bi (NO) described in step one₃)₃·5H₂The concentration of the O solution is 0.05 mol/L-0.15 mol/L; the concentration of the ethylene diamine tetraacetic acid solution in the first step is 0.05-0.15 mol/L; the concentration of the ascorbic acid solution in the first step is 0.3-0.8 mol/L. The other steps are the same as in the first or second embodiment.

The fourth concrete implementation mode: the difference between this embodiment and one of the first to third embodiments is as follows: the mass fraction of the ammonia water in the first step is 28 wt%; bi (NO) described in step one₃)₃·5H₂The volume ratio of the O solution to the EDTA solution is (2-6) to (60-100). The other steps are the same as those in the first to third embodiments.

The fifth concrete implementation mode: the difference between this embodiment and one of the first to fourth embodiments is: bi (NO) described in step one₃)₃·5H₂The volume ratio of the O solution to the ascorbic acid solution is 1: 1; the stirring speed in the first step is 500 r/min-700 r/min, and the stirring time is 0.5 h-1 h. The other steps are the same as those in the first to fourth embodiments.

The sixth specific implementation mode: the difference between this embodiment and one of the first to fifth embodiments is as follows: the volume ratio of the solution A to the solution B in the step one is (8-16) to (70-120);

stirring speed is 500 r/min-700 r/min, and stirring time is 20 min-40 min; the hydrothermal reaction temperature in the step one is 170-180 ℃, and the hydrothermal reaction time is 20-24 h; the drying temperature in the first step and the drying time in the second step are 60 ℃ and 10-12 h. The other steps are the same as those in the first to fifth embodiments.

The seventh embodiment: this embodiment and one of the first to sixth embodimentsThe difference is that: bi described in step two₂Se₃The mass ratio of the deionized water to the deionized water is (30 mg-80 mg) to 10 mL; the power of the ultrasound in the second step is 100W-200W; na in step two₂MoO₄·2H₂The volume ratio of the mass of O to the deionized water is (8 mg-12 mg) to 10 mL; the stirring speed in the second step is 300r/min to 600r/min, and the stirring time is 20min to 40 min. The other steps are the same as those in the first to sixth embodiments.

The specific implementation mode is eight: the difference between this embodiment and one of the first to seventh embodiments is: the ratio of the mass of the Se powder to the volume of the hydrazine hydrate in the second step (10 mg-15 mg) is 10 mL; the stirring speed in the second step is 400 r/min-600 r/min, and the stirring time is 20 min-40 min. The other steps are the same as those in the first to seventh embodiments.

The specific implementation method nine: the difference between this embodiment and the first to eighth embodiments is: bi described in the second to fourth step₂Se₃Solution with Na₂MoO₄The volume ratio of the solution is 1: 1; bi described in the second to fourth step₂Se₃The volume ratio of the solution to the Se powder dispersion liquid is 1: 1; the hydrothermal reaction temperature in the second step and the hydrothermal reaction time is 190-210 ℃ and 20-24 h; the stirring speed in the second step is 400 r/min-700 r/min, and the stirring time is 20 min-40 min; the centrifugal cleaning frequency in the second step is 5-7 times, the vacuum drying temperature is 60-65 ℃, and the vacuum drying time is 10-12 hours; in the step two, the annealing temperature is 380-420 ℃, and the annealing time is 20-40 min. The other steps are the same as those in the first to eighth embodiments.

The detailed implementation mode is ten: the embodiment is that the bismuth selenide/molybdenum selenide heterostructure electrode material is used as a sodium ion battery cathode material.

The first embodiment is as follows: a preparation method of a bismuth selenide/molybdenum selenide heterostructure electrode material is completed according to the following steps:

synthesis of Bi₂Se₃：

Adding 2mmol of Na₂SO₃Adding 0.8mmol Se powder into 8mL of deionized water, and stirring at 80 ℃ and a stirring speed of 200r/min for 8h to obtain a solution A;

② firstly, 4mL of 0.1mol/L Bi (NO)₃)₃·5H₂Uniformly mixing the O solution and 80mL of 0.1mol/L ethylene diamine tetraacetic acid solution, then dropwise adding 4mL0.5mol/L ascorbic acid solution, stirring at the stirring speed of 350r/min for 0.5h to obtain a mixed solution, and dropwise adding 28% by mass of ammonia water solution into the mixed solution until the mixed solution is completely transparent to obtain a solution B;

thirdly, dropwise adding the solution A obtained in the first step into the solution B obtained in the first step, and stirring for 30min at the stirring speed of 550r/min to obtain a clear solution; transferring the clear solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction at 175 ℃ for 24 hours to obtain a reaction product I;

fourthly, centrifugally cleaning the reaction product I by using deionized water until the solution is clear, performing vacuum filtration, and drying solid substances obtained after the filtration for 10 hours at 60 ℃ in vacuum to obtain Bi₂Se₃：

II, preparing Bi₂Se₃/MoSe₂Heterostructure:

50mg of Bi is treated under the ultrasonic condition₂Se₃Dispersing in 10mL of deionized water to obtain Bi₂Se₃A solution;

the power of the ultrasound in the second step is 150W;

②, adding 10mg of Na₂MoO₄·2H₂Dissolving O in 10mL deionized water, and stirring at 400r/min for 30min to obtain Na₂MoO₄A solution;

dissolving 13mg Se powder into 10mL of hydrazine hydrate, and stirring for 30min at the stirring speed of 550r/min to obtain Se powder dispersion liquid;

fourthly, mixing Bi₂Se₃Solution, Na₂MoO₄Mixing the solution with Se powder dispersion, and mixingStirring for 30min at the stirring speed of 550r/min to obtain a mixed solution; transferring the mixed solution into a high-pressure reaction kettle with a polytetrafluoroethylene inner container, sealing the high-pressure reaction kettle, and finally carrying out hydrothermal reaction at 200 ℃ for 24 hours to obtain a reaction product II;

bi described in the second to fourth step₂Se₃Solution with Na₂MoO₄The volume ratio of the solution is 1: 1;

bi described in the second to fourth step₂Se₃The volume ratio of the solution to the Se powder dispersion liquid is 1: 1;

fifthly, centrifugally cleaning the reaction product II for 7 times by using deionized water as a cleaning agent, and then drying the reaction product II in vacuum at the drying temperature of 60 ℃ for 10 hours to obtain a dried reaction product II;

sixthly, annealing the dried reaction product II under the protection of argon to obtain bismuth selenide/molybdenum selenide (Bi)₂Se₃/MoSe₂) A heterostructure electrode material;

in the step two, the annealing temperature is 400 ℃, and the annealing time is 30 min.

FIG. 1 shows Bi prepared in one step I of the example₂Se₃SEM picture of (1);

FIG. 2 shows Bi prepared in one step two of the example₂Se₃/MoSe₂SEM images of heterostructure electrode materials;

as can be seen from FIGS. 1 to 2, pure Bi₂Se₃Has a sheet structure and smooth surface, and grows MoSe₂Post-smoothing Bi₂Se₃Surface coating MoSe₂And (4) uniformly covering.

FIG. 3 shows Bi prepared in one step two of the example₂Se₃/MoSe₂An X-ray diffraction pattern of the heterostructure electrode material;

FIG. 4 is an XRD diagram, in which 1 is Bi prepared by one step I of the example₂Se₃And 2 is Bi prepared in the second step of the example₂Se₃/MoSe₂A heterostructure electrode material;

example two: bi prepared in the first embodiment₂Se₃/MoSe₂Heterostructure electrode materialThe preparation of the sodium ion battery by using the material as the negative electrode material of the sodium ion battery is completed according to the following steps:

the method comprises the following steps: preparing an electrode: bi prepared in the first embodiment₂Se₃/MoSe₂The heterostructure electrode material is prepared by mixing a conductive agent (conductive carbon black) and a binder (carboxymethyl cellulose) in a mass ratio of 7: 2: 1, continuously grinding for 1 hour in a mortar, putting the ground powder into a glass bottle, dripping a proper amount of water and continuously stirring for 8 hours to form uniform slurry, uniformly coating the slurry on the surface of a copper foil by using a scraper, pre-drying for 5min at 120 ℃, then putting the copper foil into a vacuum drying oven for overnight drying, and cutting by using a die to obtain an electrode plate (coated with Bi) for battery testing₂Se₃/MoSe₂Copper foil of heterostructure electrode material);

step two: assembling the sodium-ion battery: first coated with Bi₂Se₃/MoSe₂Putting the copper foil of the heterostructure electrode material into the center of the positive shell, and dripping two drops of 1M NaPF₆A solution in which the solvent consists of EC, DMC and FEC, wherein the volume ratio of EC to DMC is 1:1, the volume fraction of FEC in the solvent is 5%, and placing a glass fiber membrane coated with Bi₂Se₃/MoSe₂3 drops of NaPF are dripped on the copper foil of the heterostructure electrode material₆The solution was then pressed round sodium tablets placed centrally over the membrane and two drops of NaPF were added dropwise₆And finally, sequentially placing the gasket, the elastic sheet and the cathode shell into the center above the anode shell, packaging the battery by using a packaging machine to finish the assembly of the battery, wherein the whole process is carried out in a glove box filled with argon, and the water oxygen content is lower than 0.1 ppm.

FIG. 5 shows Bi prepared in one step two of the example₂Se₃/MoSe₂Capacity of heterostructure electrode materials at different current densities;

from FIG. 5, it can be seen that the current is changed from 0.1Ag^-1Increased by 100 times to 10Ag^-1The specific capacity of the heterogeneous electrode is reduced by a small extent, and the capacity is caused by single Bi₂Se₃Or MoSe₂A material.

FIG. 6 example one step two preparationOf Bi₂Se₃/MoSe₂A cycle performance map of the heterostructure electrode material;

as can be seen from FIG. 6, Bi prepared in the second step of the example was circulated at a constant current for a certain period of time₂Se₃/MoSe₂The capacity of the heterostructure electrode material is very stable, and pure Bi₂Se₃Rapid electrode decay, pure MoSe₂The capacity of the electrode is low, and the fact that the constructed heterostructure can effectively improve the electronic and ionic conduction capability of the electrode material and improve the stability, power density and energy density of the material is proved.

FIG. 7 is a Raman spectrum, in which 1 is Bi prepared in one step I of the example₂Se₃And 2 is Bi prepared in the second step of the example₂Se₃/MoSe₂A heterostructure electrode material.