Preparation method of nitrogen-doped carbon skeleton-anchored bismuth nanoflower electrode material and application thereof in sodium ion battery negative electrode
By preparing nitrogen-doped carbon framework anchored bismuth nanoflower electrode materials, the problems of low capacity and energy density of sodium-ion battery anode materials were solved, achieving high-efficiency electrochemical performance and low-cost electrode material preparation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TAIYUAN UNIVERSITY OF TECHNOLOGY
- Filing Date
- 2023-03-17
- Publication Date
- 2026-06-30
AI Technical Summary
Existing sodium-ion battery anode materials have drawbacks such as low theoretical capacity, low initial charge-discharge efficiency, and low energy density, which limit the development of sodium-ion batteries.
Using coal tar pitch as a carbon framework precursor material and metallic bismuth as an electrode active material, and utilizing recyclable metal salts as templates, nitrogen-doped carbon framework-anchored bismuth nanoflower electrode materials are constructed through solvothermal and high-temperature carbonization methods. This achieves controllable structure, low cost, and high efficiency, and the salt templates can be recycled and reused repeatedly.
The prepared electrode material exhibits excellent electrochemical performance, exposes more active sites, avoids the aggregation of active materials, and improves conductivity and sodium ion adsorption capacity, making it suitable for sodium-ion battery anodes.
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Figure CN116275077B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanomaterials technology, specifically relating to a method for preparing a nitrogen-doped carbon framework anchored bismuth nanoflower electrode material and its application in the anode of sodium-ion batteries. Background Technology
[0002] Lithium-ion batteries are widely used in electronic devices such as mobile phones, digital cameras, and laptops due to their advantages such as high specific capacity and high operating voltage. However, the scarcity of lithium resources, their uneven global distribution, and their high price limit the large-scale development of lithium-ion batteries. Therefore, seeking alternative or alternative energy storage technologies has become a focus of technological competition among countries worldwide. Sodium resources, due to their abundant reserves in the Earth's crust and good safety profile, have attracted widespread attention in the research of sodium-ion batteries. Among these, the development of high-performance sodium-ion battery anode materials is of great significance for constructing efficient sodium-ion battery systems.
[0003] In sodium-ion battery anode material systems, carbonaceous materials have been widely studied due to their low cost and good conductivity. However, carbonaceous materials also suffer from drawbacks such as low theoretical capacity, low initial charge-discharge efficiency, and low energy density, which limit the development of sodium-ion batteries. Therefore, researchers have attempted to improve the discharge specific capacity and energy density of carbonaceous materials through structural control, component modification, and compositing with other high-capacity materials.
[0004] Coal tar pitch is a carbonaceous material with high carbon content and low cost. Using coal tar pitch as a precursor, its structure and microstructure can be controlled through a recyclable salt template method. It can also be combined with high-specific-capacity metals (such as bismuth) to construct composite materials, thereby improving the overall energy density of electrode materials. The salt template can be removed with water after the preparation of nanomaterials, causing no environmental pollution, and can be recycled, helping to reduce the material preparation cost. Summary of the Invention
[0005] Technical problems to be solved
[0006] To address the shortcomings of existing methods for preparing sodium-ion battery anode materials, this invention aims to provide a method for preparing a nitrogen-doped carbon framework-anchored bismuth nanoflower electrode material and its application in sodium-ion battery anodes. Using coal tar pitch as the carbon framework precursor and metallic bismuth as the electrode active material, and utilizing recyclable metal salts as templates, a nitrogen-doped carbon framework-anchored bismuth nanoflower electrode is constructed via solvothermal and high-temperature carbonization methods. The electrode material prepared by this method exhibits excellent performance, controllable structure, low cost, high operational efficiency, and recyclable and reusable salt templates, showing broad application prospects. When applied to the anode of a sodium-ion battery, this electrode material demonstrates outstanding electrochemical performance.
[0007] The first objective of this invention is to provide a method for preparing a nitrogen-doped carbon framework anchored bismuth nanoflower electrode material.
[0008] A second objective of this invention is to provide an application of the above-mentioned electrode material in the negative electrode of a sodium-ion battery.
[0009] To achieve the first objective of this invention, the present invention adopts the following technical solution steps:
[0010] (1) Weigh a certain mass of polyvinylpyrrolidone and thiourea, measure a certain volume of organic solvent, and dissolve polyvinylpyrrolidone and thiourea in the organic solvent to form a homogeneous solution.
[0011] (2) Weigh a certain mass of bismuth nitrate pentahydrate and add it to an organic solvent. Stir it evenly in a beaker to dissolve it completely, and then add it dropwise to the solution in (1).
[0012] (3) Place the above mixed solution at 30-80℃ and stir thoroughly for 30 min. Then transfer it to a polytetrafluoroethylene high-pressure reactor and carry out a solvothermal reaction at 100-200℃ for 2-10 h. After the reaction is completed, take out the black powder and dry it to obtain bismuth sulfide nanoflower powder.
[0013] (4) Mix the above bismuth sulfide nanoflower powder, coal tar pitch and metal salt in a certain proportion, and dissolve and disperse them in an organic solvent under the action of magnetic stirring and ultrasound. Then remove the excess organic solvent in a fume hood to obtain a dark brown mixture.
[0014] (5) Place the above dark brown mixture in a high-temperature tube furnace with flowing gas. Under the alternating action of ammonia and hydrogen, heat it to 500-1000℃ at a heating rate of 2-10℃ / min and keep it at that temperature for 1-5h to achieve nitrogen doping of the above material and at the same time reduce bismuth sulfide nanoflowers to bismuth nanoflowers. Take the product out after it has cooled to room temperature with the furnace.
[0015] (6) The above product is washed and filtered with deionized water, and the black powder is collected to obtain the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material. The washing liquid can be recovered to obtain metal salt after collection and drying, and can be recycled.
[0016] The organic solvents include, but are not limited to: ethylene glycol, toluene, N-methylpyrrolidone, and N,N-dimethylformamide.
[0017] The metal salts include, but are not limited to: sodium chloride, potassium chloride, and potassium fluoride.
[0018] Preferably, the organic solvent in steps (1) and (2) is ethylene glycol.
[0019] Preferably, the metal salt in step (4) is sodium chloride.
[0020] Preferably, the organic solvent in step (4) is N-dimethylformamide.
[0021] Preferably, the heating rate in step (5) is 5℃ / min and the holding time is 2h.
[0022] A second objective of this invention is the application of the electrode material described above in the negative electrode of a sodium-ion battery.
[0023] Compared with the prior art, the present invention has the following beneficial effects:
[0024] 1. This invention prepares bismuth metallic active materials into a nanoflower-like structure and anchors it with a nitrogen-doped carbon framework, overcoming the problems of insufficient active sites and easy agglomeration in traditional methods for preparing metal-containing electrode materials. In the electrode material provided by this invention, the bismuth metallic active material exhibits a nanoflower-like structure, exposing more active sites, and the carbon framework can uniformly disperse and anchor them, avoiding agglomeration and structural damage of the active material. Simultaneously, nitrogen doping gives the entire electrode material better conductivity and more sodium ion adsorption sites.
[0025] 2. This invention provides a method for preparing nitrogen-doped anchored bismuth nanoflower electrode materials. The carbon framework material used is coal tar pitch, and the metal active material is metallic bismuth. Both materials are inexpensive, readily available, and easy to promote and apply in industrial applications.
[0026] 3. This invention provides a method for preparing nitrogen-doped carbon framework anchored bismuth nanoflower electrode materials using a recyclable salt template method. This method enables the recycling and reuse of salt templates, and the microstructure and morphology of the carbon framework can be changed by adjusting the proportion of metal salts.
[0027] 4. The introduction of ammonia gas in this invention provides an abundant nitrogen source. After high-temperature heating, nitrogen atoms are used to dope and etch the carbon framework material, which is beneficial to strengthen the anchoring of the carbon framework to the metal bismuth nanoflowers. When applied to sodium-ion batteries, it has excellent electrochemical performance. Attached Figure Description
[0028] Figure 1 The image shows the XRD pattern of the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material prepared in Example 1.
[0029] Figure 2 The image shows the SEM image of the bismuth sulfide nanoflower powder prepared in step (3) of Example 1.
[0030] Figure 3 This is a SEM image of the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material prepared in Example 1.
[0031] Figure 4 The graph shows the charge-discharge performance of the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material prepared in Example 1 when applied to a sodium-ion battery.
[0032] Figure 5 This is a comparison chart of the rate performance of the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material prepared in Example 1 when applied to a sodium-ion battery with that of pure bismuth metal material. Detailed Implementation
[0033] To better understand this invention, the invention is further described below with reference to examples, but the embodiments of this invention are not limited thereto. Other examples obtained by those skilled in the art without inventive effort are all within the scope of protection of this invention.
[0034] Example 1:
[0035] (1) Weigh 0.5g of polyvinylpyrrolidone and 0.3g of thiourea, measure 60mL of ethylene glycol, and dissolve the polyvinylpyrrolidone and thiourea in ethylene glycol to form a homogeneous solution.
[0036] (2) Weigh 0.485g of bismuth nitrate pentahydrate and add it to 10mL of ethylene glycol. Stir it evenly in a beaker until it is fully dissolved, and then add it dropwise to the solution in (1).
[0037] (3) The above mixed solution was placed in a constant temperature water bath at 65°C and stirred for 30 minutes to make it uniform. Then it was transferred to a polytetrafluoroethylene high-pressure reactor and subjected to a solvothermal reaction at 140°C for 8 hours. After the reaction was completed, the black powder was taken out and dried to obtain bismuth sulfide nanoflower powder.
[0038] (4) The above bismuth sulfide nanoflower powder, coal tar pitch and sodium chloride are mixed in a mass ratio of 1:1:20. Under the action of magnetic stirring and ultrasound, the mixture is dissolved and dispersed in N-dimethylformamide. Then, the excess N-dimethylformamide solvent is removed in a fume hood at 80°C to obtain a dark brown mixture.
[0039] (5) The above dark brown mixture was placed in a high-temperature tube furnace with flowing gas. Under the alternating action of ammonia (NH3:Ar=1:9) and hydrogen (H2.Ar=1:9), it was heated to 550°C at a heating rate of 5°C / min and held for 2 hours to achieve nitrogen doping of the above material and at the same time reduce bismuth sulfide nanoflowers to bismuth nanoflowers. The product was taken out after cooling to room temperature with the furnace.
[0040] (6) The above product is washed and filtered with deionized water, and the black powder is collected to obtain the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material. The washing liquid can be recovered and recycled to obtain metal salt after collection and drying.
[0041] (7) The nitrogen-doped carbon framework anchored bismuth nanoflower electrode material was used as the negative electrode material for sodium-ion batteries. When tested with coin cells, it showed excellent electrochemical performance.
[0042] Example 2:
[0043] (1) Weigh 0.5g of polyvinylpyrrolidone and 0.3g of thiourea, measure 60mL of ethylene glycol, and dissolve the polyvinylpyrrolidone and thiourea in ethylene glycol to form a homogeneous solution.
[0044] (2) Weigh 0.485g of bismuth nitrate pentahydrate and add it to 10mL of ethylene glycol. Stir it evenly in a beaker until it is fully dissolved, and then add it dropwise to the solution in (1).
[0045] (3) The above mixed solution was placed in a constant temperature water bath at 65°C and stirred for 30 minutes to make it uniform. Then it was transferred to a polytetrafluoroethylene high-pressure reactor and subjected to a solvothermal reaction at 160°C for 8 hours. After the reaction was completed, the black powder was taken out and dried to obtain bismuth sulfide nanoflower powder.
[0046] (4) The above bismuth sulfide nanoflower powder, coal tar pitch and sodium chloride are mixed in a mass ratio of 1:1:10. Under the action of magnetic stirring and ultrasound, the mixture is dissolved and dispersed in N-dimethylformamide. Then, the excess N-dimethylformamide solvent is removed in a fume hood at 80°C to obtain a dark brown mixture.
[0047] (5) The above dark brown mixture was placed in a high-temperature tube furnace with flowing gas. Under the alternating action of ammonia (NH3:Ar=1:9) and hydrogen (H2:Ar=1:9), it was heated to 550°C at a heating rate of 5°C / min and held for 2 hours to achieve nitrogen doping of the above material and at the same time reduce bismuth sulfide nanoflowers to bismuth nanoflowers. The product was taken out after cooling to room temperature with the furnace.
[0048] (6) The above product is washed and filtered with deionized water, and the black powder is collected to obtain the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material. The washing liquid can be recovered and recycled to obtain metal salt after collection and drying.
[0049] (7) The nitrogen-doped carbon framework anchored bismuth nanoflower electrode material was used as the negative electrode material for sodium-ion batteries. When tested with coin cells, it showed excellent electrochemical performance.
[0050] Example 3:
[0051] (1) Weigh 0.5g of polyvinylpyrrolidone and 0.3g of thiourea, measure 60mL of ethylene glycol, and dissolve the polyvinylpyrrolidone and thiourea in ethylene glycol to form a homogeneous solution.
[0052] (2) Weigh 0.485g of bismuth nitrate pentahydrate and add it to 10mL of ethylene glycol. Stir it evenly in a beaker until it is fully dissolved, and then add it dropwise to the solution in (1).
[0053] (3) The above mixed solution was placed in a constant temperature water bath at 65°C and stirred for 30 minutes to make it uniform. Then it was transferred to a polytetrafluoroethylene high-pressure reactor and subjected to a solvothermal reaction at 160°C for 10 hours. After the reaction was completed, the black powder was taken out and dried to obtain bismuth sulfide nanoflower powder.
[0054] (4) The above bismuth sulfide nanoflower powder, coal tar pitch and sodium chloride are mixed in a mass ratio of 1:1:10. Under the action of magnetic stirring and ultrasound, the mixture is dissolved and dispersed in N-dimethylformamide. Then, the excess N-dimethylformamide solvent is removed in a fume hood at 80°C to obtain a dark brown mixture.
[0055] (5) The above dark brown mixture was placed in a high-temperature tube furnace with flowing gas. Under the alternating action of ammonia (NH3:Ar=1:9) and hydrogen (H2:Ar=1:9), it was heated to 600°C at a heating rate of 5°C / min and held for 2 hours to achieve nitrogen doping of the above material and at the same time reduce bismuth sulfide nanoflowers to bismuth nanoflowers. The product was taken out after cooling to room temperature with the furnace.
[0056] (6) The above product is washed and filtered with deionized water, and the black powder is collected to obtain the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material. The washing liquid can be recovered and recycled to obtain metal salt after collection and drying.
[0057] (7) The nitrogen-doped carbon framework anchored bismuth nanoflower electrode material was used as the negative electrode material for sodium-ion batteries. When tested with coin cells, it showed excellent electrochemical performance.
[0058] Example 4:
[0059] (1) Weigh 0.5g of polyvinylpyrrolidone and 0.3g of thiourea, measure 60mL of ethylene glycol, and dissolve the polyvinylpyrrolidone and thiourea in ethylene glycol to form a homogeneous solution.
[0060] (2) Weigh 0.485g of bismuth nitrate pentahydrate and add it to 10mL of ethylene glycol. Stir it evenly in a beaker until it is fully dissolved, and then add it dropwise to the solution in (1).
[0061] (3) The above mixed solution was placed in a constant temperature water bath at 65°C and stirred for 30 minutes to make it uniform. Then it was transferred to a polytetrafluoroethylene high-pressure reactor and subjected to a solvothermal reaction at 160°C for 8 hours. After the reaction was completed, the black powder was taken out and dried to obtain bismuth sulfide nanoflower powder.
[0062] (4) The above bismuth sulfide nanoflower powder, coal tar pitch and sodium chloride are mixed in a mass ratio of 1:1:5. Under the action of magnetic stirring and ultrasound, the mixture is dissolved and dispersed in N-dimethylformamide. Then, the excess N-dimethylformamide solvent is removed in a fume hood at 80°C to obtain a dark brown mixture.
[0063] (5) The above dark brown mixture was placed in a high-temperature tube furnace with flowing gas. Under the alternating action of ammonia (NH3:Ar=1:9) and hydrogen (H2:Ar=1:9), it was heated to 550°C at a heating rate of 5°C / min and held for 2 hours to achieve nitrogen doping of the above material and at the same time reduce bismuth sulfide nanoflowers to bismuth nanoflowers. The product was taken out after cooling to room temperature with the furnace.
[0064] (6) The above product is washed and filtered with deionized water, and the black powder is collected to obtain the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material. The washing liquid can be recovered and recycled to obtain metal salt after collection and drying.
[0065] (7) The nitrogen-doped carbon framework anchored bismuth nanoflower electrode material was used as the negative electrode material for sodium-ion batteries. When tested with coin cells, it showed excellent electrochemical performance.
[0066] The examples described above are merely several specific embodiments of the present invention, and are not limited thereto. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its technical principles and concepts, and these modifications all fall within the scope of protection of the present invention.
Claims
1. A method for preparing a nitrogen-doped carbon framework anchored bismuth nanoflower electrode material, characterized in that... Includes the following steps: (1) Weigh a certain mass of polyvinylpyrrolidone and thiourea, measure a certain volume of organic solvent, and dissolve polyvinylpyrrolidone and thiourea in the organic solvent to form a homogeneous solution. (2) Weigh a certain mass of bismuth nitrate pentahydrate and add it to an organic solvent. Stir it evenly in a beaker to dissolve it completely, and then add it dropwise to the solution in (1). (3) Stir the above mixed solution thoroughly and then transfer it to a polytetrafluoroethylene high-pressure reactor. Perform a solvothermal reaction at a certain temperature and maintain it for a certain time. After the reaction is completed, take out the black powder and dry it to obtain bismuth sulfide nanoflower powder. (4) Mix the above bismuth sulfide nanoflower powder, coal tar pitch and metal salt in a certain proportion, and dissolve and disperse them in an organic solvent under the action of magnetic stirring and ultrasound. Then remove the excess organic solvent in a fume hood to obtain a dark brown mixture. (5) The above dark brown mixture is placed in a high-temperature tube furnace with flowing gas. Under the alternating action of ammonia and hydrogen, it is heated to a certain temperature at a certain heating rate and held for a certain time to achieve nitrogen doping of the above material and at the same time reduce bismuth sulfide nanoflowers to bismuth nanoflowers. The product is taken out after cooling to room temperature with the furnace. (6) The above product is washed and filtered with deionized water, and the black powder is collected to obtain the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material.
2. The preparation method according to claim 1, characterized in that: The organic solvent in step (2) is ethylene glycol.
3. The preparation method according to claim 1, characterized in that: The organic solvent in step (4) is N-dimethylformamide.
4. The preparation method according to claim 1, characterized in that: The metal salt is readily soluble in water and can be recycled after drying. It is selected from one or more of sodium chloride, potassium chloride, and potassium fluoride.
5. The preparation method according to claim 1, characterized in that: The mass ratio of coal tar pitch to metal salt is 1:5 to 1:
100.
6. The preparation method according to claim 1, characterized in that: The solvothermal reaction is carried out at a temperature of 100-200℃ for 2-20 hours.
7. The preparation method according to claim 1, characterized in that: The heating rate in the high-temperature tubular furnace is 2-10℃ / min, the holding temperature is 500-1000℃, and the holding time is 2-20h.
8. The preparation method according to claim 1, characterized in that: In step (5), nitrogen doping is achieved by etching carbon materials with ammonia in a high-temperature environment.
9. The application of the nitrogen-doped carbon framework anchored bismuth nanoflower electrode material as described in claim 1 in the anode of a sodium-ion battery.