Preparation method of hollow tubular carbon material and application thereof as negative electrode material in sodium ion battery
Hollow tubular hard carbon materials were prepared by catalytic polymerization of phenothiazine and ferric chloride, which solved the problem of low cycle efficiency of hard carbon anode materials in sodium-ion batteries and realized a sodium-ion battery anode material with high capacity and good cycle stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-15
- Publication Date
- 2026-03-20
AI Technical Summary
Existing hard carbon anode materials suffer from low cycle efficiency, low sodium storage capacity, and poor rate performance in sodium-ion batteries, which limits their large-scale application in sodium batteries. Furthermore, the use of biomass materials cannot maintain the special morphology, increasing raw material costs.
Hollow tubular hard carbon materials were prepared by carbonization at 500-900℃ using phenothiazine as raw material and ferric chloride as crosslinking agent. The materials were then catalytically polymerized to form a unique hollow carbon nanotube structure.
The hollow tubular structure optimizes the kinetic performance of sodium-ion batteries, exhibiting good rate performance and cycle stability. It provides a larger surface area and pore structure, promotes the rapid migration of sodium ions, reduces electrode structure damage, and improves the cycle life of the battery.
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Figure CN118343741B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of new energy material preparation and application, and particularly relates to a preparation method of hollow tubular carbon material and application of the hollow tubular carbon material as a negative electrode material in a sodium ion battery. BACKGROUND
[0002] In recent years, lithium ion batteries are widely used in portable electronic products, electric tools and electric vehicles and other fields due to their characteristics in energy density, working voltage and cycle life. However, the reserves of lithium on the earth are limited, which leads to the rising of its cost, so it is particularly urgent to develop a new generation of high-efficiency energy storage technology.
[0003] The reserves of sodium element on the earth are abundant, which makes the sodium battery have great potential in large-scale application. However, due to the larger ionic radius of sodium ions than lithium ions, some negative electrode materials for lithium batteries cannot be applied to sodium ion batteries, which is the main factor restricting the large-scale application of sodium batteries. Among the many negative electrode materials, hard carbon material has become the most suitable negative electrode material for commercial application due to its low charge-discharge potential, high capacity and structural stability.
[0004] Although the hard carbon negative electrode material has many application potentials, its low cycle efficiency, low sodium storage capacity and poor rate performance limit its industrial application. At present, in view of the problem of rapid capacity decay, researchers usually use complex processes to obtain special morphology to improve the transmission kinetics of the battery. However, designing special morphology will increase the cost of raw materials. From the perspective of cost, biomass with low cost and abundant raw materials is used as raw material, but the biomass material cannot maintain special morphology after carbonization, so it cannot achieve the effect of optimizing the kinetic performance. SUMMARY
[0005] In view of the above problems, the application aims to provide a hollow tubular hard carbon material for sodium ion battery negative electrode and a preparation method thereof. The material has low cost of raw materials, simple preparation process, excellent electrochemical performance and is suitable for application in sodium ion batteries.
[0006] The application uses phenothiazine as a raw material and ferric chloride as a crosslinking agent to perform carbonization at 500-900℃ to obtain a hollow tubular hard carbon material. The prepared hollow tubular structure has a unique morphology, which optimizes the kinetic performance. When used as a negative electrode material of a sodium ion battery, it shows good rate performance and excellent cycle stability.
[0007] To achieve the above-mentioned purposes, the technical scheme adopted by the application is as follows:
[0008] A preparation method of a hollow tubular carbon material, comprising the following steps:
[0009] 1) Dissolve phenothiazine in a flask containing 1,2-dichloroethane, uniformly disperse in ultrasonic, add ferric chloride and dimethylformaldehyde under nitrogen protection;
[0010] 2) Heat the obtained mixture, naturally cool to room temperature, collect the solid product after filtration; the collected solid product is washed with methanol, dilute hydrochloric acid and deionized water in turn until the unreacted phenothiazine and ferric chloride are removed;
[0011] 3) Vacuum dry the washed solid product;
[0012] 4) Put the dried solid product into a tube furnace for calcination, naturally cool to room temperature to obtain a hollow tubular carbon material.
[0013] Further, in step 1) of the above preparation method, the molar ratio of phenothiazine: ferric chloride: dimethylformaldehyde is 1:2:2.
[0014] Further, in step 2) of the above preparation method, the heating reaction conditions are: 60-100℃ for 12-24h under continuous stirring.
[0015] Further, in step 2) of the above preparation method, the concentration of dilute hydrochloric acid is 2mol / L.
[0016] Further, in step 3) of the above preparation method, the drying conditions are: 60-80℃ for 6-12h.
[0017] Further, in step 4) of the above preparation method, the calcination conditions are: under nitrogen protection, the temperature is raised to 500-900℃ at a heating rate of 1-5℃ / min, and carbonization is carried out at constant temperature for 1-4h.
[0018] The hollow tubular carbon material prepared by any one of the above preparation methods is applied in a sodium ion battery.
[0019] Further, the hollow tubular carbon material is applied as a negative electrode material in a sodium ion battery.
[0020] Further, in the above application, the sodium ion battery is specifically: the hollow tubular carbon material is used as the negative electrode sheet, the separator is a polyethylene-polypropylene-polyethylene three-layer film, and the electrolyte is a mixed solution of EC and DEC with NaPF6 as the solute, and the CR2025 button cell is assembled in an argon-filled glove box with water and oxygen less than 0.1ppm.
[0021] Preferably, the concentration of NaPF6 in the electrolyte is 1M, and the volume ratio of EC to DEC is 1:1.
[0022] The present invention utilizes the polymer formed by catalytic polymerization to prepare the negative electrode material of sodium-ion batteries. This material can be prepared by controllable pyrolysis. When this material is used as the negative electrode material of sodium-ion batteries, its unique hollow carbon nanotube structure can bring the following specific advantages:
[0023] 1. This material has a higher specific surface area and pore structure, providing more storage space for sodium ion intercalation and deintercalation. The hollow carbon tube structure provides a large surface area that can accommodate more sodium ions, thereby achieving higher capacity.
[0024] 2. The unique hollow tubular structure helps to infiltrate the electrolyte, shortens the ion transport distance, and provides more diffusion channels, promoting the rapid migration of sodium ions and high-rate charge and discharge performance.
[0025] 3. The hollow carbon nanotube structure can buffer the stress and strain caused by volume expansion and contraction, helping to reduce the structural damage of the electrode and the peeling of the material, improving the cycle stability and life of the electrode.
[0026] In summary, the present invention can improve the transport dynamics of the battery through the design of this structure-adjustable hollow tubular structure. This negative electrode material has the potential to be widely used in the field of energy storage and energy storage systems such as sodium-ion batteries, as it provides a larger surface area, reduces ion diffusion distance, maintains structural stability, and has many advantages such as low cost. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 SEM image of the hollow tubular carbon material prepared for Example 1.
[0028] Figure 2 XRD diffraction pattern of the hollow tubular carbon material prepared for Example 1.
[0029] Figure 3 Charge-discharge curve of the hollow tubular carbon material prepared for Example 1 as the negative electrode material of sodium-ion batteries at a current density of 0.1 A / g from the first cycle to the fifth cycle.
[0030] Figure 4 Rate graph of the hollow tubular carbon material prepared for Example 1 as the negative electrode material of sodium-ion batteries.
[0031] Figure 5 Cycle stability performance graph of the hollow tubular carbon material prepared for Example 1 as the negative electrode material of sodium-ion batteries. DETAILED DESCRIPTION
[0032] To explain the technical content, structural features and achieved purposes and effects of the present invention in detail, the following embodiments are combined with the drawings.
[0033] Example 1
[0034] The required phenothiazine (0.008 mol, 1.6 g), iron trichloride (0.016 mol, 2.6 g) and dimethylformaldehyde (0.016 mol, 1.42 mL) were weighed according to the molar ratio of 1:2:2; the weighed phenothiazine was dissolved in a flask containing 1,2-dichloroethane (80 mL) and uniformly dispersed in ultrasonic for 10 minutes; iron trichloride and dimethylformaldehyde were added under nitrogen environment; the obtained mixture was heated to 80°C, and stirring was continued for 18 h; after the reaction was completed, it was naturally cooled to room temperature, and the cooled reaction was filtered to collect the solid product; the collected solid product was repeatedly washed with methanol, HCl solution (2 mol / L) and deionized water, respectively, until the unreacted phenothiazine and iron trichloride were removed; the washed solid product was dried in a vacuum drying oven (12 h, 80°C); the dried solid product was calcined in a tube furnace at 700°C for 2 h at a heating rate of 3°C / min, and naturally cooled to room temperature to obtain hollow tubular carbon materials (HCTs-700).
[0035] The hollow tubular carbon material prepared in this example was used as the negative electrode sheet, the separator was a polyethylene-polypropylene-polyethylene three-layer film, and the electrolyte was a mixed solution of EC and DEC with NaPF6 as the solute, wherein the concentration of NaPF6 was 1M, and the volume ratio of EC and DEC was 1:1. CR2025 button cells were assembled in an argon-filled glove box (water and oxygen were less than 0.1 ppm). The charge-discharge test was a constant current charge-discharge measurement on a new Wei CT-4008 (Shenzhen New Wei Electronics Co., Ltd.), and the charge-discharge voltage range was 0.01-3V.
[0036] Figure 1 The scanning electron microscope photograph of the HCTs-700 prepared in this example can be seen that the prepared material is a hollow carbon tube, which provides a channel for the rapid transmission of electrons and can effectively release the internal stress caused by the long-term repeated insertion and removal of sodium ions. Figure 2 The X-ray diffraction pattern of the HCTs-700 prepared in this example is a typical XRD pattern of amorphous carbon.
[0037] Figure 3 The first five cycles of charge-discharge curves of the HCTs-700 prepared in this example as a negative electrode material for sodium ion batteries, with a charge-discharge voltage range of 0.01-3V and a current density of 0.1A / g. As can be seen from the figure, the first reversible capacity is 550mA h / g, and the first coulombic efficiency is 60%.
[0038] Figure 4The material HCTs-700 prepared in the embodiment is charged and discharged at different current densities as a sodium ion battery negative material, and the charge and discharge voltage range is 0.01-3V. The reversible capacity at the current densities of 0.05A / g and 5A / g is 328mAh / g and 146mAh / g respectively. When the current density returns to 0.05A / g, the reversible capacity returns to 325mAh / g, which shows that the sodium ion battery negative material has good reversibility.
[0039] Figure 5 The material HCTs-700 prepared in the embodiment is cycled as a sodium ion battery negative material. The charge and discharge voltage range is 0.01-3V, and the current density is 1A / g. After 1000 cycles, the capacity retention rate is 90%, and the decay per cycle is 0.01%, which shows that the material has good stability.
[0040] The hollow tubular carbon material (HCTs-700) is measured to have a reversible capacity of 328mA h / g at a current density of 0.05A / g, a reversible capacity of 146mA h / g at a current density of 5A / g, and a retention rate of 90% at a current density of 1A / g.
[0041] Example 2
[0042] The required phenothiazine (0.008 mol, 1.6 g), ferric chloride (0.016 mol, 2.6 g) and dimethylformaldehyde (0.016 mol, 1.42 mL) were weighed according to the molar ratio of 1:2:2; the weighed phenothiazine was dissolved in a flask containing 1,2-dichloroethane (80 mL) and uniformly dispersed in ultrasonic for 10 minutes; ferric chloride and dimethylformaldehyde were added under a nitrogen environment; the obtained mixture was heated to 60℃, and stirring was continued for 12h; after the reaction was completed, it was naturally cooled to room temperature, and the cooled reaction was filtered to collect the solid product; the collected solid product was repeatedly washed with methanol, HCl solution (2 mol / L) and deionized water until the unreacted phenothiazine and ferric chloride were removed; the washed solid product was dried in a vacuum drying box (12h, 80℃); the dried solid product was calcined in a tube furnace at 500℃ with a heating rate of 3℃ / min for 2h, and naturally cooled to room temperature to obtain a hollow tubular carbon material.
[0043] The hollow tubular carbon material prepared in this embodiment was used as the negative electrode, the separator was a polyethylene-polypropylene-polyethylene three-layer membrane, and the electrolyte was a mixed solution of EC and DEC with NaPF6 as the solute, wherein the concentration of NaPF6 was 1M, and the volume ratio of EC to DEC was 1:1. CR2025 coin cells were assembled in an argon-filled glove box (water and oxygen both less than 0.1ppm). Charge-discharge tests were performed using a Xinwei CT-4008 (Shenzhen Xinwei Electronics Co., Ltd.) with constant current charge-discharge measurements, and the charge-discharge voltage range was 0.01-3V.
[0044] The reversible capacity of this sodium-ion battery anode material was measured to be 240 mA h / g at a current density of 0.05 A / g, 40 mA h / g at a current density of 5 A / g, and 20% retention rate at a current density of 1 A / g.
[0045] Example 3
[0046] Weigh out the required amounts of phenothiazine (0.008 mol, 1.6 g), ferric chloride (0.016 mol, 2.6 g), and dimethylformaldehyde (0.016 mol, 1.42 mL) in a molar ratio of 1:2:2; dissolve the weighed phenothiazine in a flask containing 1,2-dichloroethane (80 mL) and disperse it evenly in an ultrasonic bath for 10 minutes; add ferric chloride and dimethylformaldehyde under a nitrogen atmosphere; heat the resulting mixture to 100 °C and stir continuously for 24 h; the reaction... After the reaction was completed, the product was allowed to cool naturally to room temperature. The cooled reactants were then filtered, and the solid product was collected. The collected solid product was washed repeatedly with methanol, HCl solution (2 mol / L), and deionized water until unreacted phenothiazine and ferric chloride were removed. The washed solid product was dried in a vacuum drying oven (12 h, 80 °C). The dried solid product was then calcined in a tube furnace at 900 °C for 2 h at a heating rate of 3 °C / min, and allowed to cool naturally to room temperature to obtain hollow tubular carbon material.
[0047] The hollow tubular carbon material prepared in this embodiment was used as the negative electrode, the separator was a polyethylene-polypropylene-polyethylene three-layer membrane, and the electrolyte was a mixed solution of EC and DEC with NaPF6 as the solute, wherein the concentration of NaPF6 was 1M, and the volume ratio of EC to DEC was 1:1. CR2025 coin cells were assembled in an argon-filled glove box (water and oxygen both less than 0.1ppm). Charge-discharge tests were performed using a Xinwei CT-4008 (Shenzhen Xinwei Electronics Co., Ltd.) with constant current charge-discharge measurements, and the charge-discharge voltage range was 0.01-3V.
[0048] The reversible capacity of this sodium-ion battery anode material was measured to be 259 mAh / g at a current density of 0.05 A / g, 52 mA h / g at a current density of 5 A / g, and 30% retention rate at a current density of 1 A / g.
[0049] Comparative Example 1
[0050] Firstly, the phenothiazine was dissolved in a flask containing chloroform and uniformly dispersed in ultrasonic for 10 minutes. Under the protection of nitrogen, aluminum chloride was added (the molar mass ratio of phenothiazine to aluminum chloride was 1:2). The obtained mixture was heated to 80°C and continuously stirred for 18h. The collected solid product was washed with methanol, 2mol / L hydrochloric acid and deionized water, respectively, to remove unreacted phenothiazine and aluminum chloride. Further purification, the washed solid particles were vacuum dried for 12h at 80°C to obtain a hard carbon precursor sample. The dried hard carbon precursor was placed in a tube furnace and heated to 700°C at a heating rate of 3°C / min under the protection of nitrogen, and carbonized at constant temperature for 2h. After natural cooling to room temperature, layered carbon block materials (LCBs-700) were obtained.
[0051] The prepared layered carbon block materials (LCBs-700) were used as negative electrode sheets, the separator was a polyethylene-polypropylene-polyethylene three-layer film, and the electrolyte was a mixed solution of EC and DEC with NaPF6 as the solute, wherein the concentration of NaPF6 was 1M and the volume ratio of EC to DEC was 1:1. CR2025 button cells were assembled in an argon-filled glove box (water and oxygen were less than 0.1ppm). The charge-discharge test was carried out on a new Wei CT-4008 (Shenzhen Xinnwei Electronics Co., Ltd.) to measure the constant current charge and discharge, and the charge and discharge voltage range was 0.01-3V.
[0052] The measured negative electrode material had a reversible capacity of 110mA h / g at a current density of 0.05A / g, a reversible capacity of 40mA h / g at a current density of 5A / g, and a retention rate of 50% at a current density of 1A / g.
[0053] Comparative Example 2
[0054] Firstly, the phenothiazine was dissolved in a flask containing chloroform and uniformly dispersed in ultrasonic for 10 minutes. Under the protection of nitrogen, iron trichloride was added (the molar mass ratio of phenothiazine to iron trichloride was 1:2). The obtained mixture was heated to 80°C and continuously stirred for 18h. The collected solid product was washed with methanol, 2mol / L hydrochloric acid and deionized water, respectively, to remove unreacted phenothiazine and iron trichloride. Further purification, the washed solid particles were vacuum dried for 12h at 80°C to obtain a hard carbon precursor sample. The dried hard carbon precursor was placed in a tube furnace and heated to 700°C at a heating rate of 3°C / min under the protection of nitrogen, and carbonized at constant temperature for 2h. After natural cooling to room temperature, sodium-ion battery negative electrode materials were obtained.
[0055] The reversible capacity of this sodium-ion battery anode material was measured to be 250 mA h / g at a current density of 0.05 A / g, 17 mA h / g at a current density of 5 A / g, and 30% at a current density of 1 A / g.
Claims
1. A method for preparing a hollow tubular carbon material, characterized in that, Includes the following steps: 1) Dissolve phenothiazine in a flask containing 1,2-dichloroethane, disperse it evenly in an ultrasonic atmosphere, and add ferric chloride and dimethylformaldehyde under nitrogen protection. 2) The mixture was heated and allowed to cool naturally to room temperature. The solid product was collected after filtration. The collected solid product was washed with methanol, dilute hydrochloric acid and deionized water in sequence until unreacted phenothiazine and ferric chloride were removed. 3) Vacuum dry the washed solid product; 4) The dried solid product is placed in a tube furnace for calcination and then naturally cooled to room temperature to obtain hollow tubular carbon material.
2. The preparation method according to claim 1, characterized in that, In step 1), the molar ratio of phenothiazine: ferric chloride: dimethylformaldehyde is 1:2:
2.
3. The preparation method according to claim 1, characterized in that, In step 2), the heating reaction conditions are: continuous stirring at 60-100℃ for 12-24 hours.
4. The preparation method according to claim 1, characterized in that, In step 2), the concentration of the dilute hydrochloric acid is 2 mol / L.
5. The preparation method according to claim 1, characterized in that, In step 3), the drying conditions are: drying at 60-80℃ for 6-12 hours.
6. The preparation method according to claim 1, characterized in that, In step 4), the calcination conditions are as follows: under nitrogen protection, the temperature is increased to 500-900℃ at a heating rate of 1-5℃ / min, and carbonized at a constant temperature for 1-4 hours.
7. The application of the hollow tubular carbon material prepared by the preparation method according to any one of claims 1-6 in sodium-ion batteries.
8. The application according to claim 7, characterized in that, The hollow tubular carbon material is used as a negative electrode material in sodium-ion batteries.
9. The application according to claim 8, characterized in that, The sodium-ion battery is specifically assembled as a CR2025 button cell in a glove box filled with argon gas and with water and oxygen levels both less than 0.1 ppm. The negative electrode is a hollow tubular carbon material, the separator is a polyethylene-polypropylene-polyethylene three-layer membrane, and the electrolyte is a mixed solution of EC and DEC with NaPF6 as the solute.
10. The application according to claim 9, characterized in that, The electrolyte has a NaPF6 concentration of 1M and an EC to DEC volume ratio of 1:1.