Self-supporting polymer-based carbon fiber electrode, preparation method thereof and dual-carbon battery
By regulating the hybridization rate of the sp3/sp2 structure, self-supporting polymer-based carbon fiber electrodes were prepared, which solved the problems of ion insertion kinetics and structural instability of carbon electrodes and achieved efficient energy storage and stability of dual-carbon batteries.
Patent Information
- Application Number
- CN202511011168.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-22
- Publication Date
- 2025-09-05
AI Technical Summary
The slow ion insertion kinetics and structural instability of carbon electrodes limit the performance of dual-carbon batteries, especially in lithium ion transport and storage.
By regulating the hybridization rate of the sp3/sp2 structure, polymer materials and carbon-based materials are blended and carbonized at a specific temperature to prepare self-supporting polymer-based carbon fiber electrodes, achieving a good balance between lithium ion and electron conduction.
A carbon electrode with excellent reaction kinetics was obtained, which improved the electrochemical performance and stability of the dual-carbon battery, especially maintaining efficient energy storage capacity during bending and folding.
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Figure CN120600769A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of application of polymer-based carbon fiber electrodes to dual-carbon batteries, and in particular to a self-supporting polymer-based carbon fiber electrode, a preparation method thereof, and a dual-carbon battery. Background Art
[0002] Polymer-based carbon fiber electrodes are porous carbon material electrodes made from polymer / polymer and a certain proportion of graphite as precursors, through pre-oxidation, carbonization and other processes. Its unique structure gives it high conductivity, large specific surface area and excellent chemical stability, making it one of the core materials for electrochemical energy storage devices. Compared with traditional carbon electrodes, self-supporting polymer carbon fiber electrodes have the advantages of no current collector, flexibility and anti-swelling, high conductivity, and self-support. The raw material cost of polymer-based carbon fiber electrodes is low, the preparation process is simple, and the design that best suits the application scenario can be made according to different application scenarios. Polymer-based carbon fiber electrodes are both light and highly flexible, and are suitable for portable / wearable devices. Compared with metal inorganic electrodes, they have better electrochemical stability when bent and folded, providing a key advantage for the integration and multifunctionality of flexible electronic devices.
[0003] Compared to traditional carbon electrodes, dual-carbon batteries (DCBs) using metal-free carbon as cathodes and anodes offer numerous advantages: 1) They have attracted significant interest due to their attractive safety profile, low cost, and high sustainability. 2) They typically involve anion / cation intercalation chemistry and can provide high output voltages (e.g., >4.5V), which opens the door to high-density energy storage. With their transition-metal-free nature, high output voltage, and safe performance, DCBs offer unique advantages in next-generation energy storage systems.
[0004] The slow ion insertion kinetics and structural instability of carbon electrodes pose a major challenge to dual-carbon batteries. 3 Hybrid carbon has a highly distorted lattice that can expand the interlayer spacing for efficient lithium ion transport and storage, but reduces its intrinsic conductivity, while sp 2 The carbon layer has high carrier mobility but limited lithium ion storage capacity. Summary of the Invention
[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a self-supporting polymer-based carbon fiber electrode and a preparation method thereof and apply them to dual-carbon batteries. 3 / sp 2 The structure is adjusted into the carbon layer with a certain hybridization rate, achieving a good trade-off between lithium ion and electron conduction, thereby obtaining a carbon electrode with excellent reaction kinetics for application in dual-carbon batteries.
[0006] To achieve the above objectives, the present invention adopts the following technical solutions.
[0007] A method for preparing a self-supporting polymer-based carbon fiber electrode, which is prepared by carbonizing a polymer material and a carbon-based material, comprises the following steps:
[0008] (1) adding the polymer material and the carbon-based material to an organic solvent, reacting at 20 to 80° C. for 1 to 5 days, heating and stirring to obtain a uniform spinning solution;
[0009] (2) The spinning solution is prepared into a membrane through a static spinning device, and the membrane is pre-oxidized in air and carbonized at a temperature of 400°C-700°C to obtain a self-supporting polymer-based carbon fiber electrode.
[0010] Preferably, in the above-mentioned method for preparing the self-supporting polymer-based carbon fiber electrode, the temperature in step (2) is 550°C.
[0011] Preferably, in the above-mentioned method for preparing the self-supporting polymer-based carbon fiber electrode, the polymer material is a mixture of polyacrylonitrile, polyvinyl pyrrolidone, polyimide or polystyrene.
[0012] Preferably, in the above-mentioned method for preparing a self-supporting polymer-based carbon fiber electrode, the carbon-based material is at least one of natural graphite, expanded graphite, graphene, fluorine-boron doped carbon or AZCA bonded graphite.
[0013] Preferably, in the above-mentioned method for preparing the self-supporting polymer-based carbon fiber electrode, the organic solvent is N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran or acetone.
[0014] A polymer-based carbon fiber dual-carbon battery is prepared by the following method:
[0015] (1) Preparation of the positive electrode of the dual-carbon battery: a carbon-based material, carbon black, and polyvinylidene fluoride are added to an organic solvent to prepare a slurry; after stirring for 0.5 to 6 hours, the slurry is evenly coated on carbon fibers, and then dried and vacuum-dried at 100 to 120° C. to completely remove the organic solvent, thereby obtaining the positive electrode of the dual-carbon battery;
[0016] (2) Preparation of dual-carbon battery electrolyte: lithium hexafluorophosphate is added to ethyl methyl carbonate, followed by vinylene carbonate to prepare a dual-carbon battery electrolyte;
[0017] (3) The above-mentioned self-supporting polymer-based carbon fiber electrode is used as the negative electrode, the positive electrode prepared in step (1) is placed in a glove box, and the dual-carbon battery electrolyte prepared in step (2) is added to obtain a polymer-based carbon fiber dual-carbon battery.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] (1) The polymer-based carbon fiber electrode of the present invention adopts a polymer material and a carbon-based material blended and carbonized as an electrode, and carbonized at a specific temperature of 450°C-650°C to obtain an optimized sp 3 / sp 2 The independent carbon structure makes it a self-supporting electrode that does not require conductive agents, adhesives and current collectors, greatly reducing the overall weight of the battery. 3 Structure or defects are reduced, but sp 2 The carbon content increases. 3 / sp 2 The hybridization value is negatively proportional to the processing temperature. Low sp in polymer-based carbon fiber electrodes 3 / sp 2 Hybridization ratio and loss of N atoms and sp 2 The results indicate that the N content in polymer-based carbon fiber electrodes decreases with increasing carbonization temperature. As the temperature increases, the content of N5 and N6 decreases, while the content of NQ increases slightly. Here, more N5 and N6 can induce non-coplanar sp 3 / sp 2 hybrid structure, thereby increasing the disordered regions in the carbon skeleton. In addition, the high content of NQ in the polymer-based carbon fiber electrodes carbonized at relatively high temperatures is combined with the more ordered sp 2 The combination of the carbon layer can lead to high electrical conductivity. We further paired the obtained carbon material with a lithium metal negative electrode to evaluate the corresponding lithium ion storage capacity. The polymer-based carbon fiber electrode carbonized at 550°C has a high specific capacity, excellent rate response and stable cycling characteristics. Therefore, we speculate that our polymer-based carbon fiber electrode can achieve a good trade-off between ion / electron conduction and lithium ion storage. At the same time, the electrochemical performance of the battery will not be significantly affected during deformation such as bending and folding. The polymer fiber electrode of the present invention does not contain metal elements and has better electrochemical properties at the same quality.
[0020] (2) The present invention is achieved by sp 3 / sp 2The structure is adjusted to a certain hybridization ratio within the carbon layer, achieving a good trade-off between lithium ion and electron conduction, thereby obtaining a carbon electrode with excellent reaction kinetics. When the polymer anode is paired with a carbon-based cathode, the high-voltage dual-carbon battery has excellent rate performance and stable cycle durability with greatly extended. The polymer and carbon-based materials are prepared by electrospinning, pre-oxidation, and carbonization. The preparation process is simple and streamlined. The prepared dual-carbon battery is made into a soft-pack battery, and its electrochemical performance is not affected by deformation processes such as bending and folding. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 The infrared spectra of Example 1, the carbon-based material and the comparative example are shown;
[0022] Figure 2 The Raman spectra of the polymer-based carbon fibers of Examples 1, 2, 3 and the comparative example are shown;
[0023] Figure 3 The magnification diagram of the half-cell assembled with the positive electrode of Examples 1, 2, 3 and the comparative example;
[0024] Figure 4 1 is a cycle diagram of half-cells assembled with polymer-based carbon fibers as positive electrodes according to Examples 1, 2, and 3;
[0025] Figure 5 This is the thermogravimetric image of the polymer-based carbon fiber electrode of Example 1;
[0026] Figure 6 This is a scanning electron microscope image of the polymer-based carbon fiber electrode of Example 1;
[0027] Figure 7 Graphs showing the rate performance of polymer-based carbon fiber dual-carbon batteries of Examples 4 and 5;
[0028] Figure 8 Graphs showing the cycle performance of polymer-based carbon fiber dual-carbon batteries of Examples 4 and 5;
[0029] Figure 9 Actual picture of the polymer-based carbon fiber dual-carbon battery soft pack lighting. DETAILED DESCRIPTION
[0030] The "polymer-based carbon fiber electrode" in the present invention refers to Figure 6 A fiber-shaped electrode is shown in FIG.
[0031] Example 1: Polymer-based carbon fiber electrode
[0032] 1g of polyacrylonitrile, 1g of graphite, and 20ml of N,N-dimethylformamide were uniformly mixed, with the graphite ratio being 100% of the polyacrylonitrile. The mixture was ultrasonically treated for 300 minutes to achieve uniform dispersion, and then stirred to obtain a homogeneous polymer solution. A film was then prepared by electrospinning at a voltage of 20kV and a flow rate of 0.6ml / h. The corresponding polymer-based carbon fiber electrode was then obtained by pre-oxidation in air at 200°C for 2 hours and annealing at 550°C in a nitrogen atmosphere for 2 hours.
[0033] Example 2: Polymer-based carbon fiber electrode
[0034] 1g of polyacrylonitrile, 1g of graphite, and 20ml of N,N-dimethylformamide were uniformly mixed, with the graphite ratio being 100% of the polyacrylonitrile. The mixture was ultrasonically treated for 300 minutes to achieve uniform dispersion, and then stirred to obtain a homogeneous polymer solution. A film was then prepared by electrospinning at a voltage of 20kV and a flow rate of 0.6ml / h. The corresponding polymer-based carbon fiber electrode was then obtained by pre-oxidation in air at 200°C for 2 hours and annealing at 450°C in a nitrogen atmosphere for 2 hours.
[0035] Example 3: Polymer-based carbon fiber electrode
[0036] 1g of polyacrylonitrile, 1g of graphite, and 20ml of N,N-dimethylformamide were uniformly mixed, with the graphite ratio being 100% of the polyacrylonitrile. The mixture was ultrasonically treated for 300 minutes to achieve uniform dispersion, and then stirred to obtain a homogeneous polymer solution. A film was then prepared by electrospinning at a voltage of 20kV and a flow rate of 0.6ml / h. The corresponding polymer-based carbon fiber electrode was then obtained by pre-oxidation in air at 200°C for 2 hours and annealing at 650°C in a nitrogen atmosphere for 2 hours.
[0037] Comparative example: polymer-based fiber electrode
[0038] 1g of polyacrylonitrile and 20ml of N,N-dimethylformamide were uniformly mixed and ultrasonicated for 300 minutes to achieve uniform dispersion. A film was then prepared by electrospinning at a voltage of 20kV and a flow rate of 0.6ml / h. The corresponding polymer-based carbon fiber electrode was then obtained by pre-oxidation in air at 200°C for 2 hours and annealing at 550°C in a nitrogen atmosphere for 2 hours.
[0039] Example 4: Preparation of polymer-based carbon fiber dual-carbon battery
[0040] 32mg of carbon-based material, 4mg of carbon black, and 4mg of polyvinylidene fluoride were added to 1.2ml of N-methylpyrrolidone to prepare a slurry; stirred overnight, the slurry was evenly coated on the carbon fiber, and then dried at 100°C and vacuum-dried at 80°C for 1 day to completely remove the organic solvent to obtain the positive electrode of the dual-carbon battery. 4M lithium hexafluorophosphate was added to ethyl methyl carbonate, followed by 2% vinylene carbonate to prepare the corresponding dual-carbon battery electrolyte. The polymer fiber electrode obtained in Example 1 was used as the negative electrode and the prepared positive electrode, and the prepared electrolyte was injected. The button cells and soft-pack batteries were assembled in a glove box.
[0041] Example 5: Preparation of polymer fiber electrode dual-carbon battery
[0042] Add 32mg of carbon-based material, 4mg of carbon black and 4mg of polyvinylidene fluoride to 1.2ml of N-methylpyrrolidone to prepare a slurry; stir overnight, evenly coat the slurry on the carbon fiber, then dry it at 100°C and vacuum dry it at 80°C for 1 day to completely remove the organic solvent to obtain the positive electrode of the dual-carbon battery. Add 4M lithium hexafluorophosphate to ethyl methyl carbonate, and then add 2% vinylene carbonate to prepare the corresponding dual-carbon battery electrolyte. Use the polymer fiber electrode obtained in the comparative example as the negative electrode and the prepared positive electrode, inject the prepared electrolyte, and assemble it into a button battery in a glove box.
[0043] Performance Testing
[0044] The infrared spectrum, Raman spectrum and thermogravimetric diagram of polymer-based carbon fibers were tested.
[0045] The cycle performance of Examples 1, 2, and 3 of polymer-based carbon fiber half-cells tested at different temperatures and the rate performance of Examples 1, 2, 3 and the comparative example are shown in Table 1.
[0046] The test characterizes the surface morphology of polymer-based carbon fiber electrodes.
[0047] Test the rate performance and cycle performance of polymer-based carbon fiber dual-carbon batteries.
[0048] The rate performance test results of the polymer-based carbon fiber dual-carbon batteries obtained in Example 4 and Example 5 are shown in Table 2.
[0049] Table 1
[0050] 30℃ 30℃ 30℃ 30℃ magnification Example 1 Example 2 Example 3 Comparative Example 2C 334.6 294.6 265.2 254.2 5C 283.6 235.1 200.8 196.3 10C 239.6 201.2 170.2 165 20C 190.5 162.4 158.9 147.7
[0051] Table 2
[0052] 30℃ 30℃ magnification Example 4 Example 5 3C 137.9 137.7 5C 125.3 108.8 10C 99.1 67.6 15C 72.3 39.7 20C 52.9 28
[0053] Conclusion: The data in Tables 1 and 2 demonstrate that by introducing carbon-based materials and regulating temperature, the polymer-based carbon fibers of Example 1, assembled into a half-cell with controllable sp2 and sp3 contents, exhibit higher capacity and are capable of storing more energy. More importantly, this represents a novel application: the polymer-based carbon fibers obtained in Example 1 exhibit higher capacity and greater energy storage when applied to dual-carbon batteries. This demonstrates the excellent flexibility and stability of polymer-based carbon fiber electrodes, making them suitable for use in dual-carbon battery applications.
[0054] Figure 1 The infrared spectra of the polymer-based carbon fiber and carbon-based material of Example 1 are shown in FIG. Figure 1 It can be seen that the polymer and carbon-based material are evenly mixed, and the polymer-based carbon fibers contain characteristic peaks of both polymer and carbon-based materials. The comparative example is a polymer-based fiber electrode. The carbon-based material is natural graphite.
[0055] Figure 2 The Raman spectra of the polymer-based carbon fibers of Examples 1, 2, 3 and the comparative example are shown in FIG. Figure 2 The integrated intensity ratio (ID / IG) is used as an indicator to evaluate the degree of order in the carbon layer. When the carbonization temperature increases from 450°C to 650°C, the ID / IG ratio tends to decrease, indicating that the sp3 structure or defects decrease, but the sp2 carbon content increases.
[0056] Figure 3 The rate diagram of the half-cell assembled with positive electrode of Examples 1, 2, 3 and Comparative Example is shown in FIG. Figure 3 It can be seen that the half-cell rate performance of the positive electrode assembled with polymer-based carbon fibers prepared at 550°C is the best.
[0057] Figure 4 The cycle diagram of the half-cell assembled with the positive electrode of Examples 1, 2 and 3 is shown in FIG. Figure 4 It can be seen that the half-cell cycle performance assembled with polymer-based carbon fibers prepared at 550°C as the positive electrode is the best.
[0058] Figure 5 The thermogravimetric diagram of the polymer-based carbon fiber electrode of Example 1 is shown in FIG. Figure 5 The decomposition temperature of polymer-based carbon fibers can be seen.
[0059] Figure 6 The scanning electron microscope image of the polymer-based carbon fiber electrode of Example 1 is shown in FIG. Figure 6 It can be seen that the carbon-based materials are evenly distributed on the polymer.
[0060] Figure 7 The rate performance diagram of the polymer-based carbon fiber dual-carbon battery of Example 4 and Example 5 is shown in FIG. Figure 7 It can be seen that the polymer-based carbon fiber dual-carbon battery has excellent electrochemical properties and high battery capacity.
[0061] Figure 8 The cycle performance diagram of the polymer-based carbon fiber dual-carbon battery of Example 4 and Example 5 is shown in FIG. Figure 8 It can be seen that the polymer-based carbon fiber dual-carbon battery has an excellent cycle life, which can make the battery have a more stable capacity retention rate.
[0062] Figure 9 This is a photo of the soft-pack lighting of the polymer-based carbon fiber dual-carbon battery.
Claims
1. A method for preparing a self-supporting polymer-based carbon fiber electrode, which is prepared by carbonizing a polymer material and a carbon-based material, characterized in that The steps include: (1) adding the polymer material and the carbon-based material to an organic solvent, reacting at 20 to 80° C. for 1 to 5 days, heating and stirring to obtain a uniform spinning solution; (2) The spinning solution is electrospun and then pre-oxidized in air and carbonized at a temperature of 400°C-700°C to obtain a self-supporting polymer-based carbon fiber electrode.
2. The method for preparing a self-supporting polymer-based carbon fiber electrode according to claim 1, wherein The temperature in step (2) is 550°C.
3. The method for preparing a self-supporting polymer-based carbon fiber electrode according to claim 1, wherein The polymer material is: polyacrylonitrile, polyvinyl pyrrolidone, polyimide or a mixture of polyacrylonitrile and polystyrene.
4. The method for preparing a self-supporting polymer-based carbon fiber electrode according to claim 1, wherein The carbon-based material is at least one of natural graphite, expanded graphite, graphene, fluorine-boron doped carbon or AZCA bonded graphite.
5. The method for preparing a self-supporting polymer-based carbon fiber electrode according to claim 1, wherein The organic solvent is N,N-dimethylformamide, N,N-dimethylacetamide, tetrahydrofuran or acetone.
6. A self-supporting polymer-based carbon fiber electrode, characterized in that Prepared by any one of claims 1-5.
7. A polymer-based carbon fiber dual-carbon battery, characterized in that Prepared by the following method: (1) Preparation of the positive electrode of the dual-carbon battery: a carbon-based material, carbon black, and polyvinylidene fluoride are added to an organic solvent to prepare a slurry; after stirring for 0.5 to 6 hours, the slurry is evenly coated on carbon fibers, and then dried and vacuum-dried at 100 to 120° C. to completely remove the organic solvent, thereby obtaining the positive electrode of the dual-carbon battery; (2) Preparation of dual-carbon battery electrolyte: lithium hexafluorophosphate is added to ethyl methyl carbonate, followed by vinylene carbonate to prepare a dual-carbon battery electrolyte; (3) The self-supporting polymer-based carbon fiber electrode described in claim 6 is used as the negative electrode, the positive electrode prepared in step (1) is placed in a glove box, and the dual-carbon battery electrolyte prepared in step (2) is added to obtain a polymer-based carbon fiber dual-carbon battery.