A synthetic polymer-based closed-pore carbon material, method of preparation and use

Abstract

This invention provides a closed-cell carbon material based on synthetic polymers, its preparation method, and its applications. The invention utilizes the flowability of the thermoplastic resin to cover the open pores in the thermosetting resin, eliminating the need for additional reaction steps such as templates or activators required in template or activation methods. A mixture of thermoplastic and thermosetting resins can be obtained in a one-step reaction. Furthermore, the closed-cell carbon material based on the synthetic polymer can be obtained by further carbonization, simplifying the preparation process and reducing production costs. Moreover, without introducing additional templates or activators, the product has high purity, low impurity content, and excellent application performance. This invention also eliminates the need for cleaning templates or activators, reducing wastewater and waste generation and minimizing environmental pollution.

Description

Technical Field

[0001] This invention belongs to the field of new material preparation technology, and in particular relates to a closed-pore carbon material based on synthetic polymer, its preparation method and application. Background Technology

[0002] Carbon materials are important functional materials, and their performance largely depends on their pore structure. Closed-pore refers to the micropore structure present in carbon materials; these pores are sealed and cannot communicate with the outside environment. Closed-pore structures have many unique advantages, such as enhancing the mechanical properties of materials, improving their adsorption performance, enhancing their catalytic activity, and extending their service life. Closed-pore carbon materials have broad application prospects in catalysis, adsorption, separation, purification, and energy storage.

[0003] Currently, strategies for constructing closed-cell structures typically involve two or more steps and are inefficient. These cumbersome processes inevitably increase costs and reduce production controllability. Worse still, the removal of hard templates and some activators involves complex and time-consuming acid dissolution, which also causes serious environmental pollution. Therefore, developing a simple and effective closed-cell structure strategy is of great significance for improving the low-pressure plateau capacity of hard carbon anodes. Summary of the Invention

[0004] The first objective of this invention is to provide a method for preparing closed-pore carbon materials based on synthetic polymers.

[0005] Therefore, the above-mentioned objective of the present invention is achieved through the following technical solution:

[0006] A method for preparing closed-pore carbon materials based on synthetic polymers, characterized in that the method includes the following steps:

[0007] S1. Phenol, furfural and metaldehyde are mixed in a certain molar ratio, added to an inorganic strong alkali solution and stirred until homogeneous to obtain a mixed solution;

[0008] The molar ratio of phenol, furfural, and metaldehyde is 1:1:0.5–1.5.

[0009] S2. The mixture in step S1 is subjected to hydrothermal reaction at a certain reaction temperature for a certain time to obtain hydrothermal products. In this way, phenol and furfural form a thermosetting resin, and phenol and triacetaldehyde form a thermoplastic resin.

[0010] The reaction temperature is 150℃~200℃; the reaction time is 1h~6h.

[0011] S3. Vacuum dry the hydrothermal product from step S2 to remove moisture;

[0012] S4. Carbonize the hydrothermal product after vacuum drying in step S3 in an inert atmosphere to obtain closed-pore carbon material.

[0013] While adopting the above technical solutions, the present invention may also adopt or combine the following technical solutions:

[0014] As a preferred technical solution of the present invention: in step S1, the molar ratio between phenol, furfural and triacetaldehyde is preferably 1:1:1.

[0015] As a preferred technical solution of the present invention: in step S1, the inorganic strong base is sodium hydroxide or potassium hydroxide or a combination of both.

[0016] As a preferred technical solution of the present invention: in step S1, the solubility of hydroxide ions in the inorganic strong alkali solution is 3 mol / L to 6 mol / L.

[0017] As a preferred technical solution of the present invention: in step S2, the reaction temperature is preferably 180℃; the reaction time is preferably 4h.

[0018] As a preferred technical solution of the present invention: in step S3, the vacuum drying reaction temperature is preferably 120°C, and the drying time is preferably 6 hours.

[0019] As a preferred technical solution of the present invention: in step S4, the carbonization process is as follows: the temperature is increased from 30°C to 1500°C at a heating rate of 2°C / min, and then held for 1h to 6h.

[0020] The second objective of this invention is to provide a closed-cell carbon material prepared by the aforementioned method for preparing closed-cell carbon materials based on synthetic polymers.

[0021] Another objective of this invention is to provide the application of the closed-pore carbon material described above in the preparation of hard carbon anodes.

[0022] This invention provides a closed-cell carbon material based on synthetic polymers, its preparation method, and its applications. A thermosetting resin is formed by reacting phenol with furfural, and a thermoplastic resin is formed by reacting phenol with paraldehyde. The fluidity of the thermoplastic resin is used to cover the open pores in the thermosetting resin, eliminating the need for additional reaction steps, such as the template agents or activators required in template or activation methods. A mixture of thermoplastic and thermosetting resins can be obtained in a one-step reaction. Furthermore, the closed-cell carbon material based on the synthetic polymer can be obtained by further carbonization, simplifying the preparation process and reducing production costs. In addition, no additional template agents or activators are introduced, resulting in high product purity, low impurity content, and good application performance. This invention eliminates the process of cleaning template agents or activators, reducing wastewater and waste generation and lowering environmental pollution. Attached Figure Description

[0023] Figure 1 This is a photograph of the phenol-furfural resin in Example 1 after high-temperature treatment.

[0024] Figure 2 This is a photograph of the phenol-melamine resin after high-temperature treatment in Example 2.

[0025] Figure 3 (a) High-resolution transmission electron microscope image of the closed-pore carbon material prepared in Example 3; (b) Selected electron diffraction pattern.

[0026] Figure 4 The nitrogen adsorption-desorption isotherm curve of the closed-pore carbon material prepared in Example 3 is shown. Detailed Implementation

[0027] The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] Phenol and furfural were mixed in a molar ratio of 1:1:1 and added to a 6M KOH solution, then stirred until homogeneous to promote the reaction between phenol and furfural. The mixture was then transferred to a 20ml PTFE hydrothermal reactor and hydrothermated at 180℃ for 4 hours. During this process, phenol and furfural formed a thermosetting resin.

[0030] Example 2

[0031] Phenol and metaldehyde were mixed in a 1:1 molar ratio and added to a 6M KOH solution, then stirred until homogeneous to promote the reaction between phenol and metaldehyde. The mixture was then transferred to a 20ml PTFE hydrothermal reactor and hydrothermated at 180℃ for 4 hours. During this process, phenol and metaldehyde formed a thermoplastic resin.

[0032] Example 3

[0033] Phenol, furfural, and metaldehyde were mixed in a molar ratio of 1:1:1 and added to a 6M KOH solution, then stirred until homogeneous to promote the reaction between phenol and the aldehydes (furfural and metaldehyde). The mixture was then transferred to a 20ml polytetrafluoroethylene hydrothermal reactor and hydrothermated at 180℃ for 4 hours. During this process, phenol and furfural formed a thermosetting resin, while phenol and metaldehyde formed a thermoplastic resin.

[0034] The hydrothermal product was vacuum dried at 120℃ for 6 hours to remove moisture.

[0035] The dried product was transferred to a tube furnace and heated from 30°C to 1500°C at a heating rate of 2°C / min. It was then carbonized at 1500°C in an inert atmosphere for 6 hours to obtain closed-cell carbon material.

[0036] Discussion of Results:

[0037] like Figure 1 As shown, phenol-furfural resin remains in a solid particulate state under high-temperature conditions (800℃ under argon atmosphere), indicating its typical thermosetting characteristics. During heating, the monomer molecules in phenol-furfural resin undergo a cross-linking reaction, forming a three-dimensional network structure. This three-dimensional network structure endows the material with rigidity and strength, preventing it from melting or deforming at high temperatures.

[0038] In comparison, Figure 2 In phenol-metaldehyde resin, under high-temperature conditions (800℃ argon atmosphere), the molecules melt and fuse together, exhibiting distinct thermoplastic characteristics. This is because the molecules in phenol-metaldehyde resin do not form a strong cross-linked structure, but are instead linked together by relatively weak physical forces. During heating, these physical forces are overcome, causing the molecular chain segments to slide, ultimately leading to the material melting and flowing.

[0039] like Figure 3 As shown, (a) is a transmission electron microscope (TEM) image at 10 nm, and (b) is a selected electron diffraction pattern. Figure 4 The isotherm curves for nitrogen adsorption-desorption of the closed-pore carbon material prepared in Example 3 are shown. The isotherms are convex, pointing towards the relative pressure axis, and have no hysteresis loop, which is a typical type III isotherm, indicating that the material is non-porous. However, Figure 3 The transmission electron microscopy image in (a) shows the presence of a porous structure, and Figure 3 (b) shows that it has an amorphous structure. This seemingly contradictory phenomenon can be explained by considering that the pores are closed, which prevents nitrogen molecules from entering and participating in the adsorption process.

[0040] The above specific embodiments are used to explain and illustrate the present invention, and are only preferred embodiments of the present invention, not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A method for preparing closed-cell carbon materials based on synthetic polymers, characterized in that: The method includes the following steps: S1. Phenol, furfural and metaldehyde are mixed in a certain molar ratio, an inorganic strong alkali solution is added, and the mixture is stirred evenly to obtain a mixed solution. The molar ratio of phenol, furfural, and metaldehyde is 1:1:0.5~1.5; S2. The mixture in step S1 is subjected to hydrothermal reaction at a certain reaction temperature for a certain time to obtain hydrothermal products. In this way, phenol and furfural form a thermosetting resin, and phenol and triacetaldehyde form a thermoplastic resin. The reaction temperature is 150℃~200℃; the reaction time is 1 h~6 h. S3. Vacuum dry the hydrothermal product from step S2 to remove moisture; S4. Carbonize the hydrothermal product after vacuum drying in step S3 in an inert atmosphere to obtain closed-cell carbon material. In step S4, the carbonization process is as follows: the temperature is increased from 30℃ to 1500℃ at a heating rate of 2℃ / min, and then held for 1 h to 6 h.

2. The method for preparing closed-cell carbon materials based on synthetic polymers according to claim 1, characterized in that: In step S1, the molar ratio of phenol, furfural, and metaldehyde is 1:1:

1.

3. The method for preparing closed-cell carbon materials based on synthetic polymers according to claim 1, characterized in that: In step S1, the inorganic strong base is sodium hydroxide, potassium hydroxide, or a combination of both.

4. The method for preparing closed-cell carbon materials based on synthetic polymers according to claim 1 or 3, characterized in that: In step S1, the concentration of hydroxide ions in the inorganic strong base solution is 3 mol / L to 6 mol / L.

5. The method for preparing closed-cell carbon materials based on synthetic polymers according to claim 1, characterized in that: In step S2, the reaction temperature is 180℃ and the reaction time is 4 h.

6. The method for preparing closed-cell carbon materials based on synthetic polymers according to claim 1, characterized in that: In step S3, the vacuum drying reaction temperature is 120℃ and the drying time is 6 h.

7. The closed-cell carbon material prepared by the method for preparing closed-cell carbon materials based on synthetic polymers according to any one of claims 1-6.

8. The application of the closed-cell carbon material according to claim 7 in the preparation of hard carbon anodes.

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