Preparation method of resin-based porous carbon material

Abstract

The invention discloses a preparation method of a resin-based porous carbon material, and the preparation method comprises the following steps: thermosetting resin is subjected to curing treatment, carbonization treatment and activation treatment, and the activation treatment adopts a mode of simultaneously introducing carbon dioxide and water vapor. According to the preparation method, CO2 and H2O are adopted as activators and are added at the same time, a remarkable synergistic effect is achieved, the specific surface area, the pore volume and the pore size distribution (especially the mesopore proportion) of the final porous carbon material can be finely regulated and controlled by accurately regulating and controlling the activation temperature, the activation time and the most critical CO2 / H2O proportion, and the specific surface area, the pore volume and the pore size distribution can be finely regulated and controlled. And the method also has obvious activation efficiency and energy consumption reduction effect, is environmentally friendly on the whole, and can obtain the resin-based porous carbon material with high overall quality.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of preparation of porous carbon materials, in particular, to a preparation method of resin-based porous carbon materials. BACKGROUND

[0002] Silicon-based anode materials have become a research hotspot due to high theoretical capacity (4200 mAh / g), but the problems of volume expansion (>300%) and poor conductivity are significant. Porous carbon materials can provide more deposition sites for silicon, reduce the expansion of silicon, and play an important role in lithium ion battery anodes due to their high specific surface area, adjustable pore structure, good chemical stability, conductivity, and surface chemical modifiability.

[0003] Phenolic resin, furan resin and other thermosetting resins are commonly used precursors for preparing porous carbon materials, which have the advantages of high carbon yield, easy molding, and designable molecular structure. The key step in preparing porous carbon is the activation process, which aims to create pore structures in the carbon matrix through physical or chemical means. Physical activation methods, such as using CO2, steam or air, are widely concerned due to their relatively simple operation, environmental friendliness and easy scale-up production.

[0004] In the prior art, single activator, such as pure CO2 or pure steam, is widely used to activate resin-based carbonization precursors: using single CO2 activation: usually at a higher temperature (800-1000℃), mainly through endothermic reaction with carbon (C+CO2→2CO) to etch the carbon skeleton to produce pores, especially micropores, with relatively slow activation rate but more regular pore channels. Using single steam activation: the activation temperature is relatively low (700-900℃), through reaction with carbon (C+H2O→CO+H2) for etching. The steam activation rate is usually faster than CO2, which can produce micropores and mesopores at the same time, but requires higher corrosion resistance of equipment.

[0005] However, the prior art has the following problems: a. limitations of single activator: pure CO2 activation tends to produce abundant micropores, but the mesopore proportion is low, and the activation time required to achieve high specific surface area is long; pure steam activation can produce certain mesopores, but the pore walls collapse or are excessively ablated due to the violent reaction, reducing the carbon yield and making it difficult to precisely control the pore size distribution. b. Lack of fine control of pore structure: single activator has limited ability to finely control the pore structure, especially the micropore / mesopore ratio and pore size distribution, making it difficult to meet the requirements of high specific surface area and wide pore size distribution. c. Efficiency and energy consumption: achieving ideal activation effect may require a long time or high temperature, affecting production efficiency and increasing energy consumption.

[0006] Therefore, it is of great significance to develop a resin-based porous carbon activation method that can effectively overcome the limitations of single activator, achieve precise control of pore structure, and have high efficiency and environmental friendliness. SUMMARY

[0007] Therefore, in order to solve one of the above problems, the present application provides a resin-based porous carbon material preparation method, and the specific technical solutions are as follows:

[0008] A resin-based porous carbon material preparation method, the preparation method comprising the following steps:

[0009] The thermosetting resin is subjected to curing treatment to obtain a resin cured block;

[0010] The resin cured block is subjected to carbonization treatment under the protection of an inert gas atmosphere to obtain a carbonized precursor;

[0011] The carbonized precursor is heated to an activation temperature under the protection of an inert gas atmosphere, then subjected to heat preservation treatment, and then an activation agent is introduced for activation reaction. After the activation reaction is completed, the introduction of the activation agent is stopped, and the cooling is carried out under the protection of an inert gas to obtain a resin-based porous carbon material.

[0012] Further, the thermosetting resin is at least one of phenolic resin and furan resin.

[0013] Further, the temperature of the curing treatment is 300-500 DEG C, and the time is 3-8 h.

[0014] Further, the temperature of the carbonization treatment is 800-1200 DEG C, and the time is 9-15 h.

[0015] Further, the temperature of the activation reaction is 800-1000 DEG C, and the time is 0.5-8 h.

[0016] Further, the inert gas is at least one of nitrogen and argon.

[0017] Further, the activation agent is a mixture of carbon dioxide and water vapor.

[0018] The volume ratio of the carbon dioxide to the water vapor is (1-4):(1-4).

[0019] Further, the volume ratio of the carbonized precursor to the activation agent is 1:(2-4).

[0020] Further, the BET specific surface area of the resin-based porous carbon material is 1600 m 2 / g-2500 m 2 / g, and the total pore volume is 0.6 cm 3 / g-1.3 cm3 / g.

[0021] Further, the resin-based porous carbon material is applied to preparation of lithium ion battery negative electrode material and gas adsorption material.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] 1. The present application uses CO2 and H2O as activators and adds them at the same time, which has a significant synergistic effect, overcomes the limitations of single activator, and achieves better results. Under the same or milder conditions, higher specific surface area and more optimized porous structure than single CO2 or single H2O activation can be obtained.

[0024] 2. The pore structure of the resin-based porous carbon material of the present application is fine and controllable: by accurately adjusting the activation temperature, activation time and the most critical CO2 / H2O ratio, the specific surface area, pore volume, pore size distribution (especially the mesopore ratio) of the final porous carbon material can be fine-tuned to meet the needs of different application scenarios.

[0025] 3. The present application can significantly improve the efficiency and reduce the energy consumption: synergistic activation can shorten the activation time required to achieve the target specific surface area and pore structure, or reduce the required activation temperature, thereby improving production efficiency and reducing energy consumption.

[0026] 4. The present application is environmentally friendly as a whole: the activator is a mixture of CO2 and H2O, both of which are environmentally friendly gases. The reaction product is mainly CO and H2 (synthesis gas), which can be considered for recycling.

[0027] 5. The present application has good adaptability of the activator to thermosetting resin, especially suitable for precursors of phenolic resin and furan resin, which has a positive effect on obtaining resin-based porous carbon materials with better quality.

[0028] 6. The product prepared by the present application has excellent performance: the resin-based porous carbon material prepared by optimizing the process parameters has high specific surface area, rich multi-level pore structure (micropores provide high adsorption capacity, mesopores provide fast mass transfer channels), good electrical conductivity and chemical stability. It has excellent application prospects in lithium ion negative electrode materials. BRIEF DESCRIPTION OF DRAWINGS

[0029] Fig. 1 is the adsorption-desorption curve diagram of the porous carbon prepared in Example 1 of the present application;

[0030] Fig. 2 is the pore size distribution diagram of the porous carbon prepared in Example 1 of the present application;

[0031] Fig. 3Adsorption / desorption curve of the porous carbon prepared in Example 1 of the present application is shown in the following figure.

[0032] Fig. 4 Adsorption / desorption curve of the porous carbon prepared in Example 1 of the present application is shown in the following figure. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with its embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and do not limit the protection scope of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] The method for preparing a resin-based porous carbon material in an embodiment of the present application comprises the following steps:

[0036] The thermosetting resin is subjected to a curing treatment to obtain a resin cured block;

[0037] The resin cured block is subjected to a carbonization treatment under the protection of an inert gas atmosphere to obtain a carbonized precursor;

[0038] The carbonized precursor is heated to an activation temperature under the protection of an inert gas atmosphere, then subjected to a holding treatment, and then subjected to an activation reaction by introducing an activation agent. After the activation reaction is completed, the introduction of the activation agent is stopped, and the cooling is performed under the protection of an inert gas to obtain a resin-based porous carbon material.

[0039] In one of the embodiments, the thermosetting resin is at least one of a phenolic resin and a furan resin.

[0040] In one of the embodiments, the temperature of the curing treatment is 300-500°C, and the time is 3-8h.

[0041] In one of the embodiments, the curing treatment is a stage-wise curing treatment, and the stage-wise treatment is first treated at a curing temperature of 150°C for 2h, then treated at a curing temperature of 200°C for 2h, and then treated at a curing temperature of 350°C for 4h.

[0042] In one of the embodiments, the temperature of the carbonization treatment is 800-1200°C, and the time is 9-15h.

[0043] In one embodiment, the carbonization treatment is as follows: heating to 600°C at a heating rate of 5°C / min to 10°C / min and keeping the temperature for 3h to 5h, then heating to 1100°C and keeping the temperature for 6h to 8h.

[0044] In one embodiment, the activation reaction temperature is 800° C. to 1000° C., and the time is 0.5 h to 8 h.

[0045] In one embodiment, the inert gas is at least one of nitrogen and argon.

[0046] In one embodiment, the activating agent is a mixture of carbon dioxide and water vapor;

[0047] The volume ratio of the carbon dioxide to the water vapor is (1-4):(1-4).

[0048] In one embodiment, the volume ratio of the carbonization precursor to the activator is 1:(2-4), preferably 1:3.

[0049] In one embodiment, after the activation reaction is completed, ash is removed using a 200-400 mesh sieve.

[0050] In one embodiment, the BET specific surface area of ​​the resin-based porous carbon material is 1600 m 2 / g~2500m 2 / g, total pore volume 0.6cm 3 / g~1.3cm 3 / g.

[0051] In one embodiment, the resin-based porous carbon material is used in the preparation of lithium-ion battery negative electrode materials and gas adsorption materials.

[0052] The mechanism of the synergistic activation reaction in the above scheme is complementary reaction pathways: CO2 activation primarily produces micropores and a mild reaction; H2O activation produces more mesopores and a faster reaction rate. When both are present, H2O can activate sites that CO2 has difficulty reacting with, while CO2 can stabilize reactive intermediates produced during H2O activation or inhibit overreaction.

[0053] Reaction kinetics: CO2 and H2O can interact with each other (such as water gas shift reaction: ), affecting the concentration and distribution of active oxidative species in the system, thereby changing the etching rate and selectivity of the carbon matrix.

[0054] Synergistic regulation of pore structure: CO2 tends to "sculpt" micropores, and H2O helps to "broaden" the pore channels to form mesopores. The synergistic effect of the two makes it possible to obtain porous carbon materials with higher specific surface area, wider pore size distribution (micropores and mesopores coexist), and more optimal pore volume under relatively mild conditions than single activator. The synergistic effect is due to the complementarity and mutual promotion of the etching behaviors of the two gases.

[0055] The embodiments of the present application will be described in detail below with specific examples.

[0056] Example 1:

[0057] A method for preparing a resin-based porous carbon material, the method comprising the following steps:

[0058] (1) precursor: phenolic resin is weighed into a mold and subjected to the following curing treatment process: first treated at a curing temperature of 150°C for 2h, then treated at a curing temperature of 200°C for 2h, and then treated at a curing temperature of 350°C for 4h to obtain a cured block;

[0059] (2) pre-carbonization: the cured block is placed in a tube furnace, and first heated to 600°C at a rate of 5°C / min under the protection of nitrogen atmosphere (nitrogen flow rate: 400mL / min), and then heated to 1100°C for 6h, and then naturally cooled to room temperature to obtain a carbonized precursor. The carbon yield is 45%, and the carbonized material is crushed to 7-10μm by an air flow crusher;

[0060] (3) synergistic activation: the carbonized precursor is placed in an activation furnace (the volume ratio of the carbonized precursor to the activator is 1:3), N2 is introduced (N2 flow rate: 400mL / min), and after 45min of oxygen removal, the temperature is raised to 850°C at a rate of 5°C / min, and after stabilization at 850°C, CO2 (flow rate: 200mL / min) and water vapor (flow rate: 200mL / min) (i.e. the volume ratio of CO2:H2O is 1:1) are introduced simultaneously. The water vapor is generated by injecting deionized water into a high-temperature gasification chamber by a precision syringe pump. The activation reaction is maintained at 850°C for 3h.

[0061] (4) cooling post-treatment: after the activation reaction is completed, the introduction of CO2 and water vapor is stopped, the heating is turned off, N2 is introduced, and the sample is naturally cooled to room temperature. The ash in the sample is removed with a 300-mesh sieve, and the sample is dried at 120°C for 5h to obtain a resin-based porous carbon material, which is labeled as CH-1:1-3h.

[0062] Example 2:

[0063] Example 2 differs from Example 1 in that the ratio of carbon dioxide to water vapor is different, and the other conditions are the same as in Example 1.

[0064] The ratio of the amount of carbon dioxide and water vapor added in Example 2 was: CO2 flow rate of 400 mL / min, H2O flow rate of 200 mL / min, i.e., the volume ratio was: CO2:H2O = 2:1. The sample was labeled: CH-2:1-3h.

[0065] Example 3:

[0066] Example 3 is different from Example 1 in that the ratio of carbon dioxide and water vapor is different, and the others are the same as Example 1;

[0067] The ratio of the amount of carbon dioxide and water vapor added in Example 3 was: CO2 flow rate of 200 mL / min, H2O flow rate of 400 mL / min, i.e., the volume ratio was: CO2:H2O = 1:2. The sample was labeled: CH-1:2-3h.

[0068] Example 4:

[0069] Example 4 is different from Example 1 in that the activation reaction time is different, and the others are the same as Example 1;

[0070] The activation reaction time in Example 4 was 4h, and the sample was labeled CH-1:1-4h.

[0071] Example 5:

[0072] Example 5 is different from Example 1 in that the activation reaction time is different, and the others are the same as Example 1;

[0073] The activation reaction time in Example 5 was 2h, and the sample was labeled: CH-1:1-2h.

[0074] Example 6:

[0075] Example 6 is different from Example 1 in that the activation reaction temperature is different, and the others are the same as Example 1;

[0076] The activation reaction temperature in Example 6 was 900℃, and the sample was labeled: CH-1:1-900℃-3h.

[0077] Example 7:

[0078] Example 7 is different from Example 1 in that the activation reaction temperature is different, and the others are the same as Example 1;

[0079] The activation reaction temperature in Example 7 was 950℃, and the sample was labeled: CH-1:1-950℃-3h.

[0080] Comparative Example 1:

[0081] Comparative Example 1 is compared with Example 1, and Comparative Example 1 only uses single carbon dioxide as the activating agent, and under an activating reaction temperature of 850℃, single CO2(200 mL / min) is passed in, and the activation time is 3h. The comparative sample is marked as: CO2-3h.

[0082] Comparative Example 2:

[0083] Comparative Example 2 is compared with Example 1, and Comparative Example 2 only uses single water vapor as the activating agent, and under an activating reaction temperature of 850℃, single water vapor (200 mL / min) is passed in, and the activation time is 3h. The comparative sample is marked as: H2O-3h.

[0084] The samples obtained in Examples 1-7 and the comparative samples obtained in Comparative Examples 1-2 are subjected to performance tests, and the results are shown in Table 1 below.

[0085] Table 1: Performance test results

[0086]

[0087] From the data analysis in Table 1, it can be seen that by simultaneously passing in carbon dioxide and water vapor as the activating agent, the resin-based porous carbon material with synergistic effect, fine control of specific surface area, pore volume and pore size distribution (especially mesopore ratio) can be produced, which can effectively solve the problems of poor pore structure control, low activation efficiency, and difficulty in balancing high specific surface area and ideal pore size distribution when using single CO2 or single water vapor as the activating agent in the preparation of resin-based porous carbon material.

[0088] In combination with Figs. 1-4 Analysis shows that:

[0089] The above examples and comparative example data fully prove the beneficial effects of the present application:

[0090] 1. Significant synergistic effect: under the same activation conditions of 850℃ and 3h, the porous carbon material CH-1:1-3h obtained by using CO2:H2O=1:1 synergistic activation (Example 1) has a specific surface area (2016 m 2 / g) and total pore volume (1.25 cm 3 / g) that are significantly higher than those of the products of single CO2 activation (1390 m 2 / g, 0.36 cm 3 / g) and single water vapor activation (1897 m 2 / g, 0.6 cm 3 / g). In particular, the mesopore volume (0.534 cm 3 / g) is much higher than that of the pure CO2 activation product (0.03 cm 3 / g), and pure water vapor (H2O) activated product (0.4 cm 3 / g).

[0091] 2. Adjustable pore structure: By changing the CO2 / H2O ratio (Examples 1-3), the pore structure of the material can be regulated. Increasing the CO2 ratio (CH-2:1-3h) tends to increase the micropore ratio, and increasing H2O (CH-1:2-3h) significantly increases the mesopore ratio. By adjusting the activation time (Examples 4-5) and temperature (Examples 6-7), the specific surface area and pore volume can also be effectively regulated.

[0092] Therefore, by utilizing the synergistic activation effect of CO2 and H2O, the present application successfully prepares resin-based porous carbon materials with high specific surface area, high pore volume, and controllable hierarchical pore structure, and the method is efficient, controllable, and has application potential.

[0093] The technical features of the above-described examples can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above-described examples are not described, however, as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0094] The above-described examples only express several embodiments of the present application, and the description is relatively specific and detailed, but it should not be understood as limiting the scope of the patent. It should be noted that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A method for preparing a resin-based porous carbon material, characterized in that: The preparation method comprises the following steps: Curing the thermosetting resin to obtain a resin cured block; Under the protection of an inert gas atmosphere, carbonizing the resin solidified block to obtain a carbonized precursor; Under the protection of an inert gas atmosphere, the carbonized precursor is heated to an activation temperature, then kept warm, and then an activator is introduced to carry out an activation reaction. After the activation reaction is completed, the introduction of the activator is stopped, and the product is cooled under the protection of an inert gas to obtain a resin-based porous carbon material.

2. The preparation method according to claim 1, characterized in that The thermosetting resin is at least one of a phenolic resin and a furan resin.

3. The preparation method according to claim 1, characterized in that The curing treatment temperature is 300° C. to 500° C., and the curing time is 3 hours to 8 hours.

4. The preparation method according to claim 1, characterized in that The temperature of the carbonization treatment is 800° C. to 1200° C., and the time is 9 hours to 15 hours.

5. The preparation method according to claim 1, characterized in that The activation reaction temperature is 800° C. to 1000° C., and the activation time is 0.5 h to 8 h.

6. The preparation method according to claim 1, characterized in that The inert gas is at least one of nitrogen and argon.

7. The preparation method according to claim 1, characterized in that The activator is a mixture of carbon dioxide and water vapor; The volume ratio of the carbon dioxide to the water vapor is (1-4):(1-4).

8. The preparation method according to claim 7, characterized in that The volume ratio of the carbonization precursor to the activator is 1:(2-4).

9. The preparation method according to claim 1, characterized in that The BET specific surface area of ​​the resin-based porous carbon material is 1600 m 2 / g~2500m 2 / g, total pore volume 0.6cm 3 / g~1.3cm 3 / g.

10. The preparation method according to claim 1, characterized in that The resin-based porous carbon material is used in the preparation of lithium-ion battery negative electrode materials and gas adsorption materials.

Images