Preparation method of porous carbon electrode material

Abstract

The invention discloses a preparation method of a porous carbon electrode material, and the method comprises the following steps: step 1, raw material selection and pretreatment: selecting waste crop straws, cleaning the waste crop straws, and drying and crushing the waste crop straws to obtain biomass powder; step 2, carbonization: uniformly mixing the biomass powder and an activating agent according to a certain proportion to obtain a mixture of the biomass powder and the activating agent, and heating and carbonizing the mixture of the biomass powder and the activating agent in a high-temperature environment in a nitrogen atmosphere. According to the preparation method of the porous carbon electrode material disclosed by the invention, the production cost is reduced, the resource utilization of wastes is realized, the porosity and the specific surface area of the porous carbon material are also improved, and good conductivity and structural stability are kept; the prepared porous carbon electrode material has high specific capacitance, good cycling stability and rapid charging and discharging capability, and is suitable for energy storage devices such as supercapacitors and lithium ion batteries.

Description

Technical Field

[0001] The invention relates to the technical field of electrode material preparation, and in particular to a method for preparing a porous carbon electrode material. Background Art

[0002] Porous carbon electrode is an electrode made of carbon material with high specific surface area and rich pore structure. It has important application value in energy storage and conversion devices such as batteries, supercapacitors and electrocatalysis due to its excellent conductivity and excellent electrochemical activity.

[0003] However, the preparation of traditional porous carbon electrode materials often relies on fossil fuels or their derivatives, which not only has a complex preparation process and high cost, but also limits its large-scale application and is not conducive to environmental protection. Therefore, those skilled in the art provide a method for preparing a porous carbon electrode material to solve the problems raised in the above background technology. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing a porous carbon electrode material to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for preparing a porous carbon electrode material, the method comprising the following steps:

[0007] Step 1: Raw material selection and pretreatment: Select waste crop straw, wash the waste crop straw, dry and crush the waste crop straw to obtain biomass powder;

[0008] Step 2, carbonization: uniformly mix the biomass powder and the activator in a certain ratio to obtain a mixture of the biomass powder and the activator, and heat and carbonize the mixture of the biomass powder and the activator in a high temperature environment under a nitrogen atmosphere to obtain a carbon material;

[0009] Step 3: Pore formation: washing the carbon material with water until it is neutral, removing the residual activator in the carbon material, and drying the carbon material. Under a nitrogen atmosphere, placing the dried carbon material in a high temperature environment for CO2 activation to obtain a porous carbon material;

[0010] Step 4: post-processing: grinding and sieving the porous carbon material to obtain porous carbon powder;

[0011] Step 5: preparing an electrode: uniformly mixing the porous carbon powder, the conductive agent and the binder in a certain proportion to obtain a porous carbon electrode slurry, and coating the porous carbon electrode slurry on a current collector, drying and compacting to obtain a porous carbon electrode;

[0012] Step 6. Performance testing and optimization: Test the performance of the porous carbon electrode to confirm whether the performance of the porous carbon electrode meets the requirements, and adjust the raw materials, optimize the carbonization and pore-forming processes according to the performance test results of the porous carbon electrode to improve the performance of the porous carbon electrode.

[0013] Preferably, the waste crop straws proposed in step 1 are corn straws and wheat straws.

[0014] Preferably, the biomass powder prepared in step 1 has a particle size of 20-80 meshes.

[0015] Preferably, the activator proposed in step 2 is ZnCl2 or KOH.

[0016] Preferably, the ratio of biomass powder to activator proposed in step 2 is 1:1-1:5.

[0017] Preferably, the carbonization temperature of the mixture of biomass powder and activator proposed in step 2 is 300-600° C., and the heating time is 1-4 h.

[0018] Preferably, the CO2 activation temperature of the dried carbon material proposed in step 3 is 800-1200°C, and the activation time is 0.5-2h.

[0019] Preferably, the ratio of the porous carbon powder to the conductive agent and the binder proposed in step five is 8:1:1, and the conductive agent and the binder are acetylene black and polytetrafluoroethylene PTFE, respectively.

[0020] Preferably, the current collector in step five is nickel foam, and the porous carbon electrode slurry is coated on the nickel foam and dried at a vacuum temperature of 110°C.

[0021] Preferably, the compacting equipment for coating the porous carbon electrode slurry on the nickel foam in step 5 is an oil press, the pressing pressure is 12.5 MPa, and the pressing time is 3 min.

[0022] Compared with the prior art, the advantages of the present invention are: the preparation method of the porous carbon electrode material proposed in the present application first uses waste crop straw as raw material, reduces the production cost of the porous carbon electrode material, realizes the resource utilization of waste, and is beneficial to environmental protection, and then improves the porosity and specific surface area of ​​the porous carbon material by combining heating carbonization and CO2 activation, maintains good conductivity and structural stability, and allows the prepared porous carbon electrode material to have high specific capacitance, good cycle stability and fast charging and discharging capabilities, and is suitable for energy storage devices such as supercapacitors and lithium-ion batteries. Finally, according to the performance test results of the porous carbon electrode material, the type of raw materials is adjusted, the carbonization and pore-forming processes are optimized, and the pore structure, specific surface area and electrochemical properties of the porous carbon material are flexibly adjusted to meet different application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a process flow chart of a method for preparing a porous carbon electrode material according to an embodiment of the present invention;

[0024] Figure 2 FIG. 1 is a process flow chart for preparing a porous carbon electrode material according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] In the description of the present invention, it should be understood that the terms "center", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In addition, the term "including" and any variation thereof are intended to cover non-exclusive inclusions.

[0026] Example 1

[0027] Combination Figure 1 and Figure 2 As shown, a method for preparing a porous carbon electrode material comprises the following steps:

[0028] Corn stalks were selected as raw materials, cleaned, dried and crushed to obtain biomass powder with a particle size of 50 mesh, ZnCl2 was selected as an activator, ZnCl2 and biomass powder were uniformly mixed in a ratio of 1:3 to obtain a mixture of biomass powder and ZnCl2, and the mixture of biomass powder and ZnCl2 was placed in a 400°C environment and heated for 2 hours under a nitrogen atmosphere to carbonize the mixture of biomass powder and ZnCl2 to obtain a carbon material, and then the carbon material was washed with water to neutralize the carbon material to remove residual ZnCl2 in the carbon material, and then the carbon material was dried, and the dried carbon material was placed in a 900°C environment for CO2 activation to obtain a porous carbon material after activation for 1 hour, and then the porous carbon material was ground and sieved to prepare porous carbon powder, and the porous carbon powder was uniformly mixed with acetylene black and polytetrafluoroethylene (PTFE) in a ratio of 8:1:1 to obtain a porous carbon electrode slurry, thereby completing the preparation of the porous carbon electrode material.

[0029] The porous carbon electrode slurry is coated on nickel foam, and the porous carbon electrode slurry coated on the nickel foam is vacuum dried at 110°C, and then the dried foam nickel is wrapped in aluminum foil into a sandwich shape, and pressed with a hydraulic press at a pressure of 12.5MPa for 3 minutes to obtain a porous carbon electrode sheet, and then the porous carbon electrode sheet is subjected to cyclic voltammetry test and constant current charge and discharge test to test whether the performance of the porous carbon electrode sheet is qualified. The test shows that the porous carbon electrode sheet has a specific capacitance of 250F / g and good cycle stability, that is, the performance of the porous carbon electrode sheet is qualified, and the preparation method of the porous carbon electrode material is feasible.

[0030] Example 2

[0031] Combination Figure 1 and Figure 2 As shown, a method for preparing a porous carbon electrode material comprises the following steps:

[0032] Wheat straw was selected as raw material, and the wheat straw was cleaned, dried and crushed to obtain biomass powder with particles of 50 mesh. KOH was selected as an activator, and KOH was evenly mixed with biomass powder in a ratio of 1:2 to obtain a mixture of biomass powder and KOH. The mixture of biomass powder and KOH was placed in an environment of 400°C and heated for 2 hours under a nitrogen atmosphere to carbonize the mixture of biomass powder and KOH to obtain a carbon material. The carbon material was then washed with water to neutralize the carbon material to remove residual KOH in the carbon material. The carbon material was then dried and placed in an environment of 1000°C for CO2 activation. After activation for 1.5 hours, a porous carbon material was obtained. The porous carbon material was then ground and sieved to make a porous carbon powder. The porous carbon powder was evenly mixed with acetylene black and polytetrafluoroethylene (PTFE) in a ratio of 8:1:1 to obtain a porous carbon electrode slurry, thereby completing the preparation of the porous carbon electrode material.

[0033] The porous carbon electrode slurry is coated on nickel foam, and the porous carbon electrode slurry coated on the nickel foam is vacuum dried at 110°C, and then the dried foam nickel is wrapped in aluminum foil into a sandwich shape, and pressed with a hydraulic press at a pressure of 12.5MPa for 3 minutes to obtain a porous carbon electrode sheet, and then the porous carbon electrode sheet is subjected to cyclic voltammetry test and constant current charge and discharge test to test whether the performance of the porous carbon electrode sheet is qualified. The test shows that the porous carbon electrode sheet has a specific capacitance of 300F / g, good cycle stability, and exhibits excellent performance under high rate charge and discharge conditions, that is, the performance of the porous carbon electrode sheet is qualified, and the preparation method of the porous carbon electrode material is feasible.

[0034] The working principle of the present invention is as follows: the preparation method of the porous carbon electrode material proposed in the present application selects waste crop straw, makes the waste crop straw into biomass powder, then evenly mixes the biomass powder with an activator, places the mixture of the biomass powder and the activator in a high temperature environment for heating and carbonization to obtain a carbon material, then washes the carbon material with water until it is neutral, removes the residual activator in the carbon material, and dries the carbon material, places the dried carbon material in a high temperature environment for CO2 activation to obtain a porous carbon material, then grinds and sieves the porous carbon material to make a porous carbon powder, evenly mixes the porous carbon powder with a conductive agent and a binder to obtain a porous carbon electrode slurry, then coats the porous carbon electrode slurry on a current collector, dries, and compacts to obtain a porous carbon electrode, and then tests the performance of the porous carbon electrode. Confirm whether the performance of the porous carbon electrode is qualified, complete the production of the porous carbon electrode, and finally, adjust the raw materials, optimize the carbonization and pore-forming processes according to the performance test results of the porous carbon electrode to improve the performance of the porous carbon electrode. This not only reduces production costs, realizes the resource utilization of waste, and is beneficial to environmental protection, but also improves the porosity and specific surface area of ​​the porous carbon material, maintains good conductivity and structural stability, and allows the prepared porous carbon electrode material to have high specific capacitance, good cycle stability and fast charge and discharge capabilities, which are suitable for energy storage devices such as supercapacitors and lithium-ion batteries. Moreover, it is also possible to adjust the type of raw materials, optimize the carbonization and pore-forming processes according to the performance test results of the porous carbon electrode, and flexibly regulate the pore structure, specific surface area and electrochemical properties of the porous carbon material to meet different application requirements.

[0035] What is described above is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing a porous carbon electrode material, characterized in that: The method comprises the following steps: Step 1: Raw material selection and pretreatment: Select waste crop straw, wash the waste crop straw, dry and crush the waste crop straw to obtain biomass powder; Step 2, carbonization: uniformly mix the biomass powder and the activator in a certain ratio to obtain a mixture of the biomass powder and the activator, and heat and carbonize the mixture of the biomass powder and the activator in a high temperature environment under a nitrogen atmosphere to obtain a carbon material; Step 3: Pore formation: washing the carbon material with water until it is neutral, removing the residual activator in the carbon material, and drying the carbon material. Under a nitrogen atmosphere, placing the dried carbon material in a high temperature environment for CO2 activation to obtain a porous carbon material; Step 4: post-processing: grinding and sieving the porous carbon material to obtain porous carbon powder; Step 5: preparing an electrode: uniformly mixing the porous carbon powder, the conductive agent and the binder in a certain proportion to obtain a porous carbon electrode slurry, and coating the porous carbon electrode slurry on a current collector, drying and compacting to obtain a porous carbon electrode; Step 6. Performance testing and optimization: Test the performance of the porous carbon electrode to confirm whether the performance of the porous carbon electrode meets the requirements, and adjust the raw materials, optimize the carbonization and pore-forming processes according to the performance test results of the porous carbon electrode to improve the performance of the porous carbon electrode.

2. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The waste crop straws proposed in the step one are corn straws and wheat straws.

3. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The biomass powder particles provided in the step are 20-80 meshes.

4. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The activator proposed in the step 2 is ZnCl2 or KOH.

5. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The ratio of the biomass powder to the activator proposed in step 2 is 1:1-1:

5.

6. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The carbonization temperature of the mixture of biomass powder and activator proposed in step 2 is 300-600° C., and the heating time is 1-4 hours.

7. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The CO2 activation temperature of the dried carbon material proposed in step 3 is 800-1200° C., and the activation time is 0.5-2 h.

8. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The ratio of the porous carbon powder to the conductive agent and the binder in step 5 is 8:1:1, and the conductive agent and the binder are acetylene black and polytetrafluoroethylene PTFE, respectively.

9. The method for preparing a porous carbon electrode material according to claim 1, characterized in that: The current collector in step 5 is nickel foam, and the porous carbon electrode slurry is coated on the nickel foam and dried at a vacuum temperature of 110°C.

10. The method for preparing a porous carbon electrode material according to claim 9, characterized in that: The compacting equipment for coating the porous carbon electrode slurry on the nickel foam in step 5 is an oil press, the pressing pressure is 12.5 MPa, and the pressing time is 3 minutes.

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