Polypyrrole-polybenzimidazole-sulfonated graphene composite material and preparation method thereof

Abstract

The invention relates to the technical field of electrochemical energy storage materials, in particular to a polypyrrole-polybenzimidazole-sulfonated graphene composite material and a preparation method thereof. The preparation method of the polypyrrole-polybenzimidazole-sulfonated graphene composite material comprises the following steps: adding a pyrrole monomer and 3, 3 '-diaminobenzidine into a phytic acid solution under the conditions of ice-water bath and magnetic stirring to obtain a precursor solution; under the conditions of ice-water bath and magnetic stirring, sequentially adding the sulfonated graphene dispersion liquid and ammonium persulfate into the precursor solution to obtain a mixed solution to be reacted; after the reaction mixed solution is subjected to hydrothermal polymerization reaction, cooling and centrifugal treatment are performed to obtain a precipitate, and the precipitate is cleaned and dried to obtain the polypyrrole-polybenzimidazole-sulfonated graphene composite material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochemical energy storage materials, in particular to a polypyrrole@polybenzimidazole@graphene sulfonate composite material and a preparation method thereof. BACKGROUND

[0002] With the rapid development of renewable energy and electric vehicles, the demand for high-performance electrochemical energy storage devices is increasingly urgent. As an important energy storage device, supercapacitors have shown great application prospects in electric vehicles, smart grids and other fields due to their high power density, fast charging and discharging capability, long cycle life and other advantages. Electrode materials, as the core component of supercapacitors, directly determine the overall performance of supercapacitors.

[0003] Conductive polymer polypyrrole (PPy) is highly concerned in the field of supercapacitor electrode materials due to its high pseudo-capacitance characteristics. However, pure polypyrrole has defects such as poor conductivity and insufficient cycle stability, which limits its practical application. In order to solve these problems, researchers try to composite polypyrrole with conductive materials such as carbon materials and metal oxides to improve performance. Polybenzimidazole (PBI) is a kind of polymer material with excellent conductivity and chemical stability, which has been explored as a conductive substrate to composite with polypyrrole in recent years. However, traditional preparation methods usually involve multi-step reactions and complex post-treatment, resulting in high cost and difficulty in large-scale production. SUMMARY

[0004] The purpose of the present application is to provide a preparation method of a polypyrrole@polybenzimidazole@graphene sulfonate composite material, which solves the problem of complex reaction and post-treatment in the prior art, resulting in high cost and difficulty in large-scale production.

[0005] The present application also provides a polypyrrole@polybenzimidazole@graphene sulfonate composite material to solve the problem of poor conductivity and structural stability of electrochemical energy storage materials in the prior art.

[0006] In order to solve the above problems, the present application provides a preparation method of a polypyrrole@polybenzimidazole@graphene sulfonate composite material, the technical scheme adopted is: A preparation method of a polypyrrole@polybenzimidazole@graphene sulfonate composite material, comprising the following steps: Step 1, under the conditions of ice water bath and magnetic stirring, pyrrole monomer and 3,3'-diamino benzidine are added to a phytic acid solution to obtain a precursor solution; Step 2, under the conditions of ice water bath and magnetic stirring, sulfonated graphene dispersion and ammonium persulfate are sequentially added to the precursor solution to obtain a reaction mixture; Step 3, after the reaction mixture is subjected to hydrothermal polymerization reaction, cooling and centrifugal treatment, the precipitate is obtained, and the precipitate is washed and dried to obtain the poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material.

[0007] The application has the advantages that: under the condition of ammonium persulfate as an initiator, the hydrothermal polymerization reaction of pyrrole monomers and 3,3'-diamino benzidine is combined with the double function design of phytic acid, a composite skeleton with high conductivity of poly-pyrrole and thermal stability of poly-benzimidazole is successfully constructed, a polymer matrix with high conductivity and structural stability is formed, and the comprehensive performance of the material is significantly improved; at the same time, the introduction of graphene sulfonate effectively optimizes the electrochemical active surface area of the composite material by using the strong acidic sites of the sulfonic acid groups, promotes the ion transport kinetics, and makes the composite skeleton further form a three-dimensional conductive network, breaking through the limitation of single performance of traditional conductive polymer materials; by using the strong interaction between graphene sulfonate and the polymer chain segments of poly-pyrrole and poly-benzimidazole, the interface bonding force is significantly enhanced, and the three-dimensional network structure of the material is more stable, which effectively solves the technical problem of easy agglomeration of graphene in the polymer matrix, and further provides an innovative solution for the application of high-performance electrochemical devices. In addition, the application realizes the molecular-level composite and the controllable micro-morphology by synergistic regulation of the hydrothermal polymerization reaction and the drying process, ensures the batch stability of the electrochemical performance of the material, and provides a technical support for the large-scale preparation of high-performance conductive polymer composites.

[0008] The preparation method of the poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material of the application combines the hydrothermal polymerization reaction to complete polymerization and self-assembly in one step, enhances the conductivity and structural stability of the material, simplifies the process, reduces energy consumption, ensures excellent performance of the composite material, and is suitable for electrode materials of supercapacitors and other electrochemical energy storage devices, thereby providing an innovative solution for the preparation of high-performance supercapacitor electrode materials.

[0009] In order to make the pyrrole monomers and 3,3'-diamino benzidine fully undergo the hydrothermal polymerization reaction, effectively construct the composite skeleton with high conductivity of poly-pyrrole and thermal stability of poly-benzimidazole, and at the same time, the growth direction of the poly-pyrrole chain segments of poly-pyrrole and poly-benzimidazole is regulated by the strong hydrogen bonding of phytic acid, preferably, the molar ratio of the pyrrole monomers and 3,3'-diamino benzidine is 1: (0.2-0.5), and the concentration of the phytic acid solution is 0.5-1 M.

[0010] In order to further enhance the interface bonding force and increase the stability of the three-dimensional network structure of the material, preferably, the mass ratio of graphene sulfonate to pyrrole monomers is (0.05-0.1):1.

[0011] As an initiator, in order to further promote the pyrrole monomer and 3,3'-diamino benzidine to fully carry out the hydrothermal polymerization reaction, preferably, the molar ratio of the ammonium persulfate to the pyrrole monomer is (1~1.5):1.

[0012] In order to further promote the pyrrole monomer and 3,3'-diamino benzidine to fully carry out the hydrothermal polymerization reaction, and effectively build a composite skeleton with high conductivity of polypyrrole and thermal stability of polybenzimidazole under the action of sulfonated graphene, preferably, the temperature of the hydrothermal polymerization reaction is 80~100℃, and the time is 6~10h.

[0013] Preferably, the hydrothermal polymerization reaction is carried out in a hydrothermal reaction kettle, and the filling degree of the hydrothermal reaction kettle is 60~80%.

[0014] In order to effectively remove the solvent in the precipitate, preferably, the temperature of the drying treatment is 60~80℃, and the time is 12~24h.

[0015] In order to make the precursor solution and the mixed solution to be reacted fully dispersed and uniformly mixed when prepared, preferably, the rotating speed of the magnetic stirring is 500~1000 rpm, and the time is 15~120 minutes.

[0016] In order to obtain the phytic acid solution without affecting the hydrothermal polymerization reaction, preferably, the solvent in the phytic acid solution is a mixed solution of deionized water and ethanol, and the volume ratio of the deionized water to the ethanol is (1~3):1.

[0017] The application further provides a polypyrrole@polybenzimidazole@sulfonated graphene composite material. A polypyrrole@polybenzimidazole@sulfonated graphene composite material is prepared by the preparation method of the polypyrrole@polybenzimidazole@sulfonated graphene composite material.

[0018] The polypyrrole@polybenzimidazole@sulfonated graphene composite material prepared by the preparation method of the polypyrrole@polybenzimidazole@sulfonated graphene composite material of the application combines the high capacitance characteristics of polypyrrole, the excellent conductivity and chemical stability of polybenzimidazole, and the high conductivity and structural stability of sulfonated graphene, and has a high-conductive three-dimensional network structure and a stable interface, and has good electrochemical performance, rate performance and good contact resistance, and is suitable for electrode materials of supercapacitors, and improves the electrochemical performance of the supercapacitor electrode.

[0019] The application further provides a preparation method of the polypyrrole-polybenzimidazole-sulfonated graphene composite material.

[0020] The polypyrrole-polybenzimidazole-sulfonated graphene composite material has the advantages that the polypyrrole-polybenzimidazole-sulfonated graphene composite material is applied to the supercapacitor electrode, and the electrochemical performance of the supercapacitor electrode is improved. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A SEM image of the polypyrrole-polybenzimidazole-sulfonated graphene composite material prepared by the preparation method of the polypyrrole-polybenzimidazole-sulfonated graphene composite material of the embodiment 2 of the application.

[0022] Figure 2 A charge-discharge curve of the polypyrrole-polybenzimidazole-sulfonated graphene composite material prepared by the preparation method of the polypyrrole-polybenzimidazole-sulfonated graphene composite material of the embodiment 2 of the application.

[0023] Figure 3 A cyclic voltammetry curve of the polypyrrole-polybenzimidazole-sulfonated graphene composite material prepared by the preparation method of the polypyrrole-polybenzimidazole-sulfonated graphene composite material of the embodiment 2 of the application.

[0024] Figure 4 An AC impedance test diagram of the polypyrrole-polybenzimidazole-sulfonated graphene composite material prepared by the preparation method of the polypyrrole-polybenzimidazole-sulfonated graphene composite material of the embodiment 2 of the application. DETAILED DESCRIPTION

[0025] The preparation method of the electrochemical energy storage material in the prior art is complex in reaction and post-processing, which leads to high cost and difficulty in large-scale production. The application provides a preparation method of a polypyrrole-polybenzimidazole-sulfonated graphene composite material, which comprises the following steps: Step 1, under the conditions of an ice water bath and magnetic stirring, pyrrole monomer and 3,3'-diamino benzidine are added into a phytic acid solution to obtain a precursor solution; Step 2, under the conditions of an ice water bath and magnetic stirring, sulfonated graphene dispersion and ammonium persulfate are sequentially added into the precursor solution to obtain a reaction mixture; Step 3, after the reaction mixture is subjected to hydrothermal polymerization reaction, cooling and centrifugal treatment, a precipitate is obtained, and the precipitate is subjected to cleaning and drying treatment to obtain the polypyrrole-polybenzimidazole-sulfonated graphene composite material.

[0026] The technical concept of the present application is: first, under the condition of ice water bath and magnetic stirring, pyrrole monomer and 3,3'-diamino benzidine are added to the phytic acid solution to obtain a precursor solution; wherein the phytic acid solution acts as a solvent and a proton source to participate in the subsequent hydrothermal polymerization reaction, and also regulates the growth direction of the poly-pyrrole chain segment through hydrogen bonding; the pyrrole monomer is used for hydrothermal polymerization to generate poly-pyrrole, which has high capacitance characteristics; 3,3'-diamino benzidine is used for hydrothermal polymerization to generate poly-benzimidazole, which has excellent conductivity and chemical stability; poly-pyrrole and poly-benzimidazole construct a composite skeleton with high conductivity of poly-pyrrole and thermal stability of poly-benzimidazole; secondly, under the condition of ice water bath and magnetic stirring, sulfonated graphene dispersion and ammonium persulfate are sequentially added to the precursor solution to obtain a reaction mixture, wherein the sulfonated graphene dispersion has high conductivity and structural stability, and the strong acidic sites of the sulfonic acid groups and the strong interaction between the sulfonic acid groups and the polymer chain segment significantly enhance the interfacial bonding force, effectively optimize the electrochemically active surface area of the composite material, and promote ion transport kinetics; ammonium persulfate acts as an initiator to trigger the polymerization of pyrrole monomer and 3,3'-diamino benzidine, and then form a copolymer of poly-pyrrole and poly-benzimidazole. Here, the three components of pyrrole monomer, 3,3'-diamino benzidine and sulfonated graphene form a tight interfacial bond through π-π conjugation and hydrogen bonding network, which can further form a three-dimensional conductive network structure of the composite skeleton, making the three-dimensional network structure of the material more stable. Finally, after the reaction mixture is subjected to hydrothermal polymerization, cooling and centrifugal treatment, a precipitate is obtained, and the precipitate is washed and dried to obtain a poly-pyrrole@poly-benzimidazole@ sulfonated graphene composite material, wherein the synergistic regulation of hydrothermal polymerization and vacuum drying process realizes molecular-level compounding and controllable micro-morphology. Precise matching of all process parameters ensures batch stability of the material's electrochemical performance, providing technical support for large-scale preparation of high-performance conductive polymer composites.

[0027] The preparation method of the poly-pyrrole@poly-benzimidazole@ sulfonated graphene composite material of the present application combines hydrothermal polymerization to complete polymerization and self-assembly in one step, enhancing the conductivity and structural stability of the material, while simplifying the process and reducing energy consumption, ensuring that the composite material has excellent performance, and being suitable for electrode materials of electrochemical energy storage devices such as supercapacitors, providing an innovative solution for the preparation of high-performance supercapacitor electrode materials.

[0028] Specifically, the preparation method of the poly-pyrrole@poly-benzimidazole@ sulfonated graphene composite material comprises the following steps: (1) pyrrole monomer and 3,3'-diamino benzidine are added into a phytic acid solution according to a certain molar ratio, and the solvent of the phytic acid solution is a mixed solution of deionized water and ethanol. Under the condition of ice water bath, a homogeneous precursor solution is formed by magnetic stirring treatment, wherein the molar ratio of pyrrole monomer and 3,3'-diamino benzidine is 1:(0.2-0.5), the concentration of the phytic acid solution is 0.5-1 M, the volume ratio of deionized water and ethanol is (1-3):1, the stirring speed of magnetic stirring is 500-800 rpm, and the stirring time is 30-120 minutes; (2) Under the condition of ice water bath and magnetic stirring, sulfonated graphene dispersion liquid is added into the precursor solution to prepare a mixed solution, wherein the mass ratio of sulfonated graphene and pyrrole monomer is (0.05-0.1):1, the sulfonated graphene dispersion liquid is ultrasonic dispersed by a cell crusher, the ultrasonic dispersion treatment power is 300-500 W, the frequency is 20 kHz, the dispersion time is 10-20 minutes, and the solution temperature is controlled below 25°C during the ultrasonic dispersion treatment to prevent agglomeration; (3) Ammonium persulfate is added into the mixed solution, and the ammonium persulfate is completely dissolved and uniformly dispersed by magnetic stirring treatment under the condition of ice water bath to obtain a reaction mixture, wherein the molar ratio of ammonium persulfate and pyrrole monomer is (1-1.5):1, the stirring speed of magnetic stirring is 800-1000 rpm, and the stirring time is 15 minutes; (4) The above reaction mixture is transferred into a hydrothermal reaction kettle, the filling degree of the hydrothermal reaction kettle is 60-80%, and the reaction kettle is placed in a constant temperature oven to perform hydrothermal polymerization reaction under a preset temperature condition, wherein, in order to ensure uniform reaction, the reaction kettle is taken out regularly every 2 hours during the reaction to perform shaking treatment, the hydrothermal polymerization reaction temperature is 80-100°C, and the time is 6-10h, which is beneficial to form a composite material with uniform structure; (5) After the completion of the hydrothermal polymerization reaction, the reaction liquid is naturally cooled to room temperature, transferred into a centrifugal tube, and subjected to centrifugal separation treatment by a high-speed centrifuge to remove supernatant and obtain a precipitate; then, the precipitate is washed with deionized water until the washing liquid is neutral; (6) The washed precipitate is placed in a vacuum drying oven for vacuum drying treatment under a preset temperature condition to finally obtain a polypyrrole@polybenzimidazole@ sulfonated graphene composite material, wherein the drying treatment temperature is 60-80°C, and the time is 12-24h.

[0029] The implementation process of the present application will be described in detail in combination with specific examples. However, those skilled in the art will understand that the following examples are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the examples. It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The present application will be described in detail below with reference to the embodiments. It should be noted that the endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges or values should be construed to be approximations that allow for significant variation. Various ranges of values that are endpoints are provided as exemplars for this approximation. The endpoints of these ranges and those of any values are not exclusive; the values of each range are uniquely and individually understood and are independent of the described range or ranges like them. It should be noted that the endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges or values should be construed to be approximations that allow for significant variation. Various ranges of values that are endpoints are provided as exemplars for this approximation. The endpoints of these ranges and those of any values are not exclusive; the values of each range are uniquely and individually understood and are independent of the described range or ranges like them.

[0030] In the following examples and comparative examples, the sulfonated graphene used in the raw materials is purchased from Suzhou Carbon-Feng Graphene Technology Co., Ltd., and the rest are ordinary commercially available products that can be directly purchased or prepared according to conventional techniques in the art.

[0031] Example 1 of the preparation method of the poly-pyrrole@poly-benzimidazole@sulfonated graphene composite material of the present application Example 1 The preparation method of the poly-pyrrole@poly-benzimidazole@sulfonated graphene composite material provided in this embodiment includes the following steps: (1) 1.0 mmol of pyrrole monomer and 0.2 mmol of 3,3'-diamino benzidine are added to a 100 mL phytic acid solution with a concentration of 0.5 M, the solvent of the phytic acid solution is a mixed solution of 50 mL deionized water and 50 mL ethanol, and a homogeneous precursor solution is formed by magnetic stirring at a speed of 500 rpm for 30 minutes under ice water bath conditions; (2) Under the conditions of ice water bath and magnetic stirring, sulfonated graphene dispersion liquid is added to the precursor solution to prepare a mixed liquid, wherein the mass ratio of sulfonated graphene to pyrrole monomer is 0.05:1, the sulfonated graphene dispersion liquid is ultrasonically dispersed by a cell crusher, the ultrasonic dispersion treatment power is 300 W, the frequency is 20 kHz, the dispersion time is 10 minutes, and the solution temperature is controlled below 25°C during the ultrasonic dispersion treatment to prevent agglomeration; (3) 1.0 mmol of ammonium persulfate is added to the mixed liquid, and the ammonium persulfate is completely dissolved and uniformly dispersed by magnetic stirring at a speed of 800 rpm for 15 minutes under ice water bath conditions to obtain a reaction mixture; (4) The above reaction mixture is transferred to a hydrothermal reaction kettle, the filling degree of the hydrothermal reaction kettle is 80%, and the reaction kettle is placed in a constant temperature oven, and a hydrothermal polymerization reaction is carried out at a temperature of 80°C for 6h, wherein in order to ensure uniform reaction, the reaction kettle is taken out periodically every 2 hours during the reaction to shake and treat uniformly; (5) After the hydrothermal polymerization reaction is completed, the reaction solution is naturally cooled to room temperature, the reaction solution is transferred to a centrifuge tube, and centrifugal separation treatment is performed by a high-speed centrifuge at 4000 rpm for 5 minutes to remove supernatant to obtain a precipitate; then, the precipitate is washed with 50 mL of deionized water for 3 times until the washing solution is neutral; (6) The washed precipitate is placed in a vacuum drying oven and vacuum dried at 60°C for 12 hours to obtain a polypyrrole-polybenzimidazole-sulfonated graphene composite material.

[0032] Example 2 The preparation method of the polypyrrole-polybenzimidazole-sulfonated graphene composite material provided in this embodiment comprises the following steps: (1) 1.0 mmol of pyrrole monomer and 0.5 mmol of 3,3'-diamino benzidine are added to a 100 mL phytic acid solution with a concentration of 1.0 M, the solvent of the phytic acid solution is a mixed solution of 75 mL of deionized water and 25 mL of ethanol, and a homogeneous precursor solution is formed by magnetic stirring at a speed of 800 rpm for 120 minutes under ice water bath conditions; (2) Under the conditions of ice water bath and magnetic stirring, sulfonated graphene dispersion liquid is added to the precursor solution to prepare a mixed solution, wherein the mass ratio of sulfonated graphene to pyrrole monomer is 0.1:1, the sulfonated graphene dispersion liquid is ultrasonically dispersed by a cell crusher, the ultrasonic dispersion treatment power is 500 W, the frequency is 20 kHz, the dispersion time is 20 minutes, and the solution temperature is controlled below 25°C during the ultrasonic dispersion treatment to prevent agglomeration; (3) 1.5 mmol of ammonium persulfate is added to the mixed solution, and the ammonium persulfate is completely dissolved and uniformly dispersed by magnetic stirring at a speed of 1000 rpm for 15 minutes under ice water bath conditions to obtain a reaction mixture; (4) The reaction mixture is transferred to a hydrothermal reaction kettle, the filling degree of the hydrothermal reaction kettle is 80%, and the reaction kettle is placed in a constant temperature oven for hydrothermal polymerization reaction at 100°C for 10 hours, wherein, in order to ensure uniform reaction, the reaction kettle is taken out regularly every 2 hours during the reaction to shake evenly; (5) After the hydrothermal polymerization reaction is completed, the reaction solution is naturally cooled to room temperature, the reaction solution is transferred to a centrifuge tube, and centrifugal separation treatment is performed by a high-speed centrifuge at 4000 rpm for 5 minutes to remove supernatant to obtain a precipitate; then, the precipitate is washed with 50 mL of deionized water for 3 times until the washing solution is neutral; (6) The washed precipitate is placed in a vacuum drying oven and vacuum dried at 60°C for 12 hours to obtain a polypyrrole-polybenzimidazole-sulfonated graphene composite material.

[0033] Example 3 The preparation method of the polypyrrole@polybenzimidazole@graphene sulfonate composite material provided in this embodiment comprises the following steps: (1) 2.0 mmol of pyrrole monomer and 0.6 mmol of 3,3'-diamino benzidine are added to a 200 mL phytic acid solution with a concentration of 0.7 M, the solvent of the phytic acid solution is a mixed solution of 100 mL deionized water and 100 mL ethanol, and a homogeneous precursor solution is formed by magnetic stirring at a speed of 600 rpm for 90 minutes under ice water bath conditions; (2) Under the conditions of ice water bath and magnetic stirring, sulfonated graphene dispersion liquid is added to the precursor solution to prepare a mixed liquid, wherein the mass ratio of sulfonated graphene to pyrrole monomer is 0.07:1, the sulfonated graphene dispersion liquid is ultrasonically dispersed by a cell crusher, the ultrasonic dispersion treatment power is 400 W, the frequency is 20 kHz, the dispersion time is 15 minutes, and the solution temperature is controlled below 25°C during the ultrasonic dispersion treatment to prevent agglomeration; (3) 2.4 mmol of ammonium persulfate is added to the mixed liquid, and the ammonium persulfate is completely dissolved and uniformly dispersed by magnetic stirring at a speed of 900 rpm for 15 minutes under ice water bath conditions to obtain a reaction mixture; (4) The above reaction mixture is transferred to a hydrothermal reaction kettle, the filling degree of the hydrothermal reaction kettle is 60%, and the reaction kettle is placed in a constant temperature oven, and the hydrothermal polymerization reaction is carried out at a temperature of 90°C for 8h, wherein in order to ensure uniform reaction, the reaction kettle is taken out regularly every 2 hours during the reaction to shake and treat; (5) After the completion of the hydrothermal polymerization reaction, the reaction liquid is naturally cooled to room temperature, and the reaction liquid is transferred to a centrifuge tube and subjected to centrifugal separation treatment by a high-speed centrifuge at 5000 rpm for 8 minutes to remove the supernatant and obtain a precipitate; then, the precipitate is washed with 100 mL of deionized water for 3 times until the washing liquid is neutral; (6) The washed precipitate is placed in a vacuum drying oven and subjected to vacuum drying treatment at a temperature of 70°C for 18h to obtain a polypyrrole@polybenzimidazole@graphene sulfonate composite material.

[0034] Example 4 The preparation method of the polypyrrole@polybenzimidazole@graphene sulfonate composite material provided in this embodiment comprises the following steps: (1) 1.5 mmol of pyrrole monomer and 0.6 mmol of 3,3'-diamino-benzidine were added into a 150 mL phytic acid solution with a concentration of 0.6 M, the solvent of the phytic acid solution was a mixed solution of 90 mL of deionized water and 60 mL of ethanol, and a homogeneous precursor solution was formed by magnetic stirring at a speed of 700 rpm for 60 minutes under an ice water bath condition; (2) A sulfonated graphene dispersion was added to the precursor solution under an ice water bath and magnetic stirring condition to prepare a mixed solution, wherein the mass ratio of the sulfonated graphene to the pyrrole monomer was 0.09:1, the sulfonated graphene dispersion was ultrasonically dispersed by a cell crusher, the ultrasonic dispersion was performed at a power of 450 W and a frequency of 20 kHz for 18 minutes, and the solution temperature was controlled below 25°C during the ultrasonic dispersion to prevent agglomeration; (3) 1.95 mmol of ammonium persulfate was added to the mixed solution, and the ammonium persulfate was completely dissolved and uniformly dispersed by magnetic stirring at a speed of 850 rpm for 15 minutes under an ice water bath condition to obtain a reaction mixture; (4) The reaction mixture was transferred to a hydrothermal reaction kettle with a filling degree of 70%, and the reaction kettle was placed in a constant temperature oven for a hydrothermal polymerization reaction at a temperature of 95°C for 9 hours, wherein the reaction kettle was periodically taken out for shaking treatment every 2 hours to ensure uniform reaction; (5) After the hydrothermal polymerization reaction was completed, the reaction solution was naturally cooled to room temperature, transferred to a centrifuge tube, and subjected to centrifugal separation treatment by a high-speed centrifuge at 5500 rpm for 7 minutes to remove the supernatant and obtain a precipitate; then, the precipitate was washed with 80 mL of deionized water for 3 times until the washing liquid was neutral; (6) The washed precipitate was placed in a vacuum drying oven and subjected to vacuum drying treatment at a temperature of 75°C for 20 hours to finally obtain a polypyrrole@polybenzimidazole@ sulfonated graphene composite material.

[0035] II. Experimental Examples Experimental Example 1 The polypyrrole@polybenzimidazole@ sulfonated graphene composite material prepared in the above Example 2 was characterized by a Zeiss Sigma 300 type SEM to characterize the morphology of the prepared polypyrrole@polybenzimidazole@ sulfonated graphene composite material, and the detection results are shown in FIG. 1. Figure 1 As can be seen from FIG. 1, the polypyrrole@polybenzimidazole@ sulfonated graphene composite material presents a uniform three-dimensional interconnected network structure and has a large electrochemical active specific surface area, which is beneficial to promote the occurrence of electrochemical reactions.

[0036] Experimental Example 2 The polypyrrole@polybenzimidazole@graphene sulfonate composite material prepared in the above-mentioned examples 1-4 was subjected to electrochemical performance detection.

[0037] Specifically, the polypyrrole@polybenzimidazole@graphene sulfonate composite material, acetylene black and polytetrafluoroethylene (PTFE) prepared in examples 1-4 were mixed in a mass ratio of 8:1:1, respectively, coated on carbon cloth to prepare working electrodes. A three-electrode system was assembled with a platinum sheet as a counter electrode, a saturated calomel electrode as a reference electrode and 1 M H2SO4 as an electrolyte, and subjected to galvanostatic charge-discharge (GCD) test to verify the performance as an electrode material of a supercapacitor. The charge-discharge test was carried out at different current densities, and the results are shown in Table 1.

[0038] Table 1: Discharge specific capacity of examples 1-4 at different current densities

[0039] As can be seen from Table 1, the polypyrrole@polybenzimidazole@graphene sulfonate composite material prepared in examples 1-4 has a large discharge specific capacity in the supercapacitor electrode prepared therefrom at each current density, and the discharge specific capacity of the polypyrrole@polybenzimidazole@graphene sulfonate composite material prepared in examples 1-4 can be as high as 514.3 F / g at a current density of 0.5 A / g. It can also be shown that the polypyrrole@polybenzimidazole@graphene sulfonate composite material prepared in examples 1-4 has good electrochemical performance.

[0040] Meanwhile, the polypyrrole@polybenzimidazole@graphene sulfonate composite material prepared in the above-mentioned example 2 was subjected to charge-discharge test at a current density of 0.5-10 A / g, and the results are shown in Figure 2 As can be seen, the charge-discharge curve shape of the polypyrrole@polybenzimidazole@graphene sulfonate composite material prepared in the present application remains basically consistent at different current densities, indicating that the material has good rate performance. The cyclic voltammetry curve at different scanning speeds is shown in Figure 3 As can be seen, the polypyrrole@polybenzimidazole@graphene sulfonate composite material has obvious electrochemical bulging near 0.3-0.5 V, indicating that the electrochemical response of the material is relatively sensitive. The alternating current impedance test is shown in Figure 4 As can be seen, the curve is composed of a small semicircle and a slanted line, the small semicircle has a small radius and a small intercept value with the horizontal axis, indicating that the electrode material has good contact resistance and internal resistance.

[0041] Thus, it is illustrated that the polypyrrole@polybenzimidazole@graphene sulfonate composite material prepared by the preparation method of the polypyrrole@polybenzimidazole@graphene sulfonate composite material has high electric capacity, excellent conductivity and chemical stability of the polypyrrole, high conductivity and structural stability of the graphene sulfonate, and has a high-conductive three-dimensional network structure and a stable interface, and has good electrochemical performance, rate performance and good contact resistance, is suitable for an electrode material of a supercapacitor, and improves the electrochemical performance of the supercapacitor electrode.

[0042] The above merely describes the preferred embodiments of the present application and is not intended to limit the present application. The present application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a polypyrrole@polybenzimidazole@graphene sulfonate composite material, characterized in that, The method comprises the following steps: Step 1, under the conditions of ice water bath and magnetic stirring, pyrrole monomer and 3,3'-diaminobenzidine are added into a phytic acid solution to obtain a precursor solution; Step 2, under the conditions of ice water bath and magnetic stirring, sulfonated graphene dispersion and ammonium persulfate are sequentially added into the precursor solution to obtain a reaction mixture; Step 3, after the reaction mixture is subjected to hydrothermal polymerization reaction, cooling and centrifugal treatment, a precipitate is obtained, and the precipitate is subjected to cleaning and drying treatment to obtain a polypyrrole@polybenzimidazole@sulfonated graphene composite material.

2. The method for preparing a polypyrole@polybenzimidazole@graphene sulfonate composite material according to claim 1, characterized in that, The molar ratio of the pyrrole monomer to 3,3'-diaminobenzidine is 1:(0.2-0.5), and the concentration of the phytic acid solution is 0.5-1 M.

3. The method for preparing poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material according to claim 1, characterized in that, The mass ratio of the sulfonated graphene to the pyrrole monomer is (0.05-0.1):

1.

4. The method for preparing poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material according to claim 1, characterized in that, The molar ratio of the ammonium persulfate to the pyrrole monomer is (1-1.5):

1.

5. The method for preparing poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material according to claim 1, characterized in that, The temperature of the hydrothermal polymerization reaction is 80-100 DEG C, and the time is 6-10 h.

6. The method for preparing poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material according to claim 1, characterized in that, The hydrothermal polymerization reaction is carried out in a hydrothermal reactor, and the filling degree of the hydrothermal reactor is 60-80%.

7. The method for preparing poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material according to claim 1, characterized in that, The temperature of the drying treatment is 60-80 DEG C, and the time is 12-24 h.

8. The method for preparing the polypyrrole@polybenzimidazole@sulfonic acid graphene composite material according to claim 1, characterized in that, The rotating speed of the magnetic stirring is 500-1000 rpm, and the time is 15-120 min.

9. The method for preparing poly-pyrrole@poly-benzimidazole@graphene sulfonate composite material according to claim 1, characterized in that, The solvent in the phytic acid solution is a mixed solution of deionized water and ethanol, and the volume ratio of the deionized water to the ethanol is (1-3):

1.

10. A polypyrole-polybenzimidazole-sulfonated graphene composite material, characterized in that, The polypyrrole@polybenzimidazole@sulfonated graphene composite material is prepared by the method of any one of claims 1-9.

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