A Schiff base organic porous polymer-ferric-carbon nanotube composite material, a preparation method and application thereof

Abstract

The application discloses a preparation method and application of a Schiff base organic porous polymer-ferrocene-carbon nanotube composite material, and comprises the following steps: (1) adding carbon nanotubes into anhydrous ethanol and performing ultrasonic treatment to obtain an anhydrous ethanol suspension of the carbon nanotubes; (2) respectively dissolving 3,3'-diaminobenzidine, p-phthaldehyde and ferrocene in anhydrous ethanol to obtain a 3,3'-diaminobenzidine anhydrous ethanol solution, a p-phthaldehyde anhydrous ethanol suspension and a ferrocene anhydrous ethanol suspension; (3) sequentially adding the anhydrous ethanol suspension of the carbon nanotubes, the p-phthaldehyde anhydrous ethanol suspension and the ferrocene anhydrous ethanol suspension into the 3,3'-diaminobenzidine anhydrous ethanol solution and performing constant-temperature stirring; and (4) performing suction filtration, washing with pure water and anhydrous ethanol and drying. When the composite material is used as a positive electrode of a super battery, the composite material has excellent energy density and cycle performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of synthesis of organic polymer, and particularly relates to a Schiff base organic porous polymer-ferricium-carbon nanotube composite material, a preparation method and application thereof. BACKGROUND

[0002] Schiff base is a kind of organic porous polymer with rich C=N structure, and is becoming an attractive research hotspot in the field of electrode materials due to its inherent high redox activity, rich specific surface area and excellent specific capacity. However, the single Schiff base polymer conjugated molecular chain is tightly packed through the π-π bond, resulting in less ion diffusion channel and redox active site, so that the electrochemical performance cannot reach the theoretical value. In recent years, the mainstream method for improving the electrochemical performance of Schiff base mainly focuses on the incorporation of heteroatoms (N, O, B, P, etc.) and the activation of Schiff base material through carbonization at high temperature (about 900 DEG C), however, through the above method, the inherent redox activity of Schiff base material cannot be effectively utilized, and even the original polymer skeleton structure will collapse at high temperature carbonization, so that the electrochemical performance is not obviously improved. SUMMARY

[0003] In view of the defects of the prior art, the application provides a Schiff base organic porous polymer-ferricium-carbon nanotube composite material, which has good electrochemical performance and cycle performance, and the application also provides a preparation method and application thereof.

[0004] A preparation method of a Schiff base organic porous polymer-ferricium-carbon nanotube composite material, comprising the following steps:

[0005] (1) carbon nanotubes are added into anhydrous ethanol and ultrasonic treatment is carried out to obtain an anhydrous ethanol suspension of carbon nanotubes;

[0006] (2) 3,3'-diaminobenzidine, p-phenylenedimethylene, and ferricium are dissolved in anhydrous ethanol to obtain a 3,3'-diaminobenzidine anhydrous ethanol solution, a p-phenylenedimethylene anhydrous ethanol suspension, and a ferricium anhydrous ethanol suspension;

[0007] (3) the anhydrous ethanol suspension of carbon nanotubes, the p-phenylenedimethylene anhydrous ethanol suspension, and the ferricium anhydrous ethanol suspension are sequentially added into the 3,3'-diaminobenzidine anhydrous ethanol solution, and constant temperature stirring is carried out at 35-45 DEG C for 2-4 h;

[0008] (4) suction filtration is carried out, pure water and anhydrous ethanol are used for exchange washing, and drying is carried out.

[0009] Preferably, the molar ratio of the 3,3'-diaminobenzidine, p-xylene dicarboxaldehyde and ferrocene is 1:(0.5-2):(0.2-1), and the mass ratio of the carbon nanotubes to the ferrocene is 2-8%.

[0010] Preferably, the molar ratio of the 3,3'-diaminobenzidine, p-xylene dicarboxaldehyde and ferrocene is 1:1:0.4.

[0011] Preferably, the mass ratio of the carbon nanotubes to the ferrocene is 5%.

[0012] Preferably, the drying condition is drying at 50-70 DEG C for 10-15 h.

[0013] A Schiff base organic porous polymer-ferrocene-carbon nanotube composite material is prepared by the preparation method of the present application.

[0014] The application of the Schiff base organic porous polymer-ferrocene-carbon nanotube composite material as a positive electrode material of a super capacitor.

[0015] Advantages of the present application:

[0016] (1) The Schiff base organic porous polymer-ferrocene-carbon nanotube composite material provided by the present application has excellent energy density and cycle performance when used as a positive electrode of a super battery.

[0017] (2) The Schiff base reaction of the present application does not require any initiator, and a composite material is prepared by combining with ferrocene and carbon nanotubes. The introduction of ferrocene can provide more electroactive and redox sites, and the introduction of carbon nanotubes can improve the mechanical properties of the polymer structural unit at the nanoscale, thereby greatly improving the cycle performance of the Schiff base material.

[0018] (3) The composite material of the present application has abundant mesoporous and macroporous structures, which is beneficial to the rapid insertion / extraction of electrolyte ions, thereby making the Schiff base organic porous polymer-ferrocene-carbon nanotube composite electrode material of the present application exhibit excellent rate performance and reversible performance. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A scanning electron microscope image of the material obtained in Example 1;

[0020] Figure 2 A scanning electron microscope image of the material obtained in Example 2;

[0021] Figure 3 A scanning electron microscope image of the material obtained in Example 3;

[0022] Figure 4 A scanning electron microscope image of the material obtained in Comparative Example 1;

[0023] Figure 5 Here is a scanning electron microscope image of the material obtained in Comparative Example 2;

[0024] Figure 6 The image shows a transmission electron microscope (TEM) image of the material obtained in Example 1.

[0025] Figure 7 Transmission electron microscope (TEM) image of the material obtained in Example 2;

[0026] Figure 8 Transmission electron microscope (TEM) image of the material obtained in Example 3;

[0027] Figure 9 The image shows a transmission electron microscope (TEM) image of the material obtained in Comparative Example 1.

[0028] Figure 10 The nitrogen adsorption-desorption isotherm diagram and pore size distribution diagram are shown.

[0029] Figure 11 XRD and FT-IR spectra are shown.

[0030] Figure 12 The graph shows the cycling performance of an asymmetric supercapacitor made of Schiff base organic porous polymer-ferrocene-carbon nanotube composite material. Detailed Implementation

[0031] Example 1

[0032] A method for preparing a Schiff base organic porous polymer-ferrocene-carbon nanotube composite material includes the following steps:

[0033] (1) Add 0.0038 g (2% of the mass of ferrocene) of carbon nanotubes to 30 mL of anhydrous ethanol and sonicate for 30 min to obtain an anhydrous ethanol suspension of carbon nanotubes.

[0034] (2) Dissolve 0.5357g of 3,3'-diaminobenzidine and 0.3353g of terephthalaldehyde in 80mL of anhydrous ethanol to obtain an anhydrous ethanol solution of 3,3'-diaminobenzidine and an anhydrous ethanol suspension of terephthalaldehyde; dissolve 0.1860g of ferrocene in 10mL of anhydrous ethanol to obtain an anhydrous ethanol suspension of ferrocene.

[0035] (3) The anhydrous ethanol suspension of carbon nanotubes, the anhydrous ethanol suspension of terephthalaldehyde, and the anhydrous ethanol suspension of ferrocene were added sequentially to the anhydrous ethanol solution of 3,3'-diaminobenzidine and stirred at 40°C for 3 hours.

[0036] (4) Filtration, exchange washing with pure water and anhydrous ethanol, constant temperature drying at 60℃ for 12h, the obtained Schiff base organic porous polymer-ferric- carbon nanotube composite material is a red powder.

[0037] Example 2

[0038] The carbon nanotube is 0.0093g (5% of the mass of ferrocene), and the others are the same as in Example 1.

[0039] Example 3

[0040] The carbon nanotube is 0.0149g (8% of the mass of ferrocene), and the others are the same as in Example 1.

[0041] Example 4

[0042] A preparation method of a Schiff base organic porous polymer-ferrocene-carbon nanotube composite material, comprising the following steps:

[0043] (1) 0.0093g (2% of the mass of ferrocene) carbon nanotubes are added to 30mL anhydrous ethanol, and ultrasonic treatment is performed for 30min to obtain an anhydrous ethanol suspension of carbon nanotubes;

[0044] (2) 0.5357g 3,3'-diaminobenzidine and 0.6706g terephthaldehyde are respectively dissolved in 80mL anhydrous ethanol to obtain a 3,3'-diaminobenzidine anhydrous ethanol solution and a terephthaldehyde anhydrous ethanol suspension; 0.4650g ferrocene is dissolved in 10mL anhydrous ethanol to obtain a ferrocene anhydrous ethanol suspension;

[0045] (3) The anhydrous ethanol suspension of carbon nanotubes, the anhydrous ethanol suspension of terephthaldehyde, and the anhydrous ethanol suspension of ferrocene are sequentially added to the 3,3'-diaminobenzidine anhydrous ethanol solution, and constant temperature stirring is performed at 35℃ for 4h;

[0046] (4) Filtration, exchange washing with pure water and anhydrous ethanol, constant temperature drying at 50℃ for 15h, the obtained Schiff base organic porous polymer-ferrocene-carbon nanotube composite material is a red powder.

[0047] Example 5

[0048] A preparation method of a Schiff base organic porous polymer-ferrocene-carbon nanotube composite material, comprising the following steps:

[0049] (1) 0.0019g (2% of the mass of ferrocene) carbon nanotubes are added to 30mL anhydrous ethanol, and ultrasonic treatment is performed for 30min to obtain an anhydrous ethanol suspension of carbon nanotubes;

[0050] (2) 0.5357 g of 3,3'-diaminobenzidine and 0.1677 g of p-xylylene aldehyde were respectively dissolved in 80 mL of anhydrous ethanol to obtain a 3,3'-diaminobenzidine anhydrous ethanol solution and a p-xylylene aldehyde anhydrous ethanol suspension; 0.0930 g of ferrocene was dissolved in 10 mL of anhydrous ethanol to obtain a ferrocene anhydrous ethanol suspension;

[0051] (3) The carbon nanotube anhydrous ethanol suspension, the p-xylylene aldehyde anhydrous ethanol suspension, and the ferrocene anhydrous ethanol suspension were sequentially added to the 3,3'-diaminobenzidine anhydrous ethanol solution, and stirred at 45°C for 2 h;

[0052] (4) Filtration, washing with pure water and anhydrous ethanol, and drying at 70°C for 10 h to obtain a Schiff base organic porous polymer-ferrocene-carbon nanotube composite material in the form of a red powder.

[0053] Example 6

[0054] The ferrocene was 0.0930 g, the carbon nanotube was 0.0047 g, and the others were the same as in Example 2.

[0055] Example 7

[0056] The ferrocene was 0.2790 g, the carbon nanotube was 0.0139 g, and the others were the same as in Example 2.

[0057] Example 8

[0058] The ferrocene was 0.3720 g, the carbon nanotube was 0.0186 g, and the others were the same as in Example 2.

[0059] Example 9

[0060] The ferrocene was 0.4650 g, the carbon nanotube was 0.0232 g, and the others were the same as in Example 2.

[0061] Comparative Example 1

[0062] A method for preparing a Schiff base organic porous polymer, comprising the following steps:

[0063] (1) 0.5357 g of 3,3'-diaminobenzidine and 0.3353 g of p-xylylene aldehyde were respectively dissolved in 80 mL of anhydrous ethanol to obtain a 3,3'-diaminobenzidine anhydrous ethanol solution and a p-xylylene aldehyde anhydrous ethanol suspension;

[0064] (2) The p-xylylene aldehyde anhydrous ethanol suspension was added to the 3,3'-diaminobenzidine anhydrous ethanol solution, and stirred at 40°C for 3 h;

[0065] (3) Filtration, exchange washing with pure water and anhydrous ethanol, constant temperature drying at 60℃ for 12h, the obtained Schiff base organic porous polymer is a red powder.

[0066] Comparative Example 2

[0067] A preparation method of a Schiff base organic porous polymer, comprising the following steps:

[0068] (1) 0.5357g of 3,3'-diaminobenzidine and 0.3353g of p-phenylenedimethylene are respectively dissolved in 80mL of anhydrous ethanol to obtain a 3,3'-diaminobenzidine anhydrous ethanol solution and a p-phenylenedimethylene anhydrous ethanol suspension; 0.1860g of ferrocene is dissolved in 10mL of anhydrous ethanol to obtain a ferrocene anhydrous ethanol suspension;

[0069] (2) The p-phenylenedimethylene anhydrous ethanol suspension and the ferrocene anhydrous ethanol suspension are added to the 3,3'-diaminobenzidine anhydrous ethanol solution, and constant temperature stirring is carried out at 40℃ for 3h;

[0070] (3) Filtration, exchange washing with pure water and anhydrous ethanol, constant temperature drying at 60℃ for 12h, to obtain a Schiff base organic porous polymer-ferrocene composite material.

[0071] Performance detection

[0072] I. Scanning electron microscopy and transmission electron microscopy

[0073] The materials obtained in Examples 1-3, Comparative Example 1 and Comparative Example 2 are subjected to scanning electron microscopy, respectively as shown in Figures 1-5 ; it can be seen from Figure 4 that the structure of the single Schiff base conductive polymer is a cluster-like porous structure; after doping with ferrocene Figure 5 , and after doping with ferrocene and carbon nanotubes, it is still a porous material;

[0074] The materials obtained in Examples 1-3 and Comparative Example 1 are subjected to transmission electron microscopy, respectively as shown in Figures 6-9 ; it can be seen that the carbon nanotubes are uniformly embedded in the polymer structure, which can provide additional channels for electrolyte ion transmission and increase the mechanical strength of the polymer molecules at the nanometer level, reducing the destruction of the skeleton caused by the expansion and contraction of the structural units in the continuous charging and discharging process.

[0075] II. BET test

[0076] The materials obtained in Examples 1-3, Comparative Example 1 and Comparative Example 2 are respectively marked as SPOP-Fc 0.4 / CNTs-2, SPOP-Fc 0.4 / CNTs-5, SPOP-Fc 0.4 / CNTs-8, SPOP, SPOP-Fc 0.4 , and the results are shown in Table 1, and the nitrogen adsorption-desorption isotherm and pore size distribution are shown in Figure 10 , wherein the nitrogen adsorption-desorption isotherm is Figure 10 , and the pore size distribution is Figure 10 .

[0077] Table 1 BET test table of Schiff base polymer materials

[0078]

[0079] From Figure 10 and Table 1, the specific surface area and pore size distribution of the sample are studied by nitrogen adsorption-desorption isotherm, and the data calculated by BET can be obtained. The specific surface area of the undoped Schiff base polymer in Comparative Example 1 is 21.53 m 2 ·g –1 ; the specific surface area of the doped ferrocene in Comparative Example 2 is increased to 37.75 m 2 ·g –1 ; and after doping ferrocene and carbon nanotubes (Examples 1-3), the specific surface area of the Schiff base organic porous polymer-ferrocene-carbon nanotube composite material reaches 79.76 m 2 ·g –1 , which shows that the introduction of ferrocene and carbon nanotubes in the present application can significantly increase the specific surface area of the Schiff base organic porous polymer, and exhibit high porosity, which is due to the destruction of the π-π conjugated structure of the Schiff base polymer after the introduction of ferrocene and carbon nanotubes, making the polymer macromolecules tend to be disordered.

[0080] SPOP-Fc 0.4 / CNTs-8 and SPOP-Fc 0.4 Compared with the above, more carbon nanotubes are incorporated, and some pore walls collapse to make the pore size larger, and the specific surface area is reduced.

[0081] III. XRD and FT-IR

[0082] The materials obtained from Examples 1-3, Comparative Example 1 and Comparative Example 2 were subjected to XRD and FT-IR detection, and the results are shown in Figure 11 , wherein, Figure 11 Figure a in the above is an XRD spectrum, Figure 11 Figure b in the above is an FT-IR spectrum.

[0083] From Figure 11From the XRD pattern a, two broad peaks at 14.1° and 19.6° can be observed, which confirms that the synthesized nanocomposites have a certain degree of crystallinity. As expected, the XRD patterns of SPOP-Fc0.4 / CNTs-X (X = 2, 5, 8) show two distinct diffraction peaks at 23.5° and 43.7°, which are attributed to the typical (002) and (100) lattice diffraction peaks of CNTs, confirming that CNTs have been successfully introduced into the polymer.

[0084] From the XRD pattern a, two broad peaks at 14.1° and 19.6° can be observed, which confirms that the synthesized nanocomposites have a certain degree of crystallinity. As expected, the XRD patterns of SPOP-Fc0.4 / CNTs-X (X = 2, 5, 8) show two distinct diffraction peaks at 23.5° and 43.7°, which are attributed to the typical (002) and (100) lattice diffraction peaks of CNTs, confirming that CNTs have been successfully introduced into the polymer. Figure 11 From the XRD pattern b, a strong characteristic peak at 486 cm -1 in the spectra of SPOP-Fc0.4 / CNTs-X (X = 2, 5, 8) can be observed, which is due to the C-Fe stretching vibration of Fc (ferrocene), the adsorption peak at 827 cm -1 is from the non-planar mixed vibration of C-H bonds on the disubstituted ring, and peaks can be found at 1239, 1480 and 1685 cm -1 , which are attributed to the C-N stretching vibration on the aromatic hydrocarbon, the C=C skeleton vibration on the benzene ring and the C=O stretching vibration (from the -COOH on the surface of CNTs). Notably, the characteristic peak appearing at 1598 cm -1 is assigned to the amine bond (C=N) stretching vibration resulting from the condensation reaction of aldehyde groups and amino groups, confirming the successful synthesis of the Schiff base polymer.

[0085] IV. Electrochemical performance

[0086] The specific capacity of the electrode material was generally tested in a three-electrode system, and a two-electrode asymmetric supercapacitor hybrid device was assembled to evaluate the energy density performance.

[0087] In Comparative Example 1, the best specific capacity of the undoped Schiff base polymer at a current density of 0.5 A / g was 196.2 C / g, and the capacity retention rate at a high current density of 10 A / g was only 30.6%;

[0088] In Example 1, Example 3, and Comparative Example 2, the best specific capacities of the materials at a current density of 0.5 A / g were 456.3, 489.3, and 350.3 C / g, respectively, all of which were higher than that of the undoped Schiff base polymer material in Comparative Example 1;

[0089] The optimal specific capacity of the Schiff base organic porous polymer-ferrocene-carbon nanotube composite material in Example 2 is 724.7 C / g at a current density of 0.5 A / g, and the capacity retention rate at a high current density of 10 A / g is 60.7%. The energy density of the supercapacitor device assembled with the material in Example 2 as the positive electrode is 65.9 Wh / kg at a power density of 344.4 W / kg, and the initial specific capacity is retained by 73.6% after 5000 continuous charge-discharge cycles at a high current density of 10 A / g, as shown in Figure 12 ; wherein the supercapacitor device is a supercapacitor device with asymmetric dual electrodes with the Schiff base-ferrocene-carbon nanotube composite material provided in Example 2 as the positive electrode and activated carbon as the negative electrode;

[0090] The materials in Comparative Examples 1 and 2 have poor cycle performance at a high current density, and thus no further experiments were performed at 10 A / g.

[0091] In summary of the above experimental results, the Schiff base organic porous polymer-ferrocene-carbon nanotube composite material of the present application has excellent energy density and cycle performance as a supercapacitor positive electrode material. This is mainly attributed to the synergistic effect of ferrocene and carbon nanotubes in the Schiff base polymer skeleton. By introducing this organic compound with a central metal atom, the electroactive part of ferrocene exists in the polymer skeleton and porous structure, which can significantly improve the electrochemical performance of the prepared Schiff base-based polymer. In addition, when the carbon nanotubes with high specific surface area and high mechanical strength are introduced into the Schiff base polymer structure, more diffusion channels and active sites for electrolyte ions can be provided, thereby greatly improving the electrochemical performance of the Schiff base conductive polymer.

Claims

1. A method for preparing a Schiff base organic porous polymer-ferric- carbon nanotube composite material, characterized in that: The method comprises the following steps: (1) adding carbon nanotubes into anhydrous ethanol and performing ultrasonic treatment to obtain a carbon nanotube anhydrous ethanol suspension; (2) dissolving 3,3'-diaminobenzidine, p-xylylene formaldehyde and ferrocene in anhydrous ethanol respectively to obtain a 3,3'-diaminobenzidine anhydrous ethanol solution, a p-xylylene formaldehyde anhydrous ethanol suspension and a ferrocene anhydrous ethanol suspension; (3) sequentially adding the carbon nanotube anhydrous ethanol suspension, the p-xylylene formaldehyde anhydrous ethanol suspension and the ferrocene anhydrous ethanol suspension into the 3,3'-diaminobenzidine anhydrous ethanol solution and stirring at a constant temperature of 35-45°C for 2-4 hours; (4) performing suction filtration, washing with pure water and anhydrous ethanol and drying; The molar ratio of the 3,3'-diaminobenzidine, the p-xylylene formaldehyde and the ferrocene is 1:(0.5-2):(0.2-1), and the mass ratio of the carbon nanotubes to the ferrocene is 2-8%.

2. The method of preparing Schiff base organic porous polymer-ferrocene-carbon nanotube composite according to claim 1, characterized in that: The molar ratio of the 3,3'-diaminobenzidine, the p-xylylene formaldehyde and the ferrocene is 1:1:0.

4.

3. The method of preparing Schiff base organic porous polymer-ferrocene-carbon nanotube composite according to claim 2, characterized in that: The mass ratio of the carbon nanotubes to the ferrocene is 5%.

4. The method of preparing Schiff base organic porous polymer-ferrocene-carbon nanotube composite according to claim 1, characterized in that: The drying condition is drying at 50-70°C for 10-15 hours.

5. A Schiff base organic porous polymer-ferricene-carbon nanotube composite material, characterized in that: The carbon nanotube-ferrocene-3,3'-diaminobenzidine complex material is prepared by the preparation method of any one of claims 1-4.

6. Application of the Schiff base organic porous polymer-ferrocene-carbon nanotube composite material of claim 5 as a positive electrode material of a supercapacitor.

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