A poly-Schiff base-nickelocene composite material and its preparation method and application

Abstract

The present invention discloses a preparation method of a poly-Schiff base-nickelocene composite material, comprising the following steps: (1) respectively adding 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde, and nickelocene to anhydrous ethanol to form an anhydrous ethanol solution of 3,3'-diaminobenzidine, an anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde, and an anhydrous ethanol solution of nickelocene; (2) adding the anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde to the anhydrous ethanol solution of 3,3'-diaminobenzidine, adding the anhydrous ethanol solution of nickelocene thereto before generating a precipitate, and stirring for 5-6 hours; (3) filtering by suction, washing with anhydrous ethanol, and drying the obtained precipitate to obtain the poly-Schiff base-nickelocene composite material. The poly-Schiff base-nickelocene composite material prepared by the present invention has a large specific surface area, good electrical conductivity and chemical stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of synthetic methods of organic materials, and in particular relates to a poly-Schiff base-nickelocene composite material, a preparation method and applications thereof. Background Art

[0002] Schiff bases are nitrogen-containing polymers usually formed by the condensation reaction of a carbonyl functional group (aldehyde or ketone) with a primary amine to form a highly stable C=N double bond (bond energy of about 615 kJ mol -1 The Schiff base condensation reaction is widely used in chemistry and biology due to its mild reaction conditions and high reaction rate. The nitrogen element in the Schiff base can coordinate with transition metal organic compounds. However, the dense packing of conjugated molecular chains of a single Schiff base polymer via π-π bonds results in a limited number of ion diffusion channels and redox active sites, resulting in electrochemical performance that cannot reach theoretical values. Summary of the Invention

[0003] The present invention provides a poly-Schiff base-nickelocene composite material having excellent electrochemical properties, and also provides a preparation method thereof and application thereof as an electrode material.

[0004] A method for preparing a poly-Schiff base-nickelocene composite material comprises the following steps:

[0005] (1) 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde, and nickelocene are added to anhydrous ethanol to form an anhydrous ethanol solution of 3,3'-diaminobenzidine, an anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde, and an anhydrous ethanol solution of nickelocene;

[0006] (2) Add the anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde to the anhydrous ethanol solution of 3,3'-diaminobenzidine, and add the anhydrous ethanol solution of nickelocene before forming a precipitate, and stir for 5-6 hours;

[0007] (3) Filtering, washing with anhydrous ethanol, and drying the obtained precipitate to obtain a poly-Schiff base-nickelocene composite material.

[0008] Preferably, the molar ratio of the 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde and nickelocene is 1:(0.5-2):(0.5-1.2).

[0009] Preferably, the molar ratio of the 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde and nickelocene is 1:1:0.8.

[0010] Preferably, the drying condition is drying at 50-70° C. for 10-16 hours.

[0011] A poly-Schiff base-nickelocene composite material is prepared by the preparation method of the invention.

[0012] The polySchiff base-nickelocene composite material of the present invention is used as a supercapacitor electrode material.

[0013] Advantages of the present invention:

[0014] (1) The poly-Schiff base-nickelocene composite material prepared by the present invention has a large specific surface area, good electrical conductivity and chemical stability;

[0015] (2) The present invention utilizes a simple condensation reaction to synthesize a highly conjugated poly-Schiff base material; nickelocene, as an electroactive organometallic compound, enters the molecular chain of the Schiff base polymer to destroy the polymer skeleton, thereby exhibiting a highly porous structure. It acts on the Schiff base to weaken the π-π conjugation effect within the polymer, from the millimeter-scale pore size of the current collector nickel foam to the micron-scale pore size formed by the molecular doping skeleton of nickelocene, thereby providing more ion active diffusion sites to further improve the electrochemical performance;

[0016] (3) When the polySchiff base-nickelocene composite material provided by the present invention is used as an electrode material for a supercapacitor, compared with the three types of electrode materials commonly used in supercapacitors (carbon-based materials, transition metal oxides, and conductive polymers), the polySchiff base has the advantages of good reversibility, high thermal stability, wide potential window, and high electronic conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a scanning electron microscope image of Comparative Example 1;

[0018] Figure 2 is a scanning electron microscope image of Example 1;

[0019] Figure 3 This is a scanning electron microscope image of Example 2;

[0020] Figure 4 This is a scanning electron microscope image of Example 3;

[0021] Figure 5 This is a scanning electron microscope image of Example 4;

[0022] Figure 6 This is the FT-IR infrared spectrum test diagram of poly Schiff base-nickelocene;

[0023] Figure 7 CV graphs of Comparative Example 1 at different scan rates;

[0024] Figure 8 The GCD diagrams of Comparative Example 1 at different scan rates are shown;

[0025] Figure 9 CV curves at different specific currents;

[0026] Figure 10 is the GCD diagram at a scan rate of 0.5 A / g;

[0027] Figure 11 is the specific capacity of the material when the current density increases from 0.5A / g to 10A / g;

[0028] Figure 12 is the GCD cycle diagram of the composite material. DETAILED DESCRIPTION

[0029] Example 1

[0030] A method for preparing a poly-Schiff base-nickelocene composite material comprises the following steps:

[0031] (1) 1.07 g of 3,3'-diaminobenzidine, 1.05 g of 4,4'-biphenyldicarboxaldehyde, and 0.94 g of nickelocene were added to 100 mL of anhydrous ethanol to form an anhydrous ethanol solution of 3,3'-diaminobenzidine, an anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde, and an anhydrous ethanol solution of nickelocene;

[0032] (2) Add the anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde to the anhydrous ethanol solution of 3,3'-diaminobenzidine, and add the anhydrous ethanol solution of nickelocene before forming a precipitate, and stir for 5 hours;

[0033] (3) Filter and wash with anhydrous ethanol, and dry the obtained precipitate at 60 ° C for 12 h to obtain a poly Schiff base-nickelocene composite material, referred to as Ni 1.0 -BDDB.

[0034] Example 2

[0035] Take 1.13g of nickelocene, that is, the molar ratio of 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde, and nickelocene is 1:1:1.2, and the other parts are the same as in Example 1. The obtained composite material is referred to as Ni 1.2 -BDDB.

[0036] Example 3

[0037] Take 0.752g of nickelocene, that is, the molar ratio of 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde, and nickelocene is 1:1:0.8, and the other parts are the same as in Example 1. The obtained composite material is referred to as Ni 0.8 -BDDB.

[0038] Example 4

[0039] Take 0.47g of nickelocene, that is, the molar ratio of 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde, and nickelocene is 1:1:0.5, and the other parts are the same as in Example 1. The obtained composite material is referred to as Ni 0.5 -BDDB.

[0040] Example 5

[0041] A method for preparing a poly-Schiff base-nickelocene composite material comprises the following steps:

[0042] (1) 1.07 g of 3,3'-diaminobenzidine, 2.1 g of 4,4'-biphenyldicarboxaldehyde, and 0.94 g of nickelocene were added to 100 mL of anhydrous ethanol to form an anhydrous ethanol solution of 3,3'-diaminobenzidine, an anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde, and an anhydrous ethanol solution of nickelocene;

[0043] (2) Add the anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde to the anhydrous ethanol solution of 3,3'-diaminobenzidine, and add the anhydrous ethanol solution of nickelocene before forming a precipitate, and stir for 6 hours;

[0044] (3) Filter and wash with anhydrous ethanol, and dry the obtained precipitate at 50°C for 16 hours to obtain a poly-Schiff base-nickelocene composite material.

[0045] Example 6

[0046] A method for preparing a poly-Schiff base-nickelocene composite material comprises the following steps:

[0047] (1) 1.07 g of 3,3'-diaminobenzidine, 0.525 g of 4,4'-biphenyldicarboxaldehyde, and 0.57 g of nickelocene were added to 100 mL of anhydrous ethanol to form an anhydrous ethanol solution of 3,3'-diaminobenzidine, an anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde, and an anhydrous ethanol solution of nickelocene;

[0048] (2) Add the anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde to the anhydrous ethanol solution of 3,3'-diaminobenzidine, and add the anhydrous ethanol solution of nickelocene before forming a precipitate, and stir for 5 hours;

[0049] (3) Filter and wash with anhydrous ethanol, and dry the obtained precipitate at 70°C for 10 h to obtain a poly-Schiff base-nickelocene composite material.

[0050] Comparative Example 1

[0051] A method for preparing a poly Schiff base comprises the following steps:

[0052] (1) 1.07 g of 3,3'-diaminobenzidine and 1.05 g of 4,4'-biphenyldicarboxaldehyde were added to 100 mL of anhydrous ethanol to form an anhydrous ethanol solution of 3,3'-diaminobenzidine and an anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde;

[0053] (2) Add the anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde to the anhydrous ethanol solution of 3,3'-diaminobenzidine and stir for 5 hours;

[0054] (3) Filter and wash with anhydrous ethanol, and dry the obtained precipitate at 60°C for 12 h to obtain poly-Schiff base material, referred to as BDDB.

[0055] Performance testing

[0056] 1. Scanning Electron Microscopy

[0057] The materials obtained from Comparative Example 1 and Examples 1-4 were subjected to scanning electron microscopy, and the results were shown in Table 1. Figure 1-Figure 5 .Depend on Figure 1 It can be seen that the undoped nickelocene poly-Schiff base material BDDB has a smooth spherical surface and a clear spherical structure; Figure 2-5 It can be seen that with the doping of different proportions of nickelocene, the morphology of the composite material has changed significantly, evolving from a spherical particle morphology to a lamellar structure.

[0058] 2. FT-IR infrared spectrum test

[0059] The poly-Schiff base-nickelocene composite materials of Examples 1-4 were tested by infrared spectroscopy. Figure 6 As shown. Figure 6 It can be seen that at 1490, 1278 and 1170 cm -1 The peaks at 1620 cm-1 come from the skeleton vibration C=C in the benzene ring, the bending vibration of the planar CH, and the stretching vibration of CN in the aromatic hydrocarbon. More importantly, the characteristic peak of the C=N bond in BDDB appears at 1620 cm-1. -1 This confirms that the Schiff base polymer has been successfully synthesized. 1.2 -BDDB、Ni 1.0 -BDDB、Ni 0.8 The characteristic peaks of the C=N bond of -BDDB and Ni0.5-BDDB are slightly shifted compared with BDDB, indicating that different proportions of nickelocene doping will affect the vibration of the C=N bond.

[0060] 3. Electrochemical performance test

[0061] 1. In order to study the charge storage performance of the electrode material BDDB, cyclic voltammetry (CV) and constant current charge-discharge (GCD) tests were carried out in a 6M KOH electrolyte three-electrode system. The characteristic curves obtained are as follows: Figure 7 and Figure 8 shown.

[0062] Figure 7 The CV curves of the BDDB electrode at different scan rates are shown. These curves have similar redox peaks. As the scan rate increases, the CV curves do not show polarization, indicating that the BDDB electrode has good rate performance at high scan rates.

[0063] Figure 8 The GCD curves of BDDB at different current densities in the potential window (0-0.5 V) are shown. Each curve has a clear platform, indicating that the redox reaction has good reversibility during charge and discharge, which is consistent with the CV analysis results.

[0064] 2. To study the electrode materials BDDB, Ni 1.2 BDDB, Ni 1.0 -BDDB、Ni 0.8 -BDDB、Ni 0.5 The charge storage performance of BDDB was tested by CV and GCD at a fixed cyclic voltammetry scan rate (10 mV / s) and constant current charge and discharge current density (0.5 A / g). The characteristic curves obtained were as follows: Figure 9-11 shown.

[0065] Figure 9 The CV curves of BDDB and Nix-BDDBs (X = 1.2, 1.0.8 and 0.5) in the potential window of 0 ~ 0.8V are shown. It can be seen that the CV curves of these electrode materials are composed of a pair of obvious redox current peaks. At the same scan rate (10 mV / s), Ni 0.8 -BDDB's redox current is higher than that of other electrodes, and its CV integral area is larger than that of other electrodes, indicating that Ni 0.8 -BDDB electrodes have a larger capacitance.

[0066] Figure 10 It also shows that at a scan rate of 0.5 A / g, the charge and discharge time on the GCD curve is almost symmetrical, indicating that the relevant reaction is reversible. The longer the charge and discharge time of the electrode material, the stronger the charge storage capacity of the electrode material. Figure 10 It can be seen that after doping with nickelocene, the charge storage capacity of Nix-BDDBs (X = 1.2, 1.0.8 and 0.5) is enhanced.

[0067] Figure 11 The results show that as the current density increases from 0.5 A / g to 10 A / g, the specific capacity of the material decays at different rates. This is because at lower scan rates, ions can reach all active material interiors, resulting in greater utilization of the electrode active material. At higher current densities, the diffusion time of electrolyte ions entering the electroactive sites and participating in the redox reaction is shortened, resulting in lower utilization of the electrode active material. Nix-BDDBs (X = 1.2, 1.0.8, and 0.5) exhibit significantly improved specific capacitance and rate performance compared to BDDB.

[0068] 3. By Figure 11 It can be seen that the specific capacitance of BDDB is low, so the next cycle performance experiment was not carried out;

[0069] In order to study Ni 0.8 - Cycling stability of BDDB electrode, long-term GCD cycling experiment was conducted, see Figure 12 .like Figure 12 Shows Ni 0.8 - Cycle stability of BDDB electrode after 5000 GCD cycles. Generally speaking, it is difficult for electrode materials to have both ultra-high specific capacity and long-term cycle stability, because when most atoms participate in the electrochemical reaction, the structure of the electrode material is more likely to collapse. At higher current density, Ni 0.8 -BDDB electrode can still maintain about 62.1% of its specific capacity after long-term cycling, and its Coulombic efficiency is close to 100%, proving that Ni 0.8 -BDDB electrode has good electrochemical stability and cycling stability.

Claims

1. A method for preparing a poly-Schiff base-nickelocene composite material, characterized in that: The following steps are involved: (1) 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde, and nickelocene are added to anhydrous ethanol to form an anhydrous ethanol solution of 3,3'-diaminobenzidine, an anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde, and an anhydrous ethanol solution of nickelocene; (2) Add the anhydrous ethanol suspension of 4,4'-biphenyldicarboxaldehyde to the anhydrous ethanol solution of 3,3'-diaminobenzidine, and add the anhydrous ethanol solution of nickelocene before forming a precipitate, and stir for 5-6 hours; (3) Filtering, washing with anhydrous ethanol, and drying the obtained precipitate to obtain a poly-Schiff base-nickelocene composite material.

2. The method for preparing the poly-Schiff base-nickelocene composite material according to claim 1, wherein: The molar ratio of the 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde and nickelocene is 1:(0.5-2):(0.5-1.2).

3. The method for preparing the poly-Schiff base-nickelocene composite material according to claim 2, wherein: The molar ratio of the 3,3'-diaminobenzidine, 4,4'-biphenyldicarboxaldehyde and nickelocene is 1:1:0.

8.

4. The method for preparing the poly-Schiff base-nickelocene composite material according to claim 1, wherein: The drying condition is to dry at 50-70° C. for 10-16 hours.

5. A poly-Schiff base-nickelocene composite material, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the polySchiff base-nickelocene composite material according to claim 5 as a supercapacitor electrode material.

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