Preparation method of sulfonated polyaniline coated Prussian blue analogue derived ferromanganese oxide composite electrode

Abstract

The invention provides a preparation method of a sulfonated polyaniline coated Prussian blue analogue derived ferromanganese oxide composite electrode, which comprises the following steps: firstly, synthesizing novel sulfonated polyaniline (SPANi) through copolymerization of aniline and 2-aminobenzene sulfonic acid, so that a sulfonic acid group (-SO3H) is fixed on a PANi main chain to serve as a proton library to provide protons for PANi; the oxidation-reduction reaction is promoted; and the pseudocapacitance characteristic is enhanced. And then further carrying out in-situ polymerization on the SPANi on a manganese iron oxide (MFO) derived from a Prussian blue analogue, so as to prepare the conducting polymer encapsulated bimetallic oxide hollow nanocube composite material SPANi / MFO. Wherein the SPANi not only coats the surface of the MFO, but also fills the cavity of the MFO, and the mass ratio of the SPANi to the MFO is 1: (0.01-0.1). The composite electrode prepared by the invention has the advantages of high capacitance capacity and rate capability and long-term cycle stability, and solves the problem of continuous capacity loss of a conductive polymer-based electrode in the operation of a supercapacitor. According to the invention, the development and application of the functional nano material electrode coated with the conductive polymer for the supercapacitor can be promoted.

Description

Technical Field

[0001] This invention belongs to the fields of polymer chemistry and physics and supercapacitor electrodes, and relates to a composite electrode of sulfonated polyaniline coated with Prussian blue analogue-derived manganese iron oxide and its preparation method. Background Technology

[0002] A supercapacitor is an electrochemical energy storage device with high energy transfer efficiency and ultra-long cycle life. This type of energy storage device lies between batteries and traditional capacitors, possessing a much higher energy density than traditional capacitors and being more environmentally friendly than batteries, making it an important branch of electrochemical power sources. Supercapacitors have significant advantages over traditional batteries, such as fuel cells and chemical batteries. Their short lifespan, poor safety, tendency to cause chemical pollution, and high cost are fatal drawbacks hindering their large-scale application. Supercapacitors, with their superior characteristics of fast energy transfer, short charging time, high power, and long durability, can effectively address these shortcomings. The electrodes of a supercapacitor are one of its core components; currently, innovation in electrode materials and structural design are mainly used to improve the overall performance of supercapacitors. Summary of the Invention

[0003] The purpose of this invention is to provide a method for preparing a sulfonated polyaniline-coated Prussian blue analogue-derived manganese iron oxide composite electrode. This composite electrode has high capacitance and good electrochemical performance. The SPANi / MFO composite electrode, due to its superior structure, achieves high capacitance in 1Ag... -1 The following value is 597.06 F g. -1 It exhibits excellent specific capacitance, retaining up to 89.05% of its initial capacitance after 10,000 cycles, demonstrating good electrochemical stability. At the same time, the supercapacitor assembled with this electrode has good flexibility and pressure resistance. This invention first provides a sulfonated polyaniline-coated Prussian blue analogue-derived manganese iron oxide composite electrode, which comprises the following components by mass percentage: SPANi: 97% MFO: 3%

[0004] This invention also provides a method for preparing a sulfonated polyaniline-coated Prussian blue analog-derived manganese iron oxide composite electrode, comprising the following:

[0005] Step 1: Mix aniline and 2-aminobenzenesulfonic acid and bathe in an ice-water bath for 8 hours under acid and initiator conditions. Then, centrifuge the mixture to separate the layers, take the lower precipitate, wash it with deionized water, and dry it in a vacuum oven at 60°C to obtain sulfonated polyaniline (SPANi).

[0006] Step 2: MnSO4 H2O and K3[Fe(CN)6] were uniformly mixed in deionized water and ethanol and aged for 24 h to synthesize manganese iron Prussian blue. The resulting manganese iron oxide (MFO) was obtained by calcining at a constant temperature of 550℃ for 6 h.

[0007] Step 2: Mix the SPANi and MFO solutions evenly and react at 0℃ for 8 hours. Centrifuge the ultrasonicated mixture, collect the precipitate at the bottom, and dry it in a 60℃ vacuum oven.

[0008] Step 3: The obtained SPANi / MFO composite material is uniformly coated onto the surface of carbon paper and dried in a vacuum oven at 50°C to obtain the electrode of the composite supercapacitor. Preferably, the SPANi is prepared by solution polymerization under ice-water bath conditions, and the SPANi / MFO composite material is prepared by in-situ polymerization. The product obtained above is coated on the current collector to prepare a composite supercapacitor electrode. The preferred method for preparing a sulfonated polyaniline-coated Prussian blue analogue-derived manganese iron oxide composite electrode is characterized by controlling the ratio of SPANi and MFO to be 1:0.03. Attached Figure Description

[0009] Figure 1 Scanning electron microscope images of PBA, SPANi / PBA, MFO, and SPANi / MFO are shown; elemental distribution maps of SPANi / PBA and SPANi / MFO are also shown. Figure 2 The following figures show SPANi / MFO electrodes with different ratios at 100 mV s. -1 Lower CV curve, 1Ag -1 Comparison of GCD curve, EIS curve and specific capacitance. Figure 3 The figure shows the cycle stability and coulombic efficiency of the SPANi / MFO electrode after 10,000 cycles.

[0010] The technical solution of the present invention will be clearly and completely described below, and detailed implementation methods and specific operation processes will be given. It should be pointed out that researchers in this field can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

[0011] Example 1 includes the following steps:

[0012] The synthesis method of SPANi electrode is as follows: First, an acidic environment is prepared by adding 40 mL of 1M HCl solution to a 100 mL flask. Then, 1 mL of aniline monomer and 3% 2-aminobenzenesulfonic acid (ABA) molar ratio of aniline are added. Finally, 225 mg of ammonium persulfate is added as an initiator to initiate the polymerization reaction, which is carried out in an ice-water bath at 0 °C for 8 h. Subsequently, the mixed liquid is centrifuged to separate the layers. The lower precipitate is taken, washed several times, and dried to finally obtain dark green SPANi powder.

[0013] The preparation method of manganese-iron Prussian blue (Mn-Fe PBA) cubes is as follows: 300 mg of polyvinylpyrrolidone was dispersed in 20 mL of a 1:1 volume ratio mixture of deionized water and ethanol, and stirred for 30 min to form a homogeneous solution. Immediately, 45 mg of MnSO4H2O was added to the above solution, and stirring was continued until the mixture became transparent; this transparent mixture was referred to as solution A. Simultaneously, 66 mg of K3[Fe(CN)6] was dissolved in 10 mL of deionized water and stirred until homogeneous to prepare solution B. Then, solution B was added dropwise to solution A at a uniform rate over a short period of time, and the resulting mixture was stirred at room temperature for 30 min. Finally, the resulting mixture was centrifuged, washed several times with deionized water and ethanol, aged for 24 h, and dried in an oven at 60 °C for 12 h to obtain a dark brown solid powder.

[0014] The preparation method of hollow manganese iron oxide (MFO) cubes is as follows: the synthesized Mn-Fe PBA cubes are placed in a tube furnace and heated to 2℃ for 1 minute. -1 The heating rate was increased to 550℃, and the temperature was maintained at a constant calcination temperature for 6 hours, followed by a heating rate of 2℃ / min. -1 Annealing at a cooling rate yields the corresponding MFO.

[0015] The synthesis method of the SPANi / MFO composite electrode is as follows: In this work, SPANi was polymerized in situ on MFO to obtain the composite electrode. 6 mL of HCl solution, 1 mL of aniline monomer, and 3% ABA (aniline molar ratio) were added to 40 mL of deionized water and mixed uniformly to obtain solution A. Simultaneously, 1 wt%, 3 wt%, 5 wt%, and 10 wt% aniline MFO and 225 mg of ammonium persulfate were respectively added to 20 mL of deionized water and ultrasonically dispersed to obtain solution B. The two solutions were then mixed uniformly and stirred at 0℃ for 8 h, gradually turning into a dark green solution with a metallic luster. Based on the different qualities of MFO, they were named SPANi / MFO1, SPANi / MFO3, SPANi / MFO5, and SPANi / MFO. 10 .

[0016] 50 mg of SPANi / MFO powder, 6.25 mg of activated carbon, 6.25 mg of polyvinylidene fluoride, and 0.5 mL of N-methylpyrrolidone were sequentially added to a salt mortar and ground for 20 min to obtain a uniform paste. This paste was then coated onto graphite paper using a coating machine and dried at 50 °C for 15 h to form an electrode. The area of ​​the active material loaded on the electrode was 1*1 cm². 2 The average mass is 1.5 mg, which is coated on the current collector to prepare a composite supercapacitor electrode.

[0017] In-situ prepared SPANi / MFO3 composite material in 1Ag -1 The following value is 597.06 F g. -1 It exhibits excellent specific capacitance, which is 76.64% higher than that of pure PANI. After 10,000 cycles, it retains a high capacitance retention of 89.05%, making this composite electrode suitable for use in supercapacitors.

Claims

1. A method for preparing a sulfonated polyaniline-coated Prussian blue analogue-derived manganese iron oxide composite electrode, characterized in that, A novel sulfonated polyaniline (SPANi) is formed by copolymerizing aniline with 2-aminobenzenesulfonic acid. Then, SPANi / MFO composite electrodes are synthesized by in-situ growth of SPANi on manganese iron oxide (MFO). The invention is further described in detail below with reference to specific examples:

1. The synthesis method of SPANi electrode is as follows: First, an acidic environment is prepared by adding 40 mL of 1M HCl solution to a 100 mL flask. Then, 1 mL of aniline monomer and 3% 2-aminobenzenesulfonic acid (ABA) are added. Finally, 225 mg of ammonium persulfate is added as an initiator to initiate the polymerization reaction. The reaction is carried out in an ice-water bath at 0 °C for 8 h. Subsequently, the mixed liquid is centrifuged to separate the layers. The lower precipitate is taken, washed several times, and dried to finally obtain dark green SPANi powder.

2. The preparation method of manganese-iron Prussian blue (Mn-Fe PBA) cubes is as follows: 300 mg of polyvinylpyrrolidone is dispersed in 20 mL of a 1:1 volume ratio mixture of deionized water and ethanol, and stirred for 30 min to form a homogeneous solution. Immediately, 45 mg of MnSO4 H2O is added to the above solution, and stirring is continued until the mixture becomes transparent; this transparent mixture is referred to as solution A. Simultaneously, 66 mg of K3[Fe(CN)6] is dissolved in 10 mL of deionized water and stirred until homogeneous to prepare solution B. Then, solution B is added dropwise to solution A at a uniform rate over a short period of time, and the resulting mixture is stirred at room temperature for 30 min. Finally, the resulting mixture is centrifuged, washed several times with deionized water and ethanol, aged for 24 h, and dried in an oven at 60 °C for 12 h to obtain a dark brown solid powder.

3. The preparation method of hollow manganese iron oxide (MFO) cubes is as follows: the synthesized Mn-Fe PBA cubes are placed in a tube furnace and heated to 2℃ for 1 minute. -1 The heating rate was increased to 550℃, and the temperature was maintained at a constant calcination temperature for 6 hours, followed by a heating rate of 2℃ / min. -1 Annealing at a cooling rate yields the corresponding MFO.

4. The synthesis method of the SPANi / MFO composite electrode is as follows: In this work, the composite electrode was prepared by in-situ polymerization of SPANi on MFO. 6 mL of HCl solution, 1 mL of aniline monomer, and 3% ABA (aniline molar ratio) were added to 40 mL of deionized water and mixed thoroughly to form solution A. Simultaneously, 1 wt%, 3 wt%, 5 wt%, and 10 wt% MFO (aniline by mass ratio) and 225 mg of ammonium persulfate were added to 20 mL of deionized water and ultrasonically dispersed to form solution B. The two solutions were then mixed thoroughly and stirred at 0℃ for 8 hours, gradually turning into a dark green solution with a metallic luster. Based on the different qualities of MFO, we name them SPANi / MFO1, SPANi / MFO3, SPANi / MFO5, and SPANi / MFO. 10 .

5. Add 50 mg of SPANi / MFO powder, 6.25 mg of activated carbon, 6.25 mg of polyvinylidene fluoride, and 0.5 mL of N-methylpyrrolidone to a salt mortar and grind for 20 min to obtain a uniform paste. Coat the paste onto graphite paper using a coating machine and dry at 50 °C for 15 h to form an electrode. The area of ​​the active material loaded on the electrode is 1*1cm. 2 The average mass is 1.5 mg, which is coated on the current collector to prepare a composite supercapacitor electrode.

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