Conductive polymer / ZIF-based composite material as well as preparation method and application thereof

Abstract

The invention belongs to the field of flow batteries, and particularly relates to a conductive polymer / ZIF-based composite material and a preparation method and application thereof. According to the preparation method, Ag-coated ZIF-8 is prepared through coordination of zinc ions and 2-methylimidazole, then Ag-coated ZIF-8 is converted into Ag-coated Zn-LDH through in-situ ion etching, 3, 4-ethylenedioxythiophene (EDOT) is taken as a monomer, the Ag-coated Zn-LDH is converted into conductive PEDOT composite Ag-coated Zn-LDH, the conductive PEDOT composite Ag-coated Zn-LDH is loaded on the surface of a carbon felt, and the modified carbon felt is taken as a flow battery electrode. The conductivity and electrocatalytic property of the electrode can be improved, so that the activity of the electrode is improved, excellent charge-discharge performance and stability are kept, and the problems of low conductivity, low electrochemical activity, low working efficiency of the whole single battery and the like of a carbon felt electrode are solved.

Description

Technical Field

[0001] The invention belongs to the field of liquid flow batteries, and in particular relates to a conductive polymer / ZIF composite material and a preparation method and application thereof. Background Art

[0002] A flow battery is a battery that separates the positive and negative electrolytes. The electrolyte is brought into the battery by a circulation pump for circulation. Energy is stored in the electrolyte during charging and released during discharge. It has the advantages of large energy storage, safety, and high efficiency. The electrode materials used in zinc-bromine flow batteries are generally carbon electrodes. Because the bromine in the electrolyte is highly corrosive, using other electrode materials and soaking in the solution for a long time will cause fatigue of the electrode material and damage quickly. Carbon electrodes have the advantages of high degree of graphitization, high temperature resistance, corrosion resistance, and good mechanical properties, which can meet the use of zinc-bromine flow batteries.

[0003] As one of the indispensable components of energy storage batteries, electrode materials play an important role in loading and depositing zinc, although they do not directly participate in the redox reaction. The physical and chemical properties of their surface greatly affect the quality and quantity of deposited zinc. In recent years, carbon-based materials such as graphite felt and conductive plastics have been widely used in electrodes of flow batteries due to their low cost and excellent chemical and thermal stability. However, the uneven current distribution of graphite felt leads to low utilization of metal electroplating, while the conductive plastic plate needs to retain a gap between the plate and the diaphragm for zinc deposition, but this increases the size of the battery stack to meet energy storage requirements. Summary of the invention

[0004] The object of the present invention is to provide a conductive polymer / ZIF composite material and a preparation method and application thereof, which can effectively improve the uniformity of current distribution, thereby reducing the zinc protrusions or zinc dendrites that may occur in zinc deposition.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a method for preparing a conductive polymer / ZIF composite material, comprising the following steps: S1: dissolving polyvinyl pyrrolidone and sodium chloride in ethylene glycol to form solution A; dissolving silver nitrate in ethylene glycol to form solution B; mixing solution A and solution B evenly, heating under high pressure for reaction and then cooling naturally to obtain silver nanowires, dispersing the silver nanowires in a methanol solution to obtain a silver nanowire solution; S2: Dissolve 2-methylimidazole in methanol, add silver nanowire solution to form solution C, dissolve zinc nitrate in methanol to form solution D, add solution D to solution C and stir to react, collect the precipitated product Ag@ZIF-8 by centrifugation; wash Ag@ZIF-8 with methanol and ethanol respectively, disperse it in methanol after washing, and stir it evenly with the methanol solution containing zinc nitrate to obtain a first mixed solution; heat the first mixed solution under high pressure to react, and then cool it naturally to obtain product E; collect product E by centrifugation and wash it with ethanol to obtain Ag@Zn-LDH; S3: Ag@Zn-LDH and 3,4-ethylenedioxythiophene monomer are dispersed in hydrochloric acid solution respectively, and a second mixed solution is obtained after mixing, and an ammonium persulfate solution is added to the second mixed solution; after heating and stirring, the product PEDOT / Ag@Zn-LDH is obtained by centrifugation.

[0006] Preferably, the mass ratio of polyvinyl pyrrolidone to sodium chloride in S1 is 1000:(1-2); the concentration of solution B in S1 is 0.1-0.3 mol / L, and the volume ratio of solution A to solution B is 1:(1-3).

[0007] Preferably, the concentration of solution C in S2 is 0.1~1 mol / L; the concentration of solution D is 0.02~0.2 mol / L, and the volume ratio of solution C to solution D is (1~2):1.

[0008] Preferably, the mass ratio of Ag@Zn-LDH and 3,4-ethylenedioxythiophene monomer in S3 is 1:(0.1~0.2).

[0009] Preferably, the pH of the hydrochloric acid solution in S3 is 2-4.

[0010] Preferably, the concentration of the ammonium persulfate solution in S3 is 10-20 wt %, and the volume ratio of the ammonium persulfate solution to the second mixed solution is (1-3):1.

[0011] Preferably, the conditions for the heating reaction under high pressure are: heating at 100-200° C. for 2-4 hours.

[0012] Preferably, the heating and stirring conditions in S3 are: stirring at 50-80° C. for 4-8 h.

[0013] In a second aspect, the present invention provides a conductive polymer / ZIF composite material prepared by the above preparation method.

[0014] In a third aspect, the present invention provides an application of a conductive polymer / ZIF composite material in the field of liquid flow batteries.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The silver nanowires prepared by using polyvinyl pyrrolidone, sodium chloride, silver nitrate and ethylene glycol as raw materials have excellent conductivity and low surface resistance, can provide more stable nucleation sites for zinc atoms, and effectively reduce Zn 2+ The nucleation overpotential of ZIF-8 can achieve the stable deposition and stripping of zinc, improve the Coulomb efficiency, and have relatively stable chemical properties, which are not easily corroded by bromine water. The metal organic framework (ZIF-8) formed by the self-assembly of zinc ions and 2-methylimidazole ligands through coordination bonds has rich metal-ligand coordination modes, adjustable porosity, large specific surface area and more active sites. The present invention forms Ag@ZIF-8 by combining ZIF-8 with silver nanowires, so that the excellent conductivity and unique surface plasmon effect of silver nanowires can improve the short board of poor conductivity of single-component metal organic framework, thereby significantly reducing the nucleation overpotential of zinc and extending the service life of the battery. PEDOT conductive polymer has a conjugated structure, which can support the migration of carriers therein. Conductive polymers with porous or fibrous structures have a high specific surface area, which provides a large number of active sites for zinc deposition reaction. Zinc deposition is significantly regulated, which provides an important development direction for the commercialization of zinc-bromine liquid flow battery stacks with high energy density and long cycle life. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 This is a battery cycle performance diagram of Example 1 of the present invention; Figure 2 This is a battery efficiency performance diagram of Example 1 of the present invention. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0019] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0020] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0021] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0022] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0023] The first object of the present invention is to provide a method for preparing a conductive polymer / ZIF composite material, comprising the following steps: S1: Dissolve polyvinyl pyrrolidone (PVP) and sodium chloride (NaCl) in ethylene glycol to form solution A; 3 ) is dissolved in ethylene glycol to form solution B; solution A and solution B are mixed and stirred evenly, heated at 100-200° C. for reaction for 2-4 hours and then naturally cooled to obtain silver nanowires, and the silver nanowires are dispersed in a methanol solution to obtain a silver nanowire solution; S2: Dissolve 2-methylimidazole in methanol, add the silver nanowire solution to form solution C, and add zinc nitrate (Zn(NO 3 ) 2 6H 2 O) was dissolved in methanol to form solution D, solution D was added to solution C and stirred for 10-30 min to react, and the precipitated product Ag@ZIF-8 was collected by centrifugation; Ag@ZIF-8 was washed with methanol and ethanol respectively, dispersed in methanol after washing, and stirred evenly with a methanol solution containing zinc nitrate to obtain a first mixed solution; the first mixed solution was heated at 100-200°C for 2-4 h and then naturally cooled to obtain product E; product E was collected by centrifugation and washed with ethanol to obtain Ag@Zn-LDH; S3: Ag@Zn-LDH and 3,4-ethylenedioxythiophene (EDOT) monomers were dispersed in hydrochloric acid solution respectively, and mixed to obtain a second mixed solution. 4 ) 2 S 2 O 8 ) solution was added to the second mixed solution; after stirring at 50-80°C for 4-8h, the product PEDOT / Ag@Zn-LDH was obtained by centrifugation.

[0024] The present invention prepares Ag@ZIF-8 by coordinating zinc ions and 2-methylimidazole, and then converts Ag@ZIF-8 into Ag@Zn-LDH by in-situ ion etching, and converts it into conductive PEDOT composite Ag@Zn-LDH by using 3,4-ethylenedioxythiophene (EDOT) as a monomer. Among them, PVP, as a polymer compound, acts as a stabilizer and dispersant during the synthesis process to help control the growth morphology of silver nanowires and prevent the silver nanowires from aggregating during the synthesis process, thereby maintaining their dispersibility and morphology. NaCl acts as an ion source in the solution and participates in the growth process of silver nanowires. It affects the reduction of silver ions and the formation of silver nanowires during the reaction process by introducing chloride ions. AgNO 3 It is the source material for synthesizing silver nanowires. Under heating conditions, silver ions (Ag⁺) will be reduced to silver metal and form silver nanowires. Ethylene glycol, as a solvent, can dissolve substances such as PVP, sodium chloride and silver nitrate, providing a suitable reaction medium. In addition, ethylene glycol also has a certain reducing property at high temperatures, which can have a certain effect on the synthesis process of silver nanowires. 2-Methylimidazole acts as a ligand in this reaction and forms a coordination complex with zinc ions, which can help stabilize zinc ions in the solution and promote the reaction between zinc ions and the surface of silver nanowires to form Ag@ZIF-8 complexes. Zn(NO 3 ) 2 6H 2O is a zinc source, which reacts with 2-methylimidazole to form a zinc-imidazole coordination compound, thereby forming a ZIF-8 structure. Methanol is used as a solvent to dissolve 2-methylimidazole, zinc nitrate and silver nanowires, and as a solvent to promote the interaction between substances during the reaction. Ethanol is used to wash the product obtained in the reaction, helping to remove the solvent and unreacted raw materials, and ensuring the purity and quality of the reaction product. Ag@ZIF-8 is a composite material composed of silver nanowires and ZIF-8 (zinc-imidazole framework structure), which combines the conductivity of silver nanowires and the porous properties of ZIF-8, providing a good substrate for subsequent conductive polymer composites. Ag@ZIF-8 is converted into Ag@Zn-LDH by in-situ ion etching. Zinc layered double hydroxide (LDH) has good ion exchange and conductivity properties, and its composite with silver nanowires makes the material have potential in electron transport and electrochemical reactions. EDOT is a common conductive polymer monomer, which forms PEDOT (poly (3,4-ethylenedioxythiophene)) through polymerization. In the present invention, EDOT plays a role in forming a conductive polymer film on the surface of Ag@Zn-LDH, thereby enhancing the conductivity of the composite material. Ammonium persulfate is used as an oxidant to start the polymerization reaction of EDOT monomers, and can effectively catalyze EDOT polymerization to form a conductive PEDOT polymer, thereby introducing conductivity into the Ag@Zn-LDH material.

[0025] The mass ratio of polyvinyl pyrrolidone and sodium chloride in S1 is 1000:(1~2), which helps to adjust the viscosity and stability of the solution and prevent the precipitation or uneven distribution of particles in the solution; the concentration of solution B in S1 is 0.1~0.3 mol / L, and the volume ratio of solution A to solution B is 1:(1~3), which can ensure that the composition of the mixed solution meets the requirements of the reaction and improve the efficiency of the reaction.

[0026] The concentration of solution C in S2 is 0.1~1 mol / L; the concentration of solution D is 0.02~0.2 mol / L, and the volume ratio of solution C to solution D is (1~2):1, which helps to control the reaction rate and the quality of the generated product.

[0027] The mass ratio of Ag@Zn-LDH and 3,4-ethylenedioxythiophene monomer described in S3 is 1:(0.1~0.2), which helps to control the composition of the composite material and ensure the optimization of the ratio between Ag@Zn-LDH and 3,4-ethylenedioxythiophene monomer. Too high ethylenedioxythiophene monomer may cause unnecessary side reactions or degradation of material performance.

[0028] The pH of the hydrochloric acid solution in S3 is 2-4, which helps to promote certain reactions and avoid hydrolysis or precipitation of metal ions in the solution, thereby ensuring the smooth progress of the reaction and improving the purity and quality of the product.

[0029] The concentration of the ammonium persulfate solution in S3 is 10-20wt%, and the volume ratio of the ammonium persulfate solution to the second mixed solution is (1-3): 1. As an oxidant, ammonium persulfate can effectively promote polymerization or other chemical reactions. This concentration and volume ratio help to provide sufficient reaction activity without excessively consuming the oxidant, thereby ensuring the controllability of the reaction process.

[0030] The second purpose of the present invention is to provide a conductive polymer / ZIF composite material, which uses a metal organic framework molecule (ZIF-8) as a sacrificial template to prepare its derivatives as electrode materials for flow batteries. The ZIF-8 molecular structure has a large surface area, a uniform pore structure, and the presence of metal ions and organic ligands, making them ideal for synthesizing metal oxides and nanoporous carbon; at the same time, ZIF-8 contains zinc and can be thermally decomposed into zinc compounds and nanoporous carbon while retaining the original morphology and porous structure of ZIF.

[0031] The third object of the present invention is to provide an application based on a conductive polymer / ZIF composite material, wherein the PEDOT / Ag@Zn-LDH is used for carbon felt modification.

[0032] Specifically, the present invention loads PEDOT on carbon felt. Based on the π-π stacking effect of the π-electron delocalization structure of the conjugated thiophene ring in PEDOT and the conjugated large π bond of carbon, the degree of polymer aggregation can be significantly reduced, thereby obtaining a uniformly coated composite material. The synergistic effect between the two can also make it exhibit properties that are superior to those of a single component. The electronic effect of Zn and PEDOT can stabilize and evenly distribute zinc deposition, effectively prevent the aggregation of zinc deposition, and avoid the problem of diaphragm penetration caused by the formation of zinc dendrites. Therefore, combining the three together can not only have the single properties of each material, but also make up for the defects of a single component, thereby extending the service life of the battery and improving the application safety of the battery.

[0033] The present invention uses the modified carbon felt as a liquid flow battery electrode, which can improve the electrical conductivity and electrocatalytic property of the electrode, thereby improving the activity of the electrode and maintaining excellent charge and discharge performance and stability, thereby solving the problems of low electrical conductivity, low electrochemical activity and low working efficiency of the entire single cell of the carbon felt electrode, while extending the service life of the battery and improving the application safety of the battery.

[0034] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0035] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0036] Example 1 Step 1: Dissolve 100g PVP and 0.1g NaCl in ethylene glycol to form solution A. 3 Dissolve in ethylene glycol to form a solution B with a concentration of 0.2 mol / L. Mix solution A and solution B in a volume ratio of 1:1 and stir evenly, then transfer to a high-pressure reactor and heat at 160 o C for 3 h, and naturally cooled after the reaction was completed, and the obtained silver nanowires were dispersed in a methanol solution to obtain a silver nanowire solution.

[0037] Step 2: Dissolve 2-methylimidazole in methanol, add the silver nanowire solution to form a solution C with a concentration of 0.5 mol / L, and then add Zn(NO 3 ) 2 6H 2 O was dissolved in methanol to form a solution D with a concentration of 0.1 mol / L. Solution D was quickly poured into solution C and stirred for 20 min (the volume ratio of solution C to solution D was 1:1). The precipitated product Ag@ZIF-8 was collected by centrifugation; Ag@ZIF-8 was washed with methanol and ethanol, respectively.

[0038] Step 3: Disperse the washed Ag@ZIF-8 in methanol and stir evenly with the methanol solution containing zinc nitrate to obtain a first mixed solution. Then, transfer the first mixed solution to a high-pressure reactor and heat it at 120 o After heating at 400 °C for 3 h, the mixture was naturally cooled to obtain product E. Product E was collected by centrifugation and washed with ethanol to obtain product Ag@Zn-LDH.

[0039] Step 4: 0.5 g of Ag@Zn-LDH and 0.05 g of EDOT monomer were ultrasonically dispersed in a hydrochloric acid solution with a pH of 3, and the second mixed solution was obtained after mixing. The second mixed solution was placed in a round-bottom flask and 15 wt% (NH 4 ) 2 S 2 O 8The solution was added dropwise into the second mixed solution (the volume ratio of the ammonium persulfate solution to the second mixed solution was 1:1); the mixture was heated and stirred at 60° C. for 5 h and then centrifuged to obtain the product PEDOT / Ag@Zn-LDH.

[0040] The product PEDOT / Ag@Zn-LDH was loaded on the surface of carbon felt, and the modified carbon felt electrode was cut into a size of 5×5 cm to assemble into a ZBFB battery for battery performance testing. Figure 1 As shown in the figure, the initial and final cycle charge-discharge curves did not change significantly, and the charge-discharge voltage was relatively stable with almost no fluctuation, proving that the ZBFB of PEDOT / Ag@Zn-LDH modified carbon felt has good electrochemical stability. Figure 2 As shown, ZBFB at 40 mA / cm 2 After 20 h of continuous operation, the average EE was 90.20%, and the battery efficiency and discharge capacity did not show obvious attenuation, indicating that the ZBFB of PEDOT / Ag@Zn-LDH modified carbon felt has excellent cycle stability. The modification of carbon felt electrode can not only effectively inhibit the formation of zinc dendrites in zinc-bromine flow battery, but also significantly improve the performance and stability of the battery.

[0041] Example 2 Step 1: Dissolve 100g PVP and 0.2g NaCl in ethylene glycol to form solution A. 3 Dissolve in ethylene glycol to form a solution B with a concentration of 0.3 mol / L. Mix solution A and solution B in a volume ratio of 1:1 and stir evenly, then transfer to a high-pressure reactor and heat at 200 o C for 2 h, and naturally cooled after the reaction was completed, and the obtained silver nanowires were dispersed in a methanol solution to obtain a silver nanowire solution.

[0042] Step 2: Dissolve 2-methylimidazole in methanol, add the silver nanowire solution to form a solution C with a concentration of 1 mol / L, and then add Zn(NO 3 ) 2 6H 2 O was dissolved in methanol to form a solution D with a concentration of 0.2 mol / L. Solution D was quickly poured into solution C and stirred for 30 min (the volume ratio of solution C to solution D was 1:1). The precipitated product Ag@ZIF-8 was collected by centrifugation; Ag@ZIF-8 was washed with methanol and ethanol, respectively.

[0043] Step 3: Disperse the washed Ag@ZIF-8 in methanol and stir evenly with the methanol solution containing zinc nitrate to obtain a first mixed solution. Then, transfer the first mixed solution to a high-pressure reactor and heat it at 150 oAfter heating at 400 °C for 2 h, the mixture was naturally cooled to obtain product E. Product E was collected by centrifugation and washed with ethanol to obtain product Ag@Zn-LDH.

[0044] Step 4: 0.8 g of Ag@Zn-LDH and 0.16 g of EDOT monomer were ultrasonically dispersed in a hydrochloric acid solution with a pH of 4, and the second mixed solution was obtained after mixing. The second mixed solution was placed in a round-bottom flask and 20 wt% (NH 4 ) 2 S 2 O 8 The solution was added dropwise into the second mixed solution (the volume ratio of the ammonium persulfate solution to the second mixed solution was 1:1); the mixture was heated and stirred at 80° C. for 4 h and then centrifuged to obtain the product PEDOT / Ag@Zn-LDH.

[0045] Example 3 Step 1: Dissolve 100g PVP and 0.1g NaCl in ethylene glycol to form solution A. 3 Dissolve in ethylene glycol to form a solution B with a concentration of 0.1 mol / L. Mix solution A and solution B in a volume ratio of 1:1 and stir evenly, then transfer to a high-pressure reactor and heat at 150 o C for 4 h, and naturally cooled after the reaction was completed, and the obtained silver nanowires were dispersed in a methanol solution to obtain a silver nanowire solution.

[0046] Step 2: Dissolve 2-methylimidazole in methanol, add the silver nanowire solution to form a solution C with a concentration of 0.1 mol / L, and then add Zn(NO 3 ) 2 6H 2 O was dissolved in methanol to form a solution D with a concentration of 0.02 mol / L. Solution D was quickly poured into solution C and stirred for 30 min (the volume ratio of solution C to solution D was 1:1). The precipitated product Ag@ZIF-8 was collected by centrifugation; Ag@ZIF-8 was washed with methanol and ethanol, respectively.

[0047] Step 3: Disperse the washed Ag@ZIF-8 in methanol and stir evenly with the methanol solution containing zinc nitrate to obtain a first mixed solution. Then, transfer the first mixed solution to a high-pressure reactor and heat it at 100 o After heating at 400 °C for 4 h, the mixture was naturally cooled to obtain product E. Product E was collected by centrifugation and washed with ethanol to obtain product Ag@Zn-LDH.

[0048] Step 4: 0.3 g of Ag@Zn-LDH and 0.03 g of EDOT monomer were ultrasonically dispersed in a hydrochloric acid solution with a pH of 2, and the second mixed solution was obtained after mixing. The second mixed solution was placed in a round-bottom flask and 10 wt% (NH4 ) 2 S 2 O 8 The solution was added dropwise into the second mixed solution (the volume ratio of the ammonium persulfate solution to the second mixed solution was 1:1); the mixture was heated and stirred at 50° C. for 8 h and then centrifuged to obtain the product PEDOT / Ag@Zn-LDH.

[0049] Example 4 Step 1: Dissolve 100g PVP and 0.15g NaCl in ethylene glycol to form solution A. 3 Dissolve in ethylene glycol to form a solution B with a concentration of 0.15 mol / L. Mix solution A and solution B in a volume ratio of 1:2 and transfer to a high-pressure reactor at 160 o C for 4 h, and naturally cooled after the reaction was completed, and the obtained silver nanowires were dispersed in a methanol solution to obtain a silver nanowire solution.

[0050] Step 2: Dissolve 2-methylimidazole in methanol, add the silver nanowire solution to form a solution C with a concentration of 0.2 mol / L, and then add Zn(NO 3 ) 2 6H 2 O was dissolved in methanol to form a solution D with a concentration of 0.05 mol / L. Solution D was quickly poured into solution C and stirred for 20 min (the volume ratio of solution C to solution D was 1:1.5). The precipitated product Ag@ZIF-8 was collected by centrifugation; Ag@ZIF-8 was washed with methanol and ethanol, respectively.

[0051] Step 3: Disperse the washed Ag@ZIF-8 in methanol and stir evenly with the methanol solution containing zinc nitrate to obtain a first mixed solution. Then, transfer the first mixed solution to a high-pressure reactor and heat it at 180 o After heating at 400 °C for 3 h, the mixture was naturally cooled to obtain product E. Product E was collected by centrifugation and washed with ethanol to obtain product Ag@Zn-LDH.

[0052] Step 4: 0.5 g of Ag@Zn-LDH and 0.05 g of EDOT monomer were ultrasonically dispersed in a hydrochloric acid solution with a pH of 3, and the second mixed solution was obtained after mixing. The second mixed solution was placed in a round-bottom flask and 12 wt% (NH 4 ) 2 S 2 O 8 The solution was added dropwise into the second mixed solution (the volume ratio of the ammonium persulfate solution to the second mixed solution was 2:1); the mixture was heated and stirred at 55° C. for 6 h and then centrifuged to obtain the product PEDOT / Ag@Zn-LDH.

[0053] Example 5 Step 1: Dissolve 100g PVP and 0.16g NaCl in ethylene glycol to form solution A. 3 Dissolve in ethylene glycol to form a solution B with a concentration of 0.25 mol / L. Mix solution A and solution B in a volume ratio of 1:3 and transfer to a high-pressure reactor at 170 o C for 2 h, and naturally cooled after the reaction was completed, and the obtained silver nanowires were dispersed in a methanol solution to obtain a silver nanowire solution.

[0054] Step 2: Dissolve 2-methylimidazole in methanol, add the silver nanowire solution to form a solution C with a concentration of 0.8 mol / L, and then add Zn(NO 3 ) 2 6H 2 O was dissolved in methanol to form a solution D with a concentration of 0.15 mol / L. Solution D was quickly poured into solution C and stirred for 20 min (the volume ratio of solution C to solution D was 1:2). The precipitated product Ag@ZIF-8 was collected by centrifugation; Ag@ZIF-8 was washed with methanol and ethanol, respectively.

[0055] Step 3: Disperse the washed Ag@ZIF-8 in methanol and stir evenly with the methanol solution containing zinc nitrate to obtain a first mixed solution. Then, transfer the first mixed solution to a high-pressure reactor at 110 o After heating at 400 °C for 4 h, the mixture was naturally cooled to obtain product E. Product E was collected by centrifugation and washed with ethanol to obtain product Ag@Zn-LDH.

[0056] Step 4: 0.5 g of Ag@Zn-LDH and 0.05 g of EDOT monomer were ultrasonically dispersed in a hydrochloric acid solution with a pH of 4, and the second mixed solution was obtained after mixing. The second mixed solution was placed in a round-bottom flask and 18 wt% (NH 4 ) 2 S 2 O 8 The solution was added dropwise into the second mixed solution (the volume ratio of the ammonium persulfate solution to the second mixed solution was 3:1); the mixture was heated and stirred at 70° C. for 4 h and then centrifuged to obtain the product PEDOT / Ag@Zn-LDH.

[0057] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a conductive polymer / ZIF composite material, characterized in that: The following steps are involved: S1: dissolving polyvinyl pyrrolidone and sodium chloride in ethylene glycol to form solution A; dissolving silver nitrate in ethylene glycol to form solution B; mixing solution A and solution B evenly, heating under high pressure for reaction and then cooling naturally to obtain silver nanowires, dispersing the silver nanowires in a methanol solution to obtain a silver nanowire solution; S2: Dissolve 2-methylimidazole in methanol, add silver nanowire solution to form solution C, dissolve zinc nitrate in methanol to form solution D, add solution D to solution C and stir to react, collect the precipitated product Ag@ZIF-8 by centrifugation; wash Ag@ZIF-8 with methanol and ethanol respectively, disperse it in methanol after washing, and stir it evenly with the methanol solution containing zinc nitrate to obtain a first mixed solution; heat the first mixed solution under high pressure to react, and then cool it naturally to obtain product E; collect product E by centrifugation and wash it with ethanol to obtain Ag@Zn-LDH; S3: Ag@Zn-LDH and 3,4-ethylenedioxythiophene monomer are dispersed in a hydrochloric acid solution respectively, and mixed to obtain a second mixed solution, and the ammonium persulfate solution is added to the second mixed solution; After heating and stirring, the product PEDOT / Ag@Zn-LDH was obtained by centrifugation.

2. A method for preparing a conductive polymer / ZIF composite material according to claim 1, characterized in that: The mass ratio of polyvinyl pyrrolidone and sodium chloride in S1 is 1000:(1~2); the concentration of solution B in S1 is 0.1~0.3 mol / L, and the volume ratio of solution A to solution B is 1:(1~3).

3. A method for preparing a conductive polymer / ZIF composite material according to claim 1, characterized in that: The concentration of solution C in S2 is 0.1~1 mol / L; the concentration of solution D is 0.02~0.2 mol / L, and the volume ratio of solution C to solution D is (1~2):

1.

4. A method for preparing a conductive polymer / ZIF composite material according to claim 1, characterized in that: The mass ratio of Ag@Zn-LDH and 3,4-ethylenedioxythiophene monomer described in S3 is 1:(0.1~0.2).

5. A method for preparing a conductive polymer / ZIF composite material according to claim 1, characterized in that: The pH of the hydrochloric acid solution in S3 is 2-4.

6. A method for preparing a conductive polymer / ZIF composite material according to claim 1, characterized in that: The concentration of the ammonium persulfate solution in S3 is 10-20 wt %, and the volume ratio of the ammonium persulfate solution to the second mixed solution is (1-3):

1.

7. A method for preparing a conductive polymer / ZIF composite material according to claim 1, characterized in that: The conditions for the heating reaction under high pressure are: heating at 100-200° C. for 2-4 hours.

8. A method for preparing a conductive polymer / ZIF composite material according to claim 1, characterized in that: The heating and stirring conditions in S3 are: stirring at 50-80°C for 4-8h.

9. A conductive polymer / ZIF composite material, characterized in that: The method is prepared by any one of claims 1 to 8.

10. Application of the conductive polymer / ZIF composite material according to claim 9 in the field of liquid flow batteries.

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