High-stability titanium carbonitride conductive fiber and preparation method and application thereof

Abstract

The application discloses a kind of high-stability titanium carbonitride conductive fibers and its preparation method and application.The specific preparation method is as follows: titanium carbonitride fiber precursor film doped with metal is prepared and collected by using electrostatic spinning process;Titanium carbonitride fiber precursor film is pre-oxidized and pyrolyzed.The prepared titanium carbonitride conductive fiber has the characteristics of high stability, high conductivity and flexibility, and can be widely used in electrochemical energy storage and conversion process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of renewable energy storage and conversion, and particularly relates to a high-stability titanium carbonitride conductive fiber and a preparation method and application thereof. BACKGROUND

[0002] The application of renewable energy relies on efficient electric energy conversion and high-density electric energy storage technology to realize energy distribution. In order to reduce ohmic loss and improve the dispersion of active components, a conductive carrier becomes a key material for the above-mentioned technology. Carbon material becomes a typical carrier due to its high specific surface area and high electron conductivity. However, under high potential and oxygen conditions, the carbon carrier is gradually oxidized, which leads to the shedding of active substances, directly hinders the participation of active substances in the reaction and the electron transfer process, and finally leads to the decrease of the stability of energy storage and conversion devices. In summary, it is urgent to develop a high-stability conductive carrier material. SUMMARY

[0003] The application provides a high-stability titanium carbonitride conductive fiber and a preparation method thereof. The process route of the method is simple and has strong implementability. The titanium carbonitride conductive fiber can be used to improve the stability of energy storage and conversion devices such as fuel cells and water electrolysis.

[0004] The technical scheme of the application is as follows:

[0005] A preparation method of a high-stability titanium carbonitride conductive fiber, comprising the following steps: dissolving a high-molecular compound, a titanium-containing precursor and other metal precursors in N,N-dimethylformamide to prepare a spinning solution; preparing and collecting a metal-doped titanium carbonitride fiber precursor film through electrospinning; pre-oxidizing and pyrolyzing the precursor film to obtain a titanium carbonitride conductive fiber.

[0006] Preferably, the high-molecular compound is one or more of polyacrylonitrile (PAN), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) and polyvinylidene fluoride (PVDF).

[0007] Preferably, the titanium-containing precursor is one or more of titanium trichloride, titanium tetrachloride and tetrabutyl titanate.

[0008] Further, the other metal precursor is a salt of other metal precursors.

[0009] Preferably, the salt of other metal precursors is ferric trichloride, cobalt chloride, nickel chloride, zinc chloride, aluminum chloride, niobium chloride or a combination thereof.

[0010] The mass ratio of the polymer, the titanium-containing precursor and the other metal precursor is 1-20:1-10:1-2. For example, the mass ratio of the polymer, the titanium-containing precursor and the other metal precursor is 2:1-10:1-2, 3:1-10:1-2, 4:1-10:1-2, 5:1-10:1-2, 6:1-10:1-2, 7:1-10:1-2, 8:1-10:1-2, 9:1-10:1-2, 10:1-10:1-2, 11:1-10:1-2, 12:1-10:1-2, 13:1-10:1-2, 14:1-10:1-2, 15:1-10:1-2, 16:1-10:1-2, 17:1-10:1-2, 18:1-10:1-2, 19:1-10:1-2 or 20:1-10:1-2. Preferably, the mass ratio of the polymer, the titanium-containing precursor and the other metal precursor is 20:10:1, 10:5:1 or 4:2:1.

[0011] Preferably, the pre-oxidation temperature is 180-250°C and the time is 1-5 hours. For example, the pre-oxidation temperature is 180°C, 185°C, 190°C, 195°C, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C, 230°C, 235°C, 240°C, 245°C or 250°C.

[0012] Preferably, the pyrolysis temperature is 800-1050°C and the time is 0.5-5 hours. For example, the pyrolysis temperature is 800°C, 850°C, 900°C, 950°C, 1000°C or 1050°C.

[0013] The present application provides a method for preparing a high-stability titanium carbonitride conductive fiber as described above, which has the advantages of simple process route and strong implementability.

[0014] The present application provides a titanium carbonitride conductive fiber as described above, which has excellent durability and can be used to improve the stability of energy storage and conversion devices such as fuel cells and water electrolysis. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0016] Figure 1 The carbonitride titanium conductive fiber precursor film effect picture of Example 1.

[0017] Figure 2 Scanning electron microscope (SEM) image of Example 1.

[0018] Figure 3 Transmission electron microscope (TEM) image of Example 1.

[0019] Figure 4 Oxygen reduction reaction polarization curve comparison image of Example 1.

[0020] Figure 5 Electrochemical surface area comparison image of the catalyst under accelerated aging test conditions of Comparative Example 1.

[0021] Figure 6 Oxygen reduction reaction polarization curve comparison image of the platinum-doped titanium carbonitride fiber-supported platinum of Comparative Example 1.

[0022] Figure 7 Hydrogen evolution stability image of the titanium carbonitride fiber-supported nickel-molybdenum alloy catalyst of Example 3. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the present application.

[0024] Example 1

[0025] Polyacrylonitrile (weight average molecular weight 150000 g / mol), tetrabutyl titanate, and ferric chloride were dissolved in 10 ml of N,N-dimethylformamide (DMF) at 0.8 g: 0.4 g: 0.2 g, and stirred in a 60°C water bath for 4 h to obtain a uniform and clear spinning solution.

[0026] The spinning solution was added to a syringe, a spinning nozzle with a size of 24G was selected, the solution flow rate was 1 mL / h, the collection distance was 15 cm, the receiving electrode voltage was 6 kV, and the counter electrode voltage was -3 kV, and the precursor film was prepared through an electrospinning process, as shown in Figure 1 .

[0027] The precursor film was pre-oxidized at 220°C in air for 3 h, and then placed in a tube furnace and pyrolyzed at 1000°C under an argon atmosphere for 1 h, and the product was a titanium carbonitride conductive fiber. The morphology of the sample was characterized using a Zeiss Supra 40 electron microscope Figure 2 , and the product was a bundle-shaped fiber array with a diameter of ~1 micrometer.

[0028] 50 mg of titanium carbonitride conductive fiber was dispersed with chloroplatinic acid in a mass ratio of 5:1 in 5 ml of ethylene glycol, stirred in an oil bath at 140°C for 4h to obtain platinum nanoparticle loaded titanium carbonitride conductive fiber (platinum loading is 9wt%), the morphology is shown in Figure 3 (Using Hitachi H-7650 transmission electron microscope for characterization), platinum nanoparticles with a diameter of about 5nm are uniformly dispersed on the surface of titanium carbonitride fiber.

[0029] The oxygen reduction performance of platinum nanoparticle loaded titanium carbonitride conductive fiber was evaluated using Chenhua 760E type electrochemical workstation, the test method was linear voltammetry scanning, the scanning speed was 10mV / s, the electrode rotation speed was 1600r / min, and the catalyst loading was 20ug / cm 2 , the polarization curve is shown in Figure 4 , the half-wave potential is about 30mV better than the same loading of commercial carbon supported platinum (Sanle HyCa-PT20), and there is no attenuation after 10,000 cycles, while the commercial carbon supported platinum attenuates by 50mV.

[0030] Comparative Example 1

[0031] The difference between the comparative example and Example 1 is only that no iron trichloride is added to prepare the spinning solution, and the titanium carbonitride conductive fiber without doping is obtained, and the other conditions are the same. Under the accelerated aging test conditions, the hydrogen region of 0.05V-0.4V is selected to compare the electrochemical surface area (ECSA) of the catalyst to evaluate its stability. As shown in Figure 5 , after 40,000 cycles, the sample doped with Fe shows better stability, and the electrochemical surface area is maintained at 96%, which is better than the undoped comparative sample (87%) and the commercial carbon supported platinum (52%).

[0032] The polarization curve Figure 6 indicates that the half-wave potential of platinum loaded on titanium carbonitride conductive fiber is better than that of the undoped sample.

[0033] Example 2

[0034] Polyacrylonitrile (weight average molecular weight is 150000g / mol), tetrabutyl titanate, and cobalt chloride were dissolved in 10ml N,N dimethylformamide (DMF) at 0.8g:0.4g:0.2g, stirred in a water bath at 60°C for 4h to obtain a uniform and clear spinning solution.

[0035] The spinning solution was added to a syringe, a spinning nozzle with a size of 24G was selected, the solution flow rate was 1mL / h, the collection distance was 15cm, the receiving electrode voltage was 6kV, and the counter electrode voltage was -3kV. The precursor film was prepared by electrospinning process.

[0036] The precursor film is pre-oxidized in air at 220°C for 3 hours, and then pyrolyzed in a tube furnace at 1050°C for 1 hour under argon atmosphere, and the product is the titanium carbonitride conductive fiber.

[0037] 50 mg of the titanium carbonitride conductive fiber is dispersed with chloroplatinic acid at a mass ratio of 5:1 in 5 ml of ethylene glycol, stirred in an oil bath at 140°C for 4h, and titanium carbonitride conductive fiber loaded with platinum nanoparticles (platinum loading of 9wt%) is obtained.

[0038] The oxygen reduction performance of the titanium carbonitride conductive fiber loaded with platinum nanoparticles is evaluated using a Chenhua 760E model electrochemical workstation, the test method is linear voltammetry scanning, the scanning speed is 10 mV / s, the electrode rotation speed is 1600 rpm, and the catalyst loading is 20 ug / cm 2 The half-wave potential of the titanium carbonitride conductive fiber loaded with platinum nanoparticles reaches 0.91 V vs RHE, and no attenuation is observed after 10,000 cycles.

[0039] Example 3

[0040] Polyacrylonitrile (weight average molecular weight of 150000 g / mol), tetrabutyl titanate, and zinc chloride are dissolved in 10 ml of N,N-dimethylformamide (DMF) at 0.8 g:0.4 g:0.2 g, and stirred in a 60°C water bath for 4h to obtain a uniform and clear spinning solution.

[0041] The spinning solution is added to a syringe, a spinning nozzle with a size of 24G is selected, the solution flow rate is 1 mL / h, the collection distance is 15 cm, the receiving electrode voltage is 6 kV, and the counter electrode voltage is -3 kV, and the precursor film is prepared through the electrospinning process.

[0042] The precursor film is pre-oxidized in air at 220°C for 3 hours, and then pyrolyzed in a tube furnace at 1050°C for 1 hour under argon atmosphere, and the product is the titanium carbonitride conductive fiber.

[0043] 50 mg of the titanium carbonitride conductive fiber is placed in a mixed solution containing nickel sulfate 120 g / L, sodium molybdate 40 g / L, and sodium citrate 40 g / L, and a constant current density of 50 mA / cm 2 is used to load a nickel-molybdenum alloy catalyst (Ni / Mo atomic ratio of 4 / 1) for 5 hours. The electrochemical hydrogen evolution performance of the titanium carbonitride conductive fiber loaded with the nickel-molybdenum alloy is evaluated using 1M KOH solution as the electrolyte, as shown in Figure 7 the current density is maintained at 91.4% after 24 hours of continuous hydrogen production at a potential of -0.2 V.

[0044] From the above examples, the application provides high-stability titanium carbonitride conductive fibers and a preparation method thereof as described above, the prepared titanium carbonitride conductive fibers have the characteristics of high stability, high conductivity and flexibility, can be used to replace commercial carbon carriers, improve the stability of electrochemical energy storage and conversion devices, and have good application prospect.

[0045] The above description is only an embodiment of the present application, and it should be pointed out that, for ordinary skilled in the art, without departing from the principles of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the protection scope of the present application. The protection scope of the present application is limited by the claims, and can include other embodiments that can be thought by those skilled in the art. If these other embodiments have structural elements that are not different from the expression of the claims, or if they include equivalent structural elements that are not substantially different from the expression of the claims, then these other embodiments should also be included in the scope of the claims.

Claims

1. A method for preparing a high-stability titanium carbonitride conductive fiber, characterized by, The method comprises the following steps: dissolving a high molecular compound, a titanium-containing precursor and other metal precursors in N,N-dimethylformamide to prepare a spinning solution; preparing and collecting a metal-doped titanium carbonitride fiber precursor film through electrostatic spinning; Pre-oxidizing and pyrolyzing the precursor film to obtain a titanium carbonitride conductive fiber; The high molecular compound is one or more of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP); The titanium-containing precursor is one or more of titanium trichloride, titanium tetrachloride and tetrabutyl titanate; The other metal precursor salt is iron trichloride; The mass ratio of the high molecular compound, the titanium-containing precursor and the other metal precursor is 1-19:1-10:1-2; The pre-oxidizing temperature is 180-245 ℃, and the time is 1-5 hours; The pyrolyzing temperature is 800-1050 ℃, and the time is 0.5-5 hours.

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