Graphene / polyaniline composite fiber as well as preparation method and application thereof

Abstract

The invention provides a preparation method of graphene / polyaniline composite fibers, and belongs to the technical field of graphene composite fibers. The preparation method comprises the following steps: (1) preparing a graphene oxide spinning solution containing polyaniline, and carrying out micro-fluidic assisted wet spinning to obtain a fiber I; and (2) dipping the fiber I in an aqueous solution containing an active metal compound, washing, and drying to obtain the graphene / polyaniline composite fiber. The obtained composite fiber has developed interlayer electroactive sites, a loose porous structure, an ordered ion diffusion channel and strong interface charge transfer, and the constructed fiber type flexible supercapacitor has excellent energy density and high capacitance characteristics.

Description

Technical Field

[0001] The present invention belongs to the technical field of graphene composite fibers, and in particular relates to a graphene / polyaniline composite fiber and a preparation method and application thereof. Background Art

[0002] As a two-dimensional material, graphene has excellent properties such as high strength, high modulus, high electrical conductivity, high thermal conductivity, high carrier mobility, high current carrying capacity, and high stability. Graphene fiber is a one-dimensional macroscopic assembly material composed of tightly and orderly arranged graphene sheets. However, during the electrode preparation process, 2D GO nanosheets have serious restacking problems, which limits the ion migration rate and makes it difficult to meet the current demand for high-performance electrodes. Through reasonable structural design and controllable preparation, researchers have found that graphene composite fibers can effectively transfer the excellent properties of graphene at the microscale to the macroscale, exhibiting excellent mechanical, electrical, thermal and other properties, thus being applied in functional fabrics, sensing, energy and other fields. At present, graphene fibers are mainly prepared by wet spinning, confined hydrothermal assembly and other methods, and their performance can be further improved by optimizing the material system and preparation process. Summary of the Invention

[0003] In order to solve the above-mentioned problems in the prior art, the present invention proposes a graphene / polyaniline composite fiber and its preparation method and application. The composite fiber has developed interlayer electroactive sites, a loose porous structure, ordered ion diffusion channels and strong interfacial charge transfer. The constructed fiber-type flexible supercapacitor has excellent energy density and high capacitance characteristics.

[0004] According to one aspect of the present invention, a method for preparing a graphene / polyaniline composite fiber is provided, comprising:

[0005] (1) preparing a graphene oxide spinning solution containing polyaniline and performing microfluidic-assisted wet spinning to obtain fiber I;

[0006] (2) Immersing fiber I in an aqueous solution containing an active metal compound, washing, and drying to obtain the graphene / polyaniline composite fiber.

[0007] Optionally, in step (1), the method for preparing the graphene oxide spinning solution containing polyaniline includes: dissolving polyaniline in a solvent under ultrasonic conditions for 0.5 to 3 hours to obtain a polyaniline solution; stirring the graphene oxide solution for 0.5 to 3 hours and then mixing it with the polyaniline solution.

[0008] Optionally, the solvent is selected from any one of N-methyl-2-pyrrolidone, deionized water, m-cresol, 1,4-cyclohexanediamine, dimethylpropyleneurea, and concentrated sulfuric acid.

[0009] Optionally, in the graphene oxide spinning solution containing polyaniline, the percentage of polyaniline in the total weight of polyaniline and graphene oxide is 5% to 50%.

[0010] Optionally, in step (1), the conditions of the microfluidic-assisted wet spinning include: the spinning solution is first passed through a spinning nozzle with a diameter of 160 to 1900 μm at an extrusion speed of 50 to 200 ml / h, and then remains in a calcium chloride / ethanol coagulation solution at 5 to 35°C for 60 to 3600 seconds to obtain the spinning; the spinning is taken out, placed in a reducing solution, washed with ethanol and deionized water, and then dried at room temperature.

[0011] Optionally, the standing temperature is 80-100° C., and the standing time is 4-12 h, preferably 6-10 h.

[0012] Optionally, the mass fraction of calcium chloride in the calcium chloride / ethanol coagulation solution is 10% to 30%.

[0013] Optionally, the concentration of the reducing solution is 10 wt.% to 57 wt.%.

[0014] Optionally, the reducing solution is selected from any one of HI solution, hydrazine solution, amino compound solution, sulfur compound solution, and hydroxyl compound solution, preferably any one of hydrazine hydrate solution, hydroxylamine solution, amine solution, amino acid solution, thiourea solution, and ascorbic acid solution.

[0015] Optionally, in step (2), the content of active metal elements in the aqueous solution containing the active metal compound is 0.05 to 0.2 mol / L.

[0016] Optionally, the active metal element is selected from any one of tin, manganese, molybdenum and vanadium.

[0017] Optionally, the aqueous solution containing the active metal compound further contains thiourea, and the content of the thiourea is 0.05 to 0.2 mol / L.

[0018] Alternatively, as an embodiment of the present application, a graphene oxide spinning solution containing polyaniline is prepared, and microfluidic-assisted wet spinning is performed using a calcium chloride / ethanol solution as a coagulation bath to obtain fiber I. Fiber I is then immersed in an aqueous solution containing tin and stirred. Tin dioxide quantum dots are in situ generated on fiber I, and the solution is washed and dried to produce the graphene / polyaniline composite fiber. The stirring may be magnetic stirring, and the stirring time is 24 to 26 hours. During the stirring process, the active metal compound gradually reacts, and the active metal oxide is generated in situ on the fiber surface.

[0019] Optionally, as another embodiment of the present application, a graphene oxide spinning solution containing polyaniline is prepared, and a calcium chloride / ethanol solution is used as a coagulation bath to perform microfluidic-assisted wet spinning to obtain fiber I; fiber I is immersed in an aqueous solution containing molybdenum element and treated hydrothermally; molybdenum sulfide is in situ generated on the fiber I, which is washed and dried to obtain the graphene / polyaniline composite fiber; the hydrothermal treatment conditions include a temperature of 160 to 240°C and a time of 16 to 32 hours.

[0020] In addition, the metal loading form on the graphene / polyaniline composite fiber of the present application also includes other forms such as metal carbide.

[0021] According to another aspect of the present invention, a graphene / polyaniline composite fiber prepared by the above preparation method is provided.

[0022] According to another aspect of the present invention, a graphene fiber supercapacitor is proposed, which includes a graphene fiber electrode and an electrolyte. The graphene fiber electrode is prepared using the above-mentioned graphene / polyaniline composite fiber; the electrolyte is selected from any one of H2SO4 / PVA and EMITFSI / PVDF-HFP.

[0023] Optionally, the specific area capacitance of the graphene fiber supercapacitor is 336-925 mF / cm in the H2SO4 / PVA electrolyte system. 2 .

[0024] The beneficial effects of the present invention include:

[0025] The preparation method of the present invention adopts a simple method under mild conditions to continuously prepare composite fibers with developed interlayer electroactive sites, loose porous structure, ordered ion diffusion channels and strong interfacial charge transfer. The constructed fiber-type flexible supercapacitor has excellent energy density and high capacitance characteristics. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the preparation process of SnO2 QDs@PGF.

[0027] Figure 2In the figure, (a) is the SEM image of chemically polymerized PANI and (b) is the TEM image of chemically polymerized PANI; (cd) are high-resolution TEM images of SnO2 quantum dots and (ef) are uniform PANI / GO spinning solutions; (gh) is the cross-sectional SEM image of PGF; (ij) is the surface SEM image of SnO2 QDs@PGF and (kl) is the cross-sectional SEM image of SnO2 QDs@PGF; (mq) is the EDS spectrum of C, N, O and Sn elements of SnO2 QDs@PGF.

[0028] Figure 3 Figure 2 is the electrochemical performance test diagram of the all-solid-state symmetrical supercapacitor assembled by GF, PGF and SnO2 QDs / PGF under PVA / H2SO4; (ac) is the electrochemical performance test diagram of the supercapacitor assembled by GF, PGF and SnO2 QDs / PGF at 0.1mA / cm 2 (d) is the CV curve of SnO2 QDs / PGF FSCs at a scan rate of 100 mV / s with bending angles of 0°, 45°, 90°, 135°, and 180°, respectively; (e) is the GCD curve of a single capacitor assembled by SnO2QDs / PGF and three capacitors in parallel; (f) is the cycle retention curve of SnO2QDs / PGF FSCs after 8000 cycles.

[0029] Figure 4 Figure 2 is the electrochemical performance test diagram of SnO2 QDs@PGF under EMITFSI / PVDFHFP; (a) is the ion storage mechanism scheme of SnO2QDs@PGF; (b) is the GCD curve of SnO2QDs@PGF; (ce) are the electrochemical performance test diagrams of SnO2QDs@PGF and PGF at 0.4mA / cm 2 GCD curve, specific capacitance comparison at different current densities, and CV comparison at a scan rate of 200 mV / s; (f) is the CV diagram of SnO2 QDs@PGF in the voltage window of 1.2-2.5 V; (g) is a comparison diagram of specific capacitance, energy density and voltage window of SnO2 QDs@PGF and other high-performance composite fibers.

[0030] Figure 5In the figure, (a) and (d) are schematic diagrams of five SnO2 QDs@PGF FSCs connected in series to an electronic device; (b) is a schematic diagram of an electronic timer in the practical application of SnO2 QDs@PGF FSCs, (c) is a schematic diagram of an alarm clock in the practical application of SnO2QDs@PGF FSCs, and (ef) are schematic diagrams of a desk lamp that requires a 3V battery for power supply in the practical application of SnO2 QDs@PGF FSCs. DETAILED DESCRIPTION

[0031] The present invention will be further described below with reference to specific examples, but they do not constitute any limitation to the present invention.

[0032] Unless otherwise specified, the drugs used in the embodiments of the present invention can be purchased commercially.

[0033] The weight percentage of polyaniline in each embodiment of the present invention refers to the percentage of the weight of polyaniline to the total weight of polyaniline and graphene oxide.

[0034] Example 1

[0035] (1) Preparation of polyaniline

[0036] 4.657 g of aniline was added to a three-necked flask, the temperature was maintained at 0°C, 50 mL of 1.0 M / L hydrochloric acid was added, 14.26 g of ammonium persulfate was dissolved in 25.75 mL of distilled water, the ammonium persulfate solution was slowly added, and the mixture was stirred for 1 h. Distilled water was added and centrifuged twice. Distilled water was then added and filtered. The resulting precipitate was added to 70 mL of 28% ammonia water and stirred for 24 h for deprotonation. Distilled water and ethanol were added and filtered three times each. The mixture was vacuum dried at 60°C to obtain PANI.

[0037] (2) Preparation of SnO2 QDs@PGF

[0038] like Figure 1 As shown in Figure 2, 40 mg of PANI was uniformly dispersed and dissolved in N-methyl-2-pyrrolidone (NMP) under ultrasound for 1.5 h, and a graphene oxide solution containing 12 g of GO (10 mg g -1) and stirred magnetically for 1.5 hours. The two were then mixed and stirred for 0.5 hours to prepare a uniform PANI / GO spinning solution containing 25% PANI by weight. The solution was then passed through a spinning nozzle with a diameter of 1120 μm at a propulsion rate of 100 ml / h and placed in a 25% calcium chloride / ethanol coagulation solution at 25°C for 600 seconds. The resulting PANI / GO fibers were then removed and placed in a HI solution at 100°C for 8 hours to obtain poly(vinyl fluoride) (PGF). The dried PGF fibers were immersed in a 50 ml mixed aqueous solution containing 0.9 g stannous chloride dihydrate (SnCl2 2H2O) and 0.304 g thiourea (CH4N2S) and stirred magnetically for 24 hours. Uniform SnO2 QDs were generated in situ on the PGF. After washing and drying at room temperature, SnO2 QDs@PGF were prepared.

[0039] Example 2

[0040] (1) Preparation of polyaniline

[0041] Same as Example 1.

[0042] (2) Preparation of SnO2 QDs@PGF

[0043] 20 mg of PANI was uniformly dispersed and dissolved in N-methyl-2-pyrrolidone (NMP) under ultrasound for 1.5 h, and a graphene oxide solution (10 mg g -1 ) and stirred magnetically for 1.5 hours. The two were then mixed and stirred for 0.5 hours to prepare a uniform PANI / GO spinning solution containing 10% PANI by weight. The solution was then passed through a spinning nozzle with a diameter of 1120 μm at a propulsion rate of 100 ml / h and placed in a 25% calcium chloride / ethanol coagulation solution at 25°C for 600 seconds. The resulting PANI / GO fibers were then removed and placed in a HI solution at 100°C for 8 hours to obtain PGF. The dried PGF fibers were then immersed in a 50 ml mixed aqueous solution containing 0.9 g stannous chloride dihydrate (SnCl2 2H2O) and 0.304 g thiourea (CH4N2S) and magnetically stirred for 24 hours. Uniform SnO2 QDs were generated in situ on the PGF. After washing and drying at room temperature, SnO2 QDs@PGF were prepared.

[0044] Example 3

[0045] (1) Preparation of polyaniline

[0046] Same as Example 1.

[0047] (2) Preparation of SnO2 QDs@PGF

[0048] 40 mg of PANI was uniformly dispersed and dissolved in N-methyl-2-pyrrolidone (NMP) under ultrasound for 1.5 h, and a graphene oxide solution (10 mg g -1 ) and stirred magnetically for 1.5 hours. The two were then mixed and stirred for 0.5 hours to prepare a uniform PANI / GO spinning solution containing 20% PANI by weight. The solution was then passed through a spinning nozzle with a diameter of 1120 μm at a propulsion rate of 100 ml / h and placed in a 25% calcium chloride / ethanol coagulation solution at 25°C for 600 seconds. The resulting PANI / GO fibers were then removed and placed in a HI solution at 100°C for 8 hours to obtain poly(vinyl fluoride) (PGF). The dried PGF fibers were immersed in a 50 ml mixed aqueous solution containing 0.9 g stannous chloride dihydrate (SnCl2 2H2O) and 0.304 g thiourea (CH4N2S) and stirred magnetically for 24 hours. Uniform SnO2 QDs were generated in situ on the PGF. After washing and drying at room temperature, SnO2 QDs@PGF were prepared.

[0049] Example 4

[0050] (1) Preparation of polyaniline

[0051] Same as Example 1.

[0052] (2) Preparation of SnO2 QDs@PGF

[0053] 60 mg of PANI was uniformly dispersed and dissolved in N-methyl-2-pyrrolidone (NMP) under ultrasound for 1.5 h, and a graphene oxide solution (10 mg g -1 ) and stirred magnetically for 1.5 hours. The two were then mixed and stirred for 0.5 hours to prepare a uniform PANI / GO spinning solution containing 30% PANI by weight. The solution was then passed through a spinning nozzle with a diameter of 1120 μm at a propulsion rate of 100 ml / h and placed in a 25% calcium chloride / ethanol coagulation solution at 25°C for 600 seconds. The resulting PANI / GO fibers were then removed and placed in a HI solution at 100°C for 8 hours to obtain poly(vinyl fluoride) (PGF). The dried PGF fibers were immersed in a 50 ml mixed aqueous solution containing 0.9 g stannous chloride dihydrate (SnCl2 2H2O) and 0.304 g thiourea (CH4N2S) and stirred magnetically for 24 hours. Uniform SnO2 QDs were generated in situ on the PGF. After washing and drying at room temperature, SnO2 QDs@PGF were prepared.

[0054] Example 5

[0055] (1) Preparation of polyaniline

[0056] Same as Example 1.

[0057] (2) Preparation of SnO2 QDs@PGF

[0058] 80 mg of PANI was uniformly dispersed and dissolved in N-methyl-2-pyrrolidone (NMP) under ultrasound for 1.5 h, and a graphene oxide solution (10 mg g -1 ) and stirred magnetically for 1.5 hours. The two were then mixed and stirred for 0.5 hours to prepare a uniform PANI / GO spinning solution containing 40% PANI by weight. The solution was then passed through a spinning nozzle with a diameter of 1120 μm at a propulsion rate of 100 ml / h and placed in a 25% calcium chloride / ethanol coagulation solution at 25°C for 600 seconds. The resulting PANI / GO fibers were then removed and placed in a HI solution at 100°C for 8 hours to obtain poly(vinyl fluoride) (PGF). The dried PGF fibers were immersed in a 50 ml mixed aqueous solution containing 0.9 g stannous chloride dihydrate (SnCl2 2H2O) and 0.304 g thiourea (CH4N2S) and stirred magnetically for 24 hours. Uniform SnO2 QDs were generated in situ on the PGF. After washing and drying at room temperature, SnO2 QDs@PGF were prepared.

[0059] Example 6

[0060] (1) Preparation of polyaniline

[0061] Same as Example 1.

[0062] (2) Preparation of SnO2 QDs@PGF

[0063] 40 mg of PANI was uniformly dispersed and dissolved in N-methyl-2-pyrrolidone (NMP) under ultrasound for 1.5 h, and a graphene oxide solution (10 mg g -1 ) and stirred for 1.5h by magnetic stirring. Then the two were mixed and stirred for 0.5h to prepare a uniform PANI / GO spinning solution with a PANI weight percentage of 25%. The solution was passed through a spinning nozzle with a diameter of 1120μm at a propulsion rate of 100ml / h and stayed in a 25% calcium chloride / ethanol coagulation solution at 25℃ for 600s. The PANI / GO fiber was taken out and placed in HI solution at 100℃ for 8 hours to obtain PGF. The dried PGF fiber was immersed in a solution containing 0.91g of ammonium molybdate tetrahydrate ((NH4)6Mo7O 24 The researchers then placed the solution in a 60ml mixed aqueous solution of 0.4H2O and 0.11g thiourea (CH4N2S) at 180°C for 24h to generate uniform MoS2 in situ on PGF. After washing and drying at room temperature, MoS2@PGF was obtained.

[0064] Example 7

[0065] 40 mg of PANI was uniformly dispersed and dissolved in N-methyl-2-pyrrolidone (NMP) under ultrasound for 1.5 h, and a graphene oxide solution (10 mg g -1 ) and stirred magnetically for 1.5 hours. The two were then mixed and stirred for 0.5 hours to prepare a uniform PANI / GO spinning solution containing 25% PANI by weight. The solution was then passed through a 1900 μm diameter spinning nozzle at a propulsion rate of 150 ml / h and placed in a 25% calcium chloride / ethanol coagulation solution at 25°C for 600 seconds. The resulting PANI / GO fibers were then removed and placed in a HI solution at 100°C for 8 hours to obtain poly(vinyl fluoride) (PGF). The dried PGF fibers were immersed in a 50 ml mixed aqueous solution containing 0.9 g stannous chloride dihydrate (SnCl2 2H2O) and 0.304 g thiourea (CH4N2S) and magnetically stirred for 24 hours, resulting in the in situ formation of uniform SnO2 QDs on the PGF. After washing and drying at room temperature, SnO2 QDs@PGF were prepared.

[0066] Comparative Example 1

[0067] The same preparation method as in Example 1 was used to prepare graphene fibers that did not contain polyaniline.

[0068] Comparative Example 2

[0069] The same preparation method as in Example 1 was used, but the weight percentage of polyaniline in the PANI / GO spinning solution was changed to 70%. At this point, the spinning solution could hardly be coagulated in the coagulation bath, and no usable graphene fibers could be obtained.

[0070] Test Case

[0071] 1. Morphology characterization

[0072] The SnO2 QDs@PGF fibers obtained in Example 1 were characterized by electron microscopy. The electron microscope models were: SEM: TESCAN MIRA LMS; TEM: JEOL JEM 2100.

[0073] First, in Figure 2 (ab) shows chemically polymerized PANI with uniform size. Figure 2 The high-crystallinity SnO2 QDs in (cd) exhibit a size range of 1 to 4 nm, and clear lattice fringes of 0.33 nm correspond to the interplanar spacing between the (110) planes of SnO2 crystals, which is consistent with the XRD results.

[0074] Secondly, PGF with an oriented structure along the main axis of the fiber was continuously prepared by microfluidic-assisted wet spinning, accompanied by uniform anchoring of PANI nanomaterials with an average size of about 50 nm on GO nanosheets at the micrometer scale in a suitable mixed solvent of deionized water / N-methyl-2-pyrrolidone (NMP), which not only reduced the aggregation and restacking of graphene nanosheets but also ensured the molecular-scale uniformity and strong interfacial effect between PANI and graphene nanosheets, as shown in TEM images ( Figure 2 The diameters of PGF and GF are about 200 μm, and the cross-sectional structure of PGF shows that there are abundant, loose porous microstructures and uniformly distributed nano-PANI spacers between graphene nanosheets ( Figure 2 of (gh)).

[0075] Third, PGF was placed in a solution of stannous chloride dihydrate and thiourea as a promoter and stabilizer, and magnetically stirred at room temperature for 24 hours, accompanied by the hydrolysis, dehydration and oxidation of SnCl2 2H2O. SnO2 quantum dots grew in situ on the surface of the conductive skeleton PGF under very mild conditions and were bridged to PGF through CO-Sn covalent bonds to ensure uniform distribution, structural stability and abundant interfacial charge diffusion channels. Scanning electron microscopy shows the side and cross-sectional morphology of tin dioxide quantum dots @PGF. Figure 2 As shown in (il), the PGF loaded with SnO2QDs shows a diameter close to 200 μm, a wrinkled and shrunken surface, and PANI nanoparticles uniformly distributed in the internal structure of the hybrid fiber, providing diffusion channels for the dynamic transport and storage of ions. EDS spectrum is shown in Figure 2 As shown in (mq), the composition and element distribution of SnO2 quantum dots are revealed. The N element is evenly distributed inside and on the surface of the fiber, and the Sn element is mainly concentrated on the surface.

[0076] Therefore, these strategies effectively ensure that SnO2 QDs@PGF has well-developed interlayer electroactive sites, loose porous structure, ordered ion diffusion channels and strong interfacial charge transfer, which are the key to the excellent electrochemical performance and practical application of fiber-type flexible supercapacitors.

[0077] 2. Electrochemical performance

[0078] The electrochemical performance of the SnO2 QDs@PGF fibers obtained in Example 1 was tested.

[0079] 2.1PVA / H2SO4 electrolyte

[0080] Table 1 Areal capacitance of GF, PGF and SnO2 QDs@PGF in PVA / H2SO4 electrolyte

[0081]

[0082] To evaluate the electrochemical performance of the assembled fiber-type flexible supercapacitors, the GCD curves of GF, PGF, and SnO2QDs@PGF FSCs in PVA / H2SO4 gel electrolyte were obtained.

[0083] Figure 3 (ac) showed that GF, PGF and SnO2 QDs@PGF FSCs were -2 GCD curve under 10mv·s -1 Comparison of CV curves and specific area capacitance at various current densities. Compared with GF and PGF, the GCD curves of SnO2QDs@PGF FSCs show an approximately isosceles triangle shape. For SnO2QDs@PGF FSCs, at 0.1mA·cm -2 The following shows 925mF·cm -2 High specific area capacitance and 20.6 μWh·cm -2 The energy density is 0.1, 0.2, 0.4, 0.8 and 1.6 mA cm -2 The specific area capacitances of SnO2QDs@PGF FSCs are 925, 885, 840, 788 and 336 mF·cm -2 , which are significantly greater than PGF (502, 475, 410, 348 and 264 mF·cm -2 ) and GF (340, 298, 236, 148 and 136 mF·cm -2 ) areal capacitance. It is noteworthy that SnO2 QDs@PGF FSCs maintain high areal capacitance, good reversibility, high Coulombic efficiency and fastest charge transfer. Compared with the area of GF and PGF, SnO2 QDs@PGF FSCs has a high areal capacitance of 10mV·s -1 The largest area is shown below, indicating higher specific capacitance and charge storage capability.

[0084] Bending stability is an important indicator for the practical application of flexible energy storage devices in portable electronics and smart clothing. The bending deformation of SnO2 QDs@PGF FSCs was measured. Figure 3 At several bending angles from 0° to 180°, the CV curves do not change significantly, indicating excellent bending deformation stability and excellent electrochemical performance.

[0085] In order to meet the requirements of practical applications, multiple fiber-type flexible supercapacitors are usually assembled in parallel. Figure 3(e) shows three parallel-connected fiber-type SnO2 QDs@PGF FSCs at 0.2 mA cm -2 The GCD curve under the same working voltage is three times that of a single flexible supercapacitor, which promotes the application of next-generation electronic products. Figure 3 (f) shows that after 8000 charge-discharge cycles, SnO2QDs@PGF FSCs exhibit excellent cycling stability with 88% capacitance retention, which illustrates the unique advantages of PANI as a molecular-level uniformity of "spacers" between graphene nanosheets and the covalent coupling strategy of SnO2 QDs on graphene nanosheets.

[0086] 2.2 Ionic Liquid Electrolytes

[0087] Table 2 Specific area capacitance of PGF and SnO2 QDs@PGF in EMITFSI / PVDF-HFP electrolyte

[0088]

[0089] Figure 4 (a) illustrates the ion storage mechanism and the strong synergistic effect between PGF and SnO2 QDs bridged by CO-Sn covalent bonds. PGF has a hierarchical structure with interconnected conductive networks and good mechanical flexibility, which enables rapid electron conduction. However, limited transfer pathways lead to poor ion storage kinetics. Through in situ covalent coupling, 1-4 nm SnO2 QDs are bridged to the PGF surface. The quantum dot size is conducive to exposing electrochemical active sites, and the shortened ion diffusion path enhances the transport capacity and rate performance. The interfacial connectivity and charge transfer between PGF and SnO2 QDs are significantly improved through the interfacial CO-Sn covalent bond. This is crucial for achieving excellent electrochemical performance and practical applications.

[0090] Using EMITFSI / PVDF-HFP as a polymer-loaded ionic liquid electrolyte, SnO2QDs@PGFFSCs were constructed and their electrochemical performance was studied in a two-electrode system. The increase in the working voltage in the ionic liquid electrolyte can significantly improve the energy density. Figure 4 In (bd), at 0.4, 0.8, 1.2, 1.6 and 2.0 mA·cm -2 The nearly symmetrical GCD curves of SnO2 QDs@PGF FSCs indicate fast ion and electron transfer kinetics and a highly reversible charge-discharge process. Notably, the areal capacitance of SnO2 QDs@PGF FSCs is as high as 678.4 mF·cm in a wide operating voltage window of 2.5 V. -2 , and at 0.4 mA·cm-2 The amazing energy density reaches 147.2μWh·cm -2 , which are much higher than PGF (area capacitance of 486.4mF·cm -2 , the energy density is 105.6μWh·cm -2 ). At 200mV·s -1 At a scan rate of , SnO2 QDs@PGF FSCs showed a larger area and a wider current density range, indicating a higher energy storage capacity, e.g. Figure 4 The electrochemical performance of SnO2QDs@PGF FSCs was specifically evaluated at different voltage windows ( Figure 4 (f)), and the CV curve is at 100mV·s -1 The consistent shape from 1.2 V to 2.5 V is maintained, indicating good electrochemical performance, which demonstrates the potential advantages for subsequent energy supply applications. Figure 4 (g) shows the performance comparison of SnO2 QDs@PGF FSCs with other published fiber-type flexible supercapacitors assembled with carbon material electrodes, such as 43.296 μWh·cm -2 PANI-GF, 37.2 μWh·cm -2 PNA / G, 3.45μWh·cm -2 PANI / MCNTs-rGO / TPU, 120.3 μWh·cm -2 VA-NiONSs / P-GF, 67.37 μWh cm -2 CDs / graphene fiber, 7.93μWh cm -2 GF@PANI and 3.4 μWh cm -2 The NSG@GF and SnO2 QDs@PGF maintain high specific capacitance and excellent energy density, confirming the surprising synergistic effect between the composition or nanostructure.

[0091] 3. Practical Application

[0092] The superior electrochemical performance of SnO2 QDs@PGF FSCs was further demonstrated by providing energy for various electronic devices in practical applications. In order to achieve the desired energy density, five fiber-type flexible supercapacitors made from SnO2 QDs@PGF fibers obtained in Example 1 were connected in series, as shown in the schematic diagram. Figure 5 (a) and Figure 5 As shown in (d). The SnO2 QDs@PGF FSCs constructed in this way can stably serve as an electronic timer ( Figure 5 (b)), alarm clock ( Figure 5(c)) and different color lamps that require 3V batteries ( Figure 5 (ef)), indicating that the constructed flexible supercapacitor has excellent energy density and high capacitance characteristics.

[0093] Any numerical value mentioned in the present invention includes all values that increase by one unit each time from the lowest value to the highest value if there is only a gap of two units between any minimum value and any maximum value. For example, if the amount of a component, or the value of a process variable such as temperature, pressure, time, etc. is stated to be 50-90, it is meant in this specification to specifically list values such as 51-89, 52-88... and 69-71 and 70-71. For non-integer values, it is appropriate to consider units of 0.1, 0.01, 0.001 or 0.0001. These are just some special examples. In this application, in a similar manner, all possible combinations of numerical values between the listed lowest value and the listed highest value are considered to have been disclosed.

[0094] It should be noted that the embodiments described above are only used to explain the present invention and do not constitute any limitation of the present invention. The present invention has been described with reference to typical embodiments, but it should be understood that the words used therein are descriptive and explanatory words, rather than restrictive words. The present invention may be modified as specified within the scope of the claims of the present invention, and the present invention may be revised without departing from the scope and spirit of the present invention. Although the present invention described therein relates to specific methods, materials and embodiments, it does not mean that the present invention is limited to the specific examples disclosed therein. On the contrary, the present invention can be extended to all other methods and applications with the same function.

Claims

1. A method for preparing a graphene / polyaniline composite fiber, characterized in that: include: (1) preparing a graphene oxide spinning solution containing polyaniline and performing microfluidic-assisted wet spinning to obtain fiber I; (2) Immersing fiber I in an aqueous solution containing an active metal compound, washing, and drying to obtain the graphene / polyaniline composite fiber.

2. The preparation method according to claim 1, characterized in that In step (1), the method for preparing the graphene oxide spinning solution containing polyaniline comprises: dissolving polyaniline in a solvent under ultrasonic conditions for 0.5 to 3 hours to obtain a polyaniline solution, stirring the graphene oxide solution for 0.5 to 3 hours, and then mixing the solution with the polyaniline solution; Preferably, the solvent is selected from any one of N-methyl-2-pyrrolidone, deionized water, m-cresol, 1,4-cyclohexanediamine, dimethylpropyleneurea, and concentrated sulfuric acid; And / or, in the graphene oxide spinning solution containing polyaniline, the percentage of polyaniline in the total weight of polyaniline and graphene oxide is 5% to 50%.

3. The preparation method according to claim 1 or 2, characterized in that In step (1), the conditions of the microfluidic-assisted wet spinning include: the spinning solution is first passed through a spinning nozzle with a diameter of 160 to 1900 μm at an extrusion speed of 50 to 200 ml / h, and then remains in a calcium chloride / ethanol coagulation solution at 5 to 35° C. for 60 to 3600 seconds to obtain the spinning; the spinning is taken out, placed in a reducing solution, washed with ethanol and deionized water, and dried at room temperature; Preferably, the standing temperature is 80-100° C., and the standing time is 4-12 hours, preferably 6-10 hours.

4. The preparation method according to claim 3, characterized in that The concentration of the reducing solution is 10 wt.% to 57 wt.%; And / or, the reducing solution is selected from any one of HI solution, hydrazine solution, amino compound solution, sulfur compound solution, and hydroxyl compound solution, preferably any one of hydrazine hydrate solution, hydroxylamine solution, amine solution, amino acid solution, thiourea solution, and ascorbic acid solution.

5. The preparation method according to claim 3 or 4, characterized in that The mass fraction of calcium chloride in the calcium chloride / ethanol coagulation solution is 10% to 30%.

6. The preparation method according to any one of claims 1 to 5, characterized in that In step (2), the content of the active metal element in the aqueous solution containing the active metal compound is 0.05 to 0.2 mol / L; and / or, the active metal element is selected from any one of tin, manganese, molybdenum and vanadium; And / or, the aqueous solution containing the active metal compound further contains thiourea, and the content of the thiourea is 0.05-0.2 mol / L.

7. The preparation method according to any one of claims 1 to 6, characterized in that The fiber I is immersed in an aqueous solution containing tin element and stirred; tin dioxide quantum dots are generated in situ on the fiber I, and the fiber is washed and dried to obtain the graphene / polyaniline composite fiber; Preferably, the stirring time is 24 to 26 hours.

8. A graphene / polyaniline composite fiber prepared by the preparation method according to any one of claims 1 to 7.

9. A graphene fiber supercapacitor, characterized in that: The graphene fiber supercapacitor includes a graphene fiber electrode and an electrolyte. The graphene fiber electrode is prepared using the graphene / polyaniline composite fiber according to claim 8; the electrolyte is selected from any one of H2SO4 / PVA and EMITFSI / PVDF-HFP.

10. The graphene fiber supercapacitor according to claim 9, characterized in that: The graphene fiber supercapacitor has an area specific capacitance of 336 to 925 mF / cm in the H2SO4 / PVA electrolyte system. 2 .

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