Carbon nanotube composite fiber counter electrode and preparation method and application thereof
By coating metal particles on the carbon nanotube film and generating sulfide nanosheets, the catalytic activity and stability of fiber quantum dot-sensitized solar cells to the electrode are solved, and the device performance is improved.
Patent Information
- Application Number
- CN202510586152.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-08
- Publication Date
- 2025-08-15
AI Technical Summary
The catalytic activity of the counter electrode materials of existing fiber quantum dot-sensitized solar cells is low, resulting in high redox potential, low open circuit voltage, low photoelectric conversion efficiency, and poor stability on high curvature fiber substrates.
Metal particles are coated on the carbon nanotube film to form a composite carbon nanotube film, then wrapped around the conductive fibers and vulcanized with a polysulfide solution to form a highly catalytically active sulfide nanosheet in situ to form a counter electrode of carbon nanotube composite fibers.
It significantly improves catalytic activity and stability, improves the open circuit voltage and photoelectric conversion efficiency of fiber quantum dot-sensitized solar cells, and achieves efficient electrochemical performance.
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Figure CN120497050A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of photovoltaics, and in particular relates to a carbon nanotube composite fiber counter electrode and a preparation method and application thereof. Background Art
[0002] In recent years, the booming development of Internet of Things (IoT) technology has promoted innovation and breakthroughs in wearable and flexible electronics, but it has also increased electricity consumption, raising further concerns about practical power sources, particularly in terms of cost and sustainability. Photovoltaic cells can provide real-time power in illuminated environments and can be further integrated with energy storage batteries to achieve continuous power supply. Fiber solar cells have become an ideal power source due to their flexible integration with wearable electronic devices. Among them, fiber-sensitized solar cells have attracted widespread attention from academia and industry due to their low cost, flexibility, lightweight, and portability. Based on the type of active material loaded on the photoanode, fiber-sensitized solar cells can generally be divided into two categories: dye-sensitized solar cells and quantum dot-sensitized solar cells. Compared to the organic dye molecules in dye-sensitized solar cells, quantum dots have a series of advantages, including adjustable band gap, high molar extinction coefficient, high moisture stability, and high thermal stability. At the same time, due to the multi-exciton effect, fiber solar cells based on quantum dots have a higher upper limit for photoelectric conversion efficiency.
[0003] Although quantum dots have made significant progress in optoelectronic performance, there is no research on the design of quantum dot-sensitized solar cell counter electrodes in fiber devices. Currently, the counter electrodes commonly used in fiber solar cells, such as carbon nanotubes and platinum, have low catalytic activity against polysulfides, resulting in high redox potentials, which in turn leads to low device open-circuit voltage and low photoelectric conversion efficiency (Chem. Soc. Rev., 2018, 47, 7659-7702). Although the use of a similar planar process, that is, the Cu2S / brass-based counter electrode generated by in-situ corrosion of the brass surface, can significantly improve battery performance, the polysulfide electrolyte will continue to react with the brass substrate, resulting in impaired long-term stability of the counter electrode and device. In particular, on fiber substrates with high curvature that need to withstand repeated bending, there are currently no reports on efficient and stable fiber counter electrodes. Therefore, it is of great research value to develop counter electrode materials with high stability and excellent catalytic activity, and to optimize the counter electrode structure to enhance its application potential in fiber devices. Summary of the Invention
[0004] The purpose of the present invention is to provide a carbon nanotube composite fiber counter electrode with high stability and excellent catalytic activity and a preparation method thereof, and to apply the same in fiber quantum dot sensitized solar cells.
[0005] The present invention provides a method for preparing a carbon nanotube composite fiber counter electrode. First, a layer of metal particles is coated on a carbon nanotube film to form a composite carbon nanotube film. The composite carbon nanotube film is then wrapped around a conductive fiber. The metal particles are then sulfurized with a polysulfide solution to in-situ generate sulfide nanosheets with high catalytic activity to form the carbon nanotube composite fiber counter electrode. The specific steps are as follows:
[0006] Step (1): dissolving the polymer in a solvent, adding metal particles, and obtaining a uniform metal particle slurry by mechanical dispersion;
[0007] Step (2): coating the metal particle slurry on the surface of the carbon nanotube film, and forming a smooth and uniform metal particle film layer after drying to obtain a composite carbon nanotube film;
[0008] Step (3): Wrap the composite carbon nanotube film tightly around the conductive fiber in the form of a spiral (at a certain angle), then sulfide the metal particles with a polysulfide solution to generate sulfide nanosheets with high catalytic activity in situ to prepare a carbon nanotube composite fiber counter electrode.
[0009] Furthermore, in step (1):
[0010] The polymer is selected from polyvinylidene fluoride, polyurethane, cellulose acetate, polyacrylonitrile, and poly(vinylidene fluoride-co-hexafluoropropylene); the mass ratio of the polymer to the solvent is 1:20-1:5;
[0011] The metal particles are selected from copper, iron, cobalt, molybdenum and the like, and have a particle size of 0.1 μm to 10 μm; the mass ratio of the metal particles to the polymer is 20:1 to 1:1.
[0012] The solvent is selected from the group consisting of: N,N-dimethylformamide, acetone, toluene, dimethyl sulfoxide, N-methylpyrrolidone, triethyl phosphate, and water.
[0013] Furthermore, in step (2):
[0014] The carbon nanotube film has a width of 1 μm-500 μm, a thickness of 0.5 μm-20 μm, and a length of 0.1 m-1000 m.
[0015] The drying temperature is 40°C-80°C, and the drying time is 1min-10min;
[0016] The thickness of the metal particle film layer is 1 μm-30 μm.
[0017] Furthermore, in step (3):
[0018] The helical angle of the spiral winding, that is, the angle between the composite carbon nanotube film and the conductive fiber, is 10°-80°.
[0019] The solvent of the polysulfide solution is water, the solute is sodium polysulfide formed by the reaction of sodium sulfide and sulfur, the ratio of the two is 4:1-1:4, the concentration is 0.5 mol / L-5 mol / L, the sulfidation time is 1 min-30 min, and the sulfidation temperature is 30°C-80°C.
[0020] The sulfide nanosheets correspond to the metal particles of copper, iron, cobalt or molybdenum, and are cuprous sulfide, iron sulfide, molybdenum sulfide or cobalt sulfide, respectively;
[0021] The conductive fiber is made of pure metal wire such as gold, platinum, titanium or tungsten, stainless steel wire, metal-plated fiber, or metal wrapped wire; the conductive fiber has a diameter of 0.1 mm to 1 mm.
[0022] The carbon nanotube composite fiber counter electrode prepared by the present invention exhibits excellent electrochemical performance. By in-situ vulcanization of metal particles coated on the surface of the carbon nanotube film, a nanosheet active catalytic layer is formed on the surface, effectively increasing the catalytic area and improving catalytic activity. Because the composite carbon nanotube film is wrapped around a highly conductive metal wire, the counter electrode resistance is significantly reduced. Furthermore, because the metal particles are bonded to the surface of the carbon nanotube film via a polymer before in-situ vulcanization and do not react with the electrolyte, the nanosheet catalytic active layer can be firmly fixed to the surface of the carbon nanotube film after vulcanization, significantly improving the counter electrode stability. This results in a fiber quantum dot-sensitized solar cell counter electrode with both high catalytic activity and high stability.
[0023] That is, the carbon nanotube composite fiber counter electrode of the present invention can be used in fiber quantum dot sensitized solar cells, specifically:
[0024] Step (1): preparing a fiber photoanode; preparing a nano-titanium dioxide layer on the surface of the titanium wire, then annealing it at 500°C in air, and finally soaking it in a ZCISSe quantum dot solution for 12-48 hours to fully adsorb the quantum dots, thereby obtaining a fiber photoanode;
[0025] Step (2): Place the carbon nanotube composite fiber counter electrode and the photoanode together in a flexible transparent plastic tube, leaving an appropriate length of the electrode outside the tube, and then inject S into the plastic tube. 2- / S n 2- The electrolyte of the redox couple is sealed with hot melt adhesive to obtain a fiber quantum dot sensitized solar cell.
[0026] Compared with the prior art, the present invention has the following technical effects:
[0027] 1. The present invention designs a carbon nanotube composite fiber counter electrode with high catalytic performance and stability for fiber quantum dot-sensitized solar cells. By constructing a nanosheet catalytic layer with a high specific surface area on a carbon nanotube film substrate, the catalytically active layer can effectively catalyze redox reactions, significantly improving catalytic activity. The porous structure of the carbon nanotube layer facilitates polymer infiltration, forming a mechanical riveting effect with the polymer, effectively enhancing the interfacial bonding strength between the catalytically active nanosheets and the carbon nanotube film substrate, thereby achieving both higher catalytic activity and stability. The fiber quantum dot-sensitized solar cell achieved by the present invention has a maximum open-circuit voltage of 0.59V and a photoelectric conversion efficiency of up to 10.707%.
[0028] 2. The carbon nanotube composite fiber counter electrode of the present invention is produced by common fiber processing techniques such as coating, soaking, and wrapping, which is simple and efficient to operate, and is conducive to the continuous preparation of fiber quantum dot sensitized solar cells. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 (a) is a schematic structural diagram of the carbon nanotube composite fiber counter electrode of the present invention and its application in quantum dot-sensitized solar cells, and (b) is an enlarged view of the carbon nanotube composite film therein.
[0030] Figure 2 This is a scanning electron microscope (SEM) image (a) of the cuprous sulfide / carbon nanotube film / stainless steel wire composite counter electrode prepared in Inventive Example 1, wherein (b) is a local magnified image of the cuprous sulfide nanosheet after passing through the electrolyte.
[0031] Figure 3 This is the current density-voltage relationship curve of the fiber quantum dot-sensitized solar cell prepared in Example 1 of the present invention.
[0032] Figure 4 (a) is a scanning electron microscope (SEM) image of the molybdenum sulfide / carbon nanotube film / titanium wire composite counter electrode prepared in Inventive Example 2, wherein (b) is a local magnified image of the molybdenum sulfide after passing through the electrolyte.
[0033] Figure 5 This is the current density-voltage relationship curve of the fiber quantum dot-sensitized solar cell prepared in Example 2 of the present invention.
[0034] Figure 6 This is a scanning electron microscope (SEM) image (a) of the iron sulfide / carbon nanotube film / tungsten wire composite counter electrode prepared in Inventive Example 3, wherein the image is a partial magnified image of the iron sulfide nanosheet after passing through the electrolyte.
[0035] Figure 7 This is the current density-voltage relationship curve of the fiber quantum dot-sensitized solar cell prepared in Example 3 of the present invention.
[0036] The numbers in the figure are: 1 is the packaging tube, 2 is the electrolyte, 3 is the photoanode, 4 is the conductive fiber, 5 is the carbon nanotube composite film, 5.1 is the catalytic active layer, and 5.2 is the carbon nanotube film. DETAILED DESCRIPTION
[0037] The present invention is further described below by way of examples with reference to the accompanying drawings. It should be noted that, for those skilled in the art, based on the concept of the present invention, several variations and improvements may be made, all of which fall within the scope of protection of the present invention.
[0038] In the present invention, room temperature refers to an ambient temperature of 10°C-30°C.
[0039] All reagents used in the following examples were purchased from outside, including various solvents, nanoparticles, electrolytes, etc., which were purchased from Sinopharm Group Chemical Reagent Co., Ltd. All equipment used in the following examples were commercially available.
[0040] Example 1, preparation of carbon nanotube composite fiber counter electrode, the specific steps are:
[0041] Step (1): 0.5 g of polyvinylidene fluoride was dissolved in 10 g of methyl pyrrolidone, and 0.5 g of copper particles with a particle size of 500 nm were added and mechanically stirred, and the mixture was fully mixed to obtain a slurry containing copper particles.
[0042] Step (2): Select a carbon nanotube film with a width of 120 μm and a thickness of 2 μm, apply a slurry containing copper particles on the carbon nanotube film at a speed of 5 mm / min, and dry it at 80°C for 4 hours to obtain a carbon nanotube film with composite copper particles.
[0043] Step (3): Use a wrapping machine to wrap the carbon nanotube film composite copper particles on a 200 μm highly conductive stainless steel wire, with the angle between the metal wire and the film being 45°, to obtain a copper particle / carbon nanotube film / stainless steel wire composite fiber electrode.
[0044] Step (4): 4.8 g of sodium sulfide and 0.64 g of sulfur were reacted and dissolved in 10 g of water to form soluble polysulfides. A copper particle / carbon nanotube film / stainless steel wire composite fiber electrode was immersed in the reaction for 1 min at a reaction temperature of 30°C to obtain a cuprous sulfide / carbon nanotube film / stainless steel wire composite fiber counter electrode.
[0045] The cuprous sulfide / carbon nanotube film / stainless steel wire composite fiber counter electrode prepared in this example is applied to a fiber quantum dot sensitized solar cell, specifically:
[0046] Step (1): 0.12 mm titanium wire was ultrasonically cleaned with acetone, isopropanol, and deionized water in sequence and dried. Titanium dioxide nanotube arrays were then grown vertically on the surface of the titanium wire by anodization. The titanium wire was then annealed at 500°C in air and then immersed in a ZCISSe quantum dot solution for 24 h. The fiber photoanode was then prepared.
[0047] Step (2): Place the carbon nanotube composite fiber counter electrode and the fiber photoanode prepared in step (1) parallely in a packaging tube, leaving an appropriate length of the two electrodes outside the tube. Then, inject an electrolyte solution containing water as the solvent, 2M sulfur, 2M sodium sulfide, 20% polymethylpyrrolidone by weight, and 0.2M potassium chloride. Seal the tube opening with hot melt adhesive, and the fiber quantum dot-sensitized solar cell device is completed.
[0048] The scanning electron microscope (SEM) image of the cuprous sulfide / carbon nanotube film / stainless steel wire composite counter electrode prepared in this example is shown in FIG. Figure 2 As shown, the composite carbon nanotube film is tightly wrapped around the stainless steel wire, and after passing through the electrolyte, flaky cuprous sulfide crystals are evenly grown on the surface.
[0049] Figure 3 The fiber quantum dot sensitized solar cell prepared in this embodiment was tested for current density-voltage relationship curve under standard sunlight of AM 1.5, and its open circuit voltage was 0.585V and short circuit current density was 24.726mA / cm 2 , filling factor 0.646, energy conversion efficiency 9.348%, showing excellent device performance. Compared with the battery with carbon nanotube counter electrode without composite nanosheets under the same preparation conditions, its photoelectric conversion performance is improved by 24.90%.
[0050] Example 2, preparation of carbon nanotube composite fiber counter electrode, the specific steps are:
[0051] Step (1): 1 g of poly(vinylidene fluoride-co-hexafluoropropylene) was dissolved in 10 g of N,N-dimethylformamide solution, and 20 g of molybdenum particles with a particle size of 1000 nm were added and mechanically stirred and fully mixed to obtain a slurry.
[0052] Step (2): Select a carbon nanotube film with a width of 200 μm and a thickness of 1 μm, coat it at a speed of 50 mm / min, and dry it at 60° C. for 2 h to obtain a carbon nanotube film with composite molybdenum particles.
[0053] Step (3): Use a wrapping machine to wrap the carbon nanotube film of composite molybdenum particles on a 200 μm highly conductive titanium wire, with the angle between the metal wire and the film being 45°, to obtain a molybdenum particle / carbon nanotube film / titanium wire composite fiber electrode.
[0054] Step (4): 2.4 g of sodium sulfide and 0.64 g of sulfur are reacted and dissolved in 10 g of water to generate soluble polysulfide, and the molybdenum particle / carbon nanotube film / titanium wire composite fiber electrode is immersed in the reaction for 30 minutes at a reaction temperature of 60°C to obtain a molybdenum sulfide / carbon nanotube film / titanium wire composite fiber counter electrode.
[0055] The molybdenum sulfide / carbon nanotube film / titanium wire composite fiber counter electrode prepared in this example is applied to fiber quantum dot sensitized solar cells, specifically:
[0056] Step (1): 0.12 mm titanium wire was ultrasonically cleaned with acetone, isopropanol, and deionized water in sequence and dried. Titanium dioxide nanotube arrays were then grown vertically on the surface of the titanium wire by anodization. The titanium wire was then annealed at 500°C in air and then immersed in a ZCISSe quantum dot solution for 24 h. The fiber photoanode was then prepared.
[0057] Step (2): Place the carbon nanotube composite fiber counter electrode and the fiber photoanode prepared in step (1) parallely in a packaging tube, leaving an appropriate length of the two electrodes outside the tube. Then, inject an electrolyte solution containing water as the solvent, 2M sulfur, 2M sodium sulfide, 20% polymethylpyrrolidone by weight, and 0.2M potassium chloride. Seal the tube opening with hot melt adhesive, and the fiber quantum dot-sensitized solar cell device is completed.
[0058] The scanning electron microscope (SEM) image of the molybdenum sulfide / carbon nanotube film / titanium wire composite counter electrode prepared in this example is shown in FIG. Figure 4 As shown, the composite carbon nanotube film is tightly wrapped around the titanium wire, and molybdenum sulfide crystals grow on the surface after passing through the electrolyte.
[0059] Figure 5 The fiber quantum dot sensitized solar cell prepared in this embodiment was tested for current density-voltage relationship curve under standard sunlight of AM 1.5, and its open circuit voltage was 0.590V and short circuit current density was 23.815mA / cm 2 , filling factor 0.634, energy conversion efficiency 8.912%, showing excellent device performance. Compared with the battery with carbon nanotube counter electrode without composite nanosheets under the same preparation conditions, its photoelectric conversion performance is improved by 9.22%.
[0060] Example 3, preparation of carbon nanotube composite fiber counter electrode, the specific steps are:
[0061] Step (1): 2 g of cellulose acetate was dissolved in 10 g of dimethyl sulfoxide solution, and then 20 g of iron particles with a diameter of 200 nm were added and mechanically stirred, and the mixture was fully mixed to obtain a slurry.
[0062] Step (2): Select an oriented carbon nanotube film with a width of 250 μm, coat it at a speed of 20 mm / min, and dry it at 120° C. for 4 h to obtain a carbon nanotube film with composite iron particles.
[0063] Step (3): Use a wrapping machine to wrap the carbon nanotube film of composite iron particles on a 200 μm highly conductive tungsten wire, with the angle between the metal wire and the iron sulfide / carbon nanotube film being 30°, to obtain an iron particle / carbon nanotube film / tungsten wire composite fiber electrode.
[0064] Step (4): 2.4 g of sodium sulfide and 0.32 g of sulfur are reacted and dissolved in 10 g of water to generate soluble polysulfide, and the iron particle / carbon nanotube / tungsten wire composite fiber electrode is immersed in the reaction for 10 minutes at a reaction temperature of 80°C to obtain an iron sulfide / carbon nanotube film / tungsten wire composite fiber counter electrode.
[0065] The iron sulfide / carbon nanotube film / tungsten filament composite fiber counter electrode prepared in this example is applied to fiber quantum dot sensitized solar cells, specifically:
[0066] Step (1): 0.12 mm titanium wire was ultrasonically cleaned with acetone, isopropanol, and deionized water in sequence and dried. Titanium dioxide nanotube arrays were then grown vertically on the surface of the titanium wire by anodization. The titanium wire was then annealed at 500°C in air and then immersed in a ZCISSe quantum dot solution for 24 h. The fiber photoanode was then prepared.
[0067] Step (2): Place the carbon nanotube composite fiber counter electrode and the fiber photoanode prepared in step (1) parallely in a packaging tube, leaving an appropriate length of the two electrodes outside the tube. Then, inject an electrolyte solution containing water as the solvent, 2M sulfur, 2M sodium sulfide, 20% polymethylpyrrolidone by weight, and 0.2M potassium chloride. Seal the tube opening with hot melt adhesive, and the fiber quantum dot-sensitized solar cell device is completed.
[0068] The scanning electron microscope (SEM) image of the iron sulfide / carbon nanotube film / tungsten wire composite counter electrode prepared in this example is shown in FIG. Figure 6 As shown, the composite carbon nanotube film is tightly wrapped around the tungsten wire, and flaky iron sulfide crystals grow on the surface after passing through the electrolyte.
[0069] Figure 7 The fiber quantum dot sensitized solar cell prepared in this embodiment was tested under standard sunlight of AM 1.5, and the current density-voltage relationship curve was 0.587 V and the short-circuit current density was 27.879 mA / cm 2, filling factor 0.655, energy conversion efficiency 10.707%, showing excellent device performance. Compared with the battery with carbon nanotube counter electrode without composite nanosheets under the same preparation conditions, its photoelectric conversion performance is improved by 24.53%.
Claims
1. A method for preparing a carbon nanotube composite fiber counter electrode, characterized in that: First, a layer of metal particles is coated on the carbon nanotube film to form a composite carbon nanotube film. The composite carbon nanotube film is then wrapped around a conductive fiber. The metal particles are then sulfurized with a polysulfide solution to in-situ generate sulfide nanosheets with high catalytic activity to form a carbon nanotube composite fiber counter electrode. The specific steps are as follows: Step (1): dissolving the polymer in a solvent, adding metal particles, and obtaining a uniform metal particle slurry by mechanical dispersion; Step (2): coating the metal particle slurry on the surface of the carbon nanotube film, and forming a smooth and uniform metal particle film layer after drying to obtain a composite carbon nanotube film; Step (3): Wrap the composite carbon nanotube film tightly around the conductive fiber in the form of a spiral (at a certain angle), then sulfide the metal particles with a polysulfide solution to generate sulfide nanosheets with high catalytic activity in situ to prepare a carbon nanotube composite fiber counter electrode.
2. The preparation method according to claim 1, characterized in that In step (1): The polymer is selected from polyvinylidene fluoride, polyurethane, cellulose acetate, polyacrylonitrile, and poly(vinylidene fluoride-co-hexafluoropropylene); the mass ratio of the polymer to the solvent is 1:20-1:5; The metal particles are selected from copper, iron, cobalt, and molybdenum, and have a particle size of 0.1 μm to 10 μm; the mass ratio of the metal particles to the polymer is 20:1 to 1:1; The solvent is selected from the group consisting of: N,N-dimethylformamide, acetone, toluene, dimethyl sulfoxide, N-methylpyrrolidone, triethyl phosphate, and water.
3. The preparation method according to claim 1, characterized in that In step (2): The carbon nanotube film has a width of 1 μm-500 μm, a thickness of 0.5 μm-20 μm, and a length of 0.1 m-1000 m; The drying temperature is 40°C-80°C, and the drying time is 1min-10min; The thickness of the metal particle film layer is 1 μm-30 μm.
4. The preparation method according to claim 1, characterized in that In step (3): The helical angle of the spiral winding, i.e. the angle between the composite carbon nanotube film and the conductive fiber, is 10°-80°; The solvent of the polysulfide solution is water, the solute is sodium polysulfide formed by the reaction of sodium sulfide and sulfur, the ratio of the two is 4:1-1:4, the concentration is 0.5 mol / L-5 mol / L, the vulcanization time is 1 min-30 min, and the vulcanization temperature is 30°C-80°C; The sulfide nanosheets correspond to the metal particles of copper, iron, cobalt or molybdenum, namely cuprous sulfide, iron sulfide, molybdenum sulfide and cobalt sulfide; The conductive fiber is made of pure metal wire of gold, platinum, titanium or tungsten, stainless steel wire, metal-plated fiber, or metal wrapped wire; the conductive fiber has a diameter of 0.1 mm to 1 mm.
5. A carbon nanotube composite fiber counter electrode obtained by the preparation method according to any one of claims 1 to 4.
6. Use of the carbon nanotube composite fiber counter electrode as claimed in claim 5 in a fiber quantum dot sensitized solar cell.
7. The application according to claim 6, wherein: Step (1): preparing a fiber photoanode; preparing a nano-titanium dioxide layer on the surface of the titanium wire, then annealing it at 500°C in air, and finally soaking it in a ZCISSe quantum dot solution for 12-48 hours to fully adsorb the quantum dots, thereby obtaining a fiber photoanode; Step (2): Place the carbon nanotube composite fiber counter electrode and the photoanode together in a flexible transparent plastic tube, leaving a section of the electrode outside the tube, and then inject S into the plastic tube. 2- / S n 2- The electrolyte of the redox couple is sealed with hot melt adhesive to obtain a fiber quantum dot sensitized solar cell.
8. A fiber quantum dot sensitized solar cell, characterized in that: The counter electrode adopts the carbon nanotube composite fiber counter electrode as claimed in claim 5.