Conductive heating graphene glass fiber cloth and preparation method thereof

Abstract

The invention relates to the technical field of electric heating materials, in particular to conductive heating graphene glass fiber cloth and a preparation method thereof. The graphene glass fiber cloth electric heating device comprises graphene glass fiber cloth and electrodes connected to the warp-wise edge of the graphene glass fiber cloth. The graphene glass fiber cloth comprises pre-deposited glass fiber cloth and a coating covering the surface of the pre-deposited glass fiber cloth; when 270V direct current is applied to the graphene glass fiber cloth electric heating device, the electric heating rate is greater than or equal to 85 DEG C / s; when 150V direct current is applied to the graphene glass fiber cloth electric heating device, the electric heating temperature stable value is larger than or equal to 200 DEG C, and the electricity-heat radiation conversion efficiency is larger than or equal to 40%. The flexibility of the glass fiber cloth can be maintained, and the glass fiber cloth has a good self-repairing effect in a high-temperature environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric heating materials, in particular to a graphene glass fiber cloth capable of electric heating and a preparation method thereof. BACKGROUND

[0002] Flexible thin film heater is a film-shaped electric heating device with bendable and foldable characteristics. As a surface heater, it has the advantages of large heat exchange area and high heat exchange power. This kind of device has the outstanding characteristics of high heating efficiency, good heat dissipation performance, large surface power density and not easy to ablate, and has broad application prospects in industrial heating, medical care, aerospace and other fields.

[0003] Graphene, as a two-dimensional carbon material, is considered as an ideal candidate for the next generation of flexible electric heating materials due to its ultra-high thermal conductivity, excellent electric-thermal conversion efficiency and extremely low resistivity. By coating a graphene layer on the surface of glass fiber through chemical vapor deposition, a graphene glass fiber cloth composite material with high electrical conductivity, flexibility and mechanical strength is prepared, which has excellent prospects for application in flexible thin film heaters.

[0004] However, in the high temperature application environment of the current flexible thin film heater, on the one hand, the graphene deposited on the surface of the glass fiber may react with oxygen in the atmosphere, leading to material structure damage and a sharp decrease in electrical conductivity; on the other hand, due to the significant difference in thermal expansion coefficient between graphene and glass fiber substrate, thermal stress will be generated during temperature cycling, leading to interfacial peeling between the graphene layer and the substrate, forming a network of micro-cracks and defects. These defects not only reduce the mechanical strength of the material, but also significantly increase the resistance, affecting the heating uniformity and efficiency.

[0005] In the field of military defense and aerospace, there is an urgent need for lightweight, high power density flexible heating systems. Traditional metal-based electric heating systems have the disadvantages of heavy weight and high energy consumption, while existing flexible thin film heaters cannot meet the stable working requirements in extreme high temperature environments. The existing technology either sacrifices flexibility by using rigid heaters or uses flexible materials but cannot guarantee high temperature stability. This supply-demand contradiction has become a key factor restricting the upgrading of related industries. SUMMARY

[0006] The purpose of the present application is to solve the problems existing in the prior art and provide a graphene glass fiber cloth capable of electric heating and a preparation method thereof.

[0007] A graphene glass fiber cloth electric heating device includes: a graphene glass fiber cloth and an electrode connected to the warp edge of the graphene glass fiber cloth; the graphene glass fiber cloth includes: a pre-deposited glass fiber cloth and a coating covering the surface of the pre-deposited glass fiber cloth; the graphene glass fiber cloth is coated onto the surface of the pre-deposited glass fiber cloth by a coating liquid, when the first... n The second coating layer should be completely dry before proceeding to the next step. n +1 coat, n It can be 1, 2 or 3; after being completely dried, it is heat-treated at 200-220℃ for 1-3 minutes, and then cooled to room temperature.

[0008] When the graphene glass fiber cloth electric heating device is subjected to 270V DC power, the electric heating rate is ≥85℃ / s; when the graphene glass fiber cloth electric heating device is subjected to 150V DC power, the electric heating temperature stability is ≥200℃, and the electro-thermal radiation conversion efficiency is ≥40%.

[0009] Preferably, the raw materials of the coating liquid include, by mass, 1-5 parts silver nitrate, 1-3 parts dopamine hydrochloride, 1-3 parts single-walled carbon nanotubes, 0.1-0.5 parts bismuthate glass powder, 0.1-0.5 parts expanded graphite, 0.1-0.5 parts dispersant, 20-30 parts of an ethanol aqueous solution with a mass fraction of 50-60%, and 10-20 parts water.

[0010] Preferably, the initial expansion temperature of the expanded graphite is 250°C. For details, please refer to the preparation method of low-temperature expandable graphite in CN1613757A (application number 2004100657397, application date 2004-11-16, publication date 2005-05-11).

[0011] Preferably, the softening point temperature of the bismuthate glass powder is 260-280℃, and the melting point temperature is 320-330℃.

[0012] Preferably, the dispersant is sodium dodecylbenzenesulfonate.

[0013] Preferably, the coating solution is prepared by the following steps: silver nitrate and dopamine hydrochloride are added to an ethanol aqueous solution and stirred evenly. The pH of the system is adjusted to 8-9, stirred for 10-15 hours, centrifuged, washed, cooled to -30 to -40°C and frozen for 1-3 hours, freeze-dried, calcined in a sealed environment at 400-500°C for 1-2 hours, cooled to room temperature, and pulverized. The product, along with single-walled carbon nanotubes, bismuthate glass powder, expanded graphite, and dispersant, is added to water and ultrasonically dispersed for 1-2 hours.

[0014] Preferably, the pre-deposited glass fiber cloth is prepared by the following steps: using pretreated glass fiber as the growth substrate, evacuating the chemical vapor deposition system and maintaining it for 10-20 minutes, purging with argon gas, heating to 1050-1100℃ and introducing a second mixed gas composed of ethanol vapor, argon and hydrogen, growing for 1-2 hours, and then introducing argon gas to cool to room temperature.

[0015] More preferably, the flow rate of ethanol vapor is 50-70 sccm, and the flow ratio of ethanol vapor, argon, and hydrogen is 5-7:5-10:5-10.

[0016] More preferably, the vacuum pressure of the chemical vapor deposition system is not higher than 2.5 Pa.

[0017] More preferably, the pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The tube furnace is evacuated, heated to 650-700°C, and treated with a first mixed gas composed of argon and oxygen for 0.5-1 hours, and then cooled to room temperature.

[0018] Specifically, the fiberglass cloth has a thickness of 0.1-0.3 mm and a basis weight of 200-300 g / m². 2 .

[0019] Specifically, the vacuum inside the tubular furnace is evacuated to a level not exceeding 2.5 Pa.

[0020] Specifically, the flow rate of the first mixed gas is 1200-1500 sccm, and the volume ratio of argon to oxygen is 10:1-2.

[0021] The above-mentioned method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating a coating liquid onto the surface of a pre-deposited glass fiber cloth, when the first... n The second coating layer should be completely dry before proceeding to the next step. n +1 coat, n The coating layers are 1, 2, or 3, with each layer having a thickness of 0.5-2 μm. After complete drying, the coating is heat-treated at 200-220℃ for 1-3 minutes and then cooled to room temperature to obtain graphene glass fiber cloth. Then, the electrodes are connected to the warp edge of the graphene glass fiber cloth.

[0022] Beneficial effects This invention utilizes chemical vapor deposition to deposit graphene on the surface of pretreated glass fiber cloth, forming a highly conductive network. The excellent electrothermal conversion efficiency and low resistivity of graphene itself provide a foundation for efficient conductive heating. Meanwhile, the single-walled carbon nanotubes in the coating solution have one-dimensional quantum conductivity and extremely high carrier mobility. Combined with graphene, they form a three-dimensional conductive network, significantly reducing the overall resistance. Furthermore, carbon-doped silver nanoparticles are formed by the polymerization and deposition of nitrate and dopamine hydrochloride, followed by calcination. These nanoparticles, in conjunction with the graphene conductive network, construct multi-scale conductive pathways, resulting in a synergistic effect that enhances conductive heating.

[0023] This invention utilizes the characteristic that bismuthate glass powder undergoes viscous flow at high temperatures, and its coefficient of expansion is similar to that of glass fiber substrate. When the temperature is high, the flow filling and expanded graphite undergo volume expansion, thereby generating internal pressure to drive the flow. This can effectively repair microcracks and defects inside the material, while compensating for volume shrinkage caused by thermal stress and maintaining structural integrity.

[0024] This invention, through pretreatment of the glass fiber cloth, can effectively enhance the stable bonding of subsequent deposition and coating layer structures on the glass fiber surface. It not only maintains the flexibility of the glass fiber cloth, but also ensures that the material maintains electrical conductivity and heating stability during deformation, reducing crack propagation caused by repeated deformation. Moreover, it has good self-healing effect in high-temperature environments, achieving a balance between flexibility, electrical conductivity and heating stability, and high-temperature self-healing of graphene glass fiber cloth, thus ensuring the stable operation of flexible thin-film heaters in extreme environments. Attached Figure Description

[0025] Figure 1 The graph shows a comparison of the electric heating rates of the graphene glass fiber cloths obtained in Examples 1-5 and Comparative Examples 1-2.

[0026] Figure 2 This is a comparison chart of the stable values ​​of the electric heating temperature of the graphene glass fiber cloth obtained in Examples 1-5 and the graphene glass fiber cloth obtained in Comparative Examples 1-2.

[0027] Figure 3 The graph shows a comparison of the electro-thermal radiation conversion efficiency of the graphene glass fiber cloths obtained in Examples 1-5 and Comparative Examples 1-2.

[0028] Figure 4 The graph shows the rate of change of the electric heating rate after the graphene glass fiber cloths obtained in Examples 1-5 and Comparative Examples 1-2 were folded 180° five times and subjected to 100V or 200V DC current. Detailed Implementation

[0029] The present invention will be further explained below with reference to specific embodiments.

[0030] The thickness of the glass fiber cloth used below is 0.20±0.05 mm, and the basis weight is 240 g / m². The bismuthate glass powder used below is sourced from Suzhou Qiumou New Materials Co., Ltd., and adopts a Bi-Cu-Zn ternary system, with a softening point of 260-280℃ and a melting point of 320-330℃. The expanded graphite used below was prepared according to Example 31 in CN1613757A, and its expansion volume at 250℃ is 45 mL / g, and its expansion volume at 300℃ is 105 mL / g.

[0031] Example 1 A method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating liquid onto the surface of a pre-deposited glass fiber cloth, allowing each layer to dry completely before coating, coating a total of 2 layers, each layer being 0.5 μm thick, heating to 200℃ after complete drying, holding at that temperature for 1 min, and cooling to room temperature to obtain the graphene glass fiber cloth; cutting the obtained graphene glass fiber cloth to 10cm × 10cm, using copper foil conductive tape to tightly adhere to the warp edge of the graphene glass fiber cloth, and fixing one end of the tape to a copper wire with solder, connecting it to the two electrode posts of the power supply.

[0032] The raw materials for the coating solution include: 1g silver nitrate, 1g dopamine hydrochloride, 1g single-walled carbon nanotubes, 0.1g bismuthate glass powder, 0.1g expanded graphite, and 0.1g sodium dodecylbenzenesulfonate.

[0033] The coating solution was prepared using the following steps: silver nitrate and dopamine hydrochloride were added to 20g of a 50% ethanol aqueous solution and stirred until homogeneous. While stirring, 0.1mol / L ammonia water was added dropwise to adjust the pH of the system to 8. The mixture was stirred for 10h, centrifuged, washed, cooled to -30℃ and frozen for 1h, freeze-dried, calcined in a sealed muffle furnace for 1h at 400℃, cooled to room temperature, and pulverized through a 100-mesh sieve. The product, along with single-walled carbon nanotubes, bismuthate glass powder, expanded graphite, and sodium dodecylbenzenesulfonate, was added to 10g of deionized water and ultrasonically dispersed for 1h at a frequency of 50kHz.

[0034] The above-mentioned pre-deposited glass fiber cloth is prepared by the following steps: pretreated glass fiber is used as the growth substrate and placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure of the entire chemical vapor deposition system is pumped to 2 Pa using a mechanical pump and maintained for 10 min. Argon gas is introduced for purging. The system is heated to 1050℃ within 30 min. A second mixed gas of 50 sccm ethanol vapor, 50 sccm argon and 50 sccm hydrogen is introduced and grown for 1 h. Then argon gas is introduced to cool down to room temperature.

[0035] The above-mentioned pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure inside the tube furnace is pumped to 2 Pa using a mechanical pump, and the system temperature is raised to 650°C in 10 min. A first mixed gas composed of argon and oxygen (total flow rate of 1200 sccm, volume ratio of argon to oxygen of 10:1) is introduced for treatment for 0.5 h, and then cooled to room temperature.

[0036] Example 2 A method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating liquid onto the surface of a pre-deposited glass fiber cloth, allowing each layer to dry completely before coating, coating a total of 4 layers, each layer being 2μm thick, heating to 220℃ after complete drying, holding at that temperature for 3 minutes, and then cooling to room temperature to obtain the graphene glass fiber cloth; cutting the obtained graphene glass fiber cloth to 10cm×10cm, attaching it tightly to the warp edge of the graphene glass fiber cloth with copper foil conductive tape, and fixing one end of the tape to a copper wire with solder, connecting it to the two electrode posts of the power supply.

[0037] The raw materials for the coating solution include: 5g silver nitrate, 3g dopamine hydrochloride, 3g single-walled carbon nanotubes, 0.5g bismuthate glass powder, 0.5g expanded graphite, and 0.5g sodium dodecylbenzenesulfonate.

[0038] The coating solution was prepared using the following steps: silver nitrate and dopamine hydrochloride were added to 30g of a 60% ethanol aqueous solution and stirred until homogeneous. While stirring, 0.2mol / L ammonia was added dropwise to adjust the pH of the system to 9. The mixture was stirred for 15h, centrifuged, washed, cooled to -40℃ and frozen for 3h, freeze-dried, calcined in a sealed muffle furnace for 2h at 500℃, cooled to room temperature, and pulverized through a 100-mesh sieve. The product, along with single-walled carbon nanotubes, bismuthate glass powder, expanded graphite, and sodium dodecylbenzenesulfonate, was added to 20g of deionized water and ultrasonically dispersed for 2h at a frequency of 70kHz.

[0039] The above-mentioned pre-deposited glass fiber cloth is prepared by the following steps: pretreated glass fiber is used as the growth substrate and placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure of the entire chemical vapor deposition system is evacuated to 2.4 Pa using a mechanical pump and maintained for 20 min. Argon gas is introduced for purging. The system is heated to 1100℃ within 60 min. A second mixed gas of 70 sccm ethanol vapor, 100 sccm argon and 100 sccm hydrogen is introduced and grown for 2 h. Then argon gas is introduced to cool down to room temperature.

[0040] The above-mentioned pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure inside the tube furnace is pumped to 2.3 Pa using a mechanical pump, and the system temperature is raised to 700°C in 20 min. A first mixed gas composed of argon and oxygen (total flow rate of 1500 sccm, volume ratio of argon to oxygen of 5:1) is introduced for treatment for 1 h, and then cooled to room temperature.

[0041] Example 3 A method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating liquid onto the surface of a pre-deposited glass fiber cloth, allowing each layer to dry completely before coating, coating a total of 3 layers, each layer being 1 μm thick, heating to 205℃ after complete drying, holding at that temperature for 2.5 min, and then cooling to room temperature to obtain the graphene glass fiber cloth; cutting the obtained graphene glass fiber cloth to 10cm × 10cm, using copper foil conductive tape to tightly adhere to the warp edge of the graphene glass fiber cloth, and fixing one end of the tape to a copper wire with solder, connecting it to the two electrode posts of the power supply.

[0042] The raw materials for the coating solution include: 2g silver nitrate, 2.5g dopamine hydrochloride, 1.5g single-walled carbon nanotubes, 0.4g bismuthate glass powder, 0.2g expanded graphite, and 0.4g sodium dodecylbenzenesulfonate.

[0043] The coating solution was prepared using the following steps: silver nitrate and dopamine hydrochloride were added to 22g of a 58% ethanol aqueous solution and stirred until homogeneous. While stirring, 0.12mol / L ammonia was added dropwise to adjust the pH of the system to 8.5. The mixture was stirred for 13h, centrifuged, washed, cooled to -33℃ and frozen for 2.5h, freeze-dried, calcined in a sealed muffle furnace for 80min at 480℃, cooled to room temperature, and pulverized through a 100-mesh sieve. The product, along with single-walled carbon nanotubes, bismuthate glass powder, expanded graphite, and sodium dodecylbenzenesulfonate, was added to 12g of deionized water and ultrasonically dispersed for 100min at a frequency of 55kHz.

[0044] The above-mentioned pre-deposited glass fiber cloth is prepared by the following steps: pretreated glass fiber is used as the growth substrate and placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure of the entire chemical vapor deposition system is pumped down to 1 Pa using a mechanical pump and held for 18 min. Argon gas is introduced for purging. The system is heated to 1090℃ within 40 min. A second mixed gas of 55 sccm ethanol vapor, 90 sccm argon and 70 sccm hydrogen is introduced and grown for 100 min. Then argon gas is introduced to cool down to room temperature.

[0045] The above-mentioned pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure inside the tube furnace is evacuated to 1 Pa using a mechanical pump, and the system temperature is raised to 690°C in 12 minutes. A first mixed gas composed of argon and oxygen (total flow rate of 1300 sccm, volume ratio of argon to oxygen of 5:0.9) is introduced for 40 minutes and then cooled to room temperature.

[0046] Example 4 A method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating liquid onto the surface of a pre-deposited glass fiber cloth, allowing each layer to dry completely before coating, coating a total of 3 layers, each layer being 1 μm thick, heating to 215℃ after complete drying, holding at that temperature for 1.5 min, and then cooling to room temperature to obtain the graphene glass fiber cloth; cutting the obtained graphene glass fiber cloth to 10cm × 10cm, using copper foil conductive tape to tightly adhere to the warp edge of the graphene glass fiber cloth, and fixing one end of the tape to a copper wire with solder, connecting it to the two electrode posts of the power supply.

[0047] The raw materials for the coating solution include: 4g silver nitrate, 1.5g dopamine hydrochloride, 2.5g single-walled carbon nanotubes, 0.2g bismuthate glass powder, 0.4g expanded graphite, and 0.2g sodium dodecylbenzenesulfonate.

[0048] The coating solution was prepared using the following steps: silver nitrate and dopamine hydrochloride were added to 28g of a 52% ethanol aqueous solution and stirred until homogeneous. While stirring, 0.18mol / L ammonia was added dropwise to adjust the pH of the system to 8.5. The mixture was stirred for 11h, centrifuged, washed, cooled to -37℃ and frozen for 1.5h, freeze-dried, calcined in a sealed muffle furnace for 100min at a calcination temperature of 420℃, cooled to room temperature, and pulverized through a 100-mesh sieve. The product, along with single-walled carbon nanotubes, bismuthate glass powder, expanded graphite, and sodium dodecylbenzenesulfonate, was added to 18g of deionized water and ultrasonically dispersed for 80min at an ultrasonic frequency of 65kHz.

[0049] The above-mentioned pre-deposited glass fiber cloth is prepared by the following steps: pretreated glass fiber is used as the growth substrate and placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure of the entire chemical vapor deposition system is pumped to 1 Pa using a mechanical pump and held for 12 min. Argon gas is introduced for purging. The system is heated to 1070℃ within 50 min. A second mixed gas of 65 sccm ethanol vapor, 70 sccm argon and 90 sccm hydrogen is introduced and grown for 80 min. Then argon gas is introduced to cool down to room temperature.

[0050] The above-mentioned pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure inside the tube furnace is evacuated to 1 Pa using a mechanical pump, and the system temperature is raised to 670°C in 18 min. A first mixed gas composed of argon and oxygen (total flow rate of 1400 sccm, volume ratio of argon to oxygen of 5:0.6) is introduced for 50 min, and then cooled to room temperature.

[0051] Example 5 A method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating liquid onto the surface of a pre-deposited glass fiber cloth, allowing each layer to dry completely before coating, coating a total of 3 layers, each layer being 1 μm thick, heating to 210℃ after complete drying, holding at that temperature for 2 min, and cooling to room temperature to obtain the graphene glass fiber cloth; cutting the obtained graphene glass fiber cloth to 10cm × 10cm, using copper foil conductive tape to tightly adhere to the warp edge of the graphene glass fiber cloth, and fixing one end of the tape to a copper wire with solder, connecting it to the two electrode posts of the power supply.

[0052] The raw materials for the coating solution include: 3g silver nitrate, 2g dopamine hydrochloride, 2g single-walled carbon nanotubes, 0.3g bismuthate glass powder, 0.3g expanded graphite, and 0.3g sodium dodecylbenzenesulfonate.

[0053] The coating solution was prepared using the following steps: silver nitrate and dopamine hydrochloride were added to 25g of a 55% ethanol aqueous solution and stirred until homogeneous. While stirring, 0.15mol / L ammonia solution was added dropwise to adjust the pH of the system to 8.5. The mixture was stirred for 12h, centrifuged, washed, cooled to -35℃ and frozen for 2h, freeze-dried, calcined in a sealed muffle furnace for 60min at a calcination temperature of 450℃, cooled to room temperature, and pulverized through a 100-mesh sieve. The product, along with single-walled carbon nanotubes, bismuthate glass powder, expanded graphite, and sodium dodecylbenzenesulfonate, was added to 15g of deionized water and ultrasonically dispersed for 90min at an ultrasonic frequency of 60kHz.

[0054] The above-mentioned pre-deposited glass fiber cloth is prepared by the following steps: pretreated glass fiber is used as the growth substrate and placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure of the entire chemical vapor deposition system is pumped to 1 Pa using a mechanical pump and held for 15 min. Argon gas is introduced for purging. The system is heated to 1080℃ within 45 min. A second mixed gas of 60 sccm ethanol vapor, 80 sccm argon and 80 sccm hydrogen is introduced and grown for 90 min. Then argon gas is introduced to cool down to room temperature.

[0055] The above-mentioned pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure inside the tube furnace is evacuated to 1 Pa using a mechanical pump, and the system temperature is raised to 680°C in 15 min. A first mixed gas composed of argon and oxygen (total flow rate of 1350 sccm, volume ratio of argon to oxygen of 2:0.3) is introduced for 45 min and then cooled to room temperature.

[0056] Comparative Example 1 A method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating liquid onto the surface of a pre-deposited glass fiber cloth, allowing each layer to dry completely before coating, coating a total of 3 layers, each layer being 1 μm thick, heating to 210℃ after complete drying, holding at that temperature for 2 min, and cooling to room temperature to obtain the graphene glass fiber cloth; cutting the obtained graphene glass fiber cloth to 10cm × 10cm, using copper foil conductive tape to tightly adhere to the warp edge of the graphene glass fiber cloth, and fixing one end of the tape to a copper wire with solder, connecting it to the two electrode posts of the power supply.

[0057] The raw materials for the coating solution include: 3g silver nitrate, 2g dopamine hydrochloride, 2g single-walled carbon nanotubes, 0.6g expanded graphite, and 0.3g sodium dodecylbenzenesulfonate.

[0058] The coating solution was prepared using the following steps: silver nitrate and dopamine hydrochloride were added to 25g of a 55% ethanol aqueous solution and stirred until homogeneous. While stirring, 0.15mol / L ammonia solution was added dropwise to adjust the pH of the system to 8.5. The mixture was stirred for 12h, centrifuged, washed, cooled to -35℃ and frozen for 2h, freeze-dried, calcined in a sealed muffle furnace for 60min at a calcination temperature of 450℃, cooled to room temperature, and pulverized through a 100-mesh sieve. The product, along with single-walled carbon nanotubes, expanded graphite, and sodium dodecylbenzenesulfonate, was added to 15g of deionized water and ultrasonically dispersed for 90min at an ultrasonic frequency of 60kHz.

[0059] The above-mentioned pre-deposited glass fiber cloth is prepared by the following steps: pretreated glass fiber is used as the growth substrate and placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure of the entire chemical vapor deposition system is pumped to 1 Pa using a mechanical pump and held for 15 min. Argon gas is introduced for purging. The system is heated to 1080℃ within 45 min. A second mixed gas of 60 sccm ethanol vapor, 80 sccm argon and 80 sccm hydrogen is introduced and grown for 90 min. Then argon gas is introduced to cool down to room temperature.

[0060] The above-mentioned pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure inside the tube furnace is evacuated to 1 Pa using a mechanical pump, and the system temperature is raised to 680°C in 15 min. A first mixed gas composed of argon and oxygen (total flow rate of 1350 sccm, volume ratio of argon to oxygen of 2:0.3) is introduced for 45 min and then cooled to room temperature.

[0061] Comparative Example 2 A method for preparing a graphene glass fiber cloth electric heating device includes the following steps: coating liquid onto the surface of a pre-deposited glass fiber cloth, allowing each layer to dry completely before coating, coating a total of 3 layers, each layer being 1 μm thick, heating to 210℃ after complete drying, holding at that temperature for 2 min, and cooling to room temperature to obtain the graphene glass fiber cloth; cutting the obtained graphene glass fiber cloth to 10cm × 10cm, using copper foil conductive tape to tightly adhere to the warp edge of the graphene glass fiber cloth, and fixing one end of the tape to a copper wire with solder, connecting it to the two electrode posts of the power supply.

[0062] The raw materials for the coating solution include: 3g silver nitrate, 2g dopamine hydrochloride, 2g single-walled carbon nanotubes, 0.6g bismuthate glass powder, and 0.3g sodium dodecylbenzenesulfonate.

[0063] The coating solution was prepared using the following steps: silver nitrate and dopamine hydrochloride were added to 25g of a 55% ethanol aqueous solution and stirred until homogeneous. While stirring, 0.15mol / L ammonia solution was added dropwise to adjust the pH of the system to 8.5. The mixture was stirred for 12h, centrifuged, washed, cooled to -35℃ and frozen for 2h, freeze-dried, calcined in a sealed muffle furnace for 60min at a calcination temperature of 450℃, cooled to room temperature, and pulverized through a 100-mesh sieve. The product, along with single-walled carbon nanotubes, bismuthate glass powder, and sodium dodecylbenzenesulfonate, was added to 15g of deionized water and ultrasonically dispersed for 90min at an ultrasonic frequency of 60kHz.

[0064] The above-mentioned pre-deposited glass fiber cloth is prepared by the following steps: pretreated glass fiber is used as the growth substrate and placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure of the entire chemical vapor deposition system is pumped to 1 Pa using a mechanical pump and held for 15 min. Argon gas is introduced for purging. The system is heated to 1080℃ within 45 min. A second mixed gas of 60 sccm ethanol vapor, 80 sccm argon and 80 sccm hydrogen is introduced and grown for 90 min. Then argon gas is introduced to cool down to room temperature.

[0065] The above-mentioned pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The pressure inside the tube furnace is evacuated to 1 Pa using a mechanical pump, and the system temperature is raised to 680°C in 15 min. A first mixed gas composed of argon and oxygen (total flow rate of 1350 sccm, volume ratio of argon to oxygen of 2:0.3) is introduced for 45 min and then cooled to room temperature.

[0066] Experimental Example 1 A DC voltage of 270V was applied to the graphene glass fiber cloth electric heating devices obtained in Examples 1-5 and Comparative Examples 1-2. An infrared thermal imager was used to vertically align with the sample surface, and the voltage and DC current were set to perform electric heating analysis and calculate the electric heating rate.

[0067] like Figure 1 As shown, the electric heating rate of the graphene glass fiber cloth electric heating device obtained in Examples 1-5 is faster than that of Comparative Examples 1-2; and the electric heating rate of the graphene glass fiber cloth electric heating device obtained in Example 5 is the fastest, which is significantly better than that of Comparative Examples 1-2.

[0068] Experimental Example 2 Apply a 150V DC voltage to the graphene glass fiber cloth electric heating devices obtained in Examples 1-5 and Comparative Examples 1-2, and continue heating for 3-5 seconds until the temperature stabilizes. Record the stable temperature values ​​for each group of electric heating devices.

[0069] like Figure 2 As shown, the electric heating temperature stability values ​​of the graphene glass fiber cloth electric heating devices obtained in Examples 1-5 are significantly higher than those in Comparative Examples 1-2; while the electric heating temperature stability value of the graphene glass fiber cloth electric heating device obtained in Example 5 is the highest.

[0070] Experimental Example 3 Referring to the thermal imaging measurement method in GB / T 7287-2008 "Test Methods for Infrared Radiation Heaters", an infrared thermal imager was placed 50 cm away from the sample to measure the temperature of the graphene glass fiber cloth electric heating devices obtained in Examples 1-5 and Comparative Examples 1-2 under a DC voltage of 150V, and the electro-thermal radiation conversion efficiency was calculated.

[0071]

[0072] In the formula, η The electro-thermal radiation conversion efficiency is expressed as %; σ is the Stefan-Boltzmann constant, 5.67 × 10⁻⁶. -8 W / (m 2 ·K 4S represents the sample area, in m². 2 ;T t T0 is the average radiant temperature in K; T0 is the ambient temperature in K; and P is the measured electrical power in W.

[0073] like Figure 3 As shown, the electro-thermal radiation conversion efficiency of the graphene glass fiber cloth electric heating devices obtained in Examples 1-5 is higher than that of Comparative Examples 1-2; while the electro-thermal radiation conversion efficiency of the graphene glass fiber cloth electric heating device obtained in Example 5 is the highest, significantly better than that of Comparative Examples 1-2.

[0074] Test Example 4 A DC voltage of 200V was applied to the graphene glass fiber cloth electric heating devices obtained in Examples 1-5 and the graphene glass fiber cloth electric heating devices obtained in Comparative Examples 1-2, and the heating was continued for 3-5 seconds. It was found that the stable temperature of each group of electric heating devices could reach 270℃.

[0075] When a 100V DC voltage was applied to the graphene glass fiber cloth electric heating device obtained in Example 5 and heated continuously for 3-5 seconds, it was found that its electric heating temperature stabilized at approximately 160°C.

[0076] Each group used a new graphene glass fiber cloth electric heating device. Following the steps in Experiment Example 1 above, the DC voltage was adjusted to 200V, and the initial electric heating rate was calculated. Then, each group's graphene glass fiber cloth electric heating device was folded 180° five times, and the electric heating rate detection steps were repeated to calculate the electric heating rate after 180° folding. Based on the initial electric heating rate and the electric heating rate after 180° folding, the rate of change of electric heating rate was calculated to characterize the self-healing capability of each group's graphene glass fiber cloth electric heating device.

[0077] Taking the graphene glass fiber cloth electric heating device obtained in Example 5, and referring to the steps in Experiment Example 1 above, the DC voltage was adjusted to 100V, and the original electric heating rate was calculated. Then, it was folded 180° five times, and the electric heating rate detection steps were performed again to calculate the electric heating rate after 180° folding. Based on the original electric heating rate and the electric heating rate after 180° folding, the rate of change of the electric heating rate was calculated.

[0078] Electric heating rate change rate = (original electric heating rate - electric heating rate after 180° fold) ÷ original electric heating rate × 100%.

[0079] like Figure 4As shown, by comparing the rate of change of the electric heating rate of the graphene glass fiber cloth electric heating device obtained in Example 5 under different DC voltages, it can be seen that repeated 180° folding causes wrinkles and breakage on the surface of the graphene glass fiber cloth, resulting in increased resistance and a significantly increased rate of change of the electric heating rate. When a 200V DC current is applied to the graphene glass fiber cloth electric heating devices obtained in Examples 1-5 and Comparative Examples 1-2, the rate of change of the electric heating rate of the graphene glass fiber cloth electric heating device obtained in Examples 1-5 (200V) is significantly smaller than that of Comparative Examples 1-2; while the rate of change of the electric heating rate of the graphene glass fiber cloth electric heating device obtained in Example 5 (200V) is the smallest, confirming that the graphene glass fiber cloth electric heating device obtained in this invention has excellent self-healing effect after treatment at 270℃.

[0080] The reason for the above results is that: the present invention utilizes chemical vapor deposition to deposit graphene on the surface of pretreated glass fiber cloth to form a highly conductive network. The excellent electrothermal conversion efficiency and low resistivity of graphene itself provide a basis for efficient conductive heating. Meanwhile, the single-walled carbon nanotubes in the coating solution have one-dimensional quantum conductivity and extremely high carrier mobility. Combined with graphene, they form a three-dimensional conductive network, which significantly reduces the overall resistance. Furthermore, carbon-doped silver nanoparticles are formed by the polymerization and deposition of nitrate and dopamine hydrochloride, followed by calcination. These nanoparticles, in conjunction with the graphene conductive network, construct multi-scale conductive pathways, resulting in excellent synergistic conductive heating effects.

[0081] This invention utilizes the viscous flow of bismuthate glass powder, which, when combined with expanded graphite, undergoes volume expansion. The resulting internal pressure drives the flow, effectively repairing microcracks and defects within the material while compensating for volume shrinkage caused by thermal stress, thus maintaining structural integrity.

[0082] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A graphene glass fiber cloth electric heating device, characterized in that, include: Graphene glass fiber cloth and electrodes connected to the radial edges of the graphene glass fiber cloth; The graphene glass fiber cloth includes: a pre-deposited glass fiber cloth and a coating applied to the surface of the pre-deposited glass fiber cloth; Graphene glass fiber cloth is coated with a coating solution onto the surface of a pre-deposited glass fiber cloth. n The second coating layer should be completely dry before proceeding to the next step. n +1 coat, n It can be 1, 2 or 3; after complete drying, heat-treat at 200-220℃ for 1-3 minutes, then cool to room temperature to obtain the final product; When the graphene glass fiber cloth electric heating device is subjected to 270V DC power, the electric heating rate is ≥85℃ / s; when the graphene glass fiber cloth electric heating device is subjected to 150V DC power, the electric heating temperature stability is ≥200℃, and the electro-thermal radiation conversion efficiency is ≥40%.

2. The graphene glass fiber cloth electric heating device according to claim 1, characterized in that, The coating solution is prepared by the following steps: silver nitrate and dopamine hydrochloride are added to an ethanol aqueous solution and stirred evenly. The pH of the system is adjusted to 8-9, stirred for 10-15 hours, centrifuged, washed, cooled to -30 to -40℃ and frozen for 1-3 hours, freeze-dried, calcined in a sealed environment at 400-500℃ for 1-2 hours, cooled to room temperature, and pulverized. The product, along with single-walled carbon nanotubes, bismuthate glass powder, expanded graphite, and dispersant, is added to water and ultrasonically dispersed for 1-2 hours.

3. The graphene glass fiber cloth electric heating device according to claim 1, characterized in that, The raw materials of the coating solution, by mass, include: 1-5 parts silver nitrate, 1-3 parts dopamine hydrochloride, 1-3 parts single-walled carbon nanotubes, 0.1-0.5 parts bismuthate glass powder, 0.1-0.5 parts expanded graphite, 0.1-0.5 parts dispersant, 20-30 parts of an ethanol aqueous solution with a mass fraction of 50-60%, and 10-20 parts water.

4. The graphene glass fiber cloth electric heating device according to claim 1, characterized in that, The pre-deposited glass fiber cloth is prepared by the following steps: using pretreated glass fiber as the growth substrate, evacuating the chemical vapor deposition system and maintaining it for 10-20 minutes, purging with argon gas, heating to 1050-1100℃ and introducing a second mixed gas composed of ethanol vapor, argon and hydrogen, growing for 1-2 hours, and then introducing argon gas to cool to room temperature.

5. The graphene glass fiber cloth electric heating device according to claim 4, characterized in that, The flow rate of ethanol vapor is 50-70 sccm, and the flow ratio of ethanol vapor, argon, and hydrogen is 5-7:5-10:5-10.

6. The graphene glass fiber cloth electric heating device according to claim 4, characterized in that, The vacuum pressure of the chemical vapor deposition system should not exceed 2.5 Pa.

7. The graphene glass fiber cloth electric heating device according to claim 4, characterized in that, The pretreated glass fiber cloth is prepared by the following steps: the glass fiber cloth is cut into rectangles, rolled into a cylindrical shape, placed in the center of a quartz glass tube, and then placed in the center of the constant temperature zone of a three-temperature zone tube furnace. The tube furnace is evacuated, heated to 650-700℃, and treated with a first mixed gas composed of argon and oxygen for 0.5-1 hours, and then cooled to room temperature.

8. The graphene glass fiber cloth electric heating device according to claim 7, characterized in that, The fiberglass cloth has a thickness of 0.1-0.3 mm and a basis weight of 200-300 g / m. 2 .

9. The graphene glass fiber cloth electric heating device according to claim 7, characterized in that, The flow rate of the first mixed gas is 1200-1500 sccm, and the volume ratio of argon to oxygen is 10:1-2.

10. A method for preparing a graphene glass fiber cloth electric heating device as described in any one of claims 1-9, characterized in that, The process includes the following steps: applying the coating solution to the surface of the pre-deposited glass fiber cloth, when the first... n The second coating layer should be completely dry before proceeding to the next step. n +1 coat, n The coating layers are 1, 2, or 3, with each layer having a thickness of 0.5-2 μm. After complete drying, the coating is heat-treated at 200-220℃ for 1-3 minutes and then cooled to room temperature to obtain graphene glass fiber cloth. Then, the electrodes are connected to the warp edge of the graphene glass fiber cloth.

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