Method for deicing by using MXene / carbon nanotube composite membrane

Abstract

The invention discloses a method for deicing by using an MXene / carbon nanotube composite membrane. The method comprises the following steps: preparing a high-concentration MXene nanosheet dispersion liquid; preparing an MXene / carbon nanotube composite slurry; performing rod coating on the MXene / carbon nanotube composite film by using an automatic coating machine; preparing an MXene / carbon nanotube composite film with a protective layer; and the MXene / carbon nanotube composite film is used for deicing. According to the preparation method provided by the invention, the effect of simply and efficiently dispersing the carbon nanotubes is realized, chemical modification is not needed, the production process is simple and efficient, and large-scale preparation can be realized. The rheological property of the slurry can be changed by controlling different proportions of MXene / carbon nanotubes, so that different compound film products can be prepared. The MXene-based composite membrane is good in stability, green, environment-friendly and low in cost; the device has good photo-thermal and electric heating effects, stable temperature rise can be achieved under low driving voltage, ice blocks can be melted, and the purpose of electric heating deicing is achieved.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of two-dimensional material films and electrothermal / photothermal de-icing, and relates to a method for de-icing using an MXene / carbon nanotube composite film. Background Art

[0002] Ice formation is a common natural phenomenon in daily life. Traditional de-icing strategies include chemical de-icing and mechanical de-icing. These methods are energy-consuming, inefficient, and environmentally unfriendly. Electrothermal and photothermal conversion are one of the most economical and environmentally friendly methods to solve the de-icing problem. Joule heat performance and photothermal conversion performance are two important factors affecting electrothermal / photothermal de-icing. In addition, it is necessary to develop lightweight flexible films to meet the de-icing requirements of aircraft, engines, wind turbine blades, etc.

[0003] As a currently emerging and efficient electrothermal / photothermal conversion material, MXene is a layered two-dimensional transition metal carbide / nitride, which has excellent Joule heat and high light absorption rate, and has potential applications in electrothermal / photothermal. Carbon nanotubes, a carbon material, are widely used because of their excellent mechanical properties, excellent electrical conductivity and heat transfer ability. Using MXene as a dispersant, carbon nanotubes are ultrasonically dispersed, and a rod coating method is used to prepare an MXene / carbon nanotube composite film with excellent electrothermal and photothermal properties. The composite film is expected to be prepared on a large scale and has broad development space in the field of de-icing. Summary of the Invention

[0004] The purpose of the present invention is to provide the preparation of an MXene / carbon nanotube composite film and its electrothermal / photothermal de-icing application. The MXene-based composite film has good stability, is green and environmentally friendly, and has low cost. The preparation process of this method is simple, efficient and fast, and the assembly scale is easy to be scaled up. The prepared MXene / carbon nanotube composite film has good photothermal and electrothermal properties, can achieve stable temperature rise under low driving voltage and light illumination, and has application prospects in electrothermal / photothermal de-icing.

[0005] The technical solution of the present invention:

[0006] A method for de-icing using an MXene / carbon nanotube composite film, comprising the following steps:

[0007] S1. Prepare a high-concentration MXene nanosheet dispersion;

[0008] Prepare a high-concentration MXene nanosheet dispersion by using the concentrated hydrochloric acid etching and ultrasonic exfoliation method disclosed in "Roll-To-Roll Fabricating MXene Membranes with Ordered Interlayer Distances For Molecule And Ion Separation";

[0009] S2. Prepare MXene / carbon nanotube composite slurry;

[0010] Mix carbon nanotube powder with a high-concentration MXene nanosheet dispersion liquid to prepare a 3-10 wt% carbon nanotube mixed dispersion liquid. Subject the mixed dispersion liquid to tip ultrasonic dispersion treatment under the conditions of an ice bath and an N 2 atmosphere to obtain a uniformly dispersed MXene / carbon nanotube composite slurry;

[0011] S3. Rod coat the MXene / carbon nanotube composite film with an automatic coater:

[0012] Place the MXene / carbon nanotube composite slurry obtained in step S2 on an automatic coater, and use a Meyer rod to uniformly scrape and coat the MXene / carbon nanotube composite slurry on a polymer substrate. Wait for the MXene / carbon nanotube composite slurry to dry, and repeat the above process for multiple scraping coatings to obtain a MXene / carbon nanotube composite film with a loading of 0.5-1.5 mg / cm 2 ;

[0013] S4. Prepare a MXene / carbon nanotube composite film with a protective layer

[0014] Immerse the MXene / carbon nanotube composite film obtained in step S3 in a polymer dispersion liquid, take it out and dry it after 5-20 min of immersion;

[0015] S5. De-ice the MXene / carbon nanotube composite film

[0016] Conduct an electrothermal de-icing performance test on the composite film. Cut the composite film according to the size and connect it to a power supply. Place ice cubes on the composite film and record the temperature change of the ice cubes in real time.

[0017] In step S1, the HCl concentration is 9 mol / L, and the ratio of the volume of HCl to the mass of the Ti 3 AlC 2 powder is 20 mL:1 mg, and the pH value of the high-concentration MXene nanosheet dispersion liquid is 5.5-6.5.

[0018] In step S1, the rotation speed of the magnetic stirring is 500 rad / s, and the rotation speed of the centrifuge during impurity removal is 3500 rpm.

[0019] In step S2, the time of ultrasonic dispersion treatment is 5-20 min.

[0020] In step S3, the groove depth of the Meyer rod is 3-12 μm, the coating speed is 5-20 mm / s, and the polymer substrate is polyethersulfone (PES) or polyethylene terephthalate (PET).

[0021] In step S4, the polymer is polyvinyl alcohol (PVA), the concentration of the polymer dispersion is 10 - 50 mg / mL, and the drying time is 10 - 30 min.

[0022] In step S5, the size of the composite film is 1 - 25 cm 2 , the input voltage is 1 - 5 V, and the size of the ice cubes is 1 - 5 cm 3 , and the ambient temperature is -5 - 20 °C.

[0023] A MXene / carbon nanotube composite film has a conductivity of 1500 - 3000 S / cm, a thickness of 0.5 - 2 μm, a thermal conductivity of 0.1 - 0.375 W / (m K), reaches 90 °C within 27 s under a 5 V voltage, and reaches 80 °C within 20 s under the intensity of solar light of 1.0 kW / m 2 . In the repeated electrothermal and photothermal performance tests, the cycling performance is good. In the de-icing test, it can effectively melt the ice cubes.

[0024] Advantages of the present invention: The MXene / carbon nanotube composite film of the present invention has excellent electrothermal and photothermal conversion performances, with rapid thermal response performance, stable cycling performance, and precise temperature adjustable performance. Because MXene has excellent light conversion performance, the MXene / carbon nanotube composite film shows good photothermal conversion performance in the field of photothermal conversion. Compared with other composite films, it can achieve the effect of de-icing for 24 h on the premise of reducing energy consumption. De-icing experiments were carried out at room temperature and cold conditions. Compared with the normal melting of ice cubes, the composite film reduces the melting time of ice cubes by half, and has excellent de-icing ability. These findings provide new ideas and methods for the application of MXene and carbon nanotubes, and provide a reliable way to solve the de-icing problem. The method for preparing the composite film and de-icing of the present invention is simple, easy to implement, efficient, fast, and the assembly scale is easy to scale up. Description of the Drawings

[0025] Figure 1 are physical diagrams of MXene / carbon nanotube composite films in some embodiments. Among them, a is the physical diagram of the MXene / carbon nanotube composite film prepared in Example 1, and b is the physical diagram of the MXene / carbon nanotube composite film prepared in Example 2.

[0026] Figure 2 are viscosity diagrams of some MXene / carbon nanotube composite dispersions, where the naming is in accordance with MX-x / MW-n. x represents the concentration (g / L) of the MXene dispersion, and n represents the mass ratio (wt%) of carbon nanotubes. The viscosity of the pure MXene dispersion is 0.01363 pa·s, while the viscosity of the MX-5 / MW-20 dispersion reaches 38.05 pa·s, and the viscosity increases exponentially, increasing by 2700 times.

[0027] Figure 3 The de-icing effect diagram of the MXene / carbon nanotube composite film in Example 3 under a voltage of 5V. Among them, a is the initial state of the ice block, and b is that the ice block completely melts within 600s.

[0028] Figure 4 The de-icing effect diagram of the MXene / carbon nanotube composite film in Example 4 under a voltage of 0V. Among them, a is the initial state of the ice block, and b is that there is no sign of melting of the ice block at 600s.

[0029] Figure 5 The de-icing effect diagram of the MXene / carbon nanotube composite film in Example 5 under a voltage of 3V. Among them, a is the initial state of the ice block, and b is that the ice block completely melts within 960s.

[0030] Figure 6 The de-icing effect diagram of the MXene / carbon nanotube composite film in Example 6 under a voltage of 5V. Among them, a is the initial state of the ice block, and b is that the ice block completely melts within 600s under cold conditions (-5°C). Detailed implementation manners

[0031] The following further illustrates the detailed implementation manners of the present invention in combination with the attached drawings and technical solutions.

[0032] Example 1:

[0033] A method for de-icing using an MXene / carbon nanotube composite film is provided, including the following steps:

[0034] S1. Prepare a high-concentration MXene nanosheet dispersion:

[0035] S101. Chemically etch the MXene raw material Ti 3 AlC 2 :

[0036] Add 2.88 g of lithium fluoride (LiF) to 36 mL of HCl (9 mol / L), stir magnetically until evenly mixed, and slowly add 1.8 g of Ti 3 AlC 2 powder to the acid, stir magnetically at 45°C for 48 h to obtain multi-layer Ti 3 C 2 T x MXene. Use a centrifuge to centrifuge the dispersion to remove impurities, wash with deionized water, and after multiple centrifugations, the pH is close to 6, that is, the chemical etching of Ti 3 AlC 2 is completed;

[0037] S102. Using the multi-layer Ti 3 C2 T x Based on MXene, ultrasonic delamination:

[0038] The washed multi-layer Ti 3 C 2 T x MXene was added to deionized water to form a 60 mL dispersion, which was placed in a tip sonicator for ultrasonic delamination to prepare nanosheets of multi-layer MXene. Under the conditions of an ice bath and an N 2 atmosphere, ultrasonic treatment was carried out for 10 min, and the ultrasonic treatment was repeated 7 times to obtain a dispersion of MXene nanosheets; then the dispersion of MXene nanosheets was centrifugally concentrated in a centrifuge at a rotation speed of 3500 rpm to a dispersion of MXene nanosheets with a concentration of 30 g / L;

[0039] S2. Preparation of MXene / carbon nanotube composite slurry:

[0040] The concentration of MXene was diluted to 12 g / L, and MWCNT powder was mixed with the MXene dispersion in a mass ratio of 10%. The mixture was ultrasonically dispersed under the conditions of an ice bath and an N 2 atmosphere to obtain a uniformly dispersed MXene / carbon nanotube composite slurry;

[0041] S3. Rod coating of MXene / carbon nanotube composite film by an automatic coater:

[0042] The MXene / carbon nanotube composite slurry obtained in step S2 was placed on an automatic coater, and the composite slurry was evenly blade-coated on a polymer (PES) substrate using a Meyer rod (groove: 12 μm). After waiting for the slurry to dry, the above process was repeated for multiple blade coatings to obtain a MXene / carbon nanotube composite film with a loading of 1 mg / cm 2 2.

[0043] S4. Preparation of MXene / carbon nanotube composite film with a protective layer

[0044] The MXene / carbon nanotube composite film obtained in step S3 was immersed in a polymer (PVA) dispersion with a concentration of 50 mg / mL, taken out after 10 min of immersion, and dried for 30 min to obtain a MXene / carbon nanotube composite film with a protective layer.

[0045] Example 2:

[0046] A method for deicing using a MXene / carbon nanotube composite film is provided, including the following steps:

[0047] The steps refer to Example 1, and the mass ratio of carbon nanotube powder in S2 was changed to 20 wt% compared with Example 1. It was found that when performing step S3, the preparation of the composite film failed. AsFigure 2 As shown, when the mass ratio of the carbon nanotube powder is too high, the viscosity of the dispersion liquid is too high, causing the rheological properties of the dispersion liquid to change, transforming from a sol to a gel, and it is difficult to form a film by bar coating.

[0048] Example 3:

[0049] Provide a method for deicing with an MXene / carbon nanotube composite film, including the following steps:

[0050] The preparation steps refer to Example 1, and change S5 to:

[0051] S5. Electrothermal deicing of the MXene / carbon nanotube composite film

[0052] Connect the two-dimensional MXene / carbon nanotube composite film loaded on the PES substrate to a 5V power supply with an electric clamp, place an ice cube with a volume of 1 cm 3 on the MXene / carbon nanotube composite film, and record the temperature change of the ice cube. The ambient temperature is 20 °C, and the ice cube gradually melts within 10 minutes.

[0053] Example 4:

[0054] Provide a method for deicing with an MXene / carbon nanotube composite film, including the following steps:

[0055] The preparation steps refer to Example 1, and change S5 to:

[0056] S5. Electrothermal deicing of the MXene / carbon nanotube composite film

[0057] Connect the two-dimensional MXene / carbon nanotube composite film loaded on the PES substrate to a 0V power supply with an electric clamp, place an ice cube with a volume of 1 cm 3 on the MXene / carbon nanotube composite film, and record the temperature change of the ice cube. The ambient temperature is 20 °C, and after 10 minutes, there is no sign of the ice cube melting.

[0058] Example 5:

[0059] Provide a method for deicing with an MXene / carbon nanotube composite film, including the following steps:

[0060] The preparation steps refer to Example 1, and change S5 to:

[0061] S5. Electrothermal deicing of the MXene / carbon nanotube composite film

[0062] Connect the two-dimensional MXene / carbon nanotube composite film loaded on the PES substrate to a 3V power supply with an electric clamp, place an ice cube with a volume of 1 cm 3The ice cube was placed on the MXene / carbon nanotube composite film, and the temperature change of the ice cube was recorded. The ambient temperature was 20 °C, and the ice cube gradually melted within 16 minutes.

[0063] Example 6:

[0064] A method for deicing using an MXene / carbon nanotube composite film is provided, including the following steps:

[0065] The preparation steps refer to Example 1, and S5 is changed to:

[0066] S5. Electrothermal deicing of the MXene / carbon nanotube composite film

[0067] The two-dimensional MXene / carbon nanotube composite film loaded on the PES substrate was connected to a 5V power supply with an electric clamp, and an ice cube with a volume of 1 cm 3 The ice cube was placed on the MXene / carbon nanotube composite film, and the temperature change of the ice cube was recorded. The ambient temperature was -5 °C, and the ice cube gradually melted within 10 minutes.

Claims

1. A method for deicing using a MXene / carbon nanotube composite film, characterized in that: The following steps are involved: S1, preparing a high concentration MXene nanosheet dispersion; High-concentration MXene nanosheet dispersion was prepared by concentrated hydrochloric acid etching and ultrasonic exfoliation method; S2, preparing MXene / carbon nanotube composite slurry; The carbon nanotube powder is mixed with a high concentration of MXene nanosheet dispersion to prepare a 3-10wt% carbon nanotube mixed dispersion, and the mixed dispersion is subjected to a cutting-edge ultrasonic dispersion treatment under the conditions of an ice bath and a N2 atmosphere to obtain a uniformly dispersed MXene / carbon nanotube composite slurry; S3, automatic coating machine rod coating MXene / carbon nanotube composite film: The MXene / carbon nanotube composite slurry obtained in step S2 is placed on an automatic coating machine, and the MXene / carbon nanotube composite slurry is evenly scraped on the polymer substrate using a Meyer rod. The MXene / carbon nanotube composite slurry is dried and the above process is repeated for multiple scrapings to obtain a loading of 0.5-1.5 mg / cm 2 MXene / carbon nanotube composite film; S4. Preparation of MXene / carbon nanotube composite film with protective layer The MXene / carbon nanotube composite film obtained in step S3 is immersed in the polymer dispersion for 5-20 minutes and then taken out and dried; S5, MXene / carbon nanotube composite membrane deicing The electric heating deicing performance of the composite film was tested. The composite film was cut to size and connected to a power source. Ice cubes were placed on the composite film, and the temperature changes of the ice cubes were recorded in real time.

2. The method according to claim 1, characterized in that In step S1, the concentration of HCl is 9 mol / L, the ratio of the volume of HCl to the mass of Ti3AlC2 powder is controlled to be 20 mL:1 mg, and the pH value of the high-concentration MXene nanosheet dispersion is 5.5-6.

5.

3. The method according to claim 1, characterized in that In step S1, the rotation speed of the magnetic stirring is 500 rad / s, and the rotation speed of the centrifuge during impurity removal is 3500 rpm.

4. The method according to claim 1, characterized in that: In step S2, the ultrasonic dispersion treatment time is 5-20 minutes.

5. The method according to claim 1, characterized in that: In step S3, the groove depth of the Meyer rod is 3-12 μm, the coating speed is 5-20 mm / s, and the polymer substrate is polyethersulfone or polyethylene terephthalate.

6. The method according to claim 1, characterized in that In step S4, the polymer is polyvinyl alcohol, the concentration of the polymer dispersion is 10-50 mg / mL, and the drying time is 10-30 min.

7. The method according to claim 1, characterized in that In step S5, the size of the composite film is 1-25 cm 2 , input voltage is 1-5V, ice cube size is 1-5cm 3 , the ambient temperature is -5-20℃.

8. The method according to claim 1, characterized in that: The MXene / carbon nanotube composite film has an electrical conductivity of 1500-3000 S / cm, a thickness of 0.5-2 μm, a thermal conductivity of 0.1-0.375 W / (m K), reaches 90°C within 27 seconds at 5 V, and a thermal conductivity of 1.0 kW / m 2 Under the intensity of sunlight, it reaches 80℃ within 20s.

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