1T-MoS2 enhanced heat-conducting and wave-absorbing integrated composite material as well as preparation method and application thereof

Abstract

The invention relates to the field of heat-conducting and wave-absorbing composite materials, and discloses a 1T-MoS2 enhanced heat-conducting and wave-absorbing integrated composite material and a preparation method and application thereof.The preparation method comprises the following steps that 1T-MoS2 of a nanoflower wrinkle structure is prepared through a hydrothermal method; carrying out electrostatic self-assembly to prepare 1T-MoS < 2 > at BNNS; and preparing the 1T-MoS2 (at) BNNS / PDMS composite material. According to the preparation method disclosed by the invention, efficient wave absorption and continuous heat transmission are simultaneously realized in the composite material by constructing a nanoflower wrinkle-shaped heterostructure, so that the electromagnetic protection and heat management performance of an electronic device is improved, and the material disclosed by the invention can realize efficient combination of heat conduction and wave absorption dual functions without high-temperature calcination or a complex multi-layer structure; the application reliability and process controllability of the material are remarkably improved, meanwhile, the preparation complexity and cost of the material are reduced, and the method has wide application prospects and remarkable economic benefits and social benefits.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of heat-conducting wave-absorbing composite materials, in particular to a 1T-MoS2 reinforced heat-conducting wave-absorbing integrated composite material, a preparation method and application thereof. BACKGROUND

[0002] In high-frequency wireless communication devices such as 5G Wi-Fi routers, the electromagnetic interference is significantly intensified by the increase of working frequency band, and the heat is quickly accumulated due to the high power density operation of the radio frequency chip and the power amplification module, which makes the electromagnetic interference and thermal runaway become the key factors limiting the stability and signal reliability of the system. Therefore, a material system capable of effectively attenuating and exporting electromagnetic waves in the 5G frequency band is urgently needed. 1T-MoS2 has high electrical conductivity and abundant defects, which can provide strong interface polarization and conductive loss, and has outstanding advantages in low-frequency wave absorption; but the high electrical conductivity will enhance the phonon scattering and reduce the heat transport, making it difficult to simultaneously have excellent wave absorption and high thermal conductivity. BNNS has high in-plane thermal conductivity and can build a heat transport network, but its electrical insulation and stacking behavior in the matrix make it unable to independently provide effective wave absorption. In the existing system, the functions of the two often interfere with each other, making it difficult to simultaneously meet the wave absorption-thermal conductivity coordination requirements.

[0003] The existing technical solution one (CN113772637A) is to use BNNS as a heat-conducting filler, and use molybdenum disulfide (MoS2) and titanium carbide (MXene) as wave-absorbing fillers. Under the premise of not damaging the performance and structure of the wave-absorbing fillers (MXene or MoS2), the BNNS with high thermal conductivity is inserted into the interlayer of the wave-absorbing fillers by calcination method to prepare a nano-composite material with heat conduction and wave absorption integration. This solution has the following shortcomings: 1) BNNS is inserted into the interlayer of MoS2 / MXene by calcination method, but the process will damage the layer structure and cannot stably maintain the electrical conductivity and polarization characteristics of 1T-MoS2, the polarization loss capacity is limited, and the intrinsic phase and interface of MoS2 cannot be engineered and regulated; 2) The calcination insertion process cannot realize efficient coordination of heat conduction and wave absorption, which easily damages the layer structure and reduces the heat transport efficiency, making it difficult for the composite material to simultaneously have excellent wave absorption capacity and high thermal conductivity.

[0004] The existing technical solution two (CN117165082A) uses BNNS as a heat-conducting filler and CoNi as a wave-absorbing filler, and provides a preparation method of a daisy-shaped heterostructure filler with heat conduction and wave absorption functions and a silicone rubber composite material. This solution has the following shortcomings: This technology prepares one-dimensional magnetic chain-like CoNi and constructs a hydrangea-like heterostructure with BNNS. However, the microwave absorption function mainly relies on magnetic fillers and cannot make full use of fillers with high conductivity and high interfacial polarization characteristics. There is room for improvement in microwave absorption efficiency at low frequencies and in the wide frequency band. The preparation process uses a "spray drying-sintering" method, which is complex and the high-temperature treatment may damage the filler structure. At the same time, the thermal conductivity of the material depends on the stacking of BNNS sheets, making it difficult to form a continuous three-dimensional thermal channel, and the synergistic effect of thermal conduction and microwave absorption is limited.

[0005] Therefore, it is necessary to construct a heterostructure with 1T-MoS2 as the microwave absorbing framework and BNNS introduced to form a continuous phonon channel, so as to simultaneously enhance electromagnetic energy dissipation and heat conduction at the microscale, thereby overcoming the limitation that microwave absorption and thermal conductivity are difficult to achieve simultaneously. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a 1T-MoS2-reinforced thermally conductive and microwave-absorbing integrated composite material, its preparation method, and its application. By constructing a nanoflower-like wrinkled heterostructure, efficient microwave absorption and continuous heat transfer are simultaneously achieved in the composite material, thereby improving the electromagnetic protection and thermal management performance of electronic devices.

[0007] To achieve the above objectives, the technical solution of the present invention is as follows: A method for preparing a 1T-MoS2 reinforced thermally conductive and microwave-absorbing composite material includes the following steps: Step 1: Preparation of 1T-MoS2 with nanoflower-like wrinkled structures using a hydrothermal method: Using Na2MoO4·2H2O and thiourea as raw materials, 1T-MoS2 with nanoflower-like folded structure was prepared by hydrothermal reaction combined with NaBH4 reduction. Step 2, electrostatic self-assembly preparation of 1T-MoS2@BNNS: PDA-MoS2 was obtained by surface modification of the 1T-MoS2 nanoflower-shaped folded structure with dopamine; PDA-MoS2 was obtained by surface modification of the 1T-MoS2 nanoflower-shaped folded structure with polyethyleneimine. h PEI-BNNS was obtained by surface modification of PDA-MoS2 and PEI-BNNS; then PDA-MoS2 and PEI-BNNS were self-assembled by opposite charge driving method to obtain 1T-MoS2@BNNS, a heterostructure filler with BNNS intercalated 1T-MoS2 nanoflowers. Step 3, Preparation of 1T-MoS2@BNNS / PDMS composite material: Using 1T-MoS2@BNNS and PDMS as raw materials, a thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS / PDMS was prepared through dispersion, homogenization, vacuum degassing and curing.

[0008] In the above scheme, the specific method for step 1 is as follows: Add Na2MoO4·2H2O and thiourea to deionized water and stir to completely dissolve the raw materials to obtain a homogeneous mixed precursor solution. The mixed precursor solution was transferred to a reaction vessel lined with polytetrafluoroethylene and reacted at 180–220 °C for 12–30 h. After the reaction was completed, the mixture was naturally cooled to room temperature, and the resulting black precipitate was collected. It was washed 2–5 times with anhydrous ethanol and deionized water, and then dried in a vacuum drying oven at 50–80 °C for 2–8 h to obtain the nanoflower-like MoS2 precursor. The obtained nanoflower-like MoS2 precursor was dispersed in deionized water and stirred under ice bath conditions to form a uniform suspension. Then, NaBH4 solution was slowly added dropwise, and the reaction was continued under ice bath conditions for 20-40 min. After that, the mixture was stirred at room temperature for 1-2 h to complete the partial phase inversion. After the reaction was completed, the product was washed with ethanol 2-5 times and dried under vacuum conditions at 50-80℃ for 2-6 h to obtain 1T-MoS2 with a nanoflower-like folded structure.

[0009] In the above scheme, step 2, the preparation method of PDA-MoS2 is as follows: The obtained nanoflower-shaped 1T-MoS2 was added to a dopamine solution and magnetically stirred at room temperature for 30–90 min to complete the self-polymerization and coating of dopamine on the surface of 1T-MoS2. After the reaction was completed, the mixture was centrifuged and washed 2–5 times with deionized water, and then vacuum dried for 2–6 h to obtain PDA-MoS2.

[0010] In the above scheme, step 2, the preparation method of PEI-BNNS is as follows: Will h -BNNS was added to an aqueous solution containing 0.5-2 wt% polyethyleneimine, sonicated for 20-40 min, and then mechanically stirred for 1-3 h. After the reaction was completed, the solid was collected by centrifugation, washed several times with ethanol and deionized water, and dried at 40-60 °C for 2-6 h to obtain PEI-BNNS.

[0011] In the above scheme, the preparation method of 1T-MoS2@BNNS in step 2 is as follows: PEI-BNNS was dispersed in a mixed solution of water and ethanol. After ultrasonic dispersion, PDA-MoS2 suspension was added dropwise under stirring. Stirring was continued for 20-40 min, and the mixture was allowed to stand for 10-14 h to allow BNNS to be uniformly embedded in the interlayer of 1T-MoS2 to form a heterostructure composite system. The obtained solid was centrifuged and washed with ethanol to remove unbound substances; then annealed at 120-180℃ for 1-3 hours under an inert atmosphere, and cooled to room temperature to obtain the thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS.

[0012] In the above scheme, step 3 is specifically implemented as follows: The obtained thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS was dried in a vacuum environment at 80℃ to obtain a solid filler. Take the above solid filler and add 20-30 parts of an auxiliary dispersion solvent composed of ethanol and isopropanol. Use ultrasound to uniformly disperse the filler to form a fluid mixed suspension system. The mixed suspension system is slowly added to PDMS and homogenized to fully disperse the composite filler in PDMS, forming a uniform PDMS prepolymer composite slurry. The PDMS prepolymer composite slurry was placed in a vacuum environment at 80℃ for degassing treatment, and then the auxiliary dispersion solvent in the system was allowed to evaporate and be removed naturally to obtain a pre-cured composite system. A curing agent was added to the pre-cured composite system and stirred to allow the curing agent and PDMS prepolymer to be mixed a second time and evenly distributed in the system. Subsequently, the system was cured in a vacuum environment at 80°C to allow the PDMS prepolymer to cross-link and form, resulting in the thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS / PDMS.

[0013] In the above scheme, in step 2, 1T-MoS2 and h - The mass ratio of BNNS is 1:1.5 to 1.5:1.

[0014] Preferably, in step 2, 1T-MoS2 and h -BNNS mass ratio is 1:1.5, 1:1 or 1.5:1.

[0015] A thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS / PDMS prepared by the preparation method described in any of the preceding claims.

[0016] Application of the above-mentioned thermally conductive and electromagnetically absorbing integrated composite material 1T-MoS2@BNNS / PDMS in thermal management and electromagnetic interference shielding of electronic devices.

[0017] Through the above technical solution, the 1T-MoS2 reinforced thermally conductive and microwave-absorbing integrated composite material, its preparation method, and its application provided by the present invention have the following beneficial effects: 1. This invention first prepares 1T-MoS2 with a nanoflower-like folded structure via a hydrothermal method. Unlike the blocky, sheet-like, or simple layered MoS2 commonly found in existing technologies, the 1T-MoS2 obtained in this invention is a three-dimensional nanoflower structure formed by the self-assembly of two-dimensional nanosheets with multi-level folds. This structure contains a large number of open interlayer voids and tortuous interfaces. On the one hand, this nanoflower-like folded structure significantly increases the specific surface area and the number of effective interfaces, which is beneficial for multiple scattering and reflection of electromagnetic waves within the structure, enhancing dielectric loss and polarization loss capabilities. On the other hand, the folds and interlayer voids provide ample spatial sites for subsequent BN intercalation and embedding, avoiding the problems of filler stacking and insufficient interfacial contact in traditional planar sheet structures.

[0018] 2. This invention embeds functionalized BNNS into the interlayer of 1T-MoS2 through electrostatic self-assembly, producing a BNNS-intercalated 1T-MoS2 nanoflower heterostructure filler, 1T-MoS2@BNNS. Compared with existing composite methods that rely on high-temperature calcination, physical mixing, or simple layered stacking, this invention employs an opposite-charge-driven electrostatic self-assembly method to achieve ordered composite between BNNS and 1T-MoS2 under mild conditions. This effectively avoids the damage to the 1T phase structure, electrical conductivity, and nanoflower morphology caused by high-temperature treatment, while significantly improving the uniformity and stability of the interfacial bonding. At the structural level, the introduction of BNNS, distributed in the interlayer and surface regions of the 1T-MoS2 nanoflowers through intercalation and partial coverage, effectively suppresses the layered recombination and structural collapse of 1T-MoS2 during subsequent processing and use, maintaining the openness and hierarchical porosity of the nanoflower structure. Meanwhile, the intercalated BNNS plays a "support-isolation" role in three-dimensional space, which is conducive to building a stable and continuous interface network and provides a structural basis for the formation of subsequent heat conduction channels.

[0019] 3. In this invention, 1T-MoS2@BNNS, a heterostructure filler with BNNS intercalated 1T-MoS2 nanoflowers, is uniformly dispersed in PDMS prepolymer to achieve a synergistic improvement in the material's efficient electromagnetic wave absorption and excellent thermal conductivity over a wide frequency band.

[0020] The composite material prepared by this invention can effectively alleviate electromagnetic interference and heat accumulation problems during the operation of electronic devices, while maintaining excellent interface stability and structural integrity. Compared with existing technologies, the material of this invention can achieve a highly efficient combination of thermal conductivity and electromagnetic absorption without high-temperature calcination or complex multilayer structures, significantly improving the application reliability and process controllability of the material. The technical solution of this invention not only helps in the thermal management and electromagnetic protection design of electronic devices, but also reduces the complexity and cost of material preparation, and has broad application prospects and significant economic and social benefits. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0022] Figure 1 This is a schematic diagram of a method for preparing a 1T-MoS2-reinforced thermally conductive and microwave-absorbing integrated composite material disclosed in an embodiment of the present invention; Figure 2 The scanning electron microscope morphology of 1T-MoS2 prepared in Example 1 is shown; (a) is a magnified image at 2 μm, and (b) is a magnified image at 500 nm. Figure 3 The transmission electron microscope morphology of the 1T-MoS2@BNNS (1.5:1) heterostructure filler prepared in Example 1; Figure 4 The transmission electron microscope morphology of the 1T-MoS2@BNNS(1:1) heterostructure filler prepared in Example 2; Figure 5 The transmission electron microscope morphology of the 1T-MoS2@BNNS (1:1.5) heterostructure filler prepared in Example 3 is shown. Figure 6 The following are three-dimensional schematic diagrams showing the minimum reflection loss, thickness, and frequency of the 1T-MoS2@BNNS / PDMS composite materials prepared in Examples 1, 2, and 3: (a) is 1T-MoS2@BNNS / PDMS composite material 1, (b) is 1T-MoS2@BNNS / PDMS composite material 2, and (c) is 1T-MoS2@BNNS / PDMS composite material 3. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0024] This invention provides a 1T-MoS2-reinforced thermally conductive and microwave-absorbing integrated composite material, its preparation method, and its applications. The raw materials used in the material preparation process include Na2MoO4·2H2O, thiourea, and deionized water as reaction media for 1T-MoS2 preparation. In the phase transformation step, NaBH4 solution is used to partially transform the 1T phase. In the heterostructure construction step, dopamine (PDA) solution is used to self-polymerize and coat the surface of 1T-MoS2, and polyethyleneimine (PEI) solution is used to coat the surface of the 1T-MoS2. hThe surface of BNNS nanosheets was modified to carry a positive charge for subsequent electrostatic self-assembly. Ethanol, deionized water, and isopropanol were used as solvents for material washing and dispersion. The composite material preparation used 1T-MoS2@BNNS composite filler, PDMS prepolymer, and its matching curing agent as the matrix system. A certain amount of water / ethanol mixed solvent or other auxiliary dispersion solvents were added as needed to adjust the dispersion state of the filler in PDMS. All raw materials were of commonly used laboratory purity, meeting the requirements for nanofiller preparation, surface modification, and composite material construction.

[0025] The experimental equipment used in the implementation of this invention includes a PTFE-lined high-pressure reactor for hydrothermal reaction, a constant-temperature oven and a vacuum drying oven for drying and precursor treatment, a high-speed centrifuge for material washing and separation, and a magnetic stirrer and an ultrasonic disperser for solution mixing and dispersion. During interface control and structural stabilization, an inert atmosphere annealing furnace is used for low-temperature heat treatment, combined with a vacuum degassing device to remove venting and solvent from the composite slurry. The preparation of the composite material also requires the use of a heating platform, molds, and a constant-temperature curing device to complete the molding and curing of PDMS. Simultaneously, an electronic balance, pH meter, measuring instruments, and conventional laboratory glassware are used for precise quantification, solution preparation, and experimental monitoring. All of the above equipment is conventional experimental equipment and can meet the preparation requirements of the 1T-MoS2@BNNS heterostructure and its PDMS composite material described in this invention.

[0026] Example 1 The preparation method flowchart is as follows Figure 1 As shown, it includes the following steps: Step 1, Preparation of 1T-MoS2 with nanoflower-like folded structures: Ten parts of Na₂MoO₄·2H₂O and 120 parts of thiourea were added to 600 parts of deionized water and magnetically stirred for 40 minutes to completely dissolve the raw materials, obtaining a homogeneous mixed precursor solution. This mixed precursor solution was transferred to a reaction vessel lined with polytetrafluoroethylene (PTFE) and reacted at 200°C for 24 hours. After the reaction, the mixture was allowed to cool naturally to room temperature, and the resulting black precipitate was collected. It was washed three times successively with anhydrous ethanol and deionized water, and then dried in a vacuum drying oven at 60°C for 4 hours to obtain the nanoflower-like MoS₂ precursor.

[0027] The dried MoS2 product obtained in the previous step was dispersed in 600 parts of deionized water and stirred under ice bath conditions to form a homogeneous suspension. Then, 25 parts of NaBH4 solution were slowly added dropwise, and the reaction continued under ice bath conditions for 30 minutes. Afterward, the mixture was stirred at room temperature for 1.5 hours to complete partial phase inversion. After the reaction, the product was washed three times with ethanol and dried at 60°C under vacuum for 4 hours to obtain 1T-MoS2 with a nanoflower-like pleated structure.Figure 2 As shown, from Figure 2 As can be seen, the prepared 1T-MoS2 has a rich and complete continuous nanoflower fold structure.

[0028] Step 2, Preparation of 1T-MoS2@BNNS heterostructure: In this embodiment, the mass ratio is 1.5:1 (1T-MoS2: h With the design target being PDA-BNNS, 100 parts of 1T-MoS2 prepared and dried in the previous steps were first added to 1000 parts of a PDA solution with a concentration of 2 mg / mL and pH=8.5. The solution was magnetically stirred at room temperature for 60 min to allow PDA to form a self-polymerized coating layer on the surface of 1T-MoS2. After the reaction was completed, the mixture was centrifuged at 8000 rpm, washed three times with 300 parts of deionized water, and then vacuum dried at 60℃ for 4 h to obtain PDA-MoS2.

[0029] Subsequently, 200 copies h -BNNS was added to 1000 parts of an aqueous solution containing 1 wt% PEI, and the mixture was sonicated for 30 min followed by mechanical stirring for 2 h. After the reaction was complete, the mixture was centrifuged and washed once each with 500 parts of ethanol and 300 parts of deionized water, and then dried at 50 °C for 4 h to obtain PEI-BNNS.

[0030] The PEI-BNNS was dispersed in a 1:1 mixture of water and ethanol (1:1) to achieve a BNNS concentration of 0.5 mg / mL. After ultrasonic dispersion, 1500 parts of PDA-MoS2 suspension (also 0.5 mg / mL) were slowly added dropwise to the PEI-BNNS suspension while stirring. Stirring was continued for 30 min, followed by standing for 12 h to allow BNNS to be uniformly embedded in the 1T-MoS2 layered wrinkles and nanoflower structure, forming a stable heterostructure composite. After standing, the solid was collected by centrifugation and washed twice with 300 parts of ethanol. The solid was then annealed at 150 °C under an argon atmosphere for 2 h to enhance interfacial bonding and stabilize the composite structure. Cooling to room temperature yielded the 1T-MoS2@BNNS (1.5:1) heterostructure filler, the morphology of which is shown in the transmission electron microscope image. Figure 3 As shown, from Figure 3 As can be seen, a small amount of BNNS is intercalated on the 1T-MoS2 nanoflower folded structure.

[0031] In this embodiment, a higher proportion of 1T-MoS2 can construct a continuous and effective dielectric / conductive loss path, which is beneficial to improving the microwave absorption performance; the introduction of BNNS further enhances the thermal conductivity of the material, enabling the heterostructure to achieve a balance between electromagnetic loss and thermal management performance.

[0032] Step 3, Preparation of 1T-MoS2@BNNS / PDMS composite material: The 1T-MoS2@BNNS (1.5:1) heterostructure filler prepared above was used as the functional filler, with a filler volume fraction of 55 vol%. 100 parts of the filler were dried under vacuum at 80℃ for 4 h, added to an auxiliary dispersion solvent composed of 25 parts of ethanol and isopropanol, and ultrasonically dispersed for 10 min. Then, it was slowly added to 90 parts of PDMS and homogenized for 10 min. The mixture was then degassed under vacuum at 80℃ for 10 min and the auxiliary dispersion solvent was evaporated. 5 parts of curing agent were added and homogenized for 5 min. Finally, the mixture was cured under vacuum at 80℃ for 30 min to obtain the 1T-MoS2@BNNS / PDMS composite material 1.

[0033] Example 2 In this embodiment, a 1:1 ratio (1T-MoS2: h The target component ratio of -BNNS) is used to construct a heterogeneous structure. Step 1 is the same as in Example 1.

[0034] In step 2, 100 parts of 1T-MoS2 were added to 1000 parts of PDA solution with a concentration of 2 mg / mL and pH=8.5. The surface was coated by stirring at room temperature for 60 min. The mixture was then centrifuged and washed three times with 300 parts of deionized water. The mixture was then vacuum dried at 60℃ for 4 h to obtain PDA-MoS2. Take 100 parts of BNNS and add them to 1000 parts of an aqueous solution containing 1 wt% PEI. Sonicate for 30 min, stir for 2 h, collect by centrifugation, wash once with ethanol and once with deionized water, and dry at 50℃ for 4 h to obtain PEI-BNNS.

[0035] PEI-BNNS was dispersed in 1500 parts water / ethanol (1:1), with a BNNS concentration of 0.5 mg / mL. After ultrasonic dispersion, 1000 parts PDA-MoS2 suspension were added dropwise, stirred for 30 min, allowed to stand for 12 h, collected by centrifugation, washed twice with 300 parts ethanol, and annealed at 150℃ for 2 h to obtain 1T-MoS2@BNNS (1:1) heterostructure filler. Its transmission electron microscope morphology is shown in the figure. Figure 4 As shown, from Figure 4 As can be seen, a significant number of BNNS intercalations are present in the 1T-MoS2 folded structure.

[0036] Step 3: Using 1T-MoS2@BNNS (1:1) heterostructure filler as functional filler, 1T-MoS2@BNNS / PDMS composite material 2 was prepared using the same method as in Example 1.

[0037] Example 3 In this embodiment, a ratio of 1:1.5 (1T-MoS2:h -BNNS) is the design ratio, and step 1 is the same as in Example 1.

[0038] In step 2, 100 parts of 1T-MoS2 were added to 1000 parts of PDA solution with a concentration of 2 mg / mL and pH=8.5. The mixture was stirred at room temperature for 60 min to complete the coating. After centrifugation, the mixture was washed three times with 300 parts of deionized water and dried under vacuum at 60℃ for 4 h to obtain PDA-MoS2. Take 150 parts of BNNS and add 1000 parts of 1wt% PEI aqueous solution, sonicate for 30 min, stir for 2 h, centrifuge to collect, wash once with ethanol and once with deionized water, and dry at 50℃ for 4 h to obtain PEI-BNNS.

[0039] PEI-BNNS was dispersed in 1500 parts of a 1:1 water / ethanol solution (BNNS concentration 0.5 mg / mL). After ultrasonic dispersion, 1000 parts of PDA-MoS2 suspension were added dropwise, stirred for 30 min, allowed to stand for 12 h, collected by centrifugation, washed twice with 300 parts of ethanol, and annealed at 150℃ for 2 h to obtain 1T-MoS2@BNNS9 (1.5:1) heterostructure filler. Its transmission electron microscope morphology is shown in the figure. Figure 5 As shown, from Figure 5 As can be seen, a large number of BNNS intercalations surround and encircle the 1T-MoS2 folded structure. The resulting 1T-MoS2@BNNS (1:1.5) heterostructure is suitable for applications where thermal conductivity is more important.

[0040] Step 3: In this embodiment, 1T-MoS2@BNNS (1:1.5) heterostructure filler is used as the functional filler, and 1T-MoS2@BNNS / PDMS composite material 3 is prepared using the same method as in Example 1.

[0041] Vector network analysis experiments were conducted on the 1T-MoS2@BNNS / PDMS composite materials 1, 2, and 3 prepared in Examples 1, 2, and 3 above, and three-dimensional schematic diagrams of their minimum reflection loss, thickness, and frequency were obtained, as shown below. Figure 6 As shown.

[0042] like Figure 6 As shown in Figure (a), the thermal conductivity of the 1T-MoS2@BNNS / PDMS composite material 1 is 4.42 W / m. −1 K −1 At 2.46mm, the minimum reflection loss is -48.8dB and the effective absorption bandwidth is 3.1GHz.

[0043] like Figure 6As shown in Figure (b), the thermal conductivity of the 1T-MoS2@BNNS / PDMS composite material 2 is 5.38 W / m. −1 K −1 At a thickness of 5.64 mm, the minimum reflection loss is -28.3 dB, and the effective absorption bandwidth is 2.1 GHz. The resulting 1T-MoS2@BNNS / PDMS composite material balances dielectric / conductive loss and thermal conductivity over a wide frequency range, making it suitable for applications requiring a balance between electromagnetic protection and heat dissipation performance.

[0044] like Figure 6 As shown in (c), the thermal conductivity of the 1T-MoS2@BNNS / PDMS composite material 3 is 5.54 W / m. −1 K −1 At 5.88mm, the minimum reflection loss is -23.1dB, and the effective absorption bandwidth is 3.2GHz. This formulation enhances the heat conduction path by increasing the proportion of BNNS, making it suitable for use in scenarios with more stringent heat dissipation requirements, while maintaining high absorption capacity without damaging the structure of 1T-MoS2.

[0045] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a 1T-MoS2 reinforced thermally conductive and microwave-absorbing integrated composite material, characterized in that, Includes the following steps: Step 1: Preparation of 1T-MoS2 with nanoflower-like wrinkled structures using a hydrothermal method: Using Na2MoO4·2H2O and thiourea as raw materials, 1T-MoS2 with nanoflower-like folded structure was prepared by hydrothermal reaction combined with NaBH4 reduction. Step 2, electrostatic self-assembly preparation of 1T-MoS2@BNNS: PDA-MoS2 was obtained by surface modification of the 1T-MoS2 nanoflower-shaped folded structure with dopamine; PDA-MoS2 was obtained by surface modification of the 1T-MoS2 nanoflower-shaped folded structure with polyethyleneimine. h PEI-BNNS was obtained by surface modification of PDA-MoS2 and PEI-BNNS; then PDA-MoS2 and PEI-BNNS were self-assembled by opposite charge driving method to obtain 1T-MoS2@BNNS, a heterostructure filler with BNNS intercalated 1T-MoS2 nanoflowers. Step 3, Preparation of 1T-MoS2@BNNS / PDMS composite material: Using 1T-MoS2@BNNS and PDMS as raw materials, a thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS / PDMS was prepared through dispersion, homogenization, vacuum degassing and curing.

2. The method for preparing a 1T-MoS2-reinforced thermally conductive and microwave-absorbing integrated composite material according to claim 1, characterized in that, The specific method for step 1 is as follows: Add Na2MoO4·2H2O and thiourea to deionized water and stir to completely dissolve the raw materials to obtain a homogeneous mixed precursor solution. The mixed precursor solution was transferred to a reaction vessel lined with polytetrafluoroethylene and reacted at 180–220 °C for 12–30 h. After the reaction was completed, the mixture was naturally cooled to room temperature, and the resulting black precipitate was collected. It was washed 2–5 times with anhydrous ethanol and deionized water, and then dried in a vacuum drying oven at 50–80 °C for 2–8 h to obtain the nanoflower-like MoS2 precursor. The obtained nanoflower-like MoS2 precursor was dispersed in deionized water and stirred under ice bath conditions to form a uniform suspension. NaBH4 solution was then slowly added dropwise, and the reaction was continued under ice bath conditions for 20–40 min. After that, the mixture was stirred at room temperature for 1–2 h to complete the partial phase inversion. After the reaction was completed, the product was washed with ethanol 2–5 times and dried under vacuum conditions at 50–80 °C for 2–6 h to obtain 1T-MoS2 with a nanoflower-like folded structure.

3. The method for preparing a 1T-MoS2-reinforced thermally conductive and microwave-absorbing integrated composite material according to claim 1, characterized in that, In step 2, the preparation method of PDA-MoS2 is as follows: The obtained nanoflower-shaped 1T-MoS2 was added to a dopamine solution and magnetically stirred at room temperature for 30–90 min to complete the self-polymerization and coating of dopamine on the surface of 1T-MoS2. After the reaction was completed, the mixture was centrifuged and washed 2–5 times with deionized water, and then vacuum dried for 2–6 h to obtain PDA-MoS2.

4. The method for preparing a 1T-MoS2 reinforced thermally conductive and microwave-absorbing integrated composite material according to claim 1, characterized in that, In step 2, the preparation method of PEI-BNNS is as follows: Will h -BNNS was added to an aqueous solution containing 0.5-2 wt% polyethyleneimine, sonicated for 20-40 min, and then mechanically stirred for 1-3 h. After the reaction was completed, the solid was collected by centrifugation, washed several times with ethanol and deionized water, and dried at 40-60 °C for 2-6 h to obtain PEI-BNNS.

5. The method for preparing a 1T-MoS2-reinforced thermally conductive and microwave-absorbing integrated composite material according to claim 1, characterized in that, In step 2, the preparation method of 1T-MoS2@BNNS is as follows: PEI-BNNS was dispersed in a mixed solution of water and ethanol. After ultrasonic dispersion, PDA-MoS2 suspension was added dropwise under stirring. Stirring was continued for 20-40 min, and the mixture was allowed to stand for 10-14 h to allow BNNS to be uniformly embedded in the interlayer of 1T-MoS2 to form a heterostructure composite system. The obtained solid was separated by centrifugation and washed with ethanol to remove unbound substances. Subsequently, under an inert atmosphere, it was annealed at 120–180°C for 1–3 hours, and then cooled to room temperature to obtain the thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS.

6. The method for preparing a 1T-MoS2 reinforced thermally conductive and microwave-absorbing integrated composite material according to claim 1, characterized in that, The specific method for step 3 is as follows: The obtained thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS was dried in a vacuum environment at 80℃ to obtain a solid filler. Take the above solid filler and add 20-30 parts of an auxiliary dispersion solvent composed of ethanol and isopropanol. Use ultrasound to uniformly disperse the filler to form a fluid mixed suspension system. The mixed suspension system is slowly added to PDMS and homogenized to fully disperse the composite filler in PDMS, forming a uniform PDMS prepolymer composite slurry. The PDMS prepolymer composite slurry was placed in a vacuum environment at 80℃ for degassing treatment, and then the auxiliary dispersion solvent in the system was allowed to evaporate and be removed naturally to obtain a pre-cured composite system. Add curing agent to the precured composite system and stir to make the curing agent and PDMS prepolymer mixed again and evenly distributed in the system; Subsequently, the PDMS prepolymer was cured in a vacuum environment at 80℃ to crosslink and form a thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS / PDMS.

7. The method for preparing a 1T-MoS2 reinforced thermally conductive and microwave-absorbing integrated composite material according to claim 1, characterized in that, In step 2, 1T-MoS2 and h - The mass ratio of BNNS is 1:1.5 to 1.5:

1.

8. The method for preparing a 1T-MoS2 reinforced thermally conductive and microwave-absorbing integrated composite material according to claim 1, characterized in that, In step 2, 1T-MoS2 and h -BNNS mass ratio is 1:1.5, 1:1 or 1.5:

1.

9. A thermally conductive and microwave-absorbing integrated composite material 1T-MoS2@BNNS / PDMS prepared by the preparation method according to any one of claims 1-8.

10. The application of the thermally conductive and electromagnetically absorbing integrated composite material 1T-MoS2@BNNS / PDMS as described in claim 9 in the thermal management and electromagnetic interference shielding of electronic devices.

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