Thermal Conductive Networks Research Articles

Enhancement on thermal management and mechanical properties of cellulose nanofiber films through synergistic filler construction and interface optimization

AbstractThis study is aimed at developing composite films with superior thermal management performance in an attempt to solve challenge rising from heat accumulation in modern high‐frequency broadband communication devices. To effectively address the interface thermal resistance (ITR) of graphene nanoplatelets (GNPs) in the composites, cobalt nanoparticles were coated onto edge‐oxidized graphene to in‐situ form a hybrid filler (EGO@Co), which was then uniformly incorporated into the carboxymethyl cellulose nanofiber (c‐CNF) matrix. A vacuum‐assisted filtration was employed to fabricate EGO@Co/c‐CNF thermally conductive multi‐layered composite films. In‐situ growth of heterogeneous structure filler Co helped to extend the thermal paths and optimize the heat transfer networks. The incorporation of edge oxidation was found to facilitate the strong hydrogen bonding interactions between filler and matrix, constructing an efficient three‐dimensional (3D) thermal conduction network, significantly enhancing both heat flux and stress transfer efficiency. After hot‐pressed, the EGO@Co40/c‐CNF films exhibited an outstanding thermal conductivity (λǁ ~ 28.4 W m−1 K−1 and λ⊥ ~ 1.1 W m−1 K−1) in addition to a high tensile strength. The optimization on the thermal filler construction and interface modification have proved to significantly enhance the microstructure and properties of the composite films, which helps to pave the way for practical opportunities in the application of novel thermally conductive materials in the TMMs fields.Highlights Cobalt nanoparticles enhanced thermal conductivity of composites. EGO strengthened filler‐matrix hydrogen bonding. Vacuum‐assisted filtration produced multi‐layered composite films. EGO@Co/c‐CNF films displayed high thermal conductivity. Thermal filler optimization boosted mechanical and thermal properties.

Constructing micro-region networks in expanded graphite for bi-directional high thermal conductivity of thermoplastic polymer composite

Thermoplastic polymers have limited application in thermal management due to its low thermal conductivity (TC). Adding high TC fillers and hot-pressing process can effectively improve in-plane TC. However, single filler orientation limits through-plane heat transfer and most of polymer-based composites have low through-plane TC (<10 W/m·K). The preparation of polymer-based composites with bi-directional high thermal conductivity is still a great challenge. In this work, a novel maleic anhydride (MA) modified nano Al2O3 (M−Al2O3)/expanded graphite (EG)/PVDF composite (MAE/P) with bi-directional high thermal conductivity was prepared by a melt self-adsorption and hot-pressing method, where the EG was used for constructing the main thermal conductive network and the M−Al2O3 was embedded in EG 3D structure to build micro-region network to greatly increase the out-plane thermal conductivity (TC) of the composite. Results show that the through-plane and in-plane TC of the MAE/P were 13.78 W/m·K and 102.24 W/m·K (50 wt% filler content), respectively. The finite element simulation computation of microstructure also amply demonstrates the effectiveness of enhancing TC by gap filling. Research shows that the key to achieving bi-directional high thermal conductivity is that more phonon transmissionpathways were constructed along vertical direction when M−Al2O3 is embedded. Moreover, the MAE/P also indicates excellent thermal infrared response capability, electromagnetic interference shielding (87.22 dB at 70 wt% filler content) and mechanics performance (over 130 MPa bending strength at 50 wt% filler content). This work provides a new method to greatly enhance bi-directional TC of thermoplastic polymer-based composites.

Simultaneously improving in-plane and through-plane thermal conductivity of insulted PVDF composite film using multi-layer and multi-filler strategies

In this paper, a multi-filler synergistic strategy combined with multi-layer hot pressing technology was developed to optimize the thermal conductivity and insulation properties of composite materials. Boron nitride nanosheets (BNNS), aluminium oxide (Al2O3) microspheres and silver (Ag) nanoparticles were incorporated to construct a three-dimensional thermal conduction network within a polyvinylidene fluoride (PVDF) thermally conductive composite film. An electrospun PVDF fiber film was first prepared to be used as a template. BNNS and Al2O3 were then electrostatically assembled on the surface of the PVDF fiber and in the film to obtain continuous BNNS/PVDF fiber film and Al2O3/PVDF fiber film, respectively. Ag nanoparticles were then prepared in situ on the Al2O3/PVDF fiber film to obtain an Ag-enhanced Al2O3/PVDF fiber film. A sandwich structured PVDF composite film (B-A@Ag-B/PVDF) was finally prepared by hot pressing, using the BNNS/PVDF fiber films as the top and bottom layers and the Ag-enhanced Al2O3/PVDF fiber film as the middle layer. The resulting B-A@Ag-B/PVDF composite film, with a total filler mass fraction of 32.1 %, had in-plane and through-plane thermal conductivities of 4.13 W m–¹ K–¹ and 1.05 W m–¹ K–¹, respectively, improvements of 1620 % and 452 % compared to those of pure PVDF. In addition, the through-plane electrical conductivity was as low as 5.38 × 10–¹¹ S/cm, matching the standards for insulating materials. The B-A@Ag-B/PVDF composite film demonstrates significant potential for advanced thermally conductive polymer composites.

Preparation and Performance Study of Composite Aramid Paper for High-Frequency Working Conditions.

When the power converter connects to the high-frequency transformer breaks through the bottleneck and reaches a frequency of 100 kHz or even higher, the high-frequency transformer's inter-turn insulation faces more serious high-frequency discharge and high-temperature problems. In order to improve the service performance of oil-immersed high-frequency transformer insulation paper, composite K-BNNS particles are prepared by ultrasonic stripping, heat treatment, and thermomagnetic stirring. Then, K-BNNS particles are mixed with PMIA (polymeric m-phenylenediamine solution) slurry to produce composite aramid paper. And the effects of K-BNNS particles with different contents on the thermal conductivity, dielectric properties, partial discharge properties, and mechanical properties of aramid paper are explored. It can be found that, when the addition of composite particles (K-BNNS) is 10%, the comprehensive performance of composite aramid paper is the best. Compared with Nomex paper, the in-plane and through-plane thermal conductivity of composite insulating paper F-10 increased by 668.33% and 760.66%, respectively. Moreover, the high-frequency breakdown voltage increased by 48.73% and the tensile strength increased by 2.49%. The main reason is that the composite particles form a complete thermal conductive network in the aramid paper matrix and a large number of hydrogen bonds with the matrix, which enhances the internal interface bonding force of the material and changes the charge transport mechanism.

Effects of new ionic liquids on mechanical properties and thermal conductivity of PC/ABS composites

According to the structural characteristics of PC/ABS containing benzene rings, an imidazole ionic liquid [MTMSiIM]H2PO2 was synthesized. [MTMSiIM]H2PO2 served as the modifier for modifying G powder via ball milling to produce ionic liquid functional graphene (Si-G). Si-G was utilized as a thermal conductive filler to investigate its impact on the mechanical properties and thermal conductivity network formation of PC/ABS composites. During the melt blending process, the imidazole group of Si-G and the benzene ring in PC/ABS form a π-π interaction. This interaction enhances the dispersion of Si-G in PC/ABS and strengthens the interface interaction between the two. As a result, it improves the mechanical properties and thermal conductivity of PC/ABS composites. Experimental results indicate that when 11 wt% of Si-G is added, the tensile strength of the composites is 63.05 MPa, marking a 9.4% and 4.5% increase compared to PC/ABS and G powder/PC/ABS, respectively. Furthermore, the flexural modulus of the 11 wt% Si-G/PC/ABS composites is 3495.37 MPa, showing a 65.5% and 5.7% improvement over PC/ABS and G powder/PC/ABS, respectively. Moreover, the 11 wt% Si-G/PC/ABS composites exhibit the highest thermal conductivity at 0.488 W·m−1 K−1, which is 103.7% and 10.4% higher than that of PC/ABS and G powder/PC/ABS, respectively.

Personalized customization of in-plane thermal conductive networks by a novel electrospinning method

Using one-dimensional (1D) nanofibers to induce the assembly of two-dimensional (2D) nanosheets is of great practical significance; naturally, electrospinning, as the most effective method to prepare long nanofibers, has attracted widespread attention. In this paper, a novel electrospinning method that can induce the directional deposition of nanofibers through electrode arrays has been proposed, optimized, and further applied to regulate the aligned assembly of boron nitride nanosheets (BNNSs) to prepare highly thermally conductive and electrically insulating polyvinylidene fluoride (PVDF)/BNNS composites. In particular, the intermittent-contact collection mode of electrospun nanofibers has further enriched the electrospinning system. The composites prepared by our strategy possess high in-plane thermal conductivity (18.86 W/(m·K)), volume resistivity (nearly 1015 Ω cm), and breakdown strength (nearly 380 kV/mm). Furthermore, excellent mechanical properties, flexibility, and thermal conduction capability are vividly demonstrated. The proposed electrospinning method and the prepared PVDF/BNNS composites have great potential in the thermal management application of electronic devices in the 5G era.

Preparation of phosphorous ionic liquids and its effect on the properties of ABS

AbstractTo improve the thermal conductivity and mechanical properties of graphene‐acrylonitrile butadiene‐styrene plastic (ABS) composite, sub‐phosphite‐based ionic liquid (IL) was synthesized, and its structure was characterized by FTIR, NMR, and mass spectrometry. IL was as a modifier, and graphite powder (G powder) was modified by the ball milling method to obtain functional graphene thermal conductive filler (G‐IL). The structure and morphology of G‐IL were characterized by FTIR, X‐ray photoelectron spectroscopy (XPS), XRD, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of the Molau test showed that the presence of IL improved the interfacial interaction of G‐IL and ABS, enhanced the dispersion of G‐IL in the ABS matrix, made G‐IL contact with each other, and it was easier to establish a thermal conduction network and promote phonon transfer. The thermal conductivity of 9 wt% G‐IL/ABS composite was 0.392 W·m−1·k−1, which was 96% and 14% higher than that of pure ABS and G/ABS composite, respectively. The tensile strength and bending modulus of 9 wt% G‐IL/ABS composite were 44.89 and 2124.37 MPa, which were 13% and 11% higher than those of pure ABS, respectively. The impact strength of 9 wt% G‐IL/ABS composite was 34.17 kJ/m2. It was 18% and 7% higher than that of pure ABS and 9 wt% G‐IL/ABS, respectively.Highlights Phosphorus imidazole ionic liquids were prepared. Graphene was modified by ionic liquids through non‐covalent. Enhanced mechanical properties and thermal conductivity of G‐IL/ABS composites.

Phase change thermal interface materials with interface adaptability and self-healing properties

Thermal stress resulting from excessive temperatures is a major cause of electronic device failure. In this work, with easy installation and good interface adaptability, Phase Change Thermal Interface Materials (PCTIMs) which possess high thermal conductivity were prepared. By incorporating phase change material stearic acid (SA) into the thermal interface material, the instantaneous heat absorption during the solid-liquid phase transition of SA effectively alleviates the problem of instantaneous high heat flux impacting electronic devices. Additionally, the solid-liquid transition reduces the modulus of TIMs, thereby minimizing the contact thermal resistance between the heat source and the heat sink during mechanical installation. To further enhance performance, the thermal interface material utilizes a dynamically cross-linked polyolefin elastomer (POE) with borate bonds, which effectively restricts the flow of SA even at its phase change point due to the three-dimensional cross-linked framework. By constructing a thermal conductive network using carbon fibers and aluminum nitride of different dimensions, the thermal conductivity of the thermal interface material reached 1.82 W∙m−1K−1 with a filler content of only 30 vol % . At 70 °C, with a force of 50 N applied to a sample area of 400 mm², the contact thermal resistance was only 2.39×10−4 K∙m2W−1. Furthermore, the PCTIMs exhibits excellent self-healing ability under thermal conditions, assuring the permanent encapsulation of small electronic devices.

Discussion on the thermal conductive network threshold of Al2O3/Co-continuous phase polymer composites

Achieving high thermal conductivity in polymer composites with micro or nanoparticle fillers are challenging. Typically, over 50 ​vol% filler loading is necessary to form a thermal conductive network. However, even with such a network in place, the increase in thermal conductivity may not be significant compared to that in electrically conductive composites. To clarify the ideal filler network structure, we endeavored to selectively disperse nano-sized Al₂O₃ nanoparticles at the interface of co-continuous SEBS/PA6 blends, with and without various filler surface modification methods. A thermal conductive network forms when all interface areas are fully covered by 2.56 ​vol% of Al2O3 nanoparticles (very close to theoretical loading content 2.29 ​vol%). In this case, the Al2O3 nanoparticle has the highest thermal conductive contribution (TCC). However, the absolute TCC values are extremely low because of the interfacial thermal resistance and it will decrease when the filler content exceeds 2.56 ​vol%, indicating that some nanoparticles are dispersed separately out of the existed thermal conductive network. These findings suggest that the construction of a connected thermal conductive network, relatively lower interfacial thermal resistance and the precise positioning of fillers within this network are essential for achieving high thermal conductivity composites.

Phase change thermal interface film with bicontinuous and textured filler network for efficient wearable heat dissipation

Wearable thermal management needs to simultaneously meet thermal conductivity, heat storage capacity, stability, flexibility, and economy, but these characteristics constrain each other in the development of phase change thermal interface materials (PhC-TIM). Therefore, relying on the economic bicontinuous structure for fillers’ orientation, a new type of bicontinuous phase change thermal interface material (BPTIM) was designed, which includes thermal storage phase composed of paraffin (PCMs) and flexible molecule styrene–butadiene–styrene (SBS), and thermal conductivity phase composed of adhesive polyurethane (PU) and thermal conductive medium hexagonal boron nitride (h-BN). In the experiment, shear force generated by stirring and optimized two-phase volume ratio resulted in the stretching and compressing of the thermal conductive phase, promoting the orientation of h-BN and forming a textured thermal-conductive network in a high PCMs content bicontinuous structure. Moreover, the introduction of SBS had brought bending resistance and thermal stability. These characteristics enabled BPTIMs to significantly reduce the surface temperature of the wearable device by 23 °C. Overall, this design provides a certain reference for the widespread application of PhC-TIM in thermal management of wearable electronic products.

Significant enhancement of bi-directional ultrahigh thermal conductivity in polymer composites fabricated via Polyetherimide@Silver core–shell structured microspheres

Nowadays, the polymer-based composites with excellent thermal-conductive ability and ideal electromagnetic interference shielding performance are in great demand with the advent of developing modern electronic technology. However, most conventional thermal-conductive materials were typically designed to enhance thermal conductivity in just one single direction (through-plane or in-plane direction), which will be inadequate to meet increasing heat-dissipation requirements. Hence, polyetherimide/Silver (PEI/Ag) composites with unique segregated thermal-conductive network were fabricated via hot-pressing the core–shell (PEI@Ag) particles, which was endowed with superior thermal-conductive ability in bi-directions. By this process, the Ag shell was deposited on the surface of various polymer microsphere, and diverse morphology of composite particles would lead to different findings. The results show the PEI@Ag composites with filler content of 18.9 vol% exhibited high in-plane thermal conductivity and through-plane thermal conductivity of 19.9 and 14.0 W/mK, respectively. Particularly, these results achieved obvious improvements of 331 % and 1264 % higher than the composites with filler random distribution, indicating the composite materials obtained outstanding advantage in both horizontal and vertical direction. The research also found that the composites prepared from PEI@Ag core–shell structures possess better properties than those prepared with Ag nanoparticles growing on polymers, indicating the importance of continuous heat-transfer path, and their heat transfer behavior was further demonstrated by finite element analysis. Besides, the composites also exhibited remarkable EMI shielding performance (40.1 dB)). In a word, this study provides viable strategies to enhance the thermal conductivity of composites based on organic solvent-soluble polymer with EMI capability for the development of electronic devices.

Exploring the thermal and optical characteristics of Ti3C2 MXene for enhanced photothermal conversion

Ti3C2 MXene, a member of the two-dimensional (2D) transition metal carbides family, has garnered significant attention for its exceptional photothermal properties. To understand the mechanistic underpinnings of this feature, we conducted a comprehensive first-principles density functional theory analysis. This study was aimed at investigating the electronic band structure and vibrational characteristics of Ti3C2 MXene to unravel its microscopic process of photothermal conversion. After obtaining its optical and thermal properties, the process by which the material moves from light absorption to heat release is elucidated. The presence of localized surface plasmon resonance (LSPR) effects in Ti3C2 is proved by Finite-difference time-domain (FDTD) simulations. The synergy between the high thermal conductivity network in the Ti layers and the LSPR phenomenon is believed to be responsible for the superior photothermal conversion capabilities. This investigation enhances the understanding of the intrinsic properties of Ti3C2 MXene, confirming its status as an ultrahigh photothermal conversion material.

Construction of 3D modified hexagonal boron nitride thermal conductivity network by ice template method and research of high heat‐conducting coefficient of epoxy resin matrix composite material

Construction of <scp>3D</scp> modified <scp>hexagonal boron nitride</scp> thermal conductivity network by ice template method and research of high heat‐conducting coefficient of epoxy resin matrix composite material

MXene quantum dots modified pitaya peel-based composite phase change material with excellent thermal properties for building energy efficiency applications

Bio-based materials have attracted much attention because their application in the construction field is conducive to energy saving and emission reduction. In this paper, a bio-based composite phase change material (CPCM) was prepared by utilizing pitaya peel as a bio-based material, MXene quantum dots (MQDs) as a modified material, and polyethylene glycol (PEG) as a phase change medium. MXene quantum dots dispersed in the pitaya peel-based porous carbon skeleton enhanced the three-dimensional thermal conductivity network of the porous carbon skeleton somewhat improved the thermal conductivity (0.676 W/mK) of the polyethylene glycol/MXene quantum dots-modified pitaya peel-based porous carbon foam (PPF) composite phase change material (PEG/PPF@M). It is worth noting that PEG/PPF@M has excellent thermal stability and its enthalpy is basically unchanged after 100 cycles, which proves the recyclable stability of PEG/PPF@M in practical applications. PEG/PPF@M has great potential for thermal management of buildings and electronic components. Overall, a novel multifunctional CPCM was prepared in this study using a simple process method, which can not only be applied in electronic products to improve the service life of electronic components, but also in the field of construction to realize energy saving and emission reduction, as well as the recycling and reuse of waste.

Investigation on the fabrication and mechanism of thermally conductive bismaleimide composites with low dielectric constant via a branched crosslink structure

In order to address the challenges associated with the low mechanical strength and inadequate thermal conductivity of bismaleimide resin(BMI), trifunctional maleimide (TMI) was synthesized by reacting toluene diisocyanate (TDI trimer) with maleic anhydride (MA) in this study and reacted with diallyl bisphenol A (DBA) and BMI to prepare BMI-TMI resin with a micro-branching structure. This well-designed micro-branching structure resulted in an 8.8 % decrease in the dielectric constant by increasing the free volume of BMI. Additionally, the micro-branching structure endowed BMI resin with improved mechanical properties, as evidenced by a 140 % increase in bending strength and a 149 % increase in impact strength of the cured product. Similarly, utilizing the free volume in micro-branched polymers to construct voids in molecular chain segments facilitates better dispersion of aluminium oxide (Al2O3) thermal conductive fillers, forming a continuous thermal conductive network and providing a high-speed channel for phonon transport, thereby significantly improving the thermal conductivity of the composite material.

PVA-assisted graphene aerogels composite phase change materials with anisotropic porous structure for thermal management

The rapid development of spacecraft thermal control systems necessitates high-performance phase change materials (PCMs) with low density, high thermal conductivity and high enthalpy. Graphene aerogels (GAs) prepared by unidirectional freezing are ideal candidates as thermal conductive networks for PCMs due to the anisotropic porous structures. However, constructing anisotropic thermal conductive composite PCMs with low graphene aerogel loading while employing environmentally friendly cross-linking agents remains challenging. To fulfill the research gap, this study explores the synthesis of poly(vinyl alcohol) (PVA)/graphene aerogels (PGAs) by hydrothermal reaction and conventional freeze-drying. Anisotropic PGAs with oriented porous structures were fabricated by unidirectional freezing. After annealing and impregnation with paraffin wax, composite PCMs with excellent shape stability were obtained. The prepared composite exhibits low density (0.82 g cm−3) and high enthalpy (165 J g−1). The combination of PVA and graphene enables the composite to achieve an ultralow graphene aerogel loading (0.85 wt%) while maintaining high thermal conductivity (1.37 W m−1 K−1), leading to a high specific thermal conductivity enhancement up to 477. This work sheds light on the potential of combing PVA and graphene to construct thermal conductive aerogels, intending to provide feasible means to develop high-performance PCMs for spacecraft thermal management.

The thermal conductivity of 3D network reinforced polypropylene matrix composites was constructed by the pickering‐like emulsion method

AbstractPolypropylene (PP) has the advantages of corrosion resistance, easy processing, and low dielectric loss, but its low thermal conductivity limits the application of its composites in fields such as electronic packaging. To solve this problem, in this work, composite microspheres with the segregated structure were prepared by coating boron nitride nanosheets (BNNSs) on the PP surface by Pickering‐like emulsion method, and BNNSs@PP composites with three‐dimensional thermal conductivity network were obtained after molding. Due to the high thermal conductivity of BNNSs and the formation of perfect thermal conduction pathways, the thermal conductivity of the composites reached 1.71 W m−1 K−1 when the content of BNNSs was 10.1 wt%, which was a 713% increase in thermal conductivity for that of pure PP. At the same time, the mechanical properties of the composites were ensured. This method provides a simple and effective technique to improve the thermal conductivity of PP‐based thermally conductive composites, which has a wide application potential in electronic packaging.

Constructing highly thermally conductive polystyrene-based composites by introducing multi-walled carbon nanotubes into melamine foam-supported boron nitride network

High-density 3D thermally conductive nanofiller network plays a vital role in the fabrication of polymer-based composites with high thermal conductivity (TC) for thermal management systems. In this work, highly thermally conductive polystyrene (PS)-based composites were prepared by introducing boron nitride nanosheets-coated melamine foam (MF@BNNSs) and carboxylated multi-walled carbon nanotubes (MWCNT–COOH). In this unique structure, MF@BNNSs can provide a 3D thermally conductive network, while MWCNT–COOH is embedded into the MF@BNNSs skeleton to improve the network-density. Specifically, the TC of PS/MWCNT/MF@BNNSs composite with 0.6 wt% MWCNT–COOH loading reaches 5.33 W /m· K, about 4.4-fold as high as that of the PS/MF@BNNSs. Moreover, the PS/MWCNT/MF@BNNSs composite exhibits effective heat dissipation capacity after assembling the power LED chip. Due to the isolation effect of MF@BNNSs skeleton, the PS/MWCNT/MF@BNNSs maintain electrical insulation properties. Consequently, the design of the thermal conductive network based on MF@BNNSs and MWCNT–COOH offered a substantial potential avenue for the preparation of polymer-based composites with high TC and insulating properties.

Significantly improved thermal conductivity of C/C composite by constructing 3D SiC nanowires network in carbon felt via vacuum thermal evaporation

Developing a nanoscale secondary thermal conduction network within carbon fiber performs is a challenging yet effective method to substantially enhance the thermal conductivity of C/C composites. In this study, a strategy for creating a three-dimensional (3D) SiC nanowires (SiCNWs) thermal conductivity network in carbon felts (CFs) was implemented using vacuum thermal evaporation technology to fabricate SiCNWs modified C/C composites (SiCNW–C/C). The growth mechanism of SiC nanowires within CFs and their impact on the microstructure and thermal conductivity of the C/C composite were thoroughly investigated. The findings indicate that a SiC nanowires thermal conduction network can be successfully established within carbon felts without catalysts by initiating nucleation sites and managing reaction pressure. An appropriate reaction pressure is crucial not only for the uniform growth of SiC nanowires but also as a key factor in modulating the content and microstructure of the SiC nanowires. SiC nanowires prepared at 150 Pa exhibit minimal structural defects and are evenly distributed throughout the carbon felts, markedly enhancing the thermal response rate of the felts. The thermal conductivity of these SiCNW-modified C/C composites, both parallel and perpendicular to the carbon fibers, increased to 173 W/m•K and 112 W/m•K, respectively, approximately tripling that of the pure C/C composite. The exceptional thermal management capabilities of SiCNW–C/C were empirically validated through simulated operational chips and finite element simulation. This work presents an effective approach for producing C/C composite with high thermal conductivity particularly through the thickness, offering promising applications in the thermal management of advanced electronics.

Developing PEEK composites with exceptional thermal conductivity and electromagnetic shielding properties by constructing a dense dual-continuous filler network

Polyether ether ketone (PEEK) has regular and rigid molecular chain and is insoluble in most organic solvents. Therefore, it is challenging to use PEEK matrix composites for thermal conductivity (TC) and electromagnetic interference (EMI) shielding applications. Herein, PEEK composites with hybrid fillers were fabricated by solution blending and non-solvent-induced phase separation (NIPS) methods based on a chemical conversion reaction between soluble precursor PEEK-dithiolane and PEEK. Synergistic interaction between hybrid fillers (graphene nanosheets and multiwalled carbon nanotubes) improves the thermal and electrical conductivity of the composites. The effect of the hot-pressing pressure on the conductive/thermal network densification was investigated. The composites performed optimally at a hot pressure of 200 MPa and a filler content of 20.08 vol%. The maximum in-plane and out-of-plane TC reached 10.46 W·m–1·K–1 and 4.8 W·m–1·K–1, respectively, which were 4619 % and 2414 % higher than the corresponding TC of PEEK. Simultaneously, the optimised composite demonstrated significantly improved electrical conductivity (3517 S/m) and EMI shielding effectiveness (66.1 dB). These excellent characteristics are attributed to the solution blending–NIPS method, which improves the dispersion of hybrid fillers in the matrix and forms an internal and external dual-continuous thermal conductive network. The dual-continuous network creates effective channels for phonon and electron transport and enhances EM wave loss. This work provides inspiration for the preparation of PEEK composites as advanced EMI protection and thermal management materials.