Thermal Conductivity Of Composites Research Articles

Boron Nitride/Carbon Fiber High-Oriented Thermal Conductivity Material with Leaves–Branches Structure

In the realm of thermal interface materials (TIMs), high thermal conductivity and low density are key for effective thermal management and are particularly vital due to the growing compactness and lightweight nature of electronic devices. Efficient directional arrangement is a key control strategy to significantly improve thermal conductivity and comprehensive properties of thermal interface materials. In the present work, drawing inspiration from natural leaf and branch structures, a simple-to-implement approach for fabricating oriented thermal conductivity composites is introduced. Utilizing carbon fibers (CFs), known for their ultra-high thermal conductivity, as branches, this design ensures robust thermal conduction channels. Concurrently, boron nitride (BN) platelets, characterized by their substantial in-plane thermal conductivity, act as leaves. These components not only support the branches but also serve as junctions in the thermal conduction network. Remarkably, the composite achieves a thermal conductivity of 11.08 W/(m·K) with just an 11.1 wt% CF content and a 1.86 g/cm3 density. This study expands the methodologies for achieving highly oriented configurations of fibrous and flake materials, which provides a new design idea for preparing high-thermal conductivity and low-density thermal interface materials.

Vertically aligned and conformal BN-coated carbon fiber to achieve enhanced thermal conductivity and electrical insulation of a thermal interface material

Due to excellent thermal conductivity, high aspect ratio, and low density, mesophase pitch-based carbon fibers (MPCFs) are highly desired in electronic packaging. However, their thermal conductivity is hard to present in the polymer matrix because of the disordered stacking and low filling. Moreover, few researches are focused on the enhancement of the electrical insulation performance for MPCFs. Herein, we report vertically aligned and insulating boron nitride (BN) coated carbon fiber (CF) powders as significant fillers for polymer composites, endowing markedly improved thermal conductivity and electrical insulation. The high-quality BN coating layer on the surface of the CF is produced by a cooling precipitation method and high-temperature treatment with ingenious use of solubility properties, exhibiting a conformal, dense, and highly crystalline structure. This preparation method overcomes the limitations of coating thickness and particle agglomeration, resulting in a 31-fold enhancement of the electrical resistivity of the CF powders. After orientation treatment in a silicone rubber matrix, such CF@BN-filled pads exhibit good thermal conductivity, significantly improved insulation performance, and excellent mechanical properties. Among them, the optimized pad achieves a thermal conductivity of 12.06 W m−1 K−1, a volume resistivity of 50 × 108 Ω cm and a breakdown voltage of 3100 V mm−1, exceptional flexibility, and a favorable compression ratio (@45 psi) of 41.7 %. This work provides unique insights into constructing carbon fiber fillers as well as the preparation of high thermal conductivity composites, thereby expanding the application scenarios of carbon fiber powder in electronic packaging.

High‐Temperature Thermal Conductivity of Fiber Hybrid Ceramic Matrix Composites with Different Modes

Thermal conductivity (TC) is one of the important thermal property evaluation parameters for high‐temperature‐resistant fiber‐reinforced composites. Herein, based on the flexible‐oriented three‐dimensional (3D) woven technology, fiber hybrid ceramic matrix composites (FH‐CMCs) with different hybrid modes are designed and fabricated by using carbon fiber and silicon carbide fiber. The representative volume element (RVE) models of fiber bundle and matrix with mesoscopic characteristics and the macroscopic RVE models with hybrid structure characteristics are established. The heat flux distribution and effective TCs of FH‐CMCs in the thickness and in‐plane directions at different temperatures are obtained by finite element analysis (FEA) and experimental tests. The results show that the FEA and experimental results of the TCs of different FH‐CMCs are in good agreement. In the range of 25–1000 °C, the effective TCs of FH‐CMC gradually decrease with the increase in temperature. The TCs in the thickness direction of different FH‐CMCs are directly proportional to the hybrid ratio, and the TCs in the in‐plane direction are inversely proportional to the hybrid ratio. The heat flux and temperature field distributions of the FH‐CMCs are mainly affected by the TCs of the components, fiber hybrid ratio, and orientation, and the distribution along different directions are obviously different. The research results are helpful to provide theoretical and experimental reference for the structural design and performance improvement of hybrid composites.

Enhancing Thermal Conductivity in Polymer Composites through Molding-Assisted Orientation of Boron Nitride.

Incrementing thermal conductivity in polymer composites through the incorporation of inorganic thermally conductive fillers is typically constrained by the requirement of high filler content. This necessity often complicates processing and adversely affects mechanical properties. This study presents the fabrication of a polystyrene (PS)/boron nitride (BN) composite exhibiting elevated thermal conductivity with a modest 10 wt% BN content, achieved through optimized compression molding. Adjustments to molding parameters, including molding-cycle numbers, temperature, and pressure, were explored. The molding process, conducted above the glass transition temperature of PS, facilitated orientational alignment of BN within the PS matrix predominantly in the in-plane direction. This orientation, achieved at low filler loading, resulted in a threefold enhancement of thermal conductivity following a single molding time. Furthermore, the in-plane alignment of BN within the PS matrix was found to intensify with increased molding time and pressure, markedly boosting the in-plane thermal conductivity of the PS/BN molded composites. Within the range of molding parameters examined, the highest thermal conductivity (1.6 W/m·K) was observed in PS/BN composites subjected to five molding cycles at 140 °C and 10 MPa, without compromising mechanical properties. This study suggests that compression molding, which allows low filler content and straightforward operation, offers a viable approach for the mass production of polymer composites with superior thermal conductivity.

Utilizing Ragone framework for optimized phase change material-based heat sink design in electronic cooling applications

This study explores the latent thermal energy storage potential of an organic phase change material with porous copper foam and its applicability in electronic cooling under varying heat load conditions. The organic phase change material, n-eicosane, is known for its inherently low thermal conductivity of 0.15 W/mK, rendering it vulnerable during power spikes despite its abundant latent heat energy for phase transition from solid to liquid. Porous copper foams are often integrated into n-eicosane to enhance the composite's thermal conductivity. However, the volume fraction of the phase change material in the porous foam that optimally improves the thermal performance can be dependent on the boundary condition, the cut-off temperature, and the thickness. A finite difference numerical model was developed and utilized to ascertain the energy consumption for the composite of n-eicosane with two kinds of porous copper foam with varying porosity under different heat rates, cut-off temperatures, and thickness. In addition, the results are compared with a metallic phase change material (gallium), a material chosen with a similar melting point but significantly high thermal conductivity and volumetric latent heat. For validation of the numerical model and to experimentally verify the effect of boundary condition (heat rate), experimental investigation was performed for n-eicosane and high porosity copper foam composite at varying heat rates to observe its melting and solidification behaviors during continuous operation until a cut-off temperature of 70 °C is reached. Experiments reveal that heat rate influences the amount of latent energy storage capability until a cutoff temperature is reached. For broad comparison, the numerical model was used to obtain the accessed energy and power density and generate thermal Ragone plots to compare and characterize pure gallium and n-eicosane - porous foam composite with varying volume fractions, cutoff temperature, and thickness under volumetric and gravimetric constraints. Overall, the proposed framework in the form of thermal Ragone plots effectively delineates the optimal points for various combinations of heat rate, cut-off point, and aspect ratio, affirming its utility for comprehensive design guidelines for PCM-based composites for electronic cooling applications

Lightweight, hydrostatic pressure‐resistance, thermal insulating epoxy syntactic foam with a multiscale ternary structure for marine engineering application

AbstractThe study of lightweight epoxy syntactic foams is of great significance for the exploitation of marine resources. In this work, glass fibers reinforced epoxy hollow spheres (GFs‐EHS) were first prepared using a template method, and a lightweight three‐phase epoxy syntactic foam (LWTP‐ESF) with a multiscale ternary structure was prepared using a molding pressing method with epoxy resin as matrix, hollow glass microspheres (HGMs), and GF‐EHS as the lightweight fillers. The effect of HGMs content on the density, uniaxial compression properties, water absorption, and thermal conductivity of obtained LWTP‐ESF was evaluated. The results indicated that the density, uniaxial compression strength, and thermal conductivity of LWTP‐ESF were consistently decreased, while the water absorption was increased with the increase in HGMs content. The highest specific compression strength and lowest thermal conductivity of LWTP‐ESF could reach 52.77 ± 0.82 MPa·cm3/g and 0.113 ± 0.005 W/(m·K), respectively. Moreover, the effect of hydrostatic pressure on the water absorption and thermal conductivity of LWTP‐ESF were also systematically analyzed. This study provides a novel system and method to prepare lightweight epoxy syntactic foams, and the prepared composites have potential applications in the field of lightweight thermal insulation materials for marine.Highlights The composites with a multiscale ternary structure were designed. The composites possessed significantly lower density and thermal conductivity. The water absorption of composites under hydrostatic pressure was evaluated. The thermal conductivity of composites under hydrostatic pressure was evaluated. The water absorption mechanism and thermal insulation mechanism were proposed.

Honeycomb networks of boron nitride/nanodiamond with interlocking interfaces enhance the application reliability of silicone rubber thermal conductivity composites

AbstractThe three‐dimensional (3D) boron nitride (BN) thermal conductive networks, crafted through layer‐by‐layer assembly, hold tremendous potential for the development of insulating thermal interface materials (TIMs) with exceptional thermal conductivity. Nevertheless, maintaining the thermal conductive stability of this structure type during application remains a considerable challenge. Herein, initially, the honeycomb networks of boron nitride/nanodiamond (ND/kBN) with interlocking interfaces were prepared by electrostatic self‐assembly and ice template method. Subsequently, thermal conductivity composites of flexible silicone rubber (VQM) were acquired through vacuum‐assisted infiltration. The composites demonstrated improved through‐plane thermal conductivity with 1.03 W/(m K) at a 9.9 vol% content of ND/kBN while exhibiting relatively ideal dielectric properties. More importantly, the thermal conductive properties of the composites still maintain at 96.1% and 91.9%, respectively, even after undergoing 30% compressive deformation for 1 h and being bent 300 times. This study presents a novel strategy that not only improves the thermal conductivity of composites but also ensures the reliability of their applications.Highlights Nanodiamond (ND) is anchored onto the kBN surface by electrostatic self‐assembly. ND/kBN filler honeycomb network with an interlocking interface was prepared. Flexible composites with high thermal conductivity (TC) were prepared. The composites exhibit excellent TC stability after experiencing deformation.

The preparation and feasibility analysis of magnetic orientation method in the study of thermal insulation composite materials in the field of electronic packaging

AbstractAs an emerging field of current technological development, the heat dissipation performance of electronic packaging materials has become the key to determining product reliability. Therefore, the applied thermal interface materials (TIMs) need to simultaneously meet the performance indicators of thermal conductivity, mechanics, and insulation. Although BN had excellent in‐plane thermal conductivity and insulation performance, it is currently difficult to achieve vertical orientation of powder which leads the layered powder cannot complete a continuous and effective heat transfer path along the Z‐axis direction inside the composite material. In order to solve the above two problems, out‐of‐plane thermal conductive composite was prepared by introducing magnetic oriented method. In order to comprehensively evaluate the thermal conductivity, mechanical and electrical properties, BN@Fe3O4/EP magnetic oriented composites were compared with BN@PDA‐Al2O3/EP composite prepared by mechanical blending method. The vertical thermal conductivity of the magnetic oriented composite material was 2.24 W/(m·K) at 30 vol%, which was 3.39 times that of the blended composite material and 12.4 times that of pure EP. This proves that the magnetic oriented composite materials prepared by the research institute can meet the vertical heat transfer needs in the field of electronic packaging and have high research value in this area.Highlights BN@Fe3O4 core–shell particles were prepared with both thermal conductivity and magnetic controllability. The thermosetting composites were prepared by heated through preliminary gel point and then cured at high temperature. The orientation of powder inside the matrix was constructed, resulted in excellent out‐of‐plane heat transfer performance. Comparisons were made between various properties of magnetic oriented materials and conventional blend materials. The magnetic orientation method is feasible in the field of electronic packaging.

Low-temperature synthesis and properties of high-purity boron nitride microspheres

Boron nitride (BN) has excellent high temperature resistance, thermal conductivity, strong insulation, and wave-transparent properties. Spherical BN is an essential filler in polymer matrix composites due to good particle mobility and high filler content. In this paper, we present a large-scale preparation for BN microspheres with uniform particle size distribution in the range of 1.0–2.8 μm via solvothermal method at low cost and high yield (∼90%), which is two orders of magnitude lower than the diameter of the spherical BN prepared by other methods. BN microspheres can achieve good crystallinity (>70%) and high purity (>99.9%) at 800 °C. The temperature resistance study showed that the BN microspheres could maintain the dense particle morphology at 1200 °C. In addition, the prepared BN microspheres have good dielectric and thermal conductivity properties (dielectric constant ∼3.4, dielectric loss ∼2.0 × 10−3, and thermal conductivity of 9.8 W m−1 K−1), which show great potential in the field of wave-transparent and thermal conductive composites. The synthesis process of BN microspheres proposed in this study provides a new idea for the preparation of ceramic micro or nano materials by polymer-derived ceramics.

Thermal Properties Characteristic of Aluminium-Alumina Composite for Solar Water Heating System Application

Thermal Energy Storage (TES) is an energy storage mechanism or material with modern technology at low costs, such as metal, concrete, composites, and others. Aluminum (Al)–Alumina (Al2O3) Composite is a solid material with high strength and hardness characteristics that can work in low-temperature applications. This study aims to analyze the features of the thermal properties of composite materials in the form of thermal conductivity and specific heat capacity. Composite specimens were prepared using powder metallurgy techniques. The weight fraction of alumina in the composite is 35%, 50%, and 65%. There are three (3) composite models, namely C1(35Al-65Al2O3), C2 (50Al-50Al2O3), and C3(65Al-35Al2O3). Models were made using the cold compaction method with a compressive load of around 20-25 MPa, and the specimens were fired in a furnace at a temperature of 550 °C with a holding time of 30 minutes. Scanning Electron Microscopy analyzed the microstructure of the composites. Composite thermal conductivity test using a thermal conductivity apparatus, and composite heat capacity test using a Differential Scanning Calorimetry (DSC). The results showed that C1(35Al-65Al2O3) composite had higher density and specific heat capacity than C2 and C3 composites. The theoretical density and specific heat capacity values of the C1 composite are 3.39 g/cm3 1.36 J/g.°C. However, the value of the thermal conductivity of C1(35Al-65Al2O3) material is lower than the other composites with a value of 0.37 W/m.°C. The greater the percentage by weight of alumina in the aluminum-alumina composite, the more theoretical density and specific heat capacity will also increase. Still, the thermal conductivity of the composite will decrease. Composite C1 35Al-65Al2O3 can potentially be a heat energy storage material used in solar water heating systems because of its high density and heat capacity.

BN nanosheets/aramid nanofibers with pearl layered structure towards highly thermal conductive composites

This work reports a composite film using (3-Aminopropyl)triethoxysilane-modified boron nitride nanosheets (BNNS) incorporated in the aramid nanofibers (ANF) network via sol–gel method. High-resolution TEM, SEM, XPS, and XRD outcomes confirmed the imitation pearl layered structure—BNNSs as thermal conductive fillers were layer-by-layer overlapped on ANF. The reasonable coordination between interfaces and fillers stimulated the thermal conductivity (35.4 W (m·k)-1) of composite film i.e., 338.43 % higher than that of ANF. The composite film exhibited good cyclic thermal stability, high tensile strength (65.9 MPa), and high volume resistivity (2.424 × 1015 Ω∙cm).

Bioinspired Thermal Conductive Cellulose Nanofibers/Boron Nitride Coating Enabled by Co-Exfoliation and Interfacial Engineering.

Thermal conductive coating materials with combination of mechanical robustness, good adhesion and electrical insulation are in high demand in the electronics industry. However, very few progresses have been achieved in constructing a highly thermal conductive composites coating that can conformably coat on desired subjects for efficient thermal dissipation, due to their lack of materials design and structure control. Herein, we report a bioinspired thermal conductive coating material from cellulose nanofibers (CNFs), boron nitride (BN), and polydopamine (PDA) by mimicking the layered structure of nacre. Owing to the strong interfacial strength, mechanical robustness, and high thermal conductivity of CNFs, they do not only enhance the exfoliation and dispersion of BN nanoplates, but also bridge BN nanoplates to achieve superior thermal and mechanical performance. The resulting composites coating exhibits a high thermal conductivity of 13.8 W/(m·K) that surpasses most of the reported thermal conductive composites coating owing to the formation of an efficient thermal conductive pathway in the layered structure. Additionally, the coating material has good interface adhesion to conformably wrap around various substrates by scalable spray coating, combined with good mechanical robustness, sustainability, electrical insulation, low-cost, and easy processability, which makes our materials attractive for electronic packaging applications.

Micromechanics of Thermal Conductive Composites: Review, Developments and Applications

Micromechanics of Thermal Conductive Composites: Review, Developments and Applications

Fused Deposition Modeling of Isotactic Polypropylene/Graphene Nanoplatelets Composites: Achieving Enhanced Thermal Conductivity through Filler Orientation.

High-performance thermally conductive composites are increasingly vital due to the accelerated advancements in communication and electronics, driving the demand for efficient thermal management in electronic packaging, light-emitting diodes (LEDs), and energy storage applications. Controlling the orderly arrangement of fillers within a polymer matrix is acknowledged as an essential strategy for developing thermal conductive composites. In this study, isotactic polypropylene/GNP (iPP/GNP) composite filament tailored for fused deposition modeling (FDM) was achieved by combining ball milling with melt extrusion processing. The rheological properties of the composites were thoroughly studied. The shear field and pressure field distributions during the FDM extrusion process were simulated and examined using Polyflow, focusing on the influence of the 3D printing processing flow field on the orientation of GNP within the iPP matrix. Exploiting the unique capabilities of FDM and through strategic printing path design, thermally conductive composites with GNPs oriented in the through-plane direction were 3D printed. At a GNP content of 5 wt%, the as-printed sample demonstrated a thermal conductivity of 0.64 W/m · K, which was 1.5 times the in-plane thermal conductivity for 0.42 W/m · K and triple pure iPP for 0.22 W/m · K. Effective medium theory (EMT) model fitting results indicated a significantly reduced interface thermal resistance in the through-plane direction compared to the in-plane direction. This work shed brilliant light on developing PP-based thermal conductive composites with arbitrarily-customized structures.

Anisotropic Rotunda-Shaped Carboxymethylcellulose/Carbon Nanotube Aerogels Supported Phase Change Materials for Efficient Solar-Thermal Energy Conversion.

For the drawbacks of phase change materials such as poor shape stability and weak solar-thermal conversion ability, a rotunda-shaped carboxymethylcellulose/carbon nanotube aerogel (CA) with three-dimensional network was constructed by freeze casting with a special mold, and then impregnated with polyethylene glycol (PEG) in this work. The PEG/CA had an enthalpy of 183.21 J/g, and a thermal conductivity of 0.324 W m-1 K-1, which was 57 % higher than the pure PEG. The ability of PEG/CA to convert solar energy to thermal energy was a positive correlation between the inclusion of CNTs and the composite material's thermal conductivity. Under simulated sunlight, its solar-thermal conversion efficiency reaches 94.41 %, and after 10 min of irradiation, the surface temperature can reach 65 °C and the internal temperature can reach 44.67 °C. This rotunda-shaped PEG/CA is promising for the efficient use of renewable solar energy due to its strong solar-thermal conversion and thermal storage capabilities.

Thermally conductive h-BN/EP composites oriented by AC electric field induction

The excellent electrical insulation properties and mechanical properties of epoxy resin (EP) have led to its rapid development in the field of microelectronic packaging. However, the poor thermal conductivity of epoxy resins (thermal conductivity of only 0.14 W/(m·K)) limits the development of components for high power. Adding h-BN to epoxy resin to prepare composites can effectively improve the thermal conductivity of epoxy resin. In this paper, h-BN/EP high thermal conductivity composites were prepared by means of AC electric field induction with the goal of making the composites low loading and high thermal conductivity (loading of 10 wt%). It was shown that the h-BN/EP composite had the highest thermal conductivity of 0.310 W/(m·K) when applied to an AC electric field of 120 V/mm and 50 Hz for 1 h. It was 2.214 times higher than that of EP and 1.325 times higher than that of the same-loaded h-BN/EP composite (0.234 W/(m·K)). A thermal conductivity model that can predict the thermal conductivity of composites prepared using the same type of method is also developed, which extends the applicability of the thermal conductivity model. The prepared composites have good thermal management capability. The method is easy to be engineered and has great potential for use in electronic packaging and even other high thermal conductivity applications.

Regulating surface energy and establishing covalent bonds to enhance interface interaction between m‐BN and polyphenylene oxide for 5G applications

AbstractIncorporation of boron nitride (BN) into polymers is a promising method to obtain composites with high thermal conductivity, low dielectric constant (Dk), and dielectric loss (Df), while the practical applications are limited by the poor interface between BN and polymer because of surface energy mismatch and absence of covalent bond connection between them. Herein, polydopamine (PDA) with good adhesion is deposited onto the BN. Then, a different amount of silane coupling agent containing vinyl reactive groups is grafted onto PDA‐coated BN. In this way, the surface energy of modified BN (m‐BN) can be adjusted to ensure BN contacts well with polymers. Moreover, reactive groups were introduced on BN for further reaction. Subsequently, covalent bonds between the m‐BN and the polyphenylene oxide (PPO) were established in situ during the curing process. The effects of the m‐BN surface energy on interface quality and thermal conductivity of composites are investigated. The m‐BN/PPO composite achieves a through‐plane thermal conductivity of 5.87 W/m·K and a low Df value of 1.53 × 10−3, as well as a low coefficient of thermal expansion (CTE) value (7.8 ppm/K) when the m‐BN loading is 32.6 vol%. This research provides a simple and efficient strategy for fabricating high‐performance composites for high‐frequency applications.Highlights Hexagonal boron nitride was modified successfully by combining non‐covalent and covalent modifications. Regulating surface energy and establishing covalent bonds enhances interface interaction between BN and polyphenylene oxide. Modified BN/polyphenylene oxide composites display improvements in thermal conductivity and dimensional stability as well as dielectric loss. Provides a feasible strategy for designing polymer composites with high thermal conductivity, dimensional stability, and low dielectric loss for 5G applications.

Castor oil‐based polyurethane ternary composites with enhanced thermal conductivity and mechanical properties by using liquid metal as second filler

AbstractWith the miniaturization, high frequency of electronic devices, and low‐carbon and sustainable development, higher requirements are put forward for thermal conductive polyurethane composites in terms of comprehensive performance and renewable raw materials. Herein, choosing bio‐based polyurethane (PU) derived from castor oil as matrix, and liquid metal (LM) and aluminum hydroxide (ATH) as hybrid thermal conductive filler, castor oil‐based PU composites were developed via high‐speed rotation and in‐situ polymerization method. The LM‐ATH hybrid filler displayed a synergistic enhancement effect on the thermal conductivity of composites due to the presence of LM‐bridging significantly improved the effective contact probability between ATH fillers. The thermal conductivity of 50LM‐ATH/PU reached 1.69 Wm−1 K−1, which was 9.9 times and 1.4 times higher than that of pure PU and 50ATH/PU, respectively. Notably, the 50LM‐ATH/PU exhibited outstanding mechanical properties including tensile strength up to 4.0 MPa and adhesion strength up to 7.9 MPa, especially elongation at break up to 120% which was improved by 200% compared with 50ATH/PU (40%). Additionally, the composite possessed excellent electric insulation, thermal stability, and inflaming retarding properties, showing great application potential in the electronic devices field.Highlights Castor oil‐based PU composites with ATH‐LM hybrid filer were developed. LM‐ATH hybrid filler of 2:8 promoted the thermal conductivity of composites. Hybrid filler than ATH‐endowed composites with better mechanical properties. The ATH‐LM/PU exhibited excellent electric insulation.

The effect of filler size on the properties of TPU / BN flexible thermal conductive composites prepared by Fused Filament Fabrication

Fused Filament Fabrication (FFF) can promote high aspect-ratio fillers to align in specific direction due to deposition-induced effect, so it is widely used in the preparation of thermal conductive composites. Though many studies about FFF have explored the influence of filler types, content, shape, and orientation on thermal conductivity during FFF, the size effect of filler is neglected. In this work, TPU/BN composites with 30 wt% h-BN were successfully printed by Fused Filament Fabrication. The size effect of h-BN on orientation, morphology, thermal conductivity, and other properties were studied. It is found that large-sized fillers are more prone to orientation and mutual contact during the FFF printing process to form thermal conductive paths. An increase in filler size results in an increase in thermal conductivity along the printing direction, which is up to 2.58 W m−1 K−1. The prepared TPU/BN composite not only has high thermal conductivity but also ensures good flexibility.

Highly thermal conductive epoxy composites enabled by 3D graphene/Cu-based dual networks for efficient thermal management

With the increasing integration of electronic devices, efficient thermal management is urgently required. Herein, 3D graphene/Cu-based dual networks were developed for highly thermal conductive epoxy (Cu@hLIG/EP) composites. Using the honeycomb-like porous laser-induced graphene (hLIG) as 3D skeleton, the Cu layer was introduced by electroless plating. The Cu@hLIG/EP composite showed a high thermal conductivity up to 16.4 W m−1 K−1, which was almost 63 times that of neat EP and 6 times that of hLIG/EP composite with similar filler loading. This increase was attributed to the pre-constructed 3D network, phonon-electron dual thermal transfer channels and reduced phonon mismatch in composites. Furthermore, by using the reprocessable EP resin, the designability of thermal conductive composites was greatly enhanced, where layered composites could be easily fabricated by the simple stacking strategy. The material/process developed demonstrates wide promise in thermal management applications.