Thermal Management Materials Research Articles

Towards high-performance polydimethylsiloxane-based materials for thermal management: A molecular dynamics study

To efficiently design high-performance polymer-based thermal interface material (TIM), it is imperative to investigate how microstructural influences thermal transport. Utilizing molecular dynamics (MD) simulations, this study examined the effects of crosslinking degree (10–40%) and alumina (Al2O3) filler doping ratios (0–23.13 wt%) on the thermomechanical behaviors of PDMS. Our findings indicated that increasing the degree of crosslinking significantly enhances thermal conductivity at lower doping rates by creating additional heat transfer channels. However, at higher doping rates, thermal conductivity improvement is mitigated due to the potential hindrance caused by fillers. Optimal thermal conductivity was observed with a 20% crosslinking degree and 14.67 wt% Al2O3 doping, achieving an 18% enhancement compared to systems without crosslinking. These results underscore the complex interplay between crosslinking and filler content in optimizing the thermal performance of PDMS-based TIMs, contributing to the advancement of materials for efficient thermal management in microelectronic devices.

Constructing bidirectional heat flow pathways by curved alumina for enhanced thermal conductivity of epoxy composites

The polymer-based composites filled with high thermal conductive fillers have received much attention in the filed of electronic package. However, traditional Al2O3 filled polymer-based composites always hardly simultaneously achieve high thermal conductivity in both horizontal and vertical directions with a low loading. Herein, curved Al2O3 particles have been fabricated via spray assembly and high-temperature sintering and subsequently are infiltrated by epoxy (EP) to obtain Al2O3/EP composites. The formation mechanism of the curved Al2O3 is analyzed in this work. The curved Al2O3 architectures are orderly stacked in EP matrix, which achieve significantly enhanced in-plane (1.21 W/m·K) and through-plane (1.46 W/m·K) thermal conductivity with a low filler loading (19.9 vol%). Importantly, the wall structure of curved Al2O3 particle consists of continuous network structure and interconnected channels, which reduce the thermal expansion coefficient of the composites. Consequently, the design of curved Al2O3 offers a new strategy for next-generation thermal management materials.

Experimental study of dual nano-network, high-temperature resistant aerogel material as an integration of thermal management functions

Thermal management system is highly desirable to guarantee the performance and thermal safety of lithium-ion batteries, but it reduces the energy density of battery modules and even is unable to provide highly effective protection. Here, a thermal management function integrated material is presented based on high-temperature resistant aerogel and phase change material and is applied at both charge–discharge process and thermal runaway condition. In this sandwich structure Paraffin@SiC nanowire/Aerogel sheet (denoted as PA@SAS) system, SiC nanowires endow the middle aerogel sheet (SAS) a dual nano-network structure. The enhanced mechanical properties of SAS were studied by compressive tests and dynamic mechanical analysis. Besides, the thermal conductivity of SAS at 600 °C is only 0.042 W/(m K). The surface phase change material layers facilitate temperature uniformity of batteries (surface temperature difference less than 1.82 °C) through latent heat. Moreover, a large-format battery module with four 58 Ah LiNi0.5Co0.2Mn0.3O2 LIBs was assembled. PA@SAS successfully prevents thermal runaway propagation, yielding a temperature gap of 602 °C through the 2 mm-thick cross section. PA@SAS also exhibits excellent performance in other safety issues such as temperature rise rate, flame heat flux, etc. The lightweight property and effective insulation performance achieves significant safety enhancement with mass and volume energy density reduction of only 0.79% and 5.4%, respectively. The originality of the present research stems from the micro and macro structure design of the proposed thermal management material and the combination of intrinsic advantages of every component. This work provides a reliable design of achieving the integration of thermal management functions into an aerogel composite and improves the thermal safety of lithium-ion batteries.

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.

An electric conductive wide-temperature flexible phase change material for all-climate battery thermal management

Battery thermal management with phase change materials (PCM) has been limited by leakage, low thermal conductivity and rigidity, and the inability to preheat at low temperatures. To solve these problems, a wide-temperature flexible composite PCM (FCPCM) was prepared with a high-temperature open refining method. Styrene ethylene butylene styrene (SEBS) and expanded graphite (EG) absorb paraffin (PA) onto a three-dimensional network. The FCPCM possesses good flexibility before and after phase transition. It can be bent and stretched arbitrarily at room temperature, and the shape memory function enable it can be restored to its original state after heating. The latent heat of the FCPCM-15 is 159.9 J/g and its thermal conductivity was 7.45 times higher than that of pure paraffin. The FCPCM also possesses a good volume conductivity of 92–2952 S/m and allows for uniform electrical heating. The excellent thermal and electrical performance of the FCPCM allows it to cool batteries at high temperatures and preheat batteries at low temperatures. After ten charge/discharge cycles at 30 °C, the battery pack’s temperature based on FCPCM cooling is still reduced by 3.9 °C. At a low temperature of −20 °C, the preheating rate of the battery pack can reach 12.9 °C/min, and the discharge voltage and capacity of the battery pack were increased by 15 % and 20.8 % after preheating. The FCPCM suggests a promising and practical approach way for the all-climate thermal management of batteries.

Mechanical–thermal coupling in micro-nanocavity graphene/paraffin phase change energy storage materials for heat management

Combining the superior thermal conductivity of graphene and the outstanding heat storage of paraffin, micro-nanocavity graphene/paraffin nanocomposites (MNGPNs) have recently served as promising thermal management materials in high-power microelectronic devices. However, current evaluations of the thermal management performances of MNGPNs are restricted in the lab condition, deviating from the complex mechanical–thermal coupling environment in practical scenarios. Here, we have investigated the structural and thermal management properties of MNGPNs with varying mechanical loads by in situ electron microscopy and in situ thermal characterizations. Our results reveal distinct mechanical–thermal coupling effects along in-plane and out-of-plane directions of MNGPNs. Specifically, mechanical loading reduces the porosity and enhances the heat transfer capacity of MNGPNs in the out-of-plane direction, while mechanical loading along the in-plane direction causes local damage to the graphene structure and weakens the heat transfer capacity of MNGPNs. Since the heat management performance of MNGPNs is dominated by the in-plane thermal transport, MNGPNs with mechanical loading show a delayed phase transition response time and unchanged phase transition enthalpy. This work provides in situ mechanical guidance for the practical application of MNGPNs for heat management.

Lauric acid based form-stable phase change material for effective electronic thermal management and energy storage application

Poor thermal management in electronic systems can lead to higher junction temperatures, accelerating failure mechanisms and reducing component lifespan. Integrating efficient thermal management techniques, such as heat sinks, is essential for ensuring durability and efficiency of electronic equipment. Heat sinks have limited capacity, but integrating phase change materials (PCMs) enhances cooling performance by harnessing latent heat storage. However, leakage and low thermal conductivity limit PCM's effectiveness. The current study developed highly conductive leakage-proof PCMs based composites using an ultrasonic and vacuum impregnation method with lauric acid as base, hexagonal boron nitride and expanded graphite as additives. The results demonstrate persistence of chemical integrity, as proven by FTIR analysis, and complete encapsulation of PCMs inside the expanded graphite structures. The form-stable composite PCMs exhibit a 450% increase in thermal conductivity and 77% photo-transmittance decrease compared to base PCMs. Despite a trade-off of a 11.5% reduction in latent heat, the composite demonstrates thermal stability up to 220 °C. Further, excellent chemical and thermal reliability is maintained even after 500 cycles. Furthermore, in thermal management for heat sink, the form stable composite efficiently dispersed heat, resulting in a 16 °C decrease in peak temperature compared to the heat sink without the composite.

Experimental investigation on hydrated salt phase change material for lithium-ion battery thermal management and thermal runaway mitigation

To efficiently ensure the suitable temperature for lithium-ion batteries, battery thermal management system based on phase change material (PCM) have gained considerable attention. A shape-stabilized composite PCM was prepared using the mixture of Na2SO4·10H2O and KAl(SO4)2·12H2O hydrated salts as phase change substrate, expanded graphite as thermal conductive filler and open-cell polyurethane foam as support material. The composite PCM containing 4 wt.% expanded graphite displayed a satisfied phase change temperature of 30.8 °C and 69.8 °C, high latent heat of 226.9 J/g, and good thermal conductivity of 1.39 W/(m·K). Meanwhile, it obtained a low subcooling degree, good leakage resistance, and excellent flame retardancy properties. Under PCM cooling in sandwich structure, during 0.5C charging and 1.5C discharging cycles, the maximum temperature and maximum temperature difference of battery were 52.47 °C and 2.20 °C, decreased by 20.4 % and 59.7 % respectively compared with nature air cooling. Furthermore, the composite PCM could significantly relieve the thermal runaway propagation between lithium-ion batteries. This work provides a feasible design and application strategy of hydrated salt based PCMs for battery thermal management and thermal runaway mitigation.

Double-network aerogel-based eutectic composite phase change materials for efficient solar energy storage and building thermal management

Phase change materials (PCMs) have shown great promise in solar energy storage and thermal management of buildings. Nevertheless, the solid-liquid PCMs currently used in these applications face multiple challenges that need to be addressed, such as inadequate solar absorption capacity, leakage issues, and low phase change enthalpy. In this research, urea and sodium acetate trihydrate (SAT) were employed as the main PCMs, while disodium hydrogen phosphate dodecahydrate (DHPD) served as the nucleating agent. Additionally, we used polyvinyl alcohol/silica (PVA/SiO2) aerogel as a porous support structure. Carbon nanotubes (CNTs) were also introduced as photothermal conversion materials to fabricate a photothermal conversion-type double-network aerogel-based eutectic composite PCM (ECPCM). The prepared ECPCM exhibited excellent shape stability, high mechanical strength, and outstanding photothermal conversion performance. Moreover, the ECPCM demonstrated good flame retardancy, low supercooling, and the absence of phase separation issues. Furthermore, the ECPCM demonstrated efficient solar energy storage capacity and outstanding performance in building thermal management. This study offers a new perspective on the advancement of ECPCMs in solar energy storage and thermal management of buildings.

Electrothermal Curable Epoxy Interface Adhesive Composite with Low Voltage: An Ideal Thermal Management and EMI Shielding Material

Electrothermal Curable Epoxy Interface Adhesive Composite with Low Voltage: An Ideal Thermal Management and EMI Shielding Material

Highly thermally conductive BNNS/PANF dielectric composite boards prepared by a facile compression moulding process

The structural design of an efficient heat conduction channel is critical for heat dissipation in electronic packaging material. The build of oriented boron nitride nanosheet (BNNS) network inside polymers has attracted much attention due to its excellent thermal conductivity and dielectric properties. However, to fabricate a BNNS/polymer composite, complex method and low thermal conductive resin for binding BNNS network are commonly involved, which severely restrict its facile production and enhancement in thermal conductivity. Herein, by utilizing para-aramid nanofibers (PANF) as assistance to BNNS to form thermal conduction network, we obtained high performance composite boards with good formability and adjustable sizes via a simple compression moulding of the BNNS/PANF aerogels. The composite boards exhibit a remarkable in-plane thermal conductivity of 10.62 W/m K−1 at 50 wt% BNNS loading, outstanding practical thermal management capability, excellent thermal stability, low dielectric constant and loss, showing great potential for electronic packaging applications. This facile construction strategy provides a feasible way for the large-scale production and application of high-performance thermal management materials in the future.

Flexible hexagonal boron nitride@liquid metal/polydimethylsiloxane composites with excellent thermal conductivity and superior mechanical properties

AbstractHexagonal boron nitride (h‐BN) has a layered lattice structure, high intrinsic thermal conductivity, and good chemical stability, and it has a promising applications in thermal management materials. However, poor interfacial compatibility and dispersion of BN flakes in the polymer matrix cause thermal contact resistance and gaps, directly impairing the performance of the composites and limiting their thermal conduction applications. Herein, the P‐BN@LM/PDMS thermally conductive composites with superior mechanical properties were fabricated by incorporating dopamine and liquid metal (LM) into BN flakes. The dopamine self‐polymerizes to form polydopamine (PDA) on the BN surface, denoted as P‐BN, which effectively improves interface compatibility and dispersion. The LM attaches to the functionalized P‐BN surface by mechanical grinding, acting as a bridge between adjacent BN flakes to enhance the integrity of the thermal conductive network within the composites. The coordination between P‐BN and LM increases interface strength, effectively improving mechanical performance. Hence, the P‐BN@LM/PDMS composites exhibit excellent thermal conductivity (4.0 W/mK) and an enhancement factor of 1373%, which is 2.22 times that of BN/PDMS composites with the same 30 wt% loading. Additionally, the composite shows superior tensile strength (2.11 MPa) and elongation at break (121%), representing 441% and 203% improvements compared with pure polydimethylsiloxane (PDMS). The P‐BN@LM/PDMS composites, with significant advantages in thermal conductivity and mechanical properties, are promising for future applications as flexible thermal interface materials in thermal management.Highlights The P‐BN@LM/PDMS composites exhibit excellent thermal conductivity (4.0 W/mK) and an enhancement factor of 1373%, making them promising for future applications as flexible thermal interface materials in thermal management. The P‐BN@LM/PDMS composites present a superior tensile strength (2.11 MPa) and elongation at break (121%). PDA formed by the self‐polymerization of dopamine on the BN surface effectively enhances interfacial compatibility and dispersion. LM attaches to the functionalized BN surface through mechanical grinding, acting as a bridge between adjacent BN flakes, thus enhancing the integrity of the thermal conductive network within the composites.

Hybrid effect of graphite and carbon fibers on thermal properties of copper/graphite/carbon fibers composites

To maintain the high thermal conductivity (TC) and reduce the coefficient of thermal expansion (CTE) of conventional copper (Cu)/graphite composites, novel Cu/graphite/carbon fibers (CFs) hybrid composites were designed by replacing part of graphite with Cu-coated CFs and prepared by spark plasma sintering (SPS) process. The incorporation of CFs resulted in increased interface density, reduced twin boundaries, and significant grain refinement of the Cu matrix. TEM observations revealed that the Cu-coating on surfaces of CFs enhanced the interfacial bonding between CFs and Cu matrix. The Cu-coated CFs can act as connecting channels between graphite particles, which partially compensate the negative effect on TC. Furthermore, strong interfacial bonding and large Cu/CFs contact areas contribute to the reduction in CTE. As a result, the Cu/30%graphite/10%CFs composite showed TC and CTE of 453.5 Wm−1 K−1 and 10.9 × 10−6 K−1, respectively. Compared to the Cu/40%graphite composite, the CTE of Cu/30%graphite/10%CFs composite was reduced by ∼20 % with only 4.4 % sacrifice in TC. Consequently, the Cu/graphite/CFs hybrid composites showed an excellent balance between TC and CTE, which are superior to the conventional Cu/graphite and Cu/CFs composites. The findings of this work provide new insights for designing and preparing new thermal management materials.

Ultrathin aerogel-structured micro/nanofiber metafabric via dual air-gelation synthesis for self-sustainable heating

Incorporating passive heating structures into personal thermal management technologies could effectively mitigate the escalating energy crisis. However, current passive heating materials struggle to balance thickness and insulating capability, resulting in compromised comfort, space efficiency, and limited thermoregulatory performance. Here, a dual air-gelation strategy, is developed to directly synthesize ultrathin and self-sustainable heating metafabric with 3D dual-network structure during electrospinning. Controlling the interactions among polymer, solvent, and water enables the microphase separation of charged jets, while adjusting the distribution of carbon black nanoparticles within charged fluids to form fibrous networks composed of interlaced aerogel micro/nanofibers with heat storage capabilities. With a low thickness of 0.18 mm, the integrated metafabric exhibits exceptional thermal insulation performance (15.8 mW m−1K−1), superhydrophobicity, enhanced mechanical properties, and high breathability while maintaining self-sustainable radiative heating ability (long-lasting warming of 8.8 °C). This strategy provides rich possibilities to develop advanced fibrous materials for smart textiles and thermal management.

Dry media reaction-based anti-hydration coating on magnesium oxide microspheres for thermal interfacial applications

Magnesium oxide (MgO) is gaining attention as a next-generation thermal management material due to its better thermal conductivity compared to other oxides and excellent insulating properties. However, its susceptibility to hydration when exposed to atmosphere, which alters its material properties, necessitates the application of anti-hydration coatings for its use in thermal management. This study explores the use of Chemical Vapor Deposition (CVD) and Plasma-Enhanced Chemical Vapor Deposition (PECVD) as alternatives to the traditional sol–gel method to form anti-hydration coatings on MgO microspheres. The surface modification process was completed within 20 min for both processes, and the water contact angles of the spheres increased from ∼33° to ∼98° with CVD and ∼125° with PECVD. Compared to CVD, PECVD was found to be more effective in applying anti-hydration coatings, thanks to the plasma activation of the MgO surface and reactants, thereby better maintaining the physical and chemical properties under conditions of 85 °C and 85 % relative humidity. Furthermore, when used as a filler in thermal interface material composites, MgO modified with PECVD exhibited adhesion strength and thermal conductivity about 1.5 times higher than bare MgO, due to the increased affinity for the hydrophobic binder.

Thermal Conductive Polymer Composites: Recent Progress and Applications.

As microelectronics technology advances towards miniaturization and higher integration, the imperative for developing high-performance thermal management materials has escalated. Thermal conductive polymer composites (TCPCs), which leverage the benefits of polymer matrices and the unique effects of nano-enhancers, are gaining focus as solutions to overheating due to their low density, ease of processing, and cost-effectiveness. However, these materials often face challenges such as thermal conductivities that are lower than expected, limiting their application in high-performance electronic devices. Despite these issues, TCPCs continue to demonstrate broad potential across various industrial sectors. This review comprehensively presents the progress in this field, detailing the mechanisms of thermal conductivity (TC) in these composites and discussing factors that influence thermal performance, such as the intrinsic properties of polymers, interfacial thermal resistance, and the thermal properties of fillers. Additionally, it categorizes and summarizes methods to enhance the TC of polymer composites. The review also highlights the applications of these materials in emerging areas such as flexible electronic devices, personal thermal management, and aerospace. Ultimately, by analyzing current challenges and opportunities, this review provides clear directions for future research and development.

New hybrid nano- and bio-based phase change material containing graphene-copper particles hosting beeswax-coconut oil for solar thermal energy storage: Predictive modeling and evaluation using machine learning

Although utilizing phase change materials (PCMs) for thermal energy storage and management has remarkably grown, the reliance on petroleum-based PCMs has raised concerns about their sustainability. Hence, in this study, the mixture of beeswax (BW) and coconut oil (CO) as a new biological-based PCM (bio-PCM) was developed. Also, the effect of 0.5, 1, and 2 wt% of graphene-copper (Gr-Cu) hybrid nanoparticles on the bio-PCM's ability in thermal energy storage (TES) was scrutinized. Thermal, chemical, physical, and stability specifications of BW-CO/Gr-Cu nano- and bio-based PCMs (bio-nPCMs) were examined by Differential Scanning Calorimeter (DSC), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Also, the thermal conductivity of bio-PCM and bio-nPCMs were explored in a range of temperatures from 25 to 60 °C. FTIR indicated no chemical reactions or new synthesis materials in the final composite. Also, all the used materials were recognized by XRD. DSC analysis showed that melting and solidification of bio-PCM start at 51 and 56 °C while adding 2 wt% Gr-Cu nanoparticles reduced the temperatures to 49.9 °C and 53.8 °C, respectively. In addition, bio-PCM had latent heats of 172.3 kJ/kg and 173.11 kJ/kg for melting and solidification, whereas 2 wt% Gr-Cu nanoparticles shifted them to 160.75 kJ/kg and 167.45 kJ/kg, in respect. On the other hand, the higher the concentration of Gr-Cu in the base PCM, the higher the thermal conductivity of bio-nPCMs maximally about 604 % higher than that of the base bio-PCM at T = 25 °C. Furthermore, a new model was proposed for the thermal conductivity that had an average error of 5 %. Machine learning was employed to estimate the thermal conductivity and latent heat. The former with R-squared, mean error (MSE), and average absolute relative deviation (%AARD) of 0.9996, 1.1253 × 10−4, 1.871, and the latter with 1, 4.7 × 10−10, and 0.01, respectively. The outcomes of this study present a procedure to develop future bio-PCMs and hybrid nanoparticles to pave the way to reaching net-zero carbon.

High-stability temperature control and frequency-domain analysis of sandwich-like insulation design based on phase change materials for satellite thermal management

High-stability temperature control and frequency-domain analysis of sandwich-like insulation design based on phase change materials for satellite thermal management

Fully 3D printed functional PDMS composites with designable structures and performances

Three-dimensional (3D) printing, as a layer-to-layer additive manufacturing technology, has received widespread attention for excellent designability. However, as for direct ink writing (DIW), current printing level is difficult to achieve high-precision printing of thermoset composites of different compositions. Therefore, fully 3D printing based on thermoset composites with high designability is proposed. The intralayer and interlayer of structure and materials prepared by this method are designable, and layer thicknesses as well as inter-layer patterns are adjustable. In this work, alumina (Al2O3) and short carbon fiber (SCF) are used as thermally conductive fillers, polydimethylsiloxane (PDMS) is conducted as thermoset matrix. Benefit from the high designability of our method, a series of Al2O3/SCF/Al2O3 (ASA) and SCF/Al2O3/SCF (SAS) composite samples with sandwich structures are fabricated and compared. The different materials and structural designs of these composite samples give them completely different properties in terms of thermal, electromagnetic shielding, and mechanical properties, making it possible to create customized designs for different scenarios. Taking thermal management materials (TMMs) as an example, we use this method to prepare ASA and SAS composites with sandwich structure, thermal conductivity of A40S30A40 and S30A40S30 reached 1.00 W/(m·K) and 1.55 W/(m·K) respectively. In all, customized and multifunctional applications make PDMS composites have a widespread prospect.

Low-temperature crystallization of BeO-assisted polycrystalline germanium layer for monolithic 3D integration

We demonstrated a new method for the low-temperature solid-phase crystallization (SPC) of germanium on beryllium oxide (BeO) films for monolithic 3D (M3D) integration. Using a wurtzite crystal BeO film, known for its high thermal conductivity of 370 W/m-k at 300 K and covalent bonding characteristics, as the underlying layer, we crystallized Ge at a reduced temperature of 410 °C. For the Ge-on-BeO, the formation of larger grains was consistently promoted at annealing temperatures of 410–500 °C, with a notable 125 % increase in the grain size at 500 °C compared to that at the SiO2 underlayer. The polycrystalline Ge layers crystallized on the BeO retained their tensile strain, as confirmed by the Raman spectra. Furthermore, its optical bandgap of ∼ 1.36 eV and average roughness of 0.847 nm at an annealing temperature of 450 °C make it more suitable for an M3D upper channel layer than Ge-on-SiO2. A comprehensive experimental analysis confirmed the enhanced crystallinity, stability, and channel properties of poly-Ge layers crystallized on BeO. Hence, this study developed a new method for the low-temperature SPC process and highlighted the potential of BeO as a crystallization-assistance thermal-management material for next-generation 3D integrated technology.