Thermally Conductive and Leakage-Proof Phase-Change Materials Composed of Dense Graphene Foam and Paraffin for Thermal Management

Abstract

Practical implementation of porous carbon-based composite phase-change materials (CPCMs) for heat dissipation in high-power-density electronics is usually limited by liquid leakage issues and unsatisfactory thermal conductivity resulting from their relatively low filler fraction and/or existence of interfacial thermal resistance between fillers. Therefore, development of shape-stable CPCMs with high thermal conductivity and large latent heat to avoid overheating of electronics remains challenging. Herein, graphene foams (GFs) with very high densities of up to 204 mg/ cm 3 have been synthesized to act as interconnected porous networks of CPCMs. Notably, the obtained CPCM with a filler loading of 11.1 wt % preserves a high heat capacity (171.8 J/g) with a retention of 84.8% while showing a 22.6-fold enhancement in the thermal conductivity as compared to pure PCM (10.13 vs 0.43 W/m•K). A higher thermal conductivity of 14.29 W/m•K can be achieved by further increasing the filler loading to 17.7 wt %, which outperforms many of the previously reported CPCMs based on the interconnected porous carbon-based frameworks. Owing to the superior interconnected network structure of the dense GFs and the strong interconnection between them and PCM molecules, these CPCMs also exhibit leakage-proof shape stability and excellent thermal reliability (at least 100 cycles). Moreover, a state-of-the-art aluminum (Al) package based on the CPCM (filler loading: 11.1 wt %) possessing weight 60% less than its pure Al panel counterpart has been demonstrated to verify better heat transfer efficiency and more efficient phonon pathways of the CPCM composite than those of the pure PCM, which holds great promise for advanced thermal management of emerging applications in electronics.

Advances in Biocarbon and Soft Material Assembly for Enthalpy Storage: Fundamentals, Mechanisms, and Multimodal Applications

“…[68,[131][132][133][134][135][136] One plausible approach to harness these characteristics for applications would be to integrate graphene sheets in composite material using different design methods, such as solution mixing/impregnation, in situ polymerization, coating, and melt grinding, [135,137] as shown in Figure 13. Li et al [138] prepared graphene foam-based nanocomposite using paraffin wax. The obtained composite overcame liquid leakage issues and unsatisfactory thermal conductivity and exhibited a 22.6-fold improvement compared with pristine paraffin, usually observed during heat dissipation in high-power-density electronics.…”

“…Li et al. [ 138 ] prepared graphene foam‐based nanocomposite using paraffin wax. The obtained composite overcame liquid leakage issues and unsatisfactory thermal conductivity and exhibited a 22.6‐fold improvement compared with pristine paraffin, usually observed during heat dissipation in high‐power‐density electronics.…”

Development and Perspectives of Thermal Conductive Polymer Composites

“…Although the thermal conductivity can be improved more effectively by high loadings or hybridizing fillers with different particle sizes and morphologies; however, as the filler particles are not in contact with each other directly, the polymer matrix with low thermal conductivity between them hinders the formation of continuous heat transfer pathways. Therefore, researchers have managed to control the distribution of fillers through various effective means, and then construct a completely continuous filler network [ 25 , 38 , 71 , 72 , 77 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 ]. This approach not only directly reduces the number/area of the interface between filler and matrix but also reduces the filler–filler interface, which fundamentally decreases the interfacial thermal resistance during heat transfer.…”

Novel Latent Heat Storage Systems Based on Liquid Metal Matrices with Suspended Phase Change Material Microparticles

“…However, the extent of k improvement via this approach is limited because of the difficulty in achieving internal thermal percolation through the highly dispersed particles . A more effective approach to improve k is by preparing relatively seamless continuous frames of high- k materials into which the PCM can be impregnated using various methods; this approach has led to much higher k values (>10 W m –1 K –1 ) than those previously reported. − However, composites prepared through this approach possess low processability because the high- k materials comprising the frames are typically rigid, which limits their facile application in systems of arbitrary form factors.…”