High thermal conductivity and electrical insulation of liquid alloy/ceramic/epoxy composites through the construction of mutually independent structures

Abstract The formation of a continuous network for thermal transport is crucial for obtaining materials with high thermal conductivity. Herein, we report a novel epoxy-based composite with unique independent structures of liquid alloy (LQA) droplets and high thermal conductivity ceramic fillers. The ceramic fillers only aggregated in the spaces between the LQA droplets due to the low compatibility of the ceramic fillers and the LQA droplets, so that the LQA droplets and the ceramic fillers eventually form independent structures. This creates a continuous network in epoxy that is advantageous for thermal transport. Thermal conductivity measurements showed that the thermal conductivity of the Epoxy/LQA/ceramic composites can reach 2.46 W m−1K−1, for an enhancement of 1055.87% relative to pure epoxy. More importantly, the independent structures endowed the composites with excellent electrical safety. The electrical resistivity of the Epoxy/LQA composites was 8.53 × 107 Ω cm, while the electrical resistivities of the three Epoxy/LQA/ceramic composites were 3.11 × 1011 Ω cm (Epoxy/LQA/Al2O3), 2.41 × 1011 Ω cm (Epoxy/LQA/Si3N4), 4.45 × 1011 Ω cm (Epoxy/LQA/h-BN), respectively. This work provides a new perspective on both the fundamental science and practical applications of thermal transport in polymer composites.