Al2O3/graphene nanoplatelet/polyvinyl alcohol composite film with high thermal conductivity in both in-plane and out-of-plane directions

A flexible graphene-based composite with both high in-plane and out-of-plane thermal conductivities has been proposed. • The in-plane and out-of-plane FOM of the composites far exceeds that of prior ones with the same graphene content. • The underlying mechanism responsible for the enhanced thermal conductivity of the composite films has been elucidated. Thermal management films are required to have high thermal conductivity in both in-plane and out-of-plane directions. Graphene has an exceptional in-plane thermal conductivity; however, developing graphene-based composite films with high thermal conductivity in both in-plane and out-of-plane directions remains challenging. In this work, flexible graphene-based composite films with high in-plane and out-of-plane thermal conductivities were fabricated by simply intercalating Al 2 O 3 particles into a graphene nanoplatelet (GNP)/polyvinyl alcohol (PVA) system. The reorientation of GNPs induced by 5 μm Al₂O₃ particles results in a composite film with an optimal composition, which exhibits a peak out-of-plane thermal conductivity of 2.85 W/(m·K) while maintaining a robust in-plane value of 13.11 W/(m·K), surpassing previously reported counterparts with similar GNP loadings. The excellent thermal performance was further verified through heat dissipation experiments using a smartphone and a direct current motor. Owing to its simplicity and cost-effectiveness, this study offers a promising strategy for fabricating high-performance thermally conductive graphene-based composites suitable for electronic devices, wearable electronics, and other related applications. Download: Download high-res image (193KB) Download: Download full-size image