Alumina-Coated Cu@Reduced Graphene Oxide Microspheres as Enhanced Antioxidative and Electrically Insulating Fillers for Thermal Interface Materials with High Thermal Conductivity

Alumina-deposited reduced graphene oxide-coated Cu microspheres (Cu@rGO@Al 2 O 3 ) are fabricated by heating graphene oxide nanosheet-coated Cu microspheres with the Al(OH) 3 outer layer under H 2 /Ar atmospheres. The Cu@rGO@Al 2 O 3 microspheres exhibit high anticorrosion and antioxidation properties. Compared with bare Cu microsphere filler, the Cu@rGO@Al 2 O 3 microsphere-filled thermal interface materials demonstrate 1.5 times higher thermal conductivity and 4.8 times higher permissible voltage (electrical insulation) due to the high thermal layer of rGO and the electrically insulating coating of Al 2 O 3 . This unique core–shell Cu@rGO@Al 2 O 3 -based composite with high thermal conductivity, antioxidative stability, and electrical insulation could be promising as efficient thermal interface materials for advanced electronic packaging techniques.