Strong graphene bulk composites with high thermal conductivity over 800 W/m·K

Polymer composites with high thermal conductivity ( κ ) are essential for advanced thermal management applications. Graphene has enabled thin films with κ values approaching 2000 W/m·K , yet bulk composites incorporating graphene fillers typically remain limited below 550 W/m·K. Here, we present an inverse phase enhancement (IPE) strategy that employs polymer resin as the reinforcing phase, yielding strong bulk composites with a record-high κ of 802 ± 10.9 W/m·K. A minimum polymer content of merely 5.9 % effectively improves the tensile strength of graphene laminated papers by 117 % while maintaining their promising κ. Mortise-tenon-like 2D joints of minimum polymers efficiently retard the sliding of graphene sheets and impede the catastrophic crack propagation. Our work opens a modular path to fully harness the exceptional κ of neat graphene assembled materials, enabling pivotal thermal applications of graphene bulk composites in heat dissipation for electronic devices and protective equipment. • Mortise-tenon-like 2D joints structure reinforces the graphene papers efficiently. • A minimum polymer content of only 5.9 % maintains the promising κ of graphene papers while improves strength. • Strong and superiorly thermal conductive bulk composites with a record κ of 802 W/m·K.