<scp>3D</scp> Surface‐Modified Spherical Graphite for Enhancing the Thermal Conductivity of Epoxy Resins

ABSTRACT This study fabricates crown‐like 3D‐structured brochantite nanocrystal‐modified spherical graphite (Cu@SG) via polydopamine (PDA)‐assisted chemical plating, and integrates it with epoxy resin (EP) to prepare high‐thermal‐conductivity composites. XRD, FTIR, and SEM characterizations show PDA enables uniform brochantite deposition via interfacial coordination, forming an SG‐PDA‐brochantite structure without damaging SG's graphitic structure (ID/IG ratio only rising from 0.22 to 0.24). At 20 wt% filler content, Cu@SG/EP achieves through‐plane and in‐plane thermal conductivities of 1.198 W/(m K) and 1.536 W/(m K), increasing by 311.1% and 398.9% versus pure EP, and 57.6% and 22.0% versus unmodified SG/EP. Despite a 10.6% flexural strength reduction, the multiscale thermal network boosts conductivity remarkably. This PDA‐assisted metallization strategy provides a new route for carbon‐based filler modification, with promising applications in electronic packaging and new energy thermal management.