Boosting Multifunctional Composites Thermal Conductivity via Nanometallic Interfacial Low-Frequency Phonon Resonance

Abstract Modulation of inter-filler heat transfer governs the overall heat-dissipation performance of thermally conductive composites for electronics. Unlike covalent/non-covalent bond interfaces constructed using organic modifiers and inorganic secondary fillers, nanometallic bond-free interfacial structures built under mild conditions also promote interfacial thermal conduction while delivering multifunctionality. However, the related interfacial heat transfer behaviors and enhancement mechanisms remain poorly understood. Herein, guided by density functional theory and molecular dynamics simulations, we demonstrate that introducing conductive TCNQ at the graphene (Gra)-silver (Ag) interface strengthens low-frequency phonon (LFP) resonance via the resulting electron-phonon coupling (EPC) effect. Electron transfer between TCNQ and Ag optimizes the EPC effect, further activating LFP resonance across Gra and Ag surfaces to facilitate phonon transport between Gra layers. To corroborate these predictions, polybenzoxazole (PBO) nanofibers (PNFs)-based composites (GTAg x /PNFs) with TCNQ-modified graphene nanosheets (GNS)/Ag nanowires (AgNWs) composite fillers are fabricated via pressure-driven self-assembly. GTAg 30 /PNFs exhibits an in-plane thermal conductivity of 28.8 W m ‑1 K ‑1 and EMI shielding effectiveness of 61.0 dB, alongside outstanding Joule heating and mechanical properties. Validated by practical cooling tests on operating electronic devices and mitigation of vehicle heat-soaking injury, this simulation-assisted low thermal resistance interface design offers a promising route toward developing high-performance multifunctional thermal management materials.