Abstract: Lightweight polymer composites with superior processability address thermal management and electromagnetic interference (EMI) in high-power electronics, particularly for energy and aerospace applications. In this work, we report a polyether ether ketone (PEEK) based composite with a polyurethane foam template that utilizes polybenzoxazine (PBZ) modified multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GnPs) to establish continuous conductive networks through resin infusion, denoted as r(MWCNTs&GnPs)@PBZ/PEEK. The architecture enables optimized phonon transport and electron tunneling dual enhancement via interconnected fillers, thereby boosting thermal conductivity (TC) and EMI shielding. The composite with a filler loading of 27.8 wt.% exhibited pronounced anisotropic TC, attaining values of 4.83 (through-plane) and 6.33 W m^-1 K^-1 (in-plane), exceeding pristine PEEK by 2000 % and 2650 %, respectively. Simultaneously, it has a total exceptional EMI shielding performance of 106.72 dB, corresponding to 99.999999997 % total shielding efficiency. The strategy provides ideas for the construction of conductive networks in polymer composites.

Key words: 3D transfer network, Thermal conductivity, Electromagnetic shielding, Interfacial thermal resistance