Phonon‐Bridge Engineering in Vertically Aligned Graphene Paper Composites Enables Efficient and Reliable Thermal Interface Materials

ABSTRACT Efficient heat dissipation is vital for emerging high‐power electronic systems, where interfacial thermal resistance remains one of the primary limitations to reliable operation. Here, we report a mechanically perforated, vertically aligned graphene paper/epoxy composite produced through an integrated perforation–stacking–cutting process. The perforation strategy not only suppresses graphene restacking but also creates interlayer phonon bridges, thereby establishing continuous through‐plane heat conduction pathways while simultaneously strengthening matrix–filler interfacial coupling. By optimizing the filler volume fraction, the composite delivers an ultrahigh through‐plane thermal conductivity of 456 W m −1 K −1 combined with a low compressive modulus of 4.8 MPa, ensuring excellent conformability and reduced interfacial resistance. The PGPE 28 sample exhibits a total thermal resistance of 0.23 K cm 2 W −1 and outstanding reliability, maintaining structural and thermal stability after 10 000 thermal‐shock cycles and 8 h of continuous operation at 60 W. When deployed at the device level, PGPE 28 markedly lowers the steady‐state temperature of LED and CPU modules compared with commercial thermal interface materials (HD90000 and Shin‐Etsu 7921) and retains robust performance under fan‐failure conditions. This work provides a scalable route for manufacturing graphene‐based TIMs that simultaneously achieve high thermal conductivity and mechanical compliance, offering a promising solution for thermal management.