High‐Throughput Screening Enables Ultrathin and High Thermal Conductivity All‐Carbon Graphene Foam Thermal Interface Materials

Rising power density and integration in electronic chips demands advanced thermal interface materials. However, the poor thermal stability (exceed 230°C) and low in-plane heat dissipation ability of vertically aligned graphene-polymer composites limit hotspot management. In this study, an ultrathin all-carbon graphene foam is fabricated using poly (methyl methacrylate) (PMMA) microspheres as a template by a high-throughput screening strategy based on finite element analysis. The incorporation of PMMA templates establishes in-plane/through-plane thermal conduction network and generates acidic environment that promotes the ring-opening of epoxy by the release of carboxyl during the pyrolysis of PMMA. In addition, CO generated during PMMA pyrolysis drives oxygen functional groups in GO to decompose into H₂O and CO₂, thereby preserving the carbon atoms. Benefited from these, the graphene foam exhibits high thermal diffusivities of 51.8 and 608.6 mm² s^-1 in the through-plane and in-plane direction, respectively. Under a pressure of 40 Psi, bond line thickness can be reduced to 29 µm and graphene foam shows an ultra-low contact thermal resistance of 0.104 Kcm² W^-1. Moreover, it reduces 16°C at ceramic heater compared with commercial thermal pad, and exhibits excellent thermal stability under high-temperature of 300°C. This study provides a pathway for the development of ultrathin, high-temperature-resistant thermal pads.