Mesophase Pitch‐Based Carbon Fiber Derived Three‐Dimensional Carbon Skeletons for Thermal Conductivity Enhancement of Carbon Fiber/Carbon/Epoxy Composites

The thermal management demands of high‐performance electronics drive the need for lightweight composites with high thermal conductivity. Carbon fiber reinforced polymer composites offer excellent mechanical properties and designability, but their intrinsic thermal conductivity is limited. In this paper, both the thermal conductivity and thermal management performance of carbon fiber/carbon/epoxy (CF/Carbon/Epoxy) composites are enhanced by constructing a three‐dimensional continuous network combined with high‐temperature heat treatment. The carbon fiber/phenolic (CF/PF) skeleton was prepared by tip‐sonic dispersion, vacuum filtration, and hot pressing. The CF/Carbon/Epoxy composites were prepared by vacuum impregnation of epoxy resin and hot‐pressing curing. The results show that CF/Carbon‐2200/Epoxy composite achieved an in‐plane thermal conductivity of 101.67 W/(mK), which is about 483 times that of neat epoxy. COMSOL finite element simulations, based on Fourier's law and the energy conservation equation, further confirm the CF/Carbon/Epoxy composite's excellent in‐plane heat conduction and temperature uniformity. Furthermore, the axial thermal conductivity of a single heat‐treated carbon fiber was calculated by the parallel thermal conduction model, revealing that heat treatment plays a key role in enhancing thermal conductivity through optimization of the bonded carbon structure. Infrared thermography, light emitting diode (LED) heat dissipation modules, and mini serial advanced technology attachment (mSATA) solid state drive (SSD) cooling verify the excellent thermal management performance of the CF/Carbon/Epoxy composite.