Joule heating synthesis of carbon fiber/graphene 3D crosslinked structure for lightning strike protection and electromagnetic interference in aerospace composites

A lightweight and low-cost protective layer for composites is a future requirement in the aviation industry. However, current methods cannot simultaneously meet the dual requirements for lightning strike protection and electromagnetic interference. Herein, an internally continuous carbon fiber felt/graphene hybrid film with superior electrical and thermal conductivity, as well as enhanced mechanical properties is prepared via the roll-to-roll Joule heating process. Graphene as the conductive bridging medium is introduced into a carbon fiber felt and Joule heated to be covalently bonded with carbon fibers to construct a 3D architectural network. The hybrid film with a graphene content of 19 wt% exhibits optimum conductivity, and the increase in electrical and thermal conductivity after curing with epoxy resin by 5.2 and 1.8 times (2690 S·m⁻¹ vs. 518 S·m⁻¹, 0.49 W·m^-1·K⁻¹ vs. 0.27 W·m^-1·K⁻¹), respectively. In addition, the hybrid film serves as a protective layer on the composite surface. The damage of the composite after the lightning strike with a peak of 100 kA was significantly reduced, maintaining a level of 98 % of residual strength. Besides, the electromagnetic shielding effectiveness of 51.94 dB was enriched in the X-band, indicating that the prepared hybrid film is a promising material to replace commercial copper meshes.