Ultra-high strength and flame retardant carbon aerogel composites with efficient electromagnetic interference shielding and superior thermal insulation via nano-repairing route

Carbon aerogel composites (CAs) have received numerous attention for protection of aircraft due to their unique properties. However, the shrinkage mismatch between rigid fibers and carbon sources during carbonization dramatically weakens the performance of CAs, and no significant breakthroughs have been made. We propose a vacuum impregnation assisted nano-repairing (VINR) strategy to fabricate crack-free carbon fiber reinforced carbon aerogel (C_f/CA) composites with high strength, electromagnetic interference shielding and thermal insulation. The cross-confined, overlapping nano-CA particles greatly limits the shrinkage of the carbon source, conferring excellent mechanical properties to C_f/CA, and its compressive strength and modulus reaches 3.93 MPa and 69.96 MPa in XY direction and 2.03 MPa and 40.67 MPa in Z direction, respectively, at 5 % strain. In addition, C_f/CA exhibits significant thermal insulation (0.054 W/(m·K) at 25 °C under air condition) and superior electromagnetic interference shielding properties (EMI SE is ∼48.52 dB at a thickness of ∼2 mm). Herein, the structurally optimized C_f/CA provides a promising solution for multi-effect protection for critical electronic devices of aircraft in special service environments.