ZIF-67 derived Co@carbon nanotubes anchored on carbon fiber for efficient microwave absorption and mechanical enhancement

Rational design of multifunctional and high-performance electromagnetic wave (EMW) absorbers is highly desirable but still remains a challenge. Herein, the 3D heterostructural Co@carbon nanotubes/carbon fiber (Co@CNTs/CF) hybrids derived from ZIF-67/CF were successfully fabricated via the in-situ synthesis of ZIF-67 on CF and subsequent catalytic chemical vapour deposition. Intriguingly, the as-obtained composites acquire adjustable EMW absorption and favorable mechanical properties simultaneously. Specifically, taking advantage of adequate conductive paths, plentiful heterogeneous interfaces, suitable defect vacancies, appropriate magnetic loss, as well as optimized impedance matching, Co@CNTs/CF delivers a brilliant EMW absorption intensity of −45.11 dB at only 1.15 mm together with a broad effective absorption bandwidth (EAB) of 4.0 GHz (1.23 mm), and an unexpected minimal reflection loss up to −65.63 dB (3.84 GHz) coupled with an EAB of 3.6 GHz at merely 1.09 mm, respectively. In addition, the tunable EAB can be achieved in 2.6–18 GHz, covering 96 % of the test frequency by changing the absorber thickness from 0.93 to 5.0 mm (29 wt%). Moreover, the maximum radar cross section reduction can reach 48.8 dBm 2 . The uniform layer of CNTs with moderate crystallinity also enables Co@CNTs/CF to improve the tensile strength and Weibull modulus compared to unsized CF. This study paves a novel avenue for developing multifunctional materials based on CF through an efficient, controllable and low-cost approach.