Co/carbon nanofiber with adjustable size and content of Co nanoparticles for tunable microwave absorption and thermal conductivity

Electromagnetic pollution and heat dissipation problems are becoming increasingly worthy of attention due to the rapid development of electronic devices, which puts forward an urgent demand for microwave absorbers with excellent thermal management performance. Herein, high-performance Co/carbon nanofiber (Co/CNF) microwave absorbers with high thermal conductivity were fabricated by facile step-by-step method. The microwave absorption properties can be readily tuned by adjusting the content and size of Co nanoparticles through concentration gradient adsorption. Benefiting from the formation of dielectric and magnetic coupling network, Co/CNF composites possess intensive dipole polarization, interface polarization, and magnetic loss. The optimal Co/CNF composites exhibit outstanding microwave absorption performance with a minimum reflection loss (RL) of −53.0 dB at 11.44 GHz, and a maximum effective absorption bandwidth (EAB) of 5.5 GHz. In addition, the thermal conductivities of the Co/CNF-natural rubber (Co/CNF-NR) composites are significantly improved. This work may inspire the exploration of high-efficiency heat-conduction microwave absorbers based on CNF.