Functionalized Carbon Nanofibers Enabling Stable and Flexible Absorbers with Effective Microwave Response at Low Thickness.

Lots of work has been done to develop microwave absorbing materials (MAM) utilized as flexible electronic devices and communication instruments. Conventionally developed powder MAM are often limited in practical applications because of the bad stability and poor durability, which is out of the scope for exploiting flexible and long-term microwave absorbers. To overcome such limitations, a facile and binder-free technique from a Co-based zeolitic imidazolate framework (ZIF-67, a member of metal-organic frameworks)-coated carbon fiber precursor is developed for the in situ horizontal growth of CoO nanoparticles, which embedded nitrogen-doped carbon array (triangular nanoplates) on the surface of carbon fibers in the carbon paper (NC-CoO/CP) as low-thickness MAM. The maximum reflection loss (RL) values reaches -16.12 and -34.34 dB when the thickness is 1.1 and 1.5 mm, respectively. As the thickness increases, the absorbing performance at low frequency performs well (RL < -20 dB). The hierarchical architecture is facilely originated from a metal-organic framework precursor. In view of the simple preparation technique, NC-CoO/CP exhibit huge potential in large-scale production of portable microwave absorbing electronic devices with strong microwave response at low thickness.