Construction of mutifunctional Cu sphere@ZIF-derived Co particle/carbon fiber composites for high-efficiency microwave absorption

Currently, the development of artificial intelligence and new-generation high-frequency communication technologies has placed increasingly higher demands on the performance of electromagnetic wave (EMW) absorbing materials with multiple functions in complex application scenarios. In this work, using Cu sphere@ZIF-67 composites as the precursor, the Cu sphere@ZIF-derived Co particles/carbon fiber flexible (CCC) composites are designed by electrostatic spinning and high-temperature calcination technique. Herein, a specific cross-linked structure is formed with the inset of ZIF-derived Co particles and Cu spheres into the CNF network, allowing effectively tuning the electromagnetic parameters, optimizing the impedance matching and improving the EMW absorption performance of CCC composites. The as-obtained composites gain a high minimum reflection loss (RL_min) of −78.33 dB and a broad effective absorption bandwidth (EAB) of 7.60 GHz. Apparently, the three-dimensional interlaced complex network structure endows the composites with enhanced thermal conductivity and superhydrophobic properties, making it conducive to heat transfer and inhibiting the absorption of surface water. Meanwhile, the conductivity of the composites is greatly sensitive to the bending deformation, enabling their applications in flexible sensing. Briefly, this work provides a novel and feasible design thought to fabricate carbon-based composites with multifunctional properties of EMW absorption, heat-conducting, self-cleaning and strain-sensitive conductivity, which opens a route for the potential application of EMW absorbing materials under some extreme conditions.