Broadband microwave absorption performance of 3D hofmann MOF-derived CoNi/C materials constructed via multi-ligand synergy

Aiming at the key difficulty in the collaborative optimization of impedance matching and attenuation capability in dielectric microwave absorbing materials, a strategy for the synergistic construction of defects and pore structures induced by metal volatilization was proposed in this paper, and one-dimensional porous carbon fibers （PCF） were successfully prepared. By introducing zinc salt into the polyacrylonitrile （PAN） electrospinning precursor, the in-situ and synchronous construction of microporous structures and defect sites inside the fibers was realized during high-temperature carbonization through the spontaneous volatilization of Zn species, without additional etching or template removal steps. The as-prepared PCF maintains the integrity of the one-dimensional continuous structure, and forms a multi-scale conductive structure of "one-dimensional fiber–two-dimensional network" through the interweaving of fibers, which effectively promotes charge transport and enhances conduction loss. The synergistic effect of porous and defect structures can precisely regulate the complex dielectric parameters of the material, intrinsically alleviating the coupling constraint between impedance matching and attenuation capability. Meanwhile, the abundant heterogeneous interfaces and defect-induced dipoles significantly strengthen the interfacial polarization and multiple relaxation processes, further improving the electromagnetic wave attenuation performance. The results show that the optimized sample PCF-4 exhibits a minimum reflection loss of −56.1 dB at 8.0 GHz with a thickness of 3.0 mm, and the broadband absorption regulation in C, X and Ku bands can be achieved by adjusting the thickness. This work provides a simple and extensible new idea for the structural design of lightweight and high-performance dielectric microwave absorbing materials.