Low-Cost and Eco-Friendly Synthesis of CoFe₂ Nanoparticles Encapsulated into Porous Carbon Nanofibers as a Lightweight and High-Performance Microwave Absorber

Lightweight, thin thickness, and high-efficiency microwave absorbers have always been a research hotspot. Herein, porous carbon nanofibers uniformly embedded with CoFe 2 nanoparticles (denoted as CoFe 2 @PCNFs) were synthesized through a simple, low-cost, and eco-friendly route. Benefiting from the unique 1D structure, 3D conductive network, porous structure, multiple heterogeneous interfaces, and synergistic effect between magnetic CoFe 2 nanoparticles (NPs) and a dielectric carbon matrix, the CoFe 2 @PCNF composite under low loading content presents excellent microwave absorption performance. It is found that the composite exhibits a remarkable reflection loss of −27.5 dB at a thin thickness of 1.48 mm and a wide effective absorption bandwidth of 4.96 GHz at a filler loading of only 5 wt %. The outstanding comprehensive microwave absorption performance of CoFe 2 @PCNFs can be attributed to satisfactory attenuation capacity and excellent impedance matching. This work reveals that the well-designed CoFe 2 @PCNF composite is a promising candidate for lightweight and high-performance microwave absorption.