Biomass-derived Co/C composites with high-efficiency electromagnetic wave absorption through activation and carbonization

Abstract

Abstract Based on the engineering of impedance matching optimization, the effective combination of dielectric materials and magnetic materials is an effective way to construct high-efficiency electromagnetic wave (EMW) absorbing materials. Herein, a series of cobalt/biomass-derived carbon (Co/C) composites were successfully synthesized through chemical activation and in-situ carbonization process with peanut shells as the biomass carbon source, and cobalt nitrate as the magnetic metal source. The biomass-derived carbon effectively constructed characteristic microscopic hierarchical porous structure with the help of chemical activation, effectively increasing the transmission path of incident EMWs. The metallic cobalt particles were randomly attached on the surface of the biomass-derived carbon, constructing abundant heterogeneous interfaces. The optimal combination of biomass-derived carbon and cobalt particles played a significant role in optimizing impedance matching. Thanks to the synergistic effect of multiple loss mechanisms and optimized impedance matching, the Co/C composites demonstrated satisfactory EMW absorbing properties. The minimum reflection loss reached −43.36 dB and the broadest effective absorption bandwidth covered 4.56 GHz. This research provides an efficient and environmentally friendly preparation method of magnetic metal/biomass-derived carbon EMW absorbing composites.