Facile construction of core–shell Carbon@CoNiO2 derived from yeast for broadband and high-efficiency microwave absorption

Abstract

Manufacturing dielectric/magnetic composites with hierarchical structure is regard as a promising strategy for the progress of high-performance microwave absorption (MA) materials. In this paper, the nano-grass structured CoNiO2 magnetic shell was uniformly anchored on the yeast-derived carbon microspheres by in-situ one-pot synthesis method. Profiting from the unique nano-grass and core–shell structure, capable dielectric/magnetic loss, along with improved impedance matching, the prepared absorber realizes desirable MA performance. The minimum reflection loss (RLmin) reaches up to −44.06 dB at 6.56 GHz. Moreover, the effective absorption bandwidth (EAB, reflection loss (RL) < -10 dB) accomplishes 7.04 GHz under a low filler loading of 20 wt%. This work endeavors a valuable insight for designing innovative core–shell structured materials with high-efficiency MA and broad bandwidth.