Facile single-step fabrication of bimetallic CoNi/carbon fiber composites for advanced microwave absorption

Abstract

Abstract This study presents a simple and effective hydrothermal method for synthesizing hierarchical cobalt-nickel (CoNi/CFs) composites for use as microwave absorbers. The unique structure features CoNi bimetallic nanoparticles uniformly embedded within a carbon matrix and decorated on the surface of interconnected carbon fibers. This architecture provides a high surface area and multiple interfaces, which are key to enhancing electromagnetic wave absorption through polarization and scattering losses. The results are highly promising. The material achieves a minimum reflection loss (RL min ) of −50.46 dB with a thin absorber thickness of only 1.7 mm. It also demonstrates a wide effective absorption bandwidth (EAB) of 5.92 GHz at a thickness of just 1.9 mm. This superior performance is a result of the synergistic effects of the hierarchical structure, excellent impedance matching, and multiple loss mechanisms, including both dielectric and magnetic losses. Our work offers a promising, lightweight, and high-performance solution for microwave absorption, with potential applications in stealth and anti-interference technologies