Salt Template-Steered Sintering Synthesis of Flaky C/Co Composites for Ultra-Wide Band Microwave Assimilation

Abstract Extensive applications of electronic equipment cause the increasing requirement for efficient microwave assimilation (EMWA) materials with light weight and a broad frequency band. Herein, we present a one-step direct synthesis method of 2D C/Co composites as an excellent EMW absorber. The synthetic method is simple, economical, and scalable with a high yield. Results showed that uniform-sized monodisperse Co nanoparticles were uniformly arranged on the flaky carbon surface via a simply salt-template-steered sintering approach using Co-oleate complex as the precursor for both Co0 and carbon. Sintering temperature can well adjust the Co nanocrystal size, composition, graphitization degree, and static magnetic and EMWA capabilities. The 2D C/Co composites produced at 600 °C exhibited excellent EMWA capabilities with high assimilation (−42.36 dB), thin thickness (1.9 mm), and broad bandwidth (9.84 GHz) in a low loading rate (25 wt%). The superior EMWA capabilities were due to the cooperation of enhanced EM parameters, multiple resonances, multiple scattering, and good impedance matching. This study suggests that 2D C/Co composites have great potential in many fields, such as catalysis, electrode materials, microwave assimilation, and sensors.