One-step preparation of CoFe2O4/FeCo/graphite nanosheets hybrid composites with tunable microwave absorption performance

The increasing use of advanced technologies in the civil and military fields has led to electromagnetic pollution. Thus, microwave absorbing materials that can transform electromagnetic energy into other forms of energy have been extensively investigated to limit the electromagnetic pollution. Herein, the CoFe2O4/FeCo/graphite nanosheets (CFG) hybrid composites were prepared by a one-step and facile liquid reduction method and the microwave absorption performances of the composites were investigated. The impedance matching and attenuation ability of the composites could be well tuned by varying the filling ratio of CFG in the matrix. Accordingly, high microwave absorption performances could be achieved. At a filling ratio of 50 wt% (CFG-50), a maximum reflection loss of - 54.3 dB at a thin thickness of 1.2 mm and an effective absorption bandwidth of 4.08 GHz at a thin thickness of 1.3 mm were achieved. Notably, in the thickness range of 1.2-5.5 mm, the effective absorption bandwidth reached up to 15.2 GHz (2.8-18 GHz), covering the entire C, X, and Ku bands. The excellent microwave absorption properties were attributed to the moderate impedance matching and attenuation capacity caused by the dielectric loss, magnetic loss, multiple reflection, and scattering. The attractive features of CFG-50: remarkable absorption, broad bandwidth, low thickness, and fast preparation make it highly suitable for practical microwave absorbing applications.