Composite of carbonyl iron particles and brine shrimp egg shell-derived porous carbon with excellent microwave absorption properties

Currently, the requirements of excellent comprehensive properties and high economic returns for microwave absorbers remain severe challenges for practical application of these materials. Herein, a composite of carbonyl iron particles (CIP) and bio-derived carbon was synthesized for microwave absorption for the first time. Brine shrimp egg shells (BSES) were chosen as the carbon precursor because the innate multilayer porous structure favours enhancing the microwave absorbing (MA) performance by inducing geometrical effect. Not only does the as-fabricated CIP/C composite exhibit outstanding MA properties, but the method is also facile and eco-friendly. Owing to the unique layered porous structure of BSES-derived carbon, well-matched complex permittivity and permeability together with the synergy of dielectric and magnetic loss, the composite displayed a remarkable reflection loss of − 55.4 dB at 13.0 GHz and a broad effective absorption bandwidth of 5.0 GHz with a thickness of only 1.5 mm, which is superior to those of most reported Fe/C composites, especially in thickness and effective absorption bandwidth. Hence, there are reasons to believe that the as-prepared CIP/C composite may have a bright prospect for practical application in civilian life and industry as an efficient MA material.