Synthesis, Characterization, and Electromagnetic Wave Absorption Properties of Composites of Reduced Graphene Oxide with Porous LiFe5O8 Microspheres

A novel three-dimensional composite of reduced graphene oxide sheets and porous LiFe5O8 micro spheres was fabricated via a facile, green, and highly tunable strategy, and the microstructure, composition, and microwave absorbing performances of the rGO/porous LiFe5O8 composite were characterized and investigated. The experimental results indicate that the porous LiFe5O8 microspheres are dispersed on the thin rGO sheets uniformly. Compared with the pure LiFe5O8 particles and porous LiFe5O8 microspheres, the as-prepared rGO/porous LiFe5O8 composites exhibit outstanding microwave-absorbing performances including efficient bandwidth and reflection loss. The rGO/porous LiFe5O8 composite (5-50) displays a maximum reflection loss of -53.4 dB at 12.2 GHz with a coating layer thickness of 2.2 mm and a broad effective bandwidth of 3.5 GHz (from 10.4 to 13.9 GHz). The outstanding microwave-absorbing performances are assigned to employing magnetic microflowers with multi-interfaces to improve impedance matching, which is ascribed to strong relaxation loss, electrical loss, and magnetic loss. This further confirms that the rGO/porous LiFe5O8 composites could be potential candidates for lightweight microwave-absorbing materials.