High efficiency microwave absorption nanocomposites of multiple-phase core-shell CoNi alloy@C loaded on rGO conducting network

A novel multiple-phase nanocomposites of core-shell CoNi alloy@C nanoparticles uniformly implanted on graphene conducting network are prepared via combining liquid phase reduction and hydrothermal reaction. The core-shell CoNi alloy@C nanoparticles are uniformly dispersed over graphene nanosheets. The abundant conductive network of reduced graphene oxide is favorable for CoNi alloy@C nanoparticles insertion. Compared to single CoNi alloy and CoNi alloy@C, the ternary CoNi alloy@C/rGO nanocomposites reveal a remarkable increase in microwave absorption. The maximum reflection loss achieves −62.4 dB at 7.84 GHz, and the effective bandwidth of reflection loss below −10 dB (90% attenuation of microwave energy) is up to 14.4 GHz. Meanwhile, through calculation of absorption efficiency, it can be obtained that the nanocomposites have a best absorption performance at 3.3 mm and the efficiency value is 24.88 dB GHz/mm. So this study provides an excellent candidate for military radars, aerospace, electronic instruments and other fields.