Hollow carbon microspheres modified with NiCo2S4 nanosheets as a high-performance microwave absorber

Due to the unique advantages including low density, good chemical stability, and superior dielectric property, carbon-based materials have been exploited as potential microwave absorbers and have become a research hotspot. Herein, a superior microwave absorbent consisting of NiCo2S4 nanosheets anchored on hollow carbon spheres is successfully designed and fabricated by a low-cost and facile strategy for the first time. The obtained C/NiCo2S4 composite shows a minimum reflection loss (RLmin) of −65.10 dB with a matching thickness of only 1.56 mm, and the effective absorption bandwidth (EAB) could reach up to 6.60 GHz at a thin thickness of 1.75 mm, which is a highly competitive carbon-based absorber. The existence of NiCo2S4 nanosheets balances the impedance matching property and enhances the dielectric loss effectively, and the cavity structure promotes the multiple reflections of the electromagnetic wave (EMW), which increases the energy loss capacity of the material. This study provides new insight into design and modification of hollow carbon spheres and broadens their application in the field of efficient microwave absorbers.