Customizing coaxial stacking VS₂ nanosheets for dual-band microwave absorption with superior performance in the C- And K_u-bands

Engineering microwave absorption materials with absorption in multiple bands and strong absorption performance in the C-band remains challenging to date. Herein, coaxial stacking VS₂ nanosheets (CSVNs) were customizedviaa facile one-step hydrothermal route for the first time and their microwave absorption (MA) properties were systematically investigated. The complex permittivity and conductivity of CSVNs could be tuned by regulating the hydrothermal reduction temperature. When the reaction temperature was 190 °C, the VS₂ nanosheets exhibited unique dual-band absorption characteristics in the C-band and K_u-band. A minimum reflection loss value of -57 dB and an average absorption intensity exceeding 15 dB in both the C (4-8 GHz) and K_u (12-18 GHz) bands were obtained. For the optimized CSVNs, the qualified bandwidth with reflection loss less than -10 dB reached up to 7 GHz, which almost covered the whole measured range of the C- and K_u-bands. Notably, this desirable microwave absorption performance, which probably results from the good conductivity of the 1T-phase CSVNs in the 2H phase, the well-matched impedance and the multiple reflections induced by their distinctive stacking structure, demonstrates that CSVNs are potential outstanding absorbers. More importantly, this study provides an effective strategy to tune the microwave performance of CSVNs by tailoring their structures.