Preparation of micro-meso-macroporous structured hydrangea-like cobaltous sulfide with sulphur vacancy for high-performance electromagnetic wave absorption

Cobaltous sulfide shows good potential as substances to absorb electromagnetic waves (EWs) due to its features of relatively high conductivity, excellent electrocatalytic activity and inexpensive price. However, there are still great challenges to achieve a broad absorption frequency and strong EW absorption capability. Herein, hydrangea-like CoS with micro-meso-macroporous multilamellar intersecting structure was synthesized by an elementary one-pot hydro-thermal synthesis. The uniquely designed morphology and content of sulphur vacancy of CoS was optimized by controlling synthesis time, which proved to effectively modulate the electromagnetic parameters. The optimized electromagnetic wave-absorbing materials (EWAMs) present the satisfactory EW-absorbing ability, including the minimum reflection loss (RL_min) of − 21.27 dB at a frequency of 12.48 GHz, a maximum effective absorption bandwidth (EAB_max) of 5.6 GHz at a thickness of 1.9 mm. The superior EW absorbing performance of CoS was thanks to the cooperative effect of impedance-match, dipole polarization, Maxwell–Wagner effect and conductive loss. Furthermore, the radar cross section (RCS) simulation results further proved its dissipation capability of CoS EWAMs in actual application scenarios. This facile structural design strategy provides a new direction for preparation of CoS-based and other EWAMs with high EW-absorbing ability, which possesses extensive their further potential practical application.