Enhanced microwave absorption performance of sulfur-doped hollow carbon microspheres with mesoporous shell as a broadband absorber

By adjusting the amount of thiourea, we successfully prepared sulfur-doped hollow carbon microspheres provided with mesoporous shell (S-doped PCHMs) with different doping ratios by one-step hydrothermal method. S-doped PCHMs possess uniform spherical morphology with mesoporous shell and interior cavity. All obtained products exhibit outstanding electromagnetic wave absorption performance with lower reflection loss (RL) value (<-46 dB), thinner thickness (<2.5 mm) and wider effective absorption bandwidth (EAB) (>4.8 GHz) compared to pure PCHMs, which can attributed to controllable complex permittivity and various attenuation mechanisms including interfacial polarization, dipole polarization as well as conduction loss. From the perspective of light weight, strong absorption and broadband characteristics, the optimal performance which belongs to S-doped PCHMs-10 is endowed with the minimum RL value of -51.83 dB at 15.05 GHz as well as EAB of 6.08 GHz (11.92 GHz-18 GHz), at this time the thickness is only 1.82 mm. Obviously, S-doped PCHMs can be considered an ideal electromagnetic wave absorber with strong absorption, lightweight and broadband.