The controllable porous structure and s-doping of hollow carbon sphere synergistically act on the microwave attenuation

Currently, the development of high-efficiency electromagnetic wave (EMW) absorbing materials has received close attention. Due to unique composition and structure, porous hollow carbon spheres (PHCSs) have been extensively studied in the EMW absorption field. In order to obtain the regulated EMW absorber, in the present study, sulfur was successfully doped into the PHCS by hydrogen peroxide etching and high temperature vulcanization. By fixing the amount of sulfur doped and the etching time, the micro-structure of the product could be effectively controlled, and the corresponding electromagnetic parameters would also change accordingly. The optimized sulfur-doped porous hollow carbon sphere (SPCHS) had the minimum reflection loss (RL) value of −27.2 dB, and the effective bandwidth of 4.76 GHz. More importantly, the best effective bandwidth (EAB, RL < −10 dB) could reach 6.72 GHz (11.28–18 GHz) at the thickness of 2.25 mm. It should be pointed out that the sample filling ratio was only 5 wt% in the paraffin matrix. In addition, when the incidence θ reached −60°, the maximum reduction of radar cross section (RCS) was −21.9 dB m2. The convenient and efficient RCS simulation provided reliable support for the practical application of SPHCS materials in the field of EMW absorption.