PANI-wrapped high-graphitized residual carbon hybrid with boosted electromagnetic wave absorption performance

Achieving a strong reflection loss and a wide effective absorption bandwidth under ultrathin thickness (d < 1.5 mm) is difficult. In this study, residual carbon@polyaniline (RC@PANI) hybrid was successfully prepared through an in-situ polymerization to overcome this issue. RC was acquired through two-step acidification to remove inorganic minerals in coal gasification fine slag. The structure, morphology, chemical composition, thermal stability, and electromagnetic parameters of the as-prepared RC@PANI with different filler loadings were tested using various analytical techniques. The RC@PANI hybrid showed an outstanding electromagnetic wave absorption (EMWA) property. When the addition amount of the RC@PANI hybrid in the mixed system was 60%, the minimal reflection loss (RLmin) value of RC@PANI was − 21.3 dB at 16.4 GHz, and the effective absorption bandwidth (RL ≤ −10 dB) covered 2.9 GHz from 15.1 GHz to 18.0 GHz at a thickness of 0.9 mm. The EMWA property of RC@PANI could be adjusted by controlling the thickness of the absorber. The RC@PANI hybrid possessed outstanding EMWA due to the good impedance matching and excellent dielectric loss. Radar cross-section simulation proved that the RC@PANI hybrid has an excellent capability to reduce the values of a strong scattering source. Thus, RC can be used as a carbon matrix for EMW-absorbing materials.