Biomass-derived carbon structures are attractive candidates for developing electromagnetic (EM)-wave-shielding materials because of their stability and unique porous structures. Lignin is the second-most abundant biomass that can be converted to porous carbon structures by using different methods. Herein, laser writing/patterning was employed to prepare lignin-derived S-doped carbon on a flexible polycarbonate substrate (C/PC) for EM wave shielding. An ultrathin carbon area (thickness of ~ 20 µm) was formed on the flexible PC after laser processing, and its average surface resistance was 50.5 Ω. The performance of the prepared C/PC as an EM-waveshielding material was examined in the X-band. Most of the incident EM waves can be reflected through S-doped carbon surface and remaining waves can be absorbed. The total shielding effectiveness (SET) attained 32.7 dB at 9.6 GHz when three layers of carbon were used as the shielding material; the absorption effectiveness (SEA) values were higher than the reflection effectiveness (SER) values throughout the X-band. This result indicated that the presence of porous conductive carbon skeletons can effectively provide surface reflections and facilitate multiple reflections and scattering of the incident EM waves. Our investigation provides a rapid and easy synthesis method for designing EM-wave-shielding materials based on lignin-derived porous carbon.
