Light-weight and high-efficiency electromagnetic wave shielding properties based on waste straw porous carbon

Light-weight and high-efficiency electromagnetic interference (EMI) shielding materials have drawn attention. Porous carbon was prepared by waste wheat straw as well as the electromagnetic shielding performance was investigated. The products have a large specific surface area owing to their porous structure. The straw carbon (SC) was prepared at 900 °C called SC-900 °C with a specific surface area of 78.98 m2 g−1 and exhibited a enhanced electromagnetic shielding performance. The average SET value of SC-900 °C is 16.79 dB with 2.0 mm thickness, and it increases to 47.58 dB with 5.0 mm thickness. EMI SE mainly comes from SEA, which means that the absorption plays a dominated role in the shielding mechanism for SC-900 °C material. The excellent electromagnetic shielding performance of SC-900 °C results from the absorption process, the special three-dimensional porous structure, the multiple polarization and scattering, interfacial polarization, as well as the impedance matching. The results show that the SC-900 °C with strong absorption, wide band, and thin thickness can be used as a promising electromagnetic wave absorber.