High-Performance Joule Heating and Electromagnetic Shielding Properties of Anisotropic Carbon Scaffolds

Highly efficient electrical heaters along with excellent electromagnetic interference (EMI) shielding properties are urgently required for the progress of miniaturization electronics, artificial intelligence, and smart heating management setups. Herein, lignin removal, which comprises two efficient and versatile steps, followed by carbonization produces multifunctional carbon monoliths derived from natural wood. The obtained carbonized wood exhibits a high specific surface area (655.14 m²/g) and electrical (17.5 S/cm) and thermal conductivity (0.58 W/m·K), superhydrophilicity (contact angle of ∼0°), and excellent EMI shielding ability and Joule heating performance. The high electrical conductivity renders a low-voltage-actuated Joule heating performance and fascinating EMI shielding effectiveness of 55 dB, primarily resulting from the absorption mechanism. Moreover, regulation of the carbonized woods derived from the longitudinal to the radial direction enables transformation of hydrophilicity, strong thermal conductivity, and absorption-dominated EMI shielding to hydrophobicity, thermal insulation, and reflection-dominated EMI shielding. This is attributed to the unique anisotropic microstructure of carbon scaffolds. It is believed that these multifunctional carbon scaffolds can be used for intelligent electronics, EMI shielding, and thermal heating instruments.