Biomass-derived fire-retardant porous carbon towards efficient electromagnetic wave absorption and shielding
Yusen Ai, Ruizhe Xing, Renliang Huang, Jie Kong, Rongxin Su
Abstract
Biomass-derived carbon materials show great potential in electromagnetic wave (EMW) absorption and shielding. However, their flammability presents a challenge for practical applications. Herein, we present a novel strategy for preparing biomass-derived fire-retardant porous carbon materials with enhanced EMW absorption and shielding performance. We obtained two carbon materials through phosphorylation and alkali etching of natural balsa wood: phosphorylated carbonized wood (PCW) and hierarchical porous phosphorylated carbonized wood (HP-PCW). Phosphorylation lowered the carbonization temperature, imparting excellent flame retardancy and improved impedance matching . Alkali etching, on the other hand, adjusts the graphitization degree of the material without altering the carbonization temperature. As a result, we successfully achieved outstanding EMW absorption and shielding performance at a relatively low annealing temperature of 660 °C. Specifically, PCW demonstrated a remarkable minimum reflection loss of −59.8 dB, with an effective absorption bandwidth covering the entire X-band (8.2–12.4 GHz) across a wide thickness range. HP-PCW demonstrated an EMW shielding effectiveness of 52 dB within the X-band. These carbon materials exhibit features such as lightweight (0.12–0.15 g/cm 3 ), robust thickness sensitivity (5.7–7.3 mm), and fire-retardancy (120 s unburned in the flame), providing valuable insight into the potential large-scale engineering application of EMW compatible materials.