FexOy-decorated biomass-derived carbon: A lightweight electromagnetic wave absorber and thermal conductor

The natural porosity architectures, polar functional groups, low density, and biocompatibility of biomass carbon materials make them highly promising for the development of lightweight electromagnetic microwave absorbers. Sugarcane bagasse served as the raw material for this investigation, and sugarcane bagasse-derived carbon/Fe_xO_y was prepared using the in-situ growth method and temperature field-directed casting. By adjusting the content of ferrite hollow spheres, magnetic conduction losses and heterogeneous interfacial polarization losses are improved. Controlling the electrical conductivity losses and multiple scattering structures of biomass-derived carbon at different annealing temperatures, impedance matching is achieved through the synergistic operation of various loss mechanisms. [email protected]–750 exhibited a minimum reflection loss (RL_min) of −46.6 dB at a filler content of only 5 wt% and a thickness of 1.9 mm and obtained a maximum effective absorption bandwidth (EAB_max) of 5.52 GHz at the same thickness. The ice template directional casting formed an orderly thermal conduction path, providing channels for phonon and electron transport, which is beneficial for the efficient heat dissipation of the microwave absorber. This finding thus offers a promising technique for creating ultra-lightweight microwave absorbers that facilitate heat dissipation.