Nanorod-Derived Conductive Carbon Networks and Titanates-Involved Multicomponent Interfaces for Broadband Microwave Absorption

Conductive carbon networks and multicomponent interfaces have been constructed in Fe₃O₄/TiO₂/C or Fe₂TiO₄/FeTiO₃/C composites by pyrolyzing core–shell structured Fe-bdc@TiO₂ nanorods at different temperatures. When the temperature rises to 700 °C, the growth of internal Fe₃O₄ nanoparticles, the gradual damage of TiO₂ shells, and the maintenance of a one-dimensional structure promote the formation of continuous conductive carbon networks in paraffin, thereby increasing complex permittivity and dielectric loss. With a further increase in temperature, phase conversion from ferromagnetic Fe₃O₄ to antiferromagnetic Fe₂TiO₄ and FeTiO₃ would result in the depletion of TiO₂ and C, generation of multiple interfaces, and collapse of the one-dimensional structure, causing a slight reduction in complex permittivity and dielectric loss. S-700 has a wide effective absorption bandwidth (EAB) of 6.84 GHz at 2.2 mm (covering the entire Ku band), and S-800 has a large EAB of 4.16 GHz at 2.8 mm, covering the entire X band. We can deduce that conductive carbon networks mainly composed of surface carbon and multiple interfaces between carbon and titanates with defects contribute significantly to conduction loss, dipole polarization, and interfacial polarization, both of which shape RL curves under the influence of interference cancellation. This work provides a feasible strategy based on the construction of conductive networks and multicomponent interfaces in metal–organic framework-derived carbon composites for broadened microwave absorption bandwidth.