Design of ultralight and stable Ti3C2Tx/SiCnw hybrid aerogel with hierarchical structure and heterogeneous interface for electromagnetic wave absorption

Abstract

Although the excellent electromagnetic wave (EMW) attenuation ability of Ti3C2Tx has been wildly accepted, its high dielectric constant tends to induce severe impedance mismatching at interfaces. In this paper, PDDA modified SiCnw was electrostatically assembled with the negatively charged Ti3C2Tx nanosheet, for the purpose of decreasing and tuning the complex permittivity of Ti3C2Tx, while constructing a large number of heterogenous interfaces to strengthen the polarization loss. Subsequently, a lightweight and porous Ti3C2Tx/SiCnw hybrid aerogel was successfully obtained by a directional freeze-drying process, which shows enhanced mechanical and wave-absorbing properties compared with pure Ti3C2Tx aerogel, with a strong absorption (−44.9 dB) and a broad bandwidth (9.5 GHz) in the frequency range of 2–18 GHz, as well as good structural stability and mechanical resilience. The excellent wave-absorbing performance is the synergistic result of well-matched impedance, enhanced multiple polarization losses (dipolar polarization, defect-induced polarization and interfacial polarization) and mild conduction loss. This study explores the specific ways to regulate the EMW loss mechanism, which is of great significance for the development of a new generation structure-function integrated absorber.