Polarization loss dominated high-performance electromagnetic wave absorption enabled by ceria-decorated MXene aerogel

A three-dimensional MXene/BC/CeO 2 aerogel with lightweight, highly elastic, and thermally insulating characteristics was constructed. • CeO 2 significantly enhances the interfacial and dipole polarization of the composite. • At an identical thickness, it achieves the broadest EAB of 6 GHz along with an optimal RL min of -49.3 dB. • The designed periodic architecture broadens the bandwidth to 14.54 GHz, covering over 90% of the target frequency range. Transition metal carbides/nitrides (MXenes) exhibit high electrical conductivity, a unique two-dimensional layered structure, and abundant surface functional groups and defects, thus holding great promise for electromagnetic wave absorption (EWA). However, issues such as impedance mismatch and a tendency to self-stack severely restrict their practical applicability. In this study, a lightweight and highly elastic Ti 3 C 2 T x MXene/bacterial cellulose (BC)/ceria (CeO 2 ) composite aerogel was developed via a facile freeze-drying method. The three-dimensional lamellar porous architecture, with MXene and BC serving as a robust skeleton, effectively prevents the stacking of MXene nanosheets, while the introduction of CeO 2 nanoparticles optimizes the impedance matching and significantly enhances the polarization loss, enabling excellent electromagnetic wave absorption with polarization loss as the dominant mechanism. By simply adjusting the CeO 2 doping content, an effective absorption bandwidth (EAB) of 6 GHz and a minimum reflection loss (RL min ) of -49.3 dB can be achieved, and through macroscopic structural design, the EAB is expected to be further broadened to 14.54 GHz. Moreover, the composite aerogel exhibits an RCS reduction of 28.12 dB·m 2 and an ultralow thermal conductivity of 0.035 W/(m·K), endowing it with potential for multispectral camouflage compatible with both radar and infrared detection. This study offers a new strategy for developing high-performance MXene-based composite wave-absorbing materials. Download: Download high-res image (416KB) Download: Download full-size image