Anisotropic Electromagnetic Absorption of Aligned Ti3C2Tx MXene/Gelatin Nanocomposite Aerogels

Abstract

Assembling Ti₃C₂T_x MXene nanosheets into three-dimensional (3D) architecture with controllable alignment is of great importance for electromagnetic wave absorption (EMA) application. However, it is a great challenge to realize it due to the weak van der Waals interconnection between MXene nanosheets. Herein, we propose to introduce gelatin molecules as a “chemical glue” to fabricate the 3D [email protected] ([email protected]) nanocomposite aerogel using a unidirectional freeze casting method. The Ti₃C₂T_x MXene nanosheets are well aligned in the [email protected] nanocomposite aerogel, yielding much enhanced yet anisotropic mechanical properties. Due to the unidirectional aligned microstructure, the [email protected] nanocomposite aerogel shows significantly anisotropic EMA properties. [email protected] shows a −59.5 dB minimum reflection loss (RL_min) at 14.04 GHz together with a 6.24 GHz effective absorption bandwidth in the parallel direction (relative to the direction of unidirectional freeze casting). However, in the vertical direction of the same [email protected] aerogel, RL_min is shifted to a much lower frequency (4.08 GHz) and the effective absorption bandwidth decreases to 0.86 GHz. The anisotropic electromagnetic energy dissipation mechanism was deeply investigated, and the impendence match plays a critical role for electromagnetic wave penetration. Our lightweight [email protected] nanocomposite aerogel with controllable MXene alignment is very promising in EMA application.