Dual cross-linked and vertically oriented MXene/polyvinyl alcohol aerogel for ultrabroadband electromagnetic interference shielding and thermal camouflage

Lightweight and porous conductive aerogels have demonstrated great potential in electromagnetic interference (EMI) shielding and thermal camouflage, while the poor mechanical properties and structural stability usually limit their applications. Herein, vertically oriented and physically/chemically dual cross-linked Ti3C2TX MXene/ polyvinyl alcohol (PVA) composite aerogel is prepared by ice-templated unidirectional freezing process and subsequent glutaraldehyde (GA) treatment. GA induced covalent crosslinking leads to the significantly enhanced structural stability and mechanical strength of the resultant MXene/PVA composite aerogels, which also endows them with desirable flame retardancy. The honeycomb-like structure of the composite aerogel contributes to its good anisotropic absorption-dominated EMI shielding performance over an ultrabroadband frequency range (8.2-40 GHz) with a low MXene content of 3.81 vol%. Furthermore, the excellent thermal insulation properties and low infrared emissivity of the highly oriented arranged MXene sheets bring the composite aerogel promising applications in thermal camouflage. Therefore, the lightweight and robust MXene/PVA composite aerogel demonstrates great potential in multi-scenario applications as a high-performance multifunctional EMI shielding material.