Preparation and EMI Shielding Properties of Lightweight and Mechanically Strong MXene/Bacterial Cellulose Composite Aerogels

With the rapid development of highly-integrated and highly-powered 5G communication and wearable electronic devices, the electromagnetic interference and electromagnetic pollution problems caused by electromagnetic waves are becoming increasingly serious. It is urgent to develop lightweight, mechanically strong and environmentally friendly electromagnetic shielding composites. Herein, the lightweight and mechanically strong MXene/bacterial cellulose (BC) composite aerogels with directional porous structures are prepared via the liquid nitrogen directional freezing followed by freeze drying method using biomass BC as matrix and conductive Ti₃C₂T_x MXene as functional fillers. The effects of Ti₃C₂T_x MXene mass fraction on the microstructures, conductive and mechanical properties, as well as EMI shielding properties of the composite aerogels are investigated in detail. The results show that the composite aerogels with a Ti₃C₂T_x MXene mass fraction of 40wt% exhibit a low mass density of 18.3 mg/cm³, as well as the highest electrical conductivity and electromagnetic interference shielding effectiveness (EMI SE) of 459.3 S/cm and 72 dB (at a thickness of 4 mm) in X band with an absorption dominated EMI shielding mechanism. Owing to the abundant hydrogen bonding interactions, the composite aerogels exhibit a high compression strength of 38.3 kPa, which is 116.1% higher than that of pure BC aerogels.