Insights into the microstructures and reinforcement mechanism of nano-fibrillated cellulose/MXene based electromagnetic interference shielding film

Recently, with the high requirement of electromagnetic interference (EMI) shielding materials, micro- or nano-fibrillated cellulose reinforced Ti 3 C 2 T x nanosheets (transition-metal carbides/carbonitrides, MXene) composites have attracted wide attention due to their complementary functional properties. Nevertheless, it is still challenging to overcome a trade-off between EMI shielding performance and mechanical enhancement with the addition of reinforcing fillers. Herein, modified bacterial cellulose nanofiber (BCNF), with well-tuned micro structure, is employed as the unique reinforcing unit to self-assembly with MXene. The mechanical and electrical properties of different cellulose-derived composites were further compared to get insights into the effect of the fiber configuration on reinforcing properties. Particularly, the optimized MXene/BCNF sample simultaneously exhibited high tensile strength (252.2 MPa), excellent folding endurance (> 10,000 times), and high electrical conductivity (443.5 S cm −1 ). With striking shielding effectiveness (19,652 dB cm 2 g −1 ), the sample effectively interferes with emitted electromagnetic waves, and is therefore a promising candidate for wearable devices and human electronic equipment. Graphic abstract