Strong and highly conductive cellulose nanofibril/silver nanowires nanopaper for high performance electromagnetic interference shielding

Recently, the rapid popularization of modern communication technologies represented by 5G will inevitably aggravate the deterioration of the electromagnetic environment. Electromagnetic interference (EMI) and electromagnetic radiation have more and more serious impacts on human production and life, and EMI shielding materials have emerged as the times require. Herein, we reported a cellulose nanofibril/silver nanowire (CNF/AgNW) nanopaper, manufactured through a step-by-step (SbS) self-assembly process, which has a unique layered structure and improved two-sidedness. The results showed that the obtained AgNWs have an ultra-high aspect ratio (up to 2857), which enabled them to form conductive paths in nanopaper at low addition levels (0.5 wt.%). When the AgNW content was 5.0 wt.%, the obtained nanopaper with a thickness of ~ 50 μm exhibited an excellent tensile strength of ~ 98.6 MPa and a high conductivity of ~ 1673 S/cm. The unique layered structure of CNF/AgNW nanopaper and the excellent synergistic interaction between CNF and AgNWs enabled the optimized CNF/AgNW nanopaper to exhibit a high EMI shielding effectiveness (SE) of up to 67.27 dB in the X band. Therefore, this strong and highly conductive CNF/AgNW nanopaper is expected to broaden new application areas including smart clothing, wearable electronic devices, and other emerging applications. Graphical abstract A strong and highly conductivity cellulose nanofibrils/silver nanowires (CNF/AgNWs) nanopaper has been manufactured through the step-by-step self-assembly process. Abundant conductive network and special interlayer structure make the CNF/AgNWs nanopaper holds high EMI shielding performance at a low thickness.