Electrically Conductive Ti3C2Tx MXene/Polypropylene Nanocomposites with an Ultralow Percolation Threshold for Efficient Electromagnetic Interference Shielding

Electrically conductive polymer nanocomposites are highly required for efficient electromagnetic interference (EMI) shielding applications. Although two-dimensional transition metal carbide/carbonitride (MXene) nanosheets with metallic electrical conductivity and layered structure show great potential for the construction of interconnected conductance networks in polymer matrices, their preferred stacking feature and intrinsic hydrophilicity inevitably cause poor dispersion in organic polymers, making it challenging to prepare MXene/polymer nanocomposites with high electrical conductivity and satisfactory EMI shielding performances at low MXene contents. Herein, we demonstrate an efficient methodology to prepare highly conductive MXene/polypropylene (PP) nanocomposites with an ultralow percolation threshold for efficient EMI shielding application. By dip-coating MXene nanosheets onto a polyethyleneimine-grafted PP textile, followed by vacuum-assisted compression molding, an interconnected conductance network of MXene nanosheets in the PP matrix is constructed facilely and efficiently. The resultant MXene/PP nanocomposite exhibits an ultralow percolation threshold of 0.027 vol %, a high electrical conductivity of 437.5 S m(-1) at a low MXene loading of 2.12 vol %, and an outstanding EMI shielding performance of more than 60 dB within the X-band, superior to most other electrically conductive polymer nanocomposites. This work provides a new approach for fabricating MXene/polymer nanocomposites with outstanding electrical conductivity for high-performance EMI shielding applications.