Ultrathin and Flexible CNTs/MXene/Cellulose Nanofibrils Composite Paper for Electromagnetic Interference Shielding

TLDR

Rapid development of portable and wearable devices demands high‑efficiency EMI shielding materials, yet practical options are limited by thickness and lack of strength or flexibility. The authors aim to develop an ultrathin, flexible CNTs/MXene/cellulose nanofibrils composite paper with gradient and sandwich structure for EMI shielding. They fabricate this composite via a facile alternating vacuum‑assisted filtration process. The composite shows tensile strength of 97.9 MPa, fracture strain of 4.6 %, electrical conductivity of 2506.6 S m⁻¹, and EMI shielding effectiveness of 38.4 dB, demonstrating superior mechanical and shielding performance.

Abstract

As the rapid development of portable and wearable devices, different electromagnetic interference (EMI) shielding materials with high efficiency have been desired to eliminate the resulting radiation pollution. However, limited EMI shielding materials are successfully used in practical applications, due to the heavy thickness and absence of sufficient strength or flexibility. Herein, an ultrathin and flexible carbon nanotubes/MXene/cellulose nanofibrils composite paper with gradient and sandwich structure is constructed for EMI shielding application via a facile alternating vacuum-assisted filtration process. The composite paper exhibits outstanding mechanical properties with a tensile strength of 97.9 ± 5.0 MPa and a fracture strain of 4.6 ± 0.2%. Particularly, the paper shows a high electrical conductivity of 2506.6 S m−1 and EMI shielding effectiveness (EMI SE) of 38.4 dB due to the sandwich structure in improving EMI SE, and the gradient structure on regulating the contributions from reflection and absorption. This strategy is of great significance in fabricating ultrathin and flexible composite paper for highly efficient EMI shielding performance and in broadening the practical applications of MXene-based composite materials.