Ultrathin, Strong, and Highly Flexible Ti₃C₂T_x MXene/Bacterial Cellulose Composite Films for High-Performance Electromagnetic Interference Shielding

Abstract

The fabrication of ultrathin films that are electrically conductive and mechanically strong for electromagnetic interference (EMI) shielding applications is challenging. Herein, ultrathin, strong, and highly flexible Ti3C2T x MXene/bacterial cellulose (BC) composite films are fabricated by a scalable in situ biosynthesis method. The Ti3C2T x MXene nanosheets are uniformly dispersed in the three-dimensional BC network to form a mechanically entangled structure that endows the MXene/BC composite films with excellent mechanical properties (tensile strength of 297.5 MPa at 25.7 wt % Ti3C2T x ) and flexibility. Importantly, a 4 μm thick Ti3C2T x /BC composite film with 76.9 wt % Ti3C2T x content demonstrates a specific EMI shielding efficiency of 29141 dB cm2 g–1, which surpasses those of most previously reported MXene-based polymer composites with similar MXene contents and carbon-based polymer composites. Our findings show that the facile, environmentally friendly, and scalable fabrication method is a promising strategy for producing ultrathin, strong, and highly flexible EMI shielding materials such as the freestanding Ti3C2T x /BC composite films for efficient EMI shielding to address EMI problems of a fast-developing modern society.

Ultralight, highly compressible, thermally stable MXene/aramid nanofiber anisotropic aerogels for electromagnetic interference shielding

“…6c briefly shows the mechanism of the anisotropic composite aerogels achieving high shielding performance. Due to the high electrical conductivity of the shielding materials and the difference of wave impedance between the interface and air, 7 about 90% of the EMW loss was attenuated by reflection. The surviving EMWs were lost through multiple reflections/scattering inside the aerogel.…”

“…1–4 Different from the fatal weakness of traditional metal materials with a high density and ease of corrosion, transition-metal carbon/nitride (MXene), as an emerging two-dimensional sheet material, exhibits great potential in the field of electromagnetic shielding due to its excellent electrical conductivity and abundant interface groups. 5–10 It is urgent to overcome the weak interaction between MXene nanosheets, for the better usage of their unique 3D structural advantages, thus improving their mechanical properties and oxidation resistance. 11 In recent years, freeze-drying, 12 hard-template, 13 chemical reduction, 14 and chemical-crosslinking 15 methods have been widely used to construct MXene-based 3D structures.…”

Gelation‐Assisted Assembly of Large‐Area, Highly Aligned, and Environmentally Stable MXene Films with an Excellent Trade‐Off between Mechanical and Electrical Properties

“…g) Comparison of the electrical conductivity and tensile strength between MAF‐0.25 and previously reported MXene‐based films. [ 14,16,23,25,27,28,31,35,38,44,48–53 ]…”

“…Benefiting from the abundant functional groups at the Ti 3 C 2 T x surface (where T x can be F, O, and OH), one way to reinforce MXene films is to introduce different interfacial interactions, such as hydrogen bonding, ionic bonding, covalent bonding, and a synergy of multiple interlayer interactions. For example, introducing polymers or nanofibers with oxygen‐containing polar groups, such as polyvinyl alcohol (PVA), [ 22 ] cellulose nanofiber (CNF), [ 23,24 ] bacterial cellulose (BC), [ 25,26 ] and aramid nanofiber (ANF), [ 27 ] can significantly improve the mechanical properties of MXene films by hydrogen bonding. Also, hydrogen and ionic bonding could be combined to construct strong and tough MXene films by sequentially introducing sodium alginate and Ca 2+ .…”

Interfacing MXene Flakes on a Magnetic Fiber Network as a Stretchable, Flexible, Electromagnetic Shielding Fabric

“…MXene materials are obtained by selectively etching away the Al layer from a MAX phase, and they have the structure M n +1 X n T x . Specifically, M is a transition metal element, X is carbon and/or nitrogen, and T x is the terminating group (–F, =O, or –OH) [ 20 , 21 ]. Compared with other two-dimensional materials that lack hydrophilicity, MXenes can be used to easily obtain composite films or fabrics through self-assembly, vacuum filtration, dip coating, and other methods [ 22 , 23 , 24 , 25 , 26 , 27 ].…”