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

Abstract

Layered MXene films have shown enormous potential for wide applications due to their high electrical conductivity and unique laminated microstructure. However, the intrinsic susceptibility to oxidation and the mechanical fragility of MXene films are the two major bottlenecks that prevent their widespread industrial applications. Here, a facile yet efficient assembly strategy is proposed to address these issues by increasing the alignment and compactness of MXene layers as well as strengthening the interlayer interactions. This method involves the gelation of MXene flakes with a multifunctional inorganic “mortar” polymer (ammonium polyphosphate, APP) followed by quasi‐solid‐state assembly enabled by a mechanical rolling process, by which the 3D gel network is transformed into 2D freestanding MXene films with unprecedented flake alignment and compactness. Besides, due to the multiple molecular‐level interactions (hydrogen bonding, coordination bonding, and electrostatic force) between APP and MXene flakes, the resultant MXene‐APP film (MAF) displays high mechanical strength (286.4 ± 20.3 MPa) and excellent electrical conductivity (8012.4 ± 325.6 S cm−1), along with remarkable environmental stability. As an application demonstration, MAF exhibits outstanding electromagnetic interference shielding effectiveness with long‐term durability, highlighting the great potential of this gelation‐assisted assembly strategy in fabricating large‐area, high‐performance MXene films for diverse real‐world applications.

High-strength, low infrared-emission nonmetallic films for highly efficient Joule/solar heating, electromagnetic interference shielding and thermal camouflage

“…S9, ESI†). 29,43 In addition, the orientation degree of MXene nanosheets and GO nanosheets was characterized by wide-angle X-ray scattering (WAXS) (Fig. 1j–l and Fig.…”

2D MXene Nanomaterials: Synthesis, Mechanism, and Multifunctional Applications in Microwave Absorption

“…It is difficult to obtain an outstanding absorption or shielding effect with a single material; thus, the structure and composition design of the material are indispensable to meet the demand for MXene‐based materials in the EMA and EMI fields. Based on previous reports, this section introduces several different product forms of high‐efficiency electromagnetic materials, including powder, [ 59 ] film, [ 5,20 ] foam, [ 60 ] sponge, [ 61 ] aerogel, [ 62 ] etc.…”

“…[4] Thanks to the vigorous advancement of novel electronic devices, the demand for lightweight, flexible, EM shielding, and absorbing materials is becoming more urgent. [5][6][7][8] In response to this demand, researchers have developed numerous functional conductive nanocomposites, such as those based on carbon nanotubes (CNTs), graphene, transition metal carbides (MXenes), and metal nanofibers. [9][10][11][12] Carbonitrides, nitrides, and transition metal carbides are the latest and most popular class of 2D materials, collectively known as MXenes.…”

From MXene Trash to Ultraflexible Composites for Multifunctional Electromagnetic Interference Shielding

“…Recently, a novel type of two-dimensional transition metal carbides/nitrides (MXenes) has been gaining a lot of attention rapidly owing to the metallic conductivity, outstanding mechanical properties, and abundant surface terminations, as these contribute to the easy processability in aqueous dispersion. − These give high potentials of MXene layers for building macrostructures applied in EMI shielding, − energy storage, catalysis, sensing, transparent conductive films, and so on. For instance, Weng et al used a vacuum-assisted filtering technique to combine MXene and an aramid nanofiber (ANF) to create a composite film with layered structure.…”