Multifunctional\nTi₃C₂T_<i>x</i> MXene Composite\nHydrogels with Strain Sensitivity\ntoward Absorption-Dominated Electromagnetic-Interference Shielding

Abstract

The fast development of terahertz\ntechnologies demands high-performance\nelectromagnetic interference (EMI) shielding materials to create safe\nelectromagnetic environments. Despite tremendous breakthroughs in\nachieving superb shielding efficiency (SE), conventional shielding\nmaterials have high reflectivity and cannot be re-edited or recycled\nonce formed, resulting in detrimental secondary electromagnetic pollution\nand poor adaptability. Herein, a hydrogel-type shielding material\nincorporating MXene and poly­(acrylic acid) is fabricated through a\nbiomineralization-inspired assembly route. The composite hydrogel\nexhibits excellent stretchability and recyclability, favorable shape\nadaptability and adhesiveness, and fast self-healing capability, demonstrating\ngreat application flexibility and reliability. More interestingly,\nthe shielding performance of the hydrogel shows absorption-dominated\nfeature due to the combination of the porous structure, moderate conductivity,\nand internal water-rich environment. High EMI SE of 45.3 dB and broad\neffective absorption bandwidth (0.2–2.0 THz) with excellent\nrefection loss of 23.2 dB can be simultaneously achieved in an extremely\nthin hydrogel (0.13 mm). Furthermore, such hydrogel demonstrates sensitive\ndeformation responses and can be used as an on-skin sensor. This work\nprovides not only an alternative strategy for designing next-generation\nEMI shielding material but also a highly efficient and convenient\nmethod for fabricating MXene composite on macroscopic scales.