Biomimetic Porous\nMXene Sediment-Based Hydrogel for\nHigh-Performance and Multifunctional Electromagnetic Interference\nShielding

Abstract

Developing high-performance and functional hydrogels\nthat mimic\nbiological materials in nature is promising yet remains highly challenging.\nThrough a facile, scalable unidirectional freezing followed by a salting-out\napproach, a type of hydrogels composed of “trashed”\nMXene sediment (MS) and biomimetic pores is manufactured. By integrating\nthe honeycomb-like ordered porous structure, highly conductive MS,\nand water, the electromagnetic interference (EMI) shielding effectiveness\nis up to 90 dB in the X band and can reach more than 40 dB in the\nultrabroadband gigahertz band (8.2–40 GHz) for the highly flexible\nhydrogel, outperforming previously reported porous EMI shields. Moreover,\nthanks to the stable framework of the MS-based hydrogel, the influences\nof water on shielding performance are quantitatively identified. Furthermore,\nthe extremely low content of silver nanowire is embedded into the\nbiomimetic hydrogels, leading to the significantly improved multiple\nreflection-induced microwave loss and thus EMI shielding performance.\nLast, the MS-based hydrogels allow sensitive and reliable detection\nof human motions and smart coding. This work thus not only achieves\nthe control of EMI shielding performance via the interior porous structure\nof hydrogels, but also demonstrates a waste-free, low-cost, and scalable\nstrategy to prepare multifunctional, high-performance MS-based biomimetic\nhydrogels.