Chemically embedding CuS microspheres into MXene aerogel for strain-adaptive triple shielding of electromagnetic wave, heat and sound

Abstract

Electromagnetic interference (EMI) shielding materials with adaptive strain capability have broad applications in wearable electronic devices. However, as an important candidate, compressible conductive foam generally suffers from a reduction in EMI shielding performance during compression, which limits its application. Here, a compressible conductive aerogel with a unique conductive compensation effect is designed to solve this problem. CuS microspheres with metal-like conductivity serve as conductive compensation sites, and are chemically embedded in the skeletons of lamellar-structured carboxymethylcellulose (CMC)/MXene aerogel through Cu–S−Ti−C chemical bonds. The incorporation of CuS induces circularly-distributed interfacial polarization to enhance the attenuation of EM waves. More importantly, these CuS microspheres act as interlayer bridges to connect the upper and lower MXene/CMC layers during compression, thereby establishing numerous conductive compensation paths to offset the negative effect of thickness reduction on shielding performance. The optimized CMC/MXene/CuS aerogel shows stable EMI shielding performance during compression, and maintains a high shielding effectiveness of 32.31 dB with increasing compressive strain. In addition, this composite aerogel exhibits good thermal insulation and sound absorption performances, achieving triple shielding functions against EM waves, heat and sound.