Compressible and conductive multi-scale composite aerogel elastomers for electromagnetic wave absorption, energy harvesting, and piezoresistive sensing

With the rapid development of electronic technology, wearable electronic devices have been widely used in the lives of people. However, integrating multiple functions, such as flexible sensing and electromagnetic protection, into a single device remains challenging. Herein, silver nanowires and cobalt-nickel@carbon were assembled into a conductive and magnetic composite aerogel enhanced by aramid nanofibers and cellulose nanofibrils by freeze-drying. It exhibited an excellent electromagnetic wave absorption ability with an optimal minimum reflection loss of −51.6 dB. Then, polydimethylsiloxane (PDMS) was introduced in the subsequent vacuum-assisted impregnation process to obtain a compressible aerogel elastomer with excellent mechanical and electrical properties. It was not only used as a piezoresistive sensor for different application scenes (e.g., human behavior monitoring, pressure array identification, and parking location recognition) but also as a triboelectric nanogenerator for high-performance energy harvesting. Such a unique and multifunctional composite aerogel elastomer will open up new potential applications for electromagnetic protection, blue energy harvesting, and piezoresistive sensing.