Stretchable polyurethane composite foam triboelectric nanogenerator with tunable microwave absorption properties at elevated temperature

Abstract

Abstract Nowadays, the integration of multiple functions such as harvesting clean energy and electromagnetic protection into single material has attracted great interest. Herein, a stretchable composite foam-based triboelectric nanogenerator (CF-TENG) with tunable microwave absorption (MA) capacity was developed by assembling self-foaming polyurethane (PU), tadpole-like CNTs@Fe3O4 nanoparticles (NPs) and conductive wires. The CF-TENG with a volume of ∅120\xa0mm\xa0×\xa03\xa0mm can generate a maximum output power of 147.9\xa0μW, corresponding to a power density of 1.3\xa0µW/cm2 and easily illuminate 35 commercial light-emitting diodes (LEDs) under periodically vertical contact and separation mode, which exhibits high efficiency in energy-harvesting. Besides, the excellent MA properties and relevant mechanisms at elevated temperatures from 253\xa0K to 333\xa0K were investigated in detail. With an ultralow filler loading of 15\xa0wt%, the minimum reflection loss (RLm) value at 253\xa0K could reach −68.5\xa0dB at 10.97\xa0GHz and effective absorption bandwidth (EAB) below −10\xa0dB achieved 4.37\xa0GHz at a thickness of 2.55\xa0mm. Temperature rise would be conducive to broadening the EAB and shifting the matching frequency towards a higher frequency band. Such a remarkable MA performance originated mainly from the dielectric-magnetic dual loss, well-matched impedance, and multiple reflections. To this end, this CF-TENG with electromagnetic protection property combining the ability to scavenge mechanical energy from ambient vibrations opens a new set of prospective applications in wearable electronics and the next-generation energy systems under invisible harsh environments.