Chitosan based aerogel fibers for piezoelectric and moisture electric energy harvesting

Taking advantages of renewable resourced materials in the preparation of multifunctional aerogel fibers which integrate thermal insulation, piezoelectric and moisture electric generation could be a promising way of relieving pressure on both energy loss and generation. A series of chitosan-konjac glucomannan (CS-KGM) aerogel fibers was obtained by means of wet-spinning method followed by freeze-drying. The CS-KGM aerogel fibers with submicron porous morphology exhibit excellent thermal insulation performance. Single layer of CS-KGM aerogel fiber with only a thickness of 0.6 mm shows a thermal insulation temperature difference of 23 °C. A stable piezoelectric output voltage of 0.35 V can be generated from a single CS-KGM aerogel fiber during a 500 press-release cycle attributing to the intrinsic piezoelectricity of CS and the porous structure. Single aerogel fibers were coated with multi-walled carbon nanotubes as a way to prepare conductive aerogels. Meanwhile, the moisture electric output voltage can be as high as 160 mV and last for >8 h at 60% relative humidity for CS-KGM single aerogel fiber assisted by a thin layer of carbon nanotube coating. Overall, CS-KGM aerogel fibers prepared in this work has good compatibility and potential applications in thermal management and energy harvesting from low density resource, which provides a new strategy for the preparation of sustainable and multifunctional wearable materials.