Functional Oxide Based Nanocomposites For Energy Harvesting Systems

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Yarn Shaped Functional Nanocomposites For Triboelectric Energy Harvesting Systems

Publication . Barras, Raquel Alexandra Antunes; Pereira, Luís; Barquinha, Pedro

Triboelectric Nanogenerators (TENGs) are mechanical to electric energy converters and ideal candidates for exploiting the wasted energy from natural cyclic movements of the human body. In this context, the work of this PhD is focused on the development of Single Electrode Yarn Shaped Triboelectric Generators (Seys-TENGs) through an innovative method of Poly-dimethylsiloxane (PDMS) curing around conductive carbon fiber yarns (CF yarns), named in-situ curing of PDMS. This process promotes the cure of PDMS inside-out through heat gener-ated by an electric current passing through the conductive yarn. A study regarding the precise control over PDMS thickness by varying the curing parameters is presented, and the correla-tion between the device dimensions and the power generation is established. Different strate-gies were adopted to enhance the overall surface charge density, namely, the introduction of porosities into the PDMS matrix, the functionalization of the CFs yarn surface using vertically aligned ZnO nanorods grown by hydrothermal synthesis, loading of PDMS with several amounts of conductive chopped carbon fibers (cCFs) and finally, the introduction of a Cellu-lose Nanocrystal (CNC) interlayer on the Seys-TENG structure. The best results were obtained using the strategy of mixing cCFs in the PDMS matrix, exploring the enhancement effect pro-vided by polarization at interfaces of conductive particles and the polymer. The optimized loading of 2 % wt. cCFs into the PDMS and in-situ curing using 0.2 A for 4 min resulted in Seys-TENGs with a diameter of 2.16 mm. A maximum power density of 1063.23 μW/m was obtained (using a loading resistor of 20 MΩ) which corresponds to an increase of 53 % com-pared with the Smooth Seys-TENG.

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Fundação para a Ciência e a Tecnologia

Número da atribuição

SFRH/BD/139224/2018