Enhanced piezoelectric energy harvesting using hybrid composites of MWCNTs and partially-reduced GO in RTV-SR for stable voltage generation

Abstract

Recent studies have explored the use of flexible devices for piezoelectric energy harvesting, which can generate energy at a few volts on a laboratory scale. In this context, multiwall carbon nanotubes (MWCNTs), partially-reduced GO (p-rGO), and their hybrid composites based on room temperature vulcanized silicone rubber (RTV-SR) have emerged as innovative and novel approaches for energy production. The composites were prepared by mixing an RTV-SR solution with MWCNTs and p-rGO powder as fillers, resulting in improved mechanical properties and reinforcement of the RTV-SR matrix. The p-rGO was synthesized from graphite nanoplatelets (GNP) using the modified Hummers' method, followed by chemical and thermal reduction. The MWCNTs were used as received from the supplier. Characterization techniques such as scanning electron microscopy, x-ray diffraction, transmission electron spectroscopy, and atomic force microscopy revealed that the p-rGO consisted of less than five layers stacked in a crystalline domain. Static mechanical property analysis demonstrated that MWCNTs exhibited exceptional filler characteristics compared to other fillers studied. Piezoelectric energy harvesting measurements were performed, and the results indicated higher voltage generation for MWCNTs; however, it exhibited instability and a decline in performance after a few cycles due to electrode cracking. In contrast, the hybrid composite demonstrated stable voltage generation. Moreover, walking and running activities may generate renewable, simple, and sufficient voltage to power light-emitting diodes (LEDs).