USE OF CARBON BASED NANOFILLERS FOR ENERGY HARVESTING APPLICATIONS

Abstract

Energy is the essential requirement for today’s life. Due to the diminution of the energy sources, it is necessary develop devices that can harvest the wasted/unused energy that exists in the ambient environment. To address this, triboelectric nanogenerators (TENGs) have been developed as an innovative paradigm for energy harvesting. TENG is a device that can harvest mechanical energy present in the surrounding environment into electrical energy by the combination of triboelectric and electrostatic induction effect. The electrical outputs obtained from TENGs depend on the friction of materials that are selected from the triboelectric series on the basis of their triboelectro-negativity and triboelectro-positivity. So, in this regard, we have selected aluminum and nylon 6,6 as triboelectro-positive materials and polyvinylidene fluoride (PVDF) as electronegative material, according to triboelectric series. In order to enhance the electronegativity of the PVDF polymer, we incorporated the carbon based nanofillers like reduced graphene oxide nanoribbons (rGONRs) and fluorinated-graphene nanoribbons (F-GNRs), which contain various functional groups such as as hydroxyl (-OH), carboxyl (-COOH), epoxy (C-O-C) and fluorine (-F), which will improve the electronegativity of the resultant materials. So, we have synthesized rGONRs through unzipping of MWCNTs and F-GNRs via chemical modification (i.e. functionalization) of rGONRs. Moreover, we have fabricated the nanofibers of nylon 6,6, PVDF and PVDF/F-GNRs composite via electro-spinning technique. These synthesized materials are examined using various characterization techniques such as X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Energy-dispersive X-ray spectroscopy (EDX), Raman spectroscopy, Atomic force microscopy (AFM) and Fourier Transformation Infrared spectrophotometer (FTIR). In this dissertation work, we have reported the comprehensive review on the triboelectric nanogenerator (TENG), fabrication of an arc-shaped single electrode mode based TENG and vertical contact-separation mode based TENG. The arch-shaped single electrode based TENG was fabricated using rGONRs/PVDF thin film act as a triboelectro-negative and aluminum would act as a triboelectro-positive material, which effectively convert mechanical energy into electrical energy. The incorporation of rGONRs in PVDF polymer enhances average surface roughness of rGONRs/PVDF thin film. With the combination of the enhancement of average viii | P a g e roughness and presence of various functional groups, which indicate improvement in charge trapping capacity of prepared film. The output performance was discussed experimentally as well as theoretically. The maximum peak voltage was found to be 0.35V. The newly designed TENG to harvest mechanical energy and opens up many new avenues of research in the energy harvesting applications. In the vertical contact–separation mode based TENG using electrospun PVDF/F-GNRs and nylon nanofibers as triboelectro-negative and triboelectro-positive materials, respectively. The fabricated nanofibers were characterized and further used in the fabrication of TENG. The obtained maximum open-circuit voltage and short-circuit current are found to be 4.59 V and 98 nA, respectively, at the maximum force of 260 N. Moreover, electrical charge (Q) after 4.52 sec is examined to be 443 nC. The fabricated TENG is stable up to 2,000 cycles without any drop in output performance and also nanostructures are not get damaged. If the generated electrical output is stored in the rechargeable battery, then it could be used to drive various portable electronic devices.