* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
GRAPHENE BASED NANOCOMPOSITE ELECTRODES FOR ENERGY STORAGE IN SUPERCAPACITORS 1Ashish Aphale*, 2Krushangi Maisuria, 3Manoj Mahapatra, 4Angela Santiago, 3Prabhakar Singh and 5,6Prabir Patra* 1 Department of Computer Science and Engineering, University of Bridgeport, CT-06604 2 Fairfield Ludlowe High School, Fairfield, CT-06824 3 Department of Materials Science, University of Connecticut, Center for Clean Energy and Engineering, Storrs, CT4 Department of Chemistry, University of Bridgeport, CT-06604 5 Department of Biomedical Engineering, University of Bridgeport, CT-06604 6 Department of Mechanical Engineering, University of Bridgeport, CT-06604 ABSTRACT Global warming and depleting fossil fuels have forced us to move towards sustainable and renewable resources for energy production. As the renewable resources of energy are not available on demand, energy storage systems are starting to play an important role in our lives. Currently the most popular commercialized energy storage devices are batteries, capacitors and fuel cells. However, because of our ever increasing appetite for energy, there is a need to improve the performances of these devices to satisfy high power requirements of various systems ranging from portable electronics to hybrid vehicles and large industrial equipments. The gap between the performances of devices and the power requirement can be filled by discovering new materials for energy storage and advancing our understanding of the electrochemical interfaces at the nanoscale level. A novel use of atomically thin carbon allotropes like graphene, carbon nanotubes (CNTs) and electrically conducting polymers (ECPs) such as polypyrrole (PPy) have been studied as high performance conducting electrodes in supercapacitor application. A novel templated sustainable nanocomposite electrode has been fabricated using cellulose extracted from Cladophora c. aegagropila algae as a component of the assembled supercapacitor device which later has been transitioned to a unique template-less freestanding nanocomposite supercapacitor electrode. The specific capacitance of polypyrrole-graphenecellulose nanocomposite as calculated from the cyclic voltammetry curve is 91.5 F g-1 at the scan rate 50 mV s-1 in the presence of 1M NaCl electrolyte. The open circuit voltage of the device with polypyrrole -graphene-cellulose electrode was found to be around 225 m V and that of the polypyrrole -cellulose device is only 53 m V without the presence of graphene in the nanocomposite electrode. Understanding the fundamentals by fabricating template nanocomposite electrode led to developing a unique nanocomposite template-less freestanding film which comprises of polypyrrole-graphene-CNT hybrid. Various experiments have been performed using different electrolytes such ascorbic acid, sodium sulfate and sulfuric acid in different scan rates. The specific capacitance of polypyrrole-graphene-CNT nanocomposite with 0.1 wt% of graphene-CNT, as calculated from cyclic voltammetry curve is 450 F g-1 at the scan rate 5 m V s-1. For the first time a nanofibrous membrane has been developed as a separator which acts as an electrolyte reservoir and ionic diffusion membrane. The performance of the fabricated supercapacitor device has been analyzed using a multimeter and compared with a conventional alkaline (1.5 V) battery. Lighting up of 2.2 V light emitting diode has been demonstrated using the fabricated supercapacitor.