High-Capacity Nano Graphene Materials for Asymmetric Electrochemical Capacitors

The two most critical barriers to the large-scale implementation of supercapacitors for powering electric vehicles (EVs) are electrode performance (e.g., device weight, internal resistance, energy density, and power density) and cost. To address these barriers, this project will adapt nano-graphene plates (NGPs) as the electrode materials ¿ in lieu of high-end carbon black ¿ in an asymmetric supercapacitor. Compared to the currently used activated carbon-based electrode, the new electrode will feature higher performance. Moreover, the NGPs can be readily mass produced, and thus would be available at much lower costs and in larger quantities. Phase I will determine proper electrode compositions and meso-porous structures that would provide high energy density and high power density for the asymmetric supercapacitors. Specific tasks include the preparation and surface functionalization of NGPs, the fabrication of asymmetric supercapacitors based on a nano-structured metal oxide electrode and a NGP electrode; and the characterization and modeling of electrochemical properties of nanocomposite supercapacitor electrodes. Phase II will focus on optimizing the materials compositions and nano-structures, and developing a processing technology for mass-producing the NGP nanocomposite electrodes. Commercial Applications and other Benefits as described by the awardee:Low-cost, light-weight, high energy density, and high power density supercapacitors should have a major impact on the markets for (1) energy storage devices for hybrid electric vehicles (HEVs) and plug-in hybrids (PHEVs), and (2) backup power sources for electronic, computer, and communications devices. The market demand for ultracapacitors is expected to reach approximately $560 million by 2011 and $1.1 billion by 2015