Asymmetric ultracapacitors achieve greater energy density versus today¿s Electric Double Layer Capacitors (EDLC) by utilizing one activated carbon EDLC electrode and one insertion (battery-like) electrode. Asymmetric ultracapacitors based on non-aqueous electrolytes provide improvements in energy density but they provide no improvement in cost, safety or in environmental impact. Alternatively, aqueous asymmetric ultracapacitors can provide improvements not only in cost, safety and in some cases, environmental impact, but can also provide greater energy density than the non-aqueous approach. This project will develop an asymmetric ultracapacitors with aqueous electrolytes, based on a 3-dimensional (3-D) mixed-oxide nanofilm cathode. The high surface area 3-D nanofilm approach will reduce resistances in solvated ion transport, in solid-state ion diffusion and in electron transport thereby maximizing power density and efficiency while reducing generated heat and rate-induced capacitance fade. This approach will also improve the utilization of the active material resulting in increases in energy density while improving cost, safety and environmental impact. Following Phase I, the system will be scaled up for HEV and PHEV applications.
Commercial Applications and Other Benefits as described by the awardee: Successful implementation of the proposed technology should lead to safe, cost-effective and environmentally benign ultracapacitor systems with increased usable energy suitable for electric vehicle, hybrid electric vehicle and plug-in hybrid electric vehicle use. Such ultracapacitor systems may also find markets in UPS, medical, consumer electronics, power tool, military and industrial applications.
