Description: Scientic, Inc. and Vanderbilt University propose to dramatically improve the performance of ultracapacitors to address several applications within NASA. As power-supply components, ultracapacitors provide extremely high power densities, fast recharging rates, and long cycle life; when used in tandem with batteries, they can greatly extend battery life. We note that ultracapacitors can assume almost any form factor that an application might require. Our recent success with a flexible substrate supports this claim. Finally, commercialization of our ultracapacitor will rely on the use of environmentally friendly materials and well understood industrial manufacturing processes in common use today. We propose to develop a novel hybrid electrochemical ultracapacitor which will combine desirable attributes such as extremely high energy-power density, excellent life-cycle reliability and safety characteristics, with low production cost and have the potential for widespread deployment in energy delivery/storage applications for the NASA. In this innovative, hybrid, demonstrated approach we will grow vertically-aligned carbon nanotubes (CNT) directly on conducting flexible substrates to reduce contact resistances, and we will exploit the more controllable CNT nano-architectures for optimum attachment of inexpensive pseudocapacitive manganese-dioxide (MnO2) nanoparticles to enhance charge efficiency and energy-power capacity. Our approach employs "green" electrolyte that increases cell voltage.

Benefits: Minimizing the use of oil in the US economy requires the invention of advanced energy storage devices that provide orders-of-magnitude efficiency gains over present commercial technology. The application of enhanced CNT ultracapacitors in the automotive, aviation, and military represents an enormous market, in which costs will be driven down and innovation will penetrate industries that might not otherwise pursue cutting edge science and engineering due to the inherent risk (and cost) associated with it. Many other applications arise in consumer and industrial electronics, usually in situations where portability is needed and where fast charging capability is also desired. These applications may not be as critical to national security and well-being as those in transportation, but they represent large markets nonetheless. Ultracapacitors possess much higher energy density than conventional capacitors, and their power density is far superior to that of batteries including fuel cells, resulting in enhanced efficiency and space and weight savings, which will benefit each of the above applications. The ability to fabricate these ultracapacitors using commonly-used environmentally-friendly techniques will facilitate their widespread commercialization.

NASA applications of ultracapacitors include Lunar and Martian surface vehicles and sensor platforms. Vehicle ultracapacitors will serve as independent power sources or back-up power sources to the high capacity batteries propelling electric vehicles by providing high power output necessary during acceleration, uphill climbing, and braking. In the case of sensor platforms ultracapacitors may improve the efficiency of charging by solar power. Among the many other ultracapacitor applications are power sources for portable electronic equipment, such as diagnostic devices and power tools. Ultracapacitors may also provide backup or bridge power for sensors and control systems for aircraft and spacecraft. Ultracapacitors, in fact, address a wide range of space-based applications, including deep-space missions, manned and unmanned planetary exploration, and space-station missions. Ultracapacitors combined with battery technology can power spacecraft, as well as the aforementioned lunar surface mobility systems and portable electronic equipment. Future missions will probe deeper into space and will utilize a wide array of advanced electronic instrumentation and electric propulsion systems. Consequently, compact, on-board electrical power generation, energy storage, and power management will be central to the success of these missions.