Tailored carbon nanofibers are under development at Florida Atlantic University. These materials exhibit an uncommon double-layer capacitance at high requencies; this feature makes them desirable for electrochemical capacitor applications. Their power and energy characteristics may be dramatically improved by surface functionalization using processes developed at Inorganic Specialists, Inc. Functional groups are attached which undergo reversible redox reactions (i.e., they provide pseudocapacitance). Preliminary results show that unctionalization increases the nanofiber's stored energy by 100 to 400%, and that the energy enhancement occurs at both low and high frequencies. The Phase I objective is to establish that surface-modified nanofibers can be made into exceptional high frequency energy storage materials. The work has two components. 1) High frequency capacitance nanofibers will be tailored with a maximum amount of edge plane sites. This should foster the attachment of a maximum number of energy-enhancing surface groups. 2) Surface functionalization procedures will be further developed, and functionalized nanocarbons will be tested for performance and electrochemical stability. Based on these two studies, an optimized material will be produced; its performance will show the feasibility of functionalized nanofiber materials. Potential Commercial Application(s) Energy storage materials with high frequency capacitance and high power are needed for wireless digital communication applications and pulse digital technology. The largest markets are in cellular phones and pagers; other applications are in satellite and defense technology. The development of new high-power, high-frequency capacitance concepts is consistent with the ever- increasing powers and frequencies required in new generations of these applications. The surface modification procedures of this proposal have broad applicability: they can improve the power and energy storage of any carbon or nanocarbon material. Phase I will demonstrate feasibility and practicality, and is anticipated that Phase II will yield materials with an eight- or ten-fold improvement in energy/power over the best nanocarbon capacitor materials currently available.
