Abstract by Nick Allen
Physics and Astronomy
Alumina Coated Carbon Nanotube Capacitors for Advanced Energy Storage
Electric double layer capacitors (EDLCs) are a unique energy storage technology that provide relatively high energy and power densities. While activated carbon is typically used for EDLC electrodes, there has been considerable interest in using carbon nanotubes (CNTs) because of their contiguous ion channels for faster ion transport and higher power output. The disadvantage of CNTs is that their surface areas are lower than that of activated carbon which reduces energy density. To improve energy densities of CNT capacitors, we propose a method of coating the CNTs with alumina, which acts as a dielectric, giving the capacitor a greater volume to store the electric field. Without the dielectric, the electric field would be across only a thin layer of solvent molecule dipoles at the surface of the CNTs. CNT forests were grown and then coated with alumina using atomic layer deposition. The resulting structures were characterized using scanning electron microscopy reveling conformal deposition. The electrodes were electrically characterized using current-voltage measurements which indicated capacitive behavior.