Discharge Capacitance of Electric Double Layer Capacitor with Electrodes Made of Carbon Nanotubes Directly Deposited on SUS304 Plates

Abstract

Carbon nanotubes were deposited directly on SUS304 plates by PECVD with acetylene and hydrogen as precursors under various deposition conditions. Roman spectroscopy showed that carbon nanotubes were not fully graphitized at the deposition temperatures, 600 to 750°C, although defects decreased with increase of deposition temperature. SEM microscopy showed that carbon nanotubes were not straight, but their growth followed the tip growth model. Pretreatment of the substrate such as polishing and dipping in HF solution was required for the successful deposition. Using non-aqueous electrolyte we fabricated electrical double layer capacitance (EDLC) with SUS304 plates, on which carbon nanotubes were deposited, without any treatment, and measured charge/discharge characteristics. Discharge capacitance decreased with cycles from initial value of 128 F/g, but stabilized at 58 F/g after 50 cycles.