Vertically aligned double-walled carbon nanotube electrode prepared by transfer methodology for electric double layer capacitor

We successfully prepared a vertically aligned double-walled carbon nanotube (DWCNT) sheet by a transfer procedure from a silicon substrate as a DWCNT seedbed that was covered with catalyst grains to an aluminum sheet as a current collector for application to a high-performance electrode for an electric double layer capacitor (EDLC). The charge–discharge characteristics and EDLC performances of the aligned DWCNT electrode were evaluated and compared with those of a vertically aligned multi-walled CNT (MWCNT) electrode. The gravimetric capacitance of the DWCNT electrode was ca. four times larger than that of the MWCNT electrode. The rate capability of the DWCNT electrode was found to be excellent. This is mainly ascribed to our transfer technique.