Study of Activated Bamboo-Shaped Multiwall Carbon Nanotubes as Supercapacitor Electrodes

Bamboo-shaped multiwall carbon nanotubes (BS-MWCNTs) activated by KOH with different KOH/CNT mass ratio are applied as electrodes for supercapacitors. The electrochemical capacitance of activated bamboo-shaped multiwall carbon nanotubes (ABS-MWCNTs) with KOH/CNT mass ratio 3:1 and 7:1 is 1.5 and 3 times that of the normal BS-MWCNTs, respectively. The activated materials still possess nanotubular morphology with many defects on the outer walls and open tips that give a significant increase of micropore volume, while keeping a noticeable mesoporosity. Both BS- MWCNTs and ABS-MWCNTs are characterized by transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). Capacitance of the electrodes has been estimated by constant-current charge and discharge cycles experiments.