Electrodes and electrolytes are two essential components of a supercapacitor and play important roles in determining the performance for the supercapacitor. In the present work, we investigated the electrochemical and capacitive behavior of aligned carbon nanotube electrodes in ionic liquid electrolytes to study the feasibility to develop high performance supercapacitors from these two components. Synthesis procedure of the carbon nanotubes and composition of the ionic liquids have been studied to achieve a high capacitance and fast charge/discharge process for the carbon nanotube electrode in the ionic liquid electrolyte.