CNTs are the allotropes of carbon and a part of fullerene (C60) structural family, having a hexagonal structure of symmetric carbon atoms available with nano-sized diameter and micro-sized length . The properties and behaviour of CNTs completely depends upon their nature of helix, and as a result of that, they act either as a semiconductor or a metal. Based on their synthesis techniques, CNTs are classified into three types namely: (a) single-walled carbon nanotubes (SWCNTs), (b) double-walled carbon nanotubes (DWCNTs), (c) multi-walled carbon nanotubes (MWCNTs). SWCNTs may be conceptually viewed as a single atom thick graphite sheet rolled into a nanoscale tube and capped by fullerene hemisphere, whereas, DWCNTs are coaxial nanostructures composed of precisely two SWCNTs, with one nestled in another, and MWCNTs can be considered as nanotubes within nanotubes. In terms of morphology, CNTs can be perceived in randomly entangled orientation and in highly aligned forms. According to the available reports, the expedition of MWCNTs started two years earlier than SWCNTs and are characterized into three crystallographic configurations such as zigzag, armchair and chiral, based on exactly the way the graphene sheet is rolled up. CNTs have various geometric structures and tubular morphologies, and based on that, they reveal good mechanical and electrical properties (5000 S cm -1 ), waviness characteristics, high aspect ratio (∼104), low-weight (∼2 g cm -3 ), excellent electrical conductivity, large surface area (SWCNT > 1600 m 2 g -1 , MWCNTs > 430 m 2 g -1 ), high melting point and low density . On the basis of the afore-mentioned properties, CNTs have been widely used as the attractive electrode materials for fabricating high-performance supercapacitors. As an example, a supercapacitor has been developed using free-standing mats of entangled MWCNTs electrodes in H2SO4 electrolyte, which has a specific capacitance of 102 Fg -1 along with a power density > 8 kW Kg -1 and an energy density of 1 Wh Kg -1 . More recently, a randomly entangled SWCNTs electrode in KOH electrolyte exhibited a higher specific capacitance of 180 F g -1 , with a maximum power density of 20 kW Kg -1 and energy density of 10 Wh Kg -1 . In this particular case, the obtained power density is higher than those reported by activated carbonbased supercapacitors, however improvement is still needed in terms of energy density. The reason for the low energy density may be due to the randomly entangled or bundled structure of MWCNTs, that could have significantly lowered the specific surface area of CNTs with an associated reduction in the supercapacitor performance .