CNFs can be fabricated with different shapes. CNFs is made from "cones" or "cups" form of graphene sheets stacked-up in several layers. It is lighter and reveal porous, hollow, helical and stacked-cup structure, which make them to generate nano-scaled quantum effect . This small quantum effect is proven to produce shorter wavefunction of charge carriers and larger electronegative absorption, which enhances the stability, mechanical properties, and electrical conductivity . CNFs can easily disperse in solution and increase the mechanical strength, and this property intensifies its practical applicability . Fabrication of CNFs into foldable and thin-film electrodes with highly desirable defects on its surface can be accomplished, which is advantageous to generate larger surface area to volume ratio and more prominent active sites for charge storage . Another advantage of CNFs is that, the mass transfer of reactants from solution to the active sites on the catalyst can be reduced by tailoring them into uniform porous structure, which allow CNFs to have faster ionic transport and higher rate of capability. At present, CNFs are synthesized by various methods, such as chemical vapor deposition, electrospinning, self-assembly, template-directed synthesis, emulsion and hydrothermal conversion. Most of the afore-mentioned methods have disadvantages of complex synthesis procedure, high cost, and uncontrollable process parameters.