In these materials systems, the nanostructure features are randomly distributed in the two-dimensional (2-D) film form mainly due to the preparatory methods. Most recent research thrust in the conducting polymers and their nanocomposite with metal oxides is directed towards the YM155 concentration electrodes with three-dimensional (3-D) nanoarchitecture

such as vertically Saracatinib datasheet aligned nanotubes [23] and nanorods [24]. These nanostructures have potential for the limiting electrolyte-ion diffusion problem by decreasing the ion diffusion paths and at the same time increasing the surface area for enhanced electrode-electrolyte interaction. In the past, randomly oriented conducting polymer nanotubes structures have been synthesized [16, 25, BIBF 1120 mw 26] for supercapacitor applications. However, the vertically oriented nanostructures, nanorods, and nanotubes have been mostly configured using the metal oxide templates [27]. Such nanostructures

have been created by more innovating nanoscale engineering methods like oxidative polymerization [28], electrochemical anodic oxidation [29], electrodeposition [30], and hydrothermal synthesis [31, 32]. Furthermore, by combining the redox conducting polymers with the well-known pseudocapacitive oxide like MnO2, forming the nanocomposites in the 3-D nanoarchitecture presents multiple advantages with enormous potential to outperform their 2-D counterparts. The composite 3-D nanostructure can be created by conformal deposition of redox-active conducting polymer, pseudocapacitive oxide layer, or their multilayer stacks over vertical nanostructures of TiO2, ZnO, or NiO serving as templates. The composite 3-D nanostructured electrodes have synergic contribution to specific capacitance based on their electroactive functions which boost energy density, and their nanoarchitecture have the ability to mitigate the ion diffusion limitation thereby enhancing the power density. In the past, 3-D nanotube polymers, PPy-PANI

[33] polymer-metal oxides, TiO2-PPy below [34, 35], ZnO-PPy [36], TiO2-NiO [23], and TiO2-V2O5 [37] have been reported. In this work, we investigate the characteristics of nanocomposite electrodes for supercapacitors having 3-D nanoscale architecture, the one comprising of vertically aligned zinc oxide nanorod arrays at the core with doped-polypyrrole conducting polymer sheath and the other vertical polypyrrole nanotubes arrays. Although polypyrrole in the doped state shows high electrical conductivity, the conversion between redox states is very slow due to the slow transportation of counter ions to balance the charge in the polymer structure [38]. The vertical polypyrrole nanotube and sheath structure are likely to decrease the charge transfer reaction time and thus enhance the charge storage capabilities [38].