Electrochemical capacitance performance of polypyrrole–titania nanotube hybrid

Abstract

In this study, the polypyrrole-titania nanotube hybrid has been synthesized for an electrochemical supercapacitor application. The highly ordered and independent titania nanotube array is fabricated by an electro-oxidation of titanium sheet through an electrochemical anodization process in an aqueous solution containing ammonium fluoride, phosphoric acid and ethylene glycol. The polypyrroletitania nanotube hybrid is then prepared by electrodepositing the conducting polypyrrole into well-aligned titania nanotubes through a normal pulse voltammetry deposition process in an organic acetonitrile solution containing pyrrole monomer and lithium perchlorate. The morphology and microstructure of polypyrrole-titania nanotube hybrid are characterized by scanning electron microscopy, infrared spectroscopy and Raman spectroscopy. The electrochemical capacitance performance is determined by cyclic voltammetry and charge/discharge measurement. It indicates that the polypyrrole film can been uniformly deposited on both surfaces of titania nanotube walls, demonstrating a heterogeneous coaxial nanotube structure. The specific capacitance of polypyrrole-titania nanotube hybrid is determined to be 179 Fg −1 based on the polypyrrole mass. The specific energy and specific power are 7.8 Wh kg −1 and 2.8 kW kg −1 at a constant charge/discharge current of 1.85 mA cm −2 , respectively. The retained specific capacitance still keeps 85% of the initial capacity even after 200 cycle numbers.This result demonstrates the satisfying stability and durability of PPy-TiO 2 nanotube hybrid electrode in a cyclic charge/discharge process. Such a composite electrode material with highly ordered and coaxial nanotube hybrid structure can contribute high energy storage for supercapacitor applications.

The role of (photo)electrochemistry in the rational design of hybrid conducting polymer/semiconductor assemblies: From fundamental concepts to practical applications

“…A very short cathodic step (-26 mA cm -2 ) was introduced to prevent change of the local pH. Note that the anodic step is short enough (10 ms) to avoid 3-dimensional growth of PPy after the nucleation step [171,172,192]. Employing high current densities (consequently high potentials), however, involves the risk of overoxidizing the forming polymer.…”

Fabrication of tungsten decorated titania nanotube arrays as electrode materials for supercapacitor applications

“…This nanostructure with a high surface area and tubular channels contributed a short diffusion path and effective electron transfer path, led to the promoted reversible redox reaction in a charge/discharge process. The specific capacitance of this nanotube hybrid was 179 F/g in 1.0 M H 2 SO 4 electrolyte solution [23]. Molybdenum oxide coated onto TiO 2 nanotubes (MoO 3 -TN) by Guan et al and these composites were used as an anode material for electrochemical supercapacitors.…”

Synthesis and Dielectric Characterization of Multi-walled Carbon Nanotubes/Polypyrrole/Titanium Dioxide Composites

“…The disadvantage in the use of homopolymers as electrodes for supercapacitors is verified from short life (6) and poor cyclability (7). In this direction, different structures have been developed such as core-shell templates of polypyrrole and polyaniline (8) and by a covering of polypyrrole on ordered titanium nanotubes (9).…”

“…On the other side, noble metal oxides are characterized by high electrochemical Faradic capacitance (9). Redox metal oxides (such as MnO 2 , RuO 2 , NiO, TiO 2 ) (13) are potential candidates for application as electrodes of supercapacitors (2) if considering reasonable long cycle life and high specific capacitance (14).…”