Search

Both polypyrrole–titanium nitride (PPy–TiN) and polypyrrole–titania (PPy–TiO2) nanotube hybrids have been prepared by incorporating electroactive polypyrrole into well-aligned titanium nitride and titania nanotube arrays through a normal pulse voltammetry deposition process. Microstructure characterization shows that the polypyrroles have been fully coated on the titanium nitride and titania nanotube arrays to form coaxial heterogenous nanohybrids. The galvanostatic charge–discharge measurements indicate that the PPy–TiN and PPy–TiO2 nanotube hybrids have specific capacitances of 1265 and 382 F g−1 at a current density of 0.6 A g−1. Both nanotube hybrids have similar cyclability, exhibiting stable capacitances of 459 and 72 F g−1 after 2000 cycles at a high current density of 15 A g−1. The highly conductive titanium nitride substrate can promote the electrochemical capacitance of polypyrrole more significantly, as compared to the titania semiconductor, contributing to a higher supercapacitance performance of PPy–TiN. This indicates that PPy–TiN nanotube hybrids can be more suitable to act as supercapacitor electrode materials. [ABSTRACT FROM AUTHOR]

A polyaniline/titanium nitride (PANI/TiN) nanotube hybrid was prepared and used for an electrochemical supercapacitor application. Firstly, the well-aligned TiN nanotube array was prepared by anodization of titanium foil and subsequent nitridation through ammonia annealing. Then, PANI was deposited into TiN nanotube through the electrochemical polymerization process. The obtained PANI/TiN nanotube hybrid had an ordered porous structure. A high specific capacitance of 1,066 F g was obtained at the charge-discharge current density of 1 A g when only the mass of PANI was considered. The specific capacitance can even achieve 864 F g at 10 A g and still keep 93 % of the initial capacity after 200 cycles. An aqueous supercapacitor, consisting of two symmetric PANI/TiN nanotube hybrid electrodes and 1.0 M HSO electrolyte solution, showed the specific capacitance of 194.8 F g, energy density of 9.74 Wh kg, and power density of 0.3 kW kg. [ABSTRACT FROM AUTHOR]

Highlights: [•] TiN nanoarray is formed by a nitridation process of TiO2 in ammonia atmosphere. [•] TiN nanoarray exhibits much higher EDLC capacitance than TiO2 nanoarray. [•] The specific capacitance of TiN nanoarray achieves a high level of 99.7mFcm−2. [•] A flexible solid-state supercapacitor is constructed by TiN nanoarray and PVA gel. [Copyright &y& Elsevier]

The polypyrrole/titania/polyaniline (PPy/TiO 2 /PANI) coaxial nanotube hybrid has been prepared through a stepwise electrodeposition process for an electrochemical energy storage. Independent TiO 2 nanotube array was used as the framework, which was formed by anodizing titanium foil at 30 V in fluoride-containing water and ethylene glycol mixture solution. The PPy was selectively coated on the outer surface of TiO 2 nanotube walls to form PPy/TiO 2 through a normal pulse voltammetry electrodeposition process. The PANI was then coated on the inner surface of TiO 2 nanotube walls to form PPy/TiO 2 /PANI coaxial nanotube hybrid through a photoassisted cyclic voltammetry electrodeposition process. The morphology and microstructure feature of PPy/TiO 2 /PANI were characterized by field-emission scanning electron microscopy and Raman spectrum. The capacitance performance was conducted by cyclic voltammetry and galvanostatic charge–discharge measurements. PPy/TiO 2 /PANI coaxial nanotube hybrid with P/N-type doping properties exhibited a high specific capacitance of 497 F g −1 at a current density of 0.5 A g −1 and a potential window of −0.2 to 0.8 V in 1.0 M H 2 SO 4 solution. The capacitance declined from 267.9 to 193.7 F g −1 after 500 cycles at a high current density of 2.0 A g −1 , showing 72.3% capacitance retention and a good cycle stability for the promising supercapacitor application. [ABSTRACT FROM AUTHOR]

Highlights: [•] PANI/TiN core–shell nanowire arrays were prepared for supercapacitor application. [•] TiN nanowire arrays contributed to high surface area and low resistance for PANI. [•] PANI/TiN core–shell nanowire arrays exhibited much higher capacitance than PANI/TiO2. [Copyright &y& Elsevier]