Facile fabrication of self-assembled polyaniline nanotubes doped with d-tartaric acid for high-performance supercapacitors

Abstract

Polyaniline (PANI) nanotubes with outstanding electrochemical properties have been successfully synthesized via a simple chemical template-free method in the presence of d-tartaric acid (d-TA) as the dopant, and ammonium persulfate ((NH4)2S2O8) as the oxidant. The morphologies and structures of PANI-(d-TA) with different [d-TA]/[aniline] molar ratios are characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD). To assess the electrochemical properties of PANI-(d-TA) materials, cyclic voltammetry (CV) and galvanostatic charging–discharging measurements are performed. The PANI-(d-TA) nanotubes electrode, with [d-TA]/[aniline] molar ratio of 1:1, exhibits larger specific capacitance (as high as 625 F g−1 at 1 A g−1) and higher capacitance retention (77% of its initial capacitance after 500 cycles) in 1 M H2SO4 aqueous solution. The remarkable electrochemical characteristics of PANI-(d-TA) are mainly attributed to their unique nanotubular structures, which provide a high electrode/electrolyte contact area and short ions diffusion path. These novel PANI-(d-TA) nanotubes will be promising electrode materials for high-performance supercapacitors.