One-pot synthesis and electrochemical properties of polyaniline nanofibers through simply tuning acid-base environment of reaction medium

A facile and efficient one-pot approach was presented to prepare polyaniline (PANi) nanofibers through simply tuning acid-base environment of reaction medium without the assistance of templates or use of organic solvents, in which aniline oligomers formed in the alkaline solution were used as seeds for the oriented growth of PANi chains under acidic conditions. The as-prepared PANi nanofibers were investigated by field-emission scanning electron microscopy, ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy and X-ray diffraction technology. Furthermore, the electrochemical properties were evaluated by cyclic voltammetry, galvanostatic charge-discharge test, and electrochemical impedance spectroscopy. More attentions were paid to the influence of aniline concentrations in alkaline and acidic reaction medium on the morphology, microstructure and properties of PANi nanofibers. It can be found that aniline concentration in alkaline medium has a stronger impact on the electrical and electrochemical properties of final products, however, their morphologies obviously depend on aniline concentration in acidic solution. Moreover, PANi nanofibers prepared at aniline concentrations of 48 mM in alkaline medium and 0.2 M in acidic medium exhibits the largest specific capacitance of 857.2 F g(-1) at the scan rate of 5 mV s(-1), and capacitance retention of 63.8% after 500 cycles. It is demonstrated that such one-pot approach can present a low cost and environmental friendly route to fabricate PANi nanofibers in fully aqueous solution as high-performance electrode materials for supercapacitors. (C) 2017 Elsevier Ltd. All rights reserved.