Abstract:

Carbon fiber cloth supported three-dimensional polyaniline networks were synthesized by electrochemical polymerization. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectrometer were applied to characterize the morphology of the electrode and analyze the characteristic groups on the electrode surface. The capacitive performance of the as-prepared electrode in four RCl(R=H,Li,Na,K) aqueous solutions was systematically compared. The electrochemical tests show that KCl electrolyte gives a wider potential window(1.8 V) than the HCl or LiCl electrolyte, and also exhibits a superior specific capacitance(501 F/g@0.5 A/g) to the NaCl electrolyte. The energy density under the current density of 10 A/g in the KCl electrolyte is even larger than that in the HCl electrolyte under 2.0 A/g. As a result, KCl is the most suitable electrolyte for the polyaniline-based capacitor. The potential window is widened and the energy density of electrochemical capacitor is remarkably improved just simply by altering the electrolyte in the aqueous solution, which avoids the issues of poor physico-chemical stability and severe environment contamination originated from the organic solutions.

Key words: potential window, energy density, capacitor, polyaniline, alkaline metal salt