The conducting polypyrrole (PPy) spherical nanoparticles are synthesized by a facile electrochemical deposition method and the polymerization is carried out by potentiostatic methods using a twoelectrode system (Au electrode) with a template-free method. The microstructure of the PPy spherical nanoparticles and their electrochemical properties can be tuned by controlling the electrodeposition time and anodic potential in the synthetic process. A maximum specific capacitance of 356 F/g is obtained for as-prepared PPy electrodes from cyclic voltammetry (CV) at a scan rate of 10 mV/s, which is superior or close to some individual PPy nanostructure, PPy/metal, and PPy/carbon materials. Also, the stability of cycling can retain 89.3% of its initial capacitance after 1000 cycles. The capability of fabricating stable polymer electrodes is expected to make an important contribution to the promotion of supercapacitor technology. (C) 2017 Elsevier Ltd. All rights reserved.