Polyaniline nanofibers (PANI-NFs) web are fabricated by electrospinning and used as electrode materials for supercapacitors. Field-emission scanning electron microscope micrographs reveal nanofibers web were made up of high aspect ratio (>50) nanofibers of length approximate to 30 m and average diameter approximate to 200 nm. Their electrochemical performance in aqueous (1M H2SO4 and Na2SO4) and organic (1M LiClO4 in propylene carbonate) electrolytes is compared with PANI powder prepared by in situ chemical oxidative polymerization of aniline. The electrochemical properties of PANI-NFs web and PANI powder are studied using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. PANI-NFs web show higher specific capacitance (approximate to 267 F g1) than chemically synthesized PANI powder (approximate to 208 F g1) in 1M H2SO4. Further, PANI-NFs web demonstrated very stable and superior performance than its counterpart due to interconnected fibrous morphology facilitating the faster Faradic reaction toward electrolyte and delivered specific capacitance approximate to 230 F g1 at 1000th cycle. Capacitance retention of PANI-NFs web (86%) is higher than that observed for PANI powder (48%) indicating the feasibility of electro spun PANI-NFs web as superior electrode materials for supercapacitors. (c) 2012 Wiley Periodicals, Inc.