Benzoyl peroxide is used as an oxidant for the oxidation of aniline to polyaniline salt via interfacial polymerization pathway (IP) for the first time in presence of sodium lauryl sulfate as emulsifier and 5-sulfophthalic acid as protonic acid. Polyaniline salt is also synthesized by interfacial polymerization using higher amount of reactants and emulsion polymerization pathways. Polyaniline salts are characterized by FT-IR, XRD and SEM. This polymerization process gives polyaniline salt containing dual dopants (5-sulfophthalic acid and dodecyl hydrogen sulfate) i.e. small and long chain molecules on polyaniline. Polyaniline salt prepared by emulsion polymerization pathway (EP) shows nanowires with a higher yield (0.98 g) compared to that of the interfacial polymerization (IP) pathway (0.73 g), which also shows nanowires morphology. However, very less yield (0.2 g) is obtained by the interfacial polymerization pathway using higher concentration of reactants (IP-H), which shows nanotubes. Polyaniline salt is mixed with Multi-walled carbon nanotube (MWCNTs) material, made electrode with stainless steel mesh and this electrode is used for the study of symmetric supercapacitor cell. Electrochemical performance is found by cyclic voltammetry, charge-discharge and electrochemical impedance spectroscopy. The results clearly indicate that the polyaniline salt containing dual dopants is a very good material for supercapacitor. (C) 2011 The Electrochemical Society. [DOI: 10.1149/2.036201jes]