Long chain protonic acid (dodecylhydrogen sulfate-DHS) along with small molecule acid (sulfuric acid-H2SO4) was introduced as dopants in polyaniline salt (PANI–H2SO4–DHS), hereafter referred as PANI, via aqueous/emulsion polymerization pathway of aniline. Polyaniline salt–acetylene black composites (PANI–AB) were prepared in one-step via aqueous/emulsion polymerization pathway using various amounts of acetylene black (AB). Formation of PANI and PANI–AB was confirmed from infrared and X-ray diffraction patterns. The highest conductivity obtained for PANI–AB composite was 6.2Scm−1, which is slightly higher than that of PANI (1.3Scm−1). PANI prepared by aqueous polymerization pathway showed nano fibres with diameter of 10–30nm. Use of 5wt% of AB with respect to the amount of aniline used in the polymerization reaction of aniline, PANI–AB showed spheres covered nano fibres with high porosity. By increasing the amount of AB to 10wt%, nano fibres are getting closure, which reduced the porosity. Further increase in the amount of AB to 15wt%, nano fibres disappear. PANI and PANI–AB were used as electrode materials in symmetric supercapacitor cell. Specific capacitance, Energy and power densities of PANI–AB composite were found to be 157.6Fg−1., 15.7Whkg−1 and 600Wkg−1 respectively.