Abstract Ferrocenesulfonic acid plays an important role in increasing the electrochemical polymerization rate of aniline. Polyaniline (PAnFc) prepared in the presence of ferrocenesulfonic acid has a rather high electrochemical activity at pH≥4 compared with polyaniline (PAn) prepared in the absence of ferrocenesulfonic acid. The cyclic voltammograms of both PAn and PAnFc in 0.5 mol dm −3 Na 2SO 4 with pH≥4 show that the low electrochemical activities are caused by the low electron transfer ability of both polymers themselves. The study on the temperature dependence of the cyclic voltammograms at pH 5.0 indicates that there are two anodic peaks and two cathodic peaks for PAnFc, however, there are only one anodic peak and one cathodic peak for PAn at the temperature <60 °C in the potential range between −0.2 and 0.6 V (vs. SCE). Based on the results from the constant current discharge of polyaniline batteries, the capacity density and energy density of PAnFc are 124.0 A h kg −1 and 126.2 W h kg −1, respectively, which are 1.58 and 1.47 times higher than the capacity density and energy density, respectively, of PAn. The FTIR spectrum of PAnFc is presented here.