Nowadays, the application of ionic liquids for improving characterization of lead acid batteries is an important issue. In this work ionic liquids (ILs), mono, bicycyclohexyl, monohexyl and tetrahexyl ammonium hydrogen sulphate, was applied as electrolyte additives on the electrochemical performance of lead acid batteries. The electrochemical and corrosion behaviors of Pb–1.66%Sb–0.24%Sn alloy in sulphuric acid solution are investigated in the presence of mentioned ILs, differing in the number of alkyl or cycloalkyl branches. Particularly, the hydrogen and oxygen evolution potential and anodic layer characteristics were investigated using cyclic, linear sweep voltammetric, electrochemical impedance spectroscopy (EIS) and Tafel plotes methods in the various concentrations of ILs as electrolyte additives in 4.0 mol dm -3 sulphuric acid. The obtained results indicate that hydrogen evolution overpotential of lead–antimony–tin alloy increases in the solution containing ILs and mainly depend on the concentration of ILs and number of alkyl and cycloalkyl branches on the cations. So, the difference between oxygen oxidation potential in anodic and cathodic scans (?E) decreases using different ILs. Hence by increasing the number of alkyl or cycloalkyl branches of ILs, corrosion rate of lead alloy decreases, whereas, inhibition efficiency (IE) which is obtained from polarization measurements shows a reverse effect. The corrosion potential (E corr ) has been shifted to the positive potential for all the concentrations and kinds of ILs. Also, compared to hexyl forms, the cyclohexyl ILs have a lower corrosion rate and higher inhabitation efficiency. Therefore, the adsorption model of the ILs on the alloy surface was proposed.