During this work, the protic ionic liquid (PIL) pyrrolidinium hydrogen sulfate, [Pyrr] [HSO4], is synthesized and its mixture with water is then characterized prior to be used as a potential electrolyte for polyaniline (Pani) based supercapacitors. The transport properties of the [Pyrr] [HSO4] - water binary mixture is determined at three different PIL/water weight ratios (i.e. 14/86, 41/59 and 70/30) as a function of the temperature from 5 to 70 degrees C. In the light of such an analysis, the optimum value of the ionic conductivity, reaching 178 mS/cm at 25 degrees C, is obtained for the [Pyrr] [HSO4]/water weight ratio close to 41/59. The electrochemical behavior of Pani is then investigated in these electrolytes to further examine the impact of their formulation on supercapacitor performances. Based on this work, the Pani electrode shows the best electrochemical performances using the electrolyte 41/59 [Pyrr] [HSO4]/water weight ratio leading to a specific capacitance of 380 F/g at 10 mV/s, a low relaxation time constant tau(0) close to 5 s and a gravimetric capacitance retention of 68% after 1000 cycles at 2 A/g.