Design of an “all solid-state” supercapacitor based on phosphoric acid doped polybenzimidazole (PBI) electrolyte

The effectiveness of phosphoric acid doped polybenzimidazole as a polymer electrolyte membrane to fabricate an all solid-state super capacitor has been explored using hydrous RuO2/carbon composite electrodes (20 wt.%) of surface area 250 m2 g−1 with many intrinsic advantages. The electrochemical evaluation of these super capacitors through cyclic voltammetry, charge/discharge and impedance measurements demonstrate the utility of this type of thin, compact and flexible supercapacitor capable of functioning at 150 °C to yield a maximum capacitance of about 290 F g−1 along with a life of more than 1,000 cycles. A power density of 300 W kg−1 and energy density of 10 Wh kg−1 have been accomplished although the equivalent series resistance (ESR) of about 3.7 Ω needs to be reduced further for high rated applications.