Performance of ionic liquid-based quasi-solid-state hybrid battery supercapacitor fabricated with porous carbon capacitive cathode and proton battery anode

The present paper reports preparation, characterization, and application of proton-conducting ionic liquid-based gel polymer electrolyte (ILGPE) obtained by immobilizing liquid electrolyte solution (0.3M NH 4 Tf in EMIMTf) to the polymer PVdF-HFP. These ILGPE offer excellent ionic conductivity similar to 1.30 x 10(-2) S/cm at room temperature and used as separator membrane in the hybrid BatCap. DSC study confirms glass transitions and melting temperatures (T-g's and T-m's) of PVdF-HFP/EMIMTF/NH4Tf decrease with increasing content of liquid electrolyte to the host polymer matrix PVdF-HFP which, in turn, is responsible for increasing flexibility of membranes. Ionic transport number measurements (t(ion) similar to 0.99, t(H)+ similar to 0.27) reveal that ions are the principal charge carriers in the present electrolyte system. The linear sweep voltammetry analysis shows the electrochemical stability window (ESW) of ILGPE film "PVdF-HFP/EMIMTf/NH4Tf' is similar to 3.35 V. Two different hybrid BatCap cells are prepared with activated carbon and MWCNTs as a capacitive electrode (cathode) and ZnSO4 center dot 7H(2)O battery anode. The performance of the BatCaps is estimated using cyclic voltammetry and galvanostatic chargedischarge techniques. The discharge capacity was observed similar to 2.4 and 17.2 inAh/g for Cell#1 and Cell#2, respectively, at the current load of 0.5 mA/cm(2). After the initial fading (similar to 20%), BatCap cells show stable performance up to 100 cycles.