Electrochemical Characteristics of Zn-Ion Hybrid Supercapacitors Based on Aqueous Solution of Different Electrolytes

Electrochemical behaviour of Zn cation based various aqueous electrolytes (ZnSO4, Zn(BF4)(2), zinc di[bis(trifluoromethylsulfonyl)imide], Zn(TFSI)(2), and zinc trifluoromethanesulfonate, Zn(OTf)(2)) has been studied in thin Zn foil divide carbon cloth hybrid supercapacitor cell and compared with Zn(ClO4)(2) aqueous electrolyte electrochemical characteristics using cyclic voltammetry, constant current charge/discharge and electrochemical impedance methods. The Ragone plots have been calculated from constant power measurements data. At moderate specific power values (10 kW kg(-1)) noticeable decrease of specific energies can be seen in the order of electrolytes: Zn(ClO4)(2) >= Zn(BF4)(2) > Zn(OTf)(2) > Zn(TFSI)(2) > ZnSO4. The stability of Zn-ion hybrid supercapacitor cells under study has been tested using the long lasting (up to 10000 cycles) constant current charge/discharge method and is very good for Zn(OTf)(2), Zn(ClO4)(2) and ZnSO4.