Electrochemical Characteristics of Carbide-Derived Carbon|1-Ethyl-3-methylimidazolium Tetrafluoroborate Supercapacitor Cells

Supercapacitor (SC) cells based on microporous titanium carbide-derived carbon [C(TiC)] electrodes in room temperature ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate) have been tested by cyclic voltammetry, constant current charge/discharge, and electrochemical impedance methods at temperatures from 25 to 80 degrees C. The limits of ideal polarizability, low frequency limiting capacitance and series resistance, time constant, complex power components, time stability, and other characteristics have been calculated and discussed. The influence of temperature on the cell capacitance, characteristic time constant values, and region of ideal polarizability has been analyzed. The comparatively high energy (40 Wh kg(-1)) and power (130 kW kg(-1)) densities per active C(TiC) weight have been calculated, weakly depending on temperature, if T < 59 degrees C. A comparison of the results to the corresponding data for the C(TiC)vertical bar 1 M(C2H5)(3)CH3NBF4+acetonitrile system indicates that 1-ethyl-3-methylimidazolium tetrafluoroborate vertical bar carbide-derived carbon SC cells demonstrate lower power densities, a narrower region of ideal polarizability, and a lower constant current cyclability at higher charge/discharge rates.