Electrochemical and Spectroscopic Studies on Rated Capacitance and Aging Mechanisms of Supercapacitors
نویسندگان
چکیده
ac Impedance spectroscopy and transient techniques in different time domains were benchmarked for their benefit to determine rated capacitances of supercapacitors quickly and reliably, for example in industrial quality control. Scaling factors are presented to estimate rated dc capacitance by extrapolating 1 Hz ac capacitance: roughly 1.5 for acetonitrile systems, and 5 for propylencarbonate. A useful dimensionless number is introduced which allows to evaluate the quality of diverse production lots. Double-layer capacitors of different manufacturers were characterized in order to predict economic life-time and the statistical distribution of rated capacitance. Capacitance is shown as a dynamic quantity depending on voltage. Novel electrolyte systems based on ionic liquids are presented.
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