Comparison and Modeling of Commercial Supercapacitors via Standardized Potentiostatic Electrochemical Impedance Spectroscopy

The main scope of the study is the characterization of the capacitive and resistive behavior of two supercapacitor cells and one hybrid supercapacitor available on the market, through potentiostatic electrochemical impedance spectroscopy (PEIS). The PEIS tests were performed by applying to all cells the same voltage perturbation in the same frequency range. In a first phase, the instrumentation used for the acquisitions was optimized, with particular care to the connections between the potentiostat and the supercapacitor cell. The Nyquist diagrams obtained for each sample are compared and capacitance/frequency graphs are deduced. The technological differences between various devices are then discussed in relation to the results. The characterization of the sample cells and the collected data are used to propose the corresponding models conceived for circuit simulation. These models are based on simple electronic components available in the standard circuit simulation software tools.