Supercapacitors degradation characterization using impedance spectroscopy

A comprehensive study of supercapacitors degradation via solely AC measurements was demonstrated. Commercial supercapacitors were examined during accelerated degradation. The microstructure of the electrode-electrolyte... [ view full abstract ]

A comprehensive study of supercapacitors degradation via solely AC measurements was demonstrated. Commercial supercapacitors were examined during accelerated degradation. The microstructure of the electrode-electrolyte interface changes upon degradation; electrolyte parasitic reactions yield the formation of precipitates on the porous surface, which limit the access of the electrolyte ions to the active area and thus reduces performance. EIS analysis using Impedance Spectroscopy Genetic Programming (ISGP) technique enables identifying how the changing microstructure is affecting the operation mechanism of supercapacitors. The most affected process is the transport of electrolyte ions at the porous electrode. Their access to the whole active area is hindered, which is shown in our analysis by the decrease of the capacitance gained in the transport and the longer time it takes to penetrate the entire pores depth. Early failure detection is also demonstrated, in a way not readily possible via conventional indicators. [1]

[1] Journal of Power Sources 355 (2017) 74-82