Chemical Analysis of Casual Elements for Deterioration of Cylindrical EDLC

Abstract

SUMMARY Chemical analysis was carried out before and after the constant voltage hold test that was an acceleration deterioration examination to clarify deterioration factors of electric double‐layer capacitor (EDLC). The results showed that the stress test slightly caused the increase of internal resistance. It was also confirmed that the range of fluorochemicals was formed on the electrode surface for approximately 10 nm in depth using electron spectroscopy for chemical analysis (ESCA). From the chemical analysis of the electrolyte using an inductively coupling plasma emission analyzer (ICP‐OES), it was confirmed that the electrolyte included silicon which is one of the ingredient elements of an electrode and that the increase in holding voltage in the stress test decreased the silicon density in the electrolyte.

Deterioration Factors of Electric Double-Layer Capacitors Obtained from Voltage Hold Test

“…It was also reported that aging model was calculated and aging diagnosis was built up using manufactured EDLCs under overvoltage and high-temperature condition [9][10][11][12][13][14][15][16][17][18][19][20]. For this chapter, we performed a voltage hold test, which is a type of accelerated degradation test for EDLCs using the application of overvoltage, on cylindrical EDLCs, which are used in actual applications [21]. We confirmed the degradation behaviors caused by the application of overvoltage by measuring the capacitance and internal resistance before and after the tests.…”