Nondisruptive In Situ Raman Analysis for Gas Evolution in Commercial Supercapacitor Cells

Abstract This paper proposes novel nondisruptive in situ Raman spectroscopy analysis for gas evolution in commercial supercapacitor cells. To accelerate gas evolution, abusive aging tests were conducted during 21 days using commercial supercapacitor cells with a Raman setup. Changes in partial pressure were recorded using the Raman setup after the aging tests under various electrochemical analysis, such as cyclic voltammetry (CV), galvanostatic charge/discharge analysis, and impedance spectroscopy. The performance of the bare supercapacitor cell was evaluated and compared with that of the Raman cell. Difference of capacitance derived from CV was less than 1% until end of life of the cells. Moreover, resistance results obtained from galvanostatic charge/discharge differed below 8%. This analysis confirmed that the Raman cell was nondisruptive with a minute effect on the supercapacitor cell itself, indicating high reliability of in situ gas analysis of practical cells.