Applied Voltage Dependence of Carbon Radical in Electric Double Layer Capacitor Measured by in situ ESR Spectroscopy and AC Cyclic Voltammetry

Abstract

In this study, the behavior of carbon radicals has been observed in a model cell of an electric double layer capacitor (EDLC) by using an in situ electron spin resonance (ESR) method and ac cyclic voltammetry (CV). The maximum ESR signal intensity of the carbon radical was observed during the anodic sweep of the applied voltage using the simultaneous measurement of the ESR, the impedance and the CV. It was found that the degradation progress of the EDLC was mainly due to the change in the concentration of the carbon radical, and that its phenomenon was not observed by CV.