• Tran, Mai T. T.
• Vivier, Vincent
• Tribollet, Bernard
• Gharbi, Oumaïma
• Turmine, Mireille

Abstract

Cyclic voltammetry is a routine electrochemical technique used for the determination of electric properties of super capacitors or energy storage devices. Typically, the capacitive charge is determined through the variation of sweep rate in a relatively constant (non-faradaic) current domain and is often used to estimate the performances of these electrodes (Fig. 1a). In fact, for ideal capacitors, the capacitive current is expected to follow a linear relationship with the sweep rate, giving a characteristic rectangle voltammogram shape.Conversely, electrochemical impedance spectroscopy (EIS) is an electrochemical technique used for the determination of interfacial processes. For metal-oxide-electrolyte interfaces, EIS can provide information on the capacitive behavior of the system as sketched in Fig. 1b, in the case of an ideal capacitor. For instance, at high frequency domains, the contribution of the oxide layer capacity can be determined whereas, in low frequency domains, the contribution of the electric double layer can be extracted.Although both techniques are used to provide similar information on the capacitive characteristics of solid-electrolyte interfaces, a clear correlation between the results obtained with each technique has not yet been clearly established. In particular, when a non-ideal behaviour described by a constant phase element (CPE) is invoked, the relationship between the capacitances obtained from the two techniques is not straightforward

Topics

• phase
• electrochemical-induced impedance spectroscopy
• interfacial
• cyclic voltammetry
• cloud-point extraction