Current response, pseudo-capacitive

Electrochemical processes which pass through a surface intermediate species will exhibit a pseudo-capacitive current response (11) This form of behavior is observable in Figure 1(d). 

Indeed, at high bias (Figure 1(d)) the transient current response appears to be solely determined by this pseudo-capacitance, for the capacitance values determined from these scans ( vlO F) are two orders of magnitude larger than typical semiconductor space charge capacitances (12). 

In linear or pseudo-linear systems, the current response to a sinusoidal voltage input will be a sinusoid at the same frequency but shifted in phase (either forward or backward depending on the system s characteristics) that is determined by the ratio of capacitive and resistive components of the output current (Fig. 1). In a linear system, the response current signal I(t) is shifted in phase (i ) and has a different amplitude, 1a ... 

The geometry-induced current and potential distributions cause a frequency or time-constant dispersion that distorts the impedance response of a disk elec-trode. Huang et ai, 7,i02.,205 j ye shown that current and potential distributions induce a high-frequency pseudo-CPE behavior in the global impedance response of a disk electrode with a local ideally capacitive behavior, a blocking disk electrode exhibiting a local CPE behavior, and a disk electrode exhibiting Faradaic behavior. 

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