title: Electrochemical impedance spectroscopy investigations of a microelectrode behavior in a thin-layer cell: Experimental and theoretical studies.
abstract: Electrochemical impedance spectroscopy experiments were performed on a microdisk electrode in a thin-layer cell using a scanning electrochemical microscope for controlling the cell geometry. Experimental data showed that when the thin-layer thickness diminished, an additional low-frequency response appeared. It was ascribed to the radial diffusion of the electroactive species and was strongly dependent on the thin-layer dimensions (both thickness and diameter). Moreover, the numerical simulation of the impedance diagrams by finite element method calculations confirmed this behavior. An equivalent circuit based on a Randles-type circuit was proposed. Thus, the diffusion was described by introducing two electrical elements: one for the spherical diffusion and the other for the radial contribution. A nonlinear Simplex algorithm was used, and this circuit was shown to fit the impedance diagrams with a good accuracy.
authors.affiliation: UPR 15 du CNRS, Laboratoire Interfaces et Systèmes Electrochimiques, Université Pierre et Marie Curie, 4, place Jussieu, case courrier 133, 75252 Paris, Cedex 05, France.
authors.forename: C
authors.initials: C
authors.lastname: Gabrielli
authors.forename: M
authors.initials: M
authors.lastname: Keddam
authors.forename: N
authors.initials: N
authors.lastname: Portail
authors.forename: P
authors.initials: P
authors.lastname: Rousseau
authors.forename: H
authors.initials: H
authors.lastname: Takenouti
authors.forename: V
authors.initials: V
authors.lastname: Vivier