A complete system for electrochemical impedance spectroscopy which combines FFT methods and staircase voltammetry

A flexible system has been constructed that allows impedance data to be rapidly measured over a range of frequencies (250 Hz¯200 kHz) at each static potential applied to a working electrode during a staircase voltammetric scan. The data collected can be analysed in terms of a series of frequency-dependent ac voltammograms or a series of potential-dependent impedance diagrams. Preliminary tests of the instrument are reported. Ac voltammograms recorded with this instrument and with commercial equipment for a model reversible electrochemical reaction showed good agreement with each other and with theory.