Surface Topography and Electrical Response of Metal-Electrolyte Interface

摘要

The small-signal impedance of chemical cells with ''blocking'' electrodes is dominated at low frequencies (f < approx.100 Hz) by the impedance of the metal-electrolyte interfaces which is accurately represented by Z/sub i/ = A(j omega )/sup -n/. The frequency exponent n(n < 1) is sensitive to the texture of the interface, and several recent theories have been proposed that relate n to the fractal dimension d-bar of the rough interface. However, we have found no correlation between n and d-bar from experiments using aqueous electrolytes and metal and semiconductor electrodes. A new model for the transient response of a rough electrode-electrolyte interface to a constant voltage pulse is proposed. Computer simulations, similar to the diffusion limited aggregation model, using measured profiles as a fixed (non-growing) clusters, gave exponents n in good agreement with experiments. (ERA citation 12:045941)