SHORT-PULSE TECHNIQUES. PART 2. PERTURBATION TIMES IN ALKALI-HALIDE SYSTEMS.
NAVAL RESEARCH LAB WASHINGTON D C
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A new technique involving the perturbation of a system from equilibrium using very short galvanostatic pulses and miniature cells was applied to study of the electrical bouble layer at Pt electrodes. The perturbation time, the time required for the double layer to begin charging, was determined for hydrogen- and alkali metal-halide systems and for reversible hydrogen systems in several acids and NaOH. The perturbation time was essentially independent of charging-current density and of the anion in solution but was strongly dependent on the cation species and electrolyte concentration. Models to explain the absence of electrode polarization during the initial flow of charge into the double layer are discussed. A model which involves a very fast Faradaic process and which is consistent with the experimental observations is proposed. It is suggested that the perturbation time, which is less than 100 nanosec for 1 M solutions, represents the time required for movement of ions into or out of the compact double layer. Author
- Physical Chemistry