Investigation of Charge Transport Across the Ag|AgI-interface: (I) Occurrence of Periodic Phenomena During Anodic Dissolution of Silver

摘要

By drawing a constant electric current through a symmetric electrochemical cell of the type Ag|α-AgI|Ag we observed, under certain experimental conditions, strong periodic oscillations of the voltage across the cell. Depending on current density and applied mechanical force, these oscillations show either periodic or irregular behaviour. Further experiments show that these strong voltage oscillations are caused by the anodic interface at which Ag-metal is dissolved electrochemically into the solid electrolyte. The phenomenon itself is reproducible, but the appearance of the oscillations is very sensitive to the experimental conditions. We present experimental results for different experimental conditions and cell types and discuss a possible mechanism for the observed phenomenon. An important element of the attempt to find a microscopic explanation is the basic process of forming lattice vacancies in the metal at the anodic interface. The behaviour of these vacancies is crucial for the kinetic properties of the metal-solid electrolyte interface under non-equilibrium conditions.