Silver migration at the Ag|Sm0.2Ce0.8O1.9 interface

Abstract

The behavior of a silver electrode contacting Ce0.8Sm 0.2O1.9 (samaria-doped ceria or SDC) electrolyte under external cathodic polarization in the temperature range 350-700°C was examined by means of long-term polarization experiments, scanning electron microscopy, and electrochemical impedance spectroscopy. A silver deposit is formed around the silver cathode via a surface migration mechanism without the occurrence of the gas-phase transport phenomenon during polarization. This results in an increase in both the electrode-electrolyte contact area and the triple-phase boundary length, which in turn causes decreases in charge transfer resistance and electrolyte resistance. © 2014 The Author(s).