Determination of Oxygen Pathway in Silver Cathodes by Secondary-Ion Mass Spectroscopy Using Oxygen Isotope Exchange

Abstract

Oxygen isotope exchange and time-of-flight secondary-ion mass spectroscopy were used to visualize the oxygen pathway in a silver cathode for solid-oxide fuel cells. 18O was electrochemically transferred into the electrolyte through the silver cathode and immobilized by quenching. The three-dimensional distributions of 16O, 18O, 107Ag, 109Ag, and GaO were analyzed by secondary-ion mass spectroscopy. The oxygen pathway was determined as follows: oxygen atoms were placed uniformly on the silver cathode surface, diffused along the silver grain boundaries from the surface to the Ag/electrolyte interface, spread through the entire interface, were ionized, and transferred into the electrolyte. © 2011 The Electrochemical Society.