The use of low-energy SIMS (LE-SIMS) for nanoscale fuel cell material development

Low-energy secondary ion mass spectrometry has been used to investigate the matrix structure and interface attributes of a novel Ce_0.85Sm _0.15O₂/CeO₂ multilayer fuel cell material. Nanoscale oxide systems have shown enhanced ionic conductivities when produced to form highly oriented epitaxial structures. The Sm-doped CeO₂ material system is of particular interest for fuel cell technology because of its inherently high ionic conductivity at low operating temperatures (600-800 °C). For this study, a nanometer-scale Ce_0.85Sm _0.15O₂/CeO₂ multilayer was grown by pulsed laser deposition. The sample was annealed at 700 °C in an oxygen ambience. High-resolution, low-energy depth profiling using Cs revealed some diffusion of the multilayer structure after annealing, along with a possible volume change for the Sm-doped layers. Changes in layer volume will lead to an increase in the mechanical strain and may cause the material to crack. The findings presented here suggest that the Ce_0.85Sm_0.15O₂/CeO ₂ multilayer structure in its current form may not possess the level of thermal stability required for use within a fuel cell environment.