INVESTIGADORES
FRECHERO Marisa Alejandra
congresos y reuniones científicas
Título:
Understanding ion transport across grain boundaries.
Autor/es:
LEON,C.; MARISA A. FRECHERO; ROCCI, M.; SANCHEZ-SANTOLINO, G.; KUMAR, AMIT; SCHMIDT,R.; RIVERA-CALZADA, A.; SALAFRANCA, JUAN; JESSE, STEPHEN; VARELA, M.; PANTELIDES,S.; KALININ, SERGEI; PENNYCOOK, STEVE; SANTAMARIA, JACOBO
Lugar:
Barcelona
Reunión:
Encuentro; 7th. International Discussion Meeting on Relaxation in Complex Systems; 2013
Institución organizadora:
Universitat Politècnica de Catalunya
Resumen:
Understanding ion transport in ionically conducting materials is nowadays of primary importance in order to
optimize their use as electrolytes in solid state batteries and fuel cells. Since solid electrolytes are usually in
polycrystalline form, it is blocking of ions at grain boundaries that eventually limits ion transport through the
material. However, the microscopic origin of the barrier for ion transport across grain boundaries is not well
established yet. Here we present a study of structure, composition, and ion transport across a single grain boundary
in a bicrystal of the oxide ion conductor 9 mol % yttria stabilized zirconia (YSZ) by combining STEM-EELS
aberration corrected microscopy, nanoscale electrochemical strain microscopy (ESM), and broadband dielectric
spectroscopy measurements. We obtain relevant microscopic parameters that determine ion transport properties at
the nanoscale such as the built-in potential at the interfacial plane, the space charge layer thickness, and the Debye
screening length. The values obtained for these magnitudes are much lower than previous estimates from
measurements on ceramic samples that present a complex distribution of multiple grain boundaries. In fact, we find
a remarkable agreement with the predictions of simple theoretical space charge models, thus solving doubts cast
recently on their predictive value to describe ion transport across grain boundaries.