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Título:
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Paving the way to nanoionics: atomic origin of barriers for ionic transport through interfaces
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Autores:
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Frechero, M. A. ;
Rocci, Mirko ;
Sánchez Santolino, Gabriel ;
Salafranca, Juan ;
Schmidt, Rainer ;
Díaz Guillén, M. R. ;
Durá, O. J. ;
Rivera Calzada, Alberto Carlos ;
Varela del Arco, María ;
Santamaría Sánchez-Barriga, Jacobo ;
León Yebra, Carlos
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Tipo de documento:
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texto impreso
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Editorial:
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Nature Publishing Group, 2015-12-17
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Dimensiones:
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application/pdf
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Nota general:
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cc_by
info:eu-repo/semantics/openAccess
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Idiomas:
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Palabras clave:
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Estado = Publicado
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Materia = Ciencias: Física: Electricidad
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Materia = Ciencias: Física: Electrónica
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Tipo = Artículo
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Resumen:
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The blocking of ion transport at interfaces strongly limits the performance of electrochemical nanodevices for energy applications. The barrier is believed to arise from space-charge regions generated by mobile ions by analogy to semiconductor junctions. Here we show that something different is at play by studying ion transport in a bicrystal of yttria (9% mol) stabilized zirconia (YSZ), an emblematic oxide ion conductor. Aberration-corrected scanning transmission electron microscopy (STEM) provides structure and composition at atomic resolution, with the sensitivity to directly reveal the oxygen ion profile. We find that Y segregates to the grain boundary at Zr sites, together with a depletion of oxygen that is confined to a small length scale of around 0.5nm. Contrary to the main thesis of the space-charge model, there exists no evidence of a long-range O vacancy depletion layer. Combining ion transport measurements across a single grain boundary by nanoscale electrochemical strain microscopy (ESM), broadband dielectric spectroscopy measurements, and density functional calculations, we show that grain-boundary-induced electronic states act as acceptors, resulting in a negatively charged core. Besides the possible effect of the modified chemical bonding, this negative charge gives rise to an additional barrier for ion transport at the grain boundary.
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En línea:
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https://eprints.ucm.es/35279/1/LeonC145%20libre%20%2B%20CC.pdf
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