Ionic conductivity and activation energy for oxygen ion transport in superlattices—the semicoherent multilayer system YSZ (ZrO2 + 9.5 mol% Y2O3)/Y2O3

Abstract

The oxygen ion conductivity of YSZ (ZrO(2) + 9.5 mol% Y(2)O(3))/Y(2)O(3) multilayer systems is measured parallel to the interfaces as a function of temperature between 350 and 700 degrees C. The multilayer samples are prepared by pulsed laser deposition (PLD). The film thicknesses, the crystallinity, the texture and the microstructure are investigated by SEM, XRD, HRTEM and SAED. To separate the interface contribution of the total conductivity from the bulk contribution the thickness of the YSZ and Y(2)O(3) layers is varied systematically. The total conductivity of the YSZ films increases when their thickness is decreased from 0.53 microm to 24 nm. It depends linearly on the reciprocal thickness of the individual layers, thus on the number of YSZ/Y(2)O(3) interfaces. This behaviour results from the parallel connection between individual conduction paths in the bulk and the interfacial regions. The activation energy for the ionic conductivity decreases from 1.13 to 0.99 kJ mol(-1) by decreasing the thicknesses of the individual YSZ layers. HRTEM studies show that the YSZ/Y(2)O(3) interfaces are semicoherent. The correlation between interface structure and ionic conduction is discussed.

Tensile Lattice Distortion Does Not Affect Oxygen Transport in Yttria-Stabilized Zirconia–CeO2 Heterointerfaces

“…7,10,[12][13][14][15][16] Polycrystalline 9.5YSZ-Y 2 O 3 multilayered films {(0001) Al 2 O 3 |Y 2 O 3 | (9.5YSZ|Y 2 O 3 ) x n} grown on sapphire substrates with (quasi-)coherent hetero-interfaces along each columnar grain showed that the conductivity slightly increased and the activation energy slightly decreased with increasing the number of interfaces 10 . According to the authors, the grain boundary conduction pathway played a negligible role in the charge transport.…”

Edge dislocation slows down oxide ion diffusion in doped CeO2 by segregation of charged defects

“…This high density of dislocations makes the study of their effect on the properties of the material of paramount importance. The elastic strain effects in oxides have been extensively studied for transport [9][10][11] , (electro)catalytic activity [12][13][14] and multiferroic properties 15,16 . On the other hand, only a few recent studies directly assessed the potential role of dislocations on the electrical 17,18 , magnetic 19 and chemical 20,21 properties of oxides, probably because of the intrinsic difficulty in studying these extended defects one at a time with high spatial resolution.…”

“…Elastic strain is considered as a new knob to enhance the performance of oxide electrochemical devices, including solid oxide fuel cells (SOFCs) [9][10][11] , photocatalysts 22 , batteries 23 , electrolysers 24 and redox-based resistive memories 25 , by accelerating ion conduction. However, in most of these studies, the influence of strain was interpreted in terms of elastic strain alone, while plastic strain, that is, strain accommodated by dislocations, has been overlooked.…”

First-principles study of compensation mechanisms in negatively charged LaGaO3/MgAl2O4interfaces

“…11, 12 Korte et al found ionic conductivity to increase linearly with increasing density of phase boundaries in YSZ/Y 2 O 3 heterostructures, and the activation energy was found to decrease for strained YSZ layers. 13 There has been much debate on enhanced ionic conductivity along YSZ/SrTiO 3 heterointerfaces. Garcia-Barriocanal et al…”