Strongly enhanced oxygen ion transport through samarium-doped CeO2 nanopillars in nanocomposite films

Abstract

Enhancement of oxygen ion conductivity in oxides is important for low-temperature (<500 °C) operation of solid oxide fuel cells, sensors and other ionotronic devices. While huge ion conductivity has been demonstrated in planar heterostructure films, there has been considerable debate over the origin of the conductivity enhancement, in part because of the difficulties of probing buried ion transport channels. Here we create a practical geometry for device miniaturization, consisting of highly crystalline micrometre-thick vertical nanocolumns of Sm-doped CeO2 embedded in supporting matrices of SrTiO3. The ionic conductivity is higher by one order of magnitude than plain Sm-doped CeO2 films. By using scanning probe microscopy, we show that the fast ion-conducting channels are not exclusively restricted to the interface but also are localized at the Sm-doped CeO2 nanopillars. This work offers a pathway to realize spatially localized fast ion transport in oxides of micrometre thickness.

Influence of Metal Fragment Mobility and Solution Dynamics on Cationic Rearrangements in Multimetallic Alkoxide Frameworks

“…The two methyl proton doublets were observed in a ratio of 4 : 10. The 27 Al NMR spectrum showed a single singlet at 68 ppm, which is in the characteristic range for tetrahedrally coordinated aluminium and is in good agreement with the chemical shifts of heterotrimetallic derivatives [{M 2 (OPr i ) 9 }Ba{Al(OPr i )4}] (M = Zr, Hf). [46] Conclusions Targeted construction of ligand-supported multimetallic clusters is challenged by the dynamic solution equilibria arising from the coordination preferences of the individual metals and fluxionality of both ligands and cations.…”

“…[10-13,17À21] Among functional metal oxides, cerium oxides are of potential importance both as monophasic material and particularly in conjunction with other metal oxides due to their reducible nature and oxygen capturing properties shown in solid-oxide fuel cells and high temperature sensor applications. [22][23][24][25][26][27][28][29][30] The seminal contributions by Bradley and Mehrotra on alkali metal nona-alkoxodizirconates (MZr 2 (OR) 9 ) demonstrated their highly covalent character by the volatility and solubility in non-polar organic solvents, which triggered the chemistry of heterometallic alkoxides. The versatile coordinating ability of {M 2 (OR) 9 } À groups in chelating different metal atoms to build heterometallic alkoxides is known for a large number of mixedmetal alkoxide assemblies.…”

Research Update: Fast and tunable nanoionics in vertically aligned nanostructured films

“…Very recently, as shown in Figure 1(d), new and novel device architectures, vertically aligned nanostructured (VAN) films, [43][44][45][46][47][48][49][50][51][52][53] were developed to overcome several issues in conventional ionic devices as mentioned above. Basically, the development of ionic devices by using VAN films started from a similar motivation of laterally aligned heteroepitaxy films.…”

“…In this section, we will introduce several interesting examples, such as memories using RS phenomena, 46 oxide fuel cells, 43,[47][48][49][50] and water splitting. 53 Further applications, as yet unexplored, would be entirely possible by tailoring the various properties of VAN films.…”

Progress on Piezoresponse Force Microscopy: From Single-frequency to Band-excitation and General-mode

“…I will also introduce general-mode (G-mode) PFM, which was recently developed by ORNL and will allow deeper investigations of the properties of materials on a nanoscale using the analyses of big data. [14,15] 고체 산화물 연료전지 [16,17] …”