Simulation of ordering in large defect clusters in gadolinium-doped ceria

Ye, Fei; Mori, Toshiyuki; Ou, Ding Rong; Cormack, Alastair N.; Lewis, Raymond J.; Drennan, John

doi:10.1016/j.ssi.2008.06.025

Cited by 46 publications

(58 citation statements)

References 20 publications

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“…Therefore, we designated the defect structures discussed in this study as the dumbbell model, in contrast to the chain model as previously reported. 25 Since oxygen vacancy ordering is generally accompanied with dopant cations ordering, 38 the enhanced ordering of all oxygen vacancies will also increase the ordering level of associated cations, difficult to be directly verified by the experimental techniques though. Therefore, the ordered structure of the dopant cations should not be neglected.…”

Section: Discussionmentioning

confidence: 99%

“…In order to compare with the chain model of ordered defect clusters, the curved chain structure with the highest binding energy among all possible structures investigated in previous report are also displayed. 25 Figure 3(c) is the most stable atomic structure of 2V O¨4 Gd Ce in chain model, where V O¨− V O¨i s separated by 111 /2 and Gd 3+ are situated at the second neighbor sites. These three atomic structures shown in Fig.…”

Section: Fig 2 (A)mentioning

confidence: 99%

“…23,24 It was suggested that the oxygen vacancies tended to form curved chains in the defect clusters and related dopant cations preferred to locate at the second nearest neighbor with respect to the corresponding oxygen vacancies. 25 Although this chain structure model illustrated the ordered structure of defect clusters, detailed evolutional pathway of defect clusters and related structure formation of nano-domain still remains unclear. Additionally, interesting questions also come out based on the chain model put forward.…”

Section: Introductionmentioning

confidence: 96%

“…Large defect clusters in GDC containing up to six oxygen vacancies and twelve associated dopant cations were investigated by atomistic simulation calculations. These results were then compared with the chain model as previously reported 25 and a more stable unique structure was established. Finally, ordered defect cluster structure was determined and the nano-domain formation was rationalized in terms of this unique structure.…”

Section: Introductionmentioning

confidence: 99%

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Ordered structures of defect clusters in gadolinium-doped ceria

Mori

et al. 2011

The Journal of Chemical Physics

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The nano-domain, with short-range ordered structure, has been widely observed in rare-earth-doped ceria. Atomistic simulation has been employed to investigate the ordering structure of the nano-domain, as a result of aggregation and segregation of dopant cations and the associated oxygen vacancies in gadolinium-doped ceria. It is found that the binding energy of defect cluster increases as a function of cluster size, which provides the intrinsic driving force for the defect cluster growth. However, the ordered structures of the defect clusters are different from the chain model as previously reported. Adjacent oxygen vacancies prefer to locate along 〈110〉/2 lattice vector, which results in a unique stable structure (isosceles triangle) formation. Such isosceles triangle structure can act as the smallest unit of cluster growth to form a symmetric dumbbell structure. This unique dumbbell structure is hence considered as a building block for the development of larger defect clusters, leading to nano-domain formation in rare-earth-doped ceria.

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Section: Discussionmentioning

confidence: 99%

Section: Fig 2 (A)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

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Ordered structures of defect clusters in gadolinium-doped ceria

Mori

et al. 2011

The Journal of Chemical Physics

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“…[18][19][20] The conductivity showed the maximum at the composition around x=0.15 in Y x Ce 1-x O 2-x/2 (x=0.1, 0.15, 0.2 and 0.25) system. Also, the activation energy of Y doped CeO 2 electrolytes was minimized at the same composition (i.e.…”

Section: Microanalysis Of Doped Ceo 2 Electrolytesmentioning

confidence: 99%

Nano-structure design of doped ceria solid electrolytes for intermediate temperature operation of solid oxide fuel cell

Mori

et al. 2010

Trans. Mat. Res. Soc. Japan

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Doped ceria (CeO 2 ) compounds are fluorite related oxides which show oxide ionic conductivity higher than yttria-stabilized zirconia in oxidizing atmosphere. As a consequence of this, considerable interest has been shown in application of these materials for intermediate temperature (300-500C) operation of solid oxide fuel cells (SOFCs). In this review paper, our experimental data was re-introduced to propose a new design paradigm for development of high quality doped CeO 2 electrolytes. Based on our experimental data, our original idea a control of nano-inhomogeity of doped CeO 2 electrolytes was proposed. In our work, the nano-sized powders and dense sintered bodies of M doped CeO 2 (M: Sm, Gd, Y, Yb, Dy, Ho, Tb and La) specimens were fabricated using ammonium carbonate co-precipitation method, conventional sintering method and pulsed electric current sintering method. Also nano-structural features of those specimens were carefully observed for conclusion of relationship between electrolytic properties and microstructure in doped CeO 2 . It is essential that the electrolytic properties of doped CeO 2 reflect in changes of microstructure even down to the atomic scale. Accordingly, a combined approach of ultimate analysis, simulation and processing route design is required to develop the superior quality doped CeO 2 electrolytes for the intermediate temperature operation of SOFCs.

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Scalable Oxygen‐Ion Transport Kinetics in Metal‐Oxide Films: Impact of Thermally Induced Lattice Compaction in Acceptor Doped Ceria Films

Rupp

Fabbri

Marrocchelli

et al. 2014

Adv Funct Materials

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In this paper, we focus on the effect of processing‐dependent lattice strain on oxygen ion conductivity in ceria based solid electrolyte thin films. This is of importance for technological applications, such as micro‐SOFCs, microbatteries, and resistive RAM memories. The oxygen ion conductivity can be significantly modified by control of lattice strain, to an extent comparable to the effect of doping bulk ceria with cations of different diameters. The interplay of dopant radii, lattice strain, microstrain, anion‐cation near order and oxygen ion transport is analyzed experimentally and interpreted with computational results. Key findings include that films annealed at 600 °C exhibit lattice parameters close to those of their bulk counterparts. With increasing anneal temperature, however, the films exhibited substantial compaction with lattice parameters decreasing by as much as nearly 2% (viz, Δd600–1100 °C: –1.7% (Sc+3) > –1.5% (Gd+3) > –1.2% (La+3)) for the annealing temperature range of 600–1100 °C. Remarkably 2/3rd of the lattice parameter change obtained in bulk ceria upon changing the acceptor diameter from the smaller Sc to larger La, can be reproduced by post annealing a film with fixed dopant diameter. While the impact of lattice compaction on defect association/ordering cannot be entirely excluded, DFT computation revealed that the main effect appears to result in an increase in migration energy and consequent drop in ionic conductivity. As a consequence, it is clear that annealing procedures should be held to a minimum to maintain the optimum level of oxygen ion conductivity for energy‐related applications. Results reveal also the importance to understand the role of electro‐chemo‐mechanical coupling that is active in thin film materials.

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Simulation of ordering in large defect clusters in gadolinium-doped ceria

Cited by 46 publications

References 20 publications

Ordered structures of defect clusters in gadolinium-doped ceria

Ordered structures of defect clusters in gadolinium-doped ceria

Nano-structure design of doped ceria solid electrolytes for intermediate temperature operation of solid oxide fuel cell

Scalable Oxygen‐Ion Transport Kinetics in Metal‐Oxide Films: Impact of Thermally Induced Lattice Compaction in Acceptor Doped Ceria Films

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