Direct Probing of Nanodimensioned Oxide Multilayers with the Aid of Focused Ion Beam Milling

Kuru, Yener; Jalili, Helia; Cai, Zhuhua; Yildiz, Bilge; Tuller, Harry L.

doi:10.1002/adma.201102401

Cited by 13 publications

(14 citation statements)

References 35 publications

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“…Scanning probe techniques are ideal in revealing local electronic, magnetic or electrochemical properties on the surface 25–29. Nevertheless, challenges arise when attempting to apply them to interrogate interfaces of multilayers buried beneath the surface30 and under the harsh working conditions of SOFC cathodes (high temperatures and in oxygen environments). Previous successful attempts at exposing the local interface properties of oxides to scanning probe characterization26, 27 have not provided a generalized capability to expose buried interfaces in a controllable fashion and have been limited to room temperature measurements.…”

Section: Introductionmentioning

confidence: 99%

Electronic Activation of Cathode Superlattices at Elevated Temperatures – Source of Markedly Accelerated Oxygen Reduction Kinetics

Chen

Cai

Kuru

et al. 2013

Advanced Energy Materials

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102

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Solid‐oxide fuel cells are an attractive energy conversion technology for clean electric power production. To render them more affordable, discovery of new cathode materials with high reactivity to oxygen reduction reaction (ORR) at temperatures below 700 °C is needed. Recent studies have demonstrated that La0.8Sr0.2CoO3/(La0.5Sr0.5)2CoO4 (LSC113/214) hetero‐interfaces exhibit orders of magnitude faster ORR kinetics compared with either single phase at 500 °C. To obtain a microscopic level understanding and control of such unusual enhancement, we implemented a novel combination of in situ scanning tunneling spectroscopy and focused ion beam milling to probe the local electronic structure at nanometer resolution in model multilayer superlattices. At 200–300 °C, the LSC214 layers are electronically activated through an interfacial coupling with LSC113. Such electronic activation is expected to facilitate charge transfer to oxygen, and concurrent with the anisotropically fast oxygen incorporation on LSC214, quantitatively explains the vastly accelerated ORR kinetics near the LSC113/214 interface. Our results contribute to an improved understanding of oxide hetero‐interfaces at elevated temperatures and identify electronically coupled oxide structures as the basis of novel cathodes with exceptional performance.

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Section: Introductionmentioning

confidence: 99%

Electronic Activation of Cathode Superlattices at Elevated Temperatures – Source of Markedly Accelerated Oxygen Reduction Kinetics

Chen

Cai

Kuru

et al. 2013

Advanced Energy Materials

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102

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“…3. The buried LSC 113/214 interfaces in ML structure are exposed to the surface by grazing incidence FIB milling to facilitate STM/STS characterization (16), as shown in Fig. 2 (a) and (b).…”

Section: Resultsmentioning

confidence: 99%

“…Figure adapted from ref. (16) The PLD was performed using a KrF excimer laser with wavelength of 248 nm. The films were deposited at 700 o C under 10 mTorr oxygen pressure.…”

Section: Methodsmentioning

confidence: 99%

Electronic Activation at Oxide Hetero-Structure at Elevated Temperatures – Source of Markedly Accelerated Oxygen Reduction Kinetics

et al. 2013

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To understand ultra-fast oxygen reduction reaction kinetics near La 0.8 Sr 0.2 CoO 3 /(La 0.5 Sr 0.5) 2 CoO 4 (LSC 113/214) interface, a combination of in-situ scanning tunneling spectroscopy and focused ion beam milling was used to study the local electronic structure near LSC 113/214 interface at elevated temperature and in oxygen. The electronic activation of LSC 214 by the coupling with LSC 113 , concurrent with the fast oxygen incorporation on LSC 214 , was identified to be a key reason. These results put forward the electronically coupled oxide structures as novel cathodes. We generalize and further test this idea on a La 0.8 Sr 0.2 CoO 3 /La 2 NiO 4 system, which shows a similar electronic activation of La 2 NiO 4 at elevated temperatures.

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“…Lastly, PLD opens up a more convenient route for fabricating multilayer systems or single films with compositional variations. This can be easily realized by rapidly rastering the laser beam between different targets under computer controlled conditions [18,19].…”

Section: Materials Processingmentioning

confidence: 99%

“…A novel approach for exposing the interface in multilayer structures was recently developed, using shallow angle focused ion beam (FIB) milling which expands the interface region from the nanometer to the micrometer scale, facilitating the characterization of interfaces by scanning tunneling microscopy/spectroscopy (STM/S). Figure 4 schematically shows how a combination of FIB milling and STM can be used to study the electronic structure near interfaces, first demonstrated at room temperature with a superlattice of (La, Sr)MnO 3 (LSM) and STF [19]. This method has been further extended recently to high temperatures and an oxygen gas environment by combining FIB and in situ STM/S [27], thereby demonstrating for the first time the ability to probe the electronic structure across heterointerfaces with nanoscale resolution at high temperature and in an oxygen/gas environment.…”

Section: Chemical Structural and Morphologicalmentioning

confidence: 99%

Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

et al. 2014

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Functional materials for energy conversion and storage exhibit strong coupling between electrochemistry and mechanics. For example, ceramics developed as electrodes for both solid oxide fuel cells and batteries exhibit cyclic volumetric expansion upon reversible ion transport. Such chemomechanical coupling is typically far from thermodynamic equilibrium, and thus is challenging to quantify experimentally and computationally. In situ measurements and atomistic simulations are under rapid development to explore how this coupling can be used to potentially improve both device performance and durability. Here, we review the commonalities of coupling between electrochemical and mechanical states in fuel cell and battery materials, illustrating with specific cases the progress in materials processing, in situ characterization, and computational modeling and simulation. We also highlight outstanding questions and opportunities in these applications -both to better understand the limiting mechanisms within the materials and to significantly advance the durability and predictability of device performance required for renewable energy conversion and storage.

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Direct Probing of Nanodimensioned Oxide Multilayers with the Aid of Focused Ion Beam Milling

Cited by 13 publications

References 35 publications

Electronic Activation of Cathode Superlattices at Elevated Temperatures – Source of Markedly Accelerated Oxygen Reduction Kinetics

Electronic Activation of Cathode Superlattices at Elevated Temperatures – Source of Markedly Accelerated Oxygen Reduction Kinetics

Electronic Activation at Oxide Hetero-Structure at Elevated Temperatures – Source of Markedly Accelerated Oxygen Reduction Kinetics

Chemomechanics of ionically conductive ceramics for electrical energy conversion and storage

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