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To develop high performance solid ionic conductors, various kinds of compounds and solid solutions have been prepared and the relations between their crystal structures and conductivities have been studied. Here, the prospect and development of the solid ionic conductors were mentioned especially focusing on the 38 year’s results by the present author’s laboratory together with the innovative experimental methods.

The coupling between ionic degrees of freedom and ferroelectricity has received renewed attention in recent years, given that surface electrochemical processes have been shown to be intrinsically linked to ferroelectric phase stability in ultrathin ferroelectric films. However, the coupling between bulk ionic transport and local polarization switching has received less attention, as typically the bulk ionic mobilities are low for common ferroelectrics at room temperature. Here, we use the coupled band-excitation method in conjunction with site-correlated time-of-flight secondary ion mass spectrometry, to determine the coupling between ferroelectric switching and ionic motion in single crystal KTiOPO4. The local scanning probe measurements indicate a substantial softening, as determined by resonant frequency changes, during reversal of polarization along one direction. These changes are correlated with the mass spectrometry measurements, showing a polarization-dependent accumulation of K ions at the polar surfaces, thus corroborating their role in the screening process. These studies shed light on the interplay between ionic dynamics and bulk ferroelectric switching and have implications for studies on domain wall conductivity, chemical switching, and bulk and surface-screening phenomena., Export Date: 22 October 2018; Article; Correspondence Address: Vasudevan, R.K.; Center for Nanophase Materials Sciences, Oak Ridge National LaboratoryUnited States; email: vasudevanrk@ornl.gov; Funding details: DOE, U.S. Department of Energy; Funding details: VR, Vetenskapsrådet; Funding details: SSF, Stiftelsen för Strategisk Forskning; Funding details: SC, Office of Science; Funding details: DE-AC05-00OR22725; Funding details: DMSE, Division of Materials Sciences and Engineering; Funding details: CNMS2017-066; Funding text: A portion of this work was sponsored by the U.S. Department of Energy (DOE), Office of Science, Materials Sciences and Engineering Division (R.K.V. and S.V.K.). Research was conducted at the Center for Nanophase Materials Sciences (A.I., S.J., O.S.O.), which is a DOE Office of Science User Facility, and using instrumentation within ORNL’s Materials Characterization Core provided by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. G.L. and C.C. acknowledge support and access to the Center for Nanophase Materials Sciences through the proposal CNMS2017-066. G.L. and C.C. also acknowledge support from the Swedish Foundation for Strategic Research and the Swedish Research Council (VR) through its Linné Center for Advanced Optics and Photonics (ADOPT). QC 20181112

Solid inorganic and polymeric electrolytes have the potential to enable rechargeable batteries with higher energy densities, compared to current lithium-ion technology, which uses liquid electrolyte. Inorganic materials such as ceramics and glasses conduct lithium ions well, but they are brittle, which makes incorporation into a battery difficult. Polymers have the flexibility for facile use in a battery, but their transport properties tend to be inferior to inorganics. Thus, there is growing interest in composite electrolytes with inorganic and organic phases in intimate contact. This article begins with a discussion of ion transport in single-phase electrolytes. A dimensionless number (the Newman number) is presented for quantifying the efficacy of electrolytes. An effective medium framework for predicting transport properties of composite electrolytes containing only one conducting phase is then presented. The opportunities and challenges presented by composite electrolytes containing two conducting phases are addressed. Finally, the importance and status of reaction kinetics at the interfaces between solid electrolytes and electrodes are covered, using a lithium-metal electrode as an example.

[EN] Increased availability of methane from shale gas and stranded gas deposits in the recent years may facilitate the production of ethylene by means of potentially more competitive routes than the state-of-the-art steam cracking processes. One appealing route is the oxidative coupling of methane (OCM), which is considered in this work for the production of ethylene by means of the use of catalytic membrane reactors (CMR) based on Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) ceramic material. In a first approach, a screening of 15 formulations as catalysts for the ethylene-ethane production was conducted on CMR consisting of disk-shaped planar BSCF membranes. At 900 degrees C, the maximum C-2 selectivity was 70%, reached with Ba0.5Sr0.5FeO3-delta and La0.5Ce0.1Sr0.4Co0.8Fe0.2O3-delta catalysts. On the other hand, low CH4 conversions (X-CH4) resulted in C-2 yields below 3%. Operation at 1,000 degrees C significantly shifted X-CH4 for all the activated membranes due to the decrease in CH4/O-2 ratios, thus obtaining C-2 yields close to 9% and productivities of ca. 1.2ml.min(-1).cm(-2) with Ce0.9Gd0.1O2-delta and Ba0.5Sr0.5Co0.8Fe0.2O3-delta impregnated with Mn-Na2WO4 catalysts. The performance of OCM reaction was also studied in a tubular catalytic membrane reactor. Tubular configuration improved C-2 yield by minimizing CH4/O-2 ratios up to 1.7, obtaining a maximum of 15.6% at 900 degrees C with a BSCF capillary membrane activated with a packed bed of 2 wt% Mn/5 wt% Na2WO4 on SiO2 catalyst.

[EN] Increased availability of methane from shale gas and stranded gas deposits in the recent years may facilitate the production of ethylene by means of potentially more competitive routes than the state-of-the-art steam cracking processes. One appealing route is the oxidative coupling of methane (OCM), which is considered in this work for the production of ethylene by means of the use of catalytic membrane reactors (CMR) based on Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) ceramic material. In a first approach, a screening of 15 formulations as catalysts for the ethylene-ethane production was conducted on CMR consisting of disk-shaped planar BSCF membranes. At 900 degrees C, the maximum C-2 selectivity was 70%, reached with Ba0.5Sr0.5FeO3-delta and La0.5Ce0.1Sr0.4Co0.8Fe0.2O3-delta catalysts. On the other hand, low CH4 conversions (X-CH4) resulted in C-2 yields below 3%. Operation at 1,000 degrees C significantly shifted X-CH4 for all the activated membranes due to the decrease in CH4/O-2 ratios, thus obtaining C-2 yields close to 9% and productivities of ca. 1.2ml.min(-1).cm(-2) with Ce0.9Gd0.1O2-delta and Ba0.5Sr0.5Co0.8Fe0.2O3-delta impregnated with Mn-Na2WO4 catalysts. The performance of OCM reaction was also studied in a tubular catalytic membrane reactor. Tubular configuration improved C-2 yield by minimizing CH4/O-2 ratios up to 1.7, obtaining a maximum of 15.6% at 900 degrees C with a BSCF capillary membrane activated with a packed bed of 2 wt% Mn/5 wt% Na2WO4 on SiO2 catalyst.

Solid inorganic and polymeric electrolytes have the potential to enable rechargeable batteries with higher energy densities, compared to current lithium-ion technology, which uses liquid electrolyte. Inorganic materials such as ceramics and glasses conduct lithium ions well, but they are brittle, which makes incorporation into a battery difficult. Polymers have the flexibility for facile use in a battery, but their transport properties tend to be inferior to inorganics. Thus, there is growing interest in composite electrolytes with inorganic and organic phases in intimate contact. This article begins with a discussion of ion transport in single-phase electrolytes. A dimensionless number (the Newman number) is presented for quantifying the efficacy of electrolytes. An effective medium framework for predicting transport properties of composite electrolytes containing only one conducting phase is then presented. The opportunities and challenges presented by composite electrolytes containing two conducting phases are addressed. Finally, the importance and status of reaction kinetics at the interfaces between solid electrolytes and electrodes are covered, using a lithium-metal electrode as an example.

The viability of water gas shift catalytic system for mobile application passes through obligatory reactor volume reduction, achieved normally by using less charge of more efficient catalyst. Completely new concept for catalyst design is proposed: a catalytic system including classically reported WGS catalysts of different nature or active phase (Cu, Pt or Au) mechanically mixed with an ionic conductor. The influence of the later on catalyst activity is studied and discussed, more precisely its effect on the rate of the reaction-limiting step and catalysts’ efficiency. It is demonstrated with this study, that the presence of an ionic conductor in contact with a WGS catalyst is essential for the water supply (dissociation and transport), thereby potentiating the water activation step, whatever the mechanism and catalyst overall performance.

In this study, the mixed electron-ion conductive nanocomposite of the industrial-grade rare-earth material (Le(3+), Pr3+ and Nd3+ triple-doped ceria oxide, noted as LCPN) and commercial p-type semiconductor Ni0.8Co0.15Al0.05Li-oxide (hereafter referred to as NCAL) were studied and evaluated as a functional semiconductor-ionic conductor layer for the advanced low temperature solid oxide fuel cells (LT-SOFCs) in an electrolyte layer-free fuel cells (EFFCs) configuration. The enhanced electrochemical performance of the EFFCs were analyzed based on the different semiconductor-ionic compositions with various weight ratios of LCPN and NCAL. The morphology and microstructure of the raw material, as prepared LCPN as well the commercial NCAL were investigated and characterized by Xray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectrometer (EDS), respectively. The EFFC performances and electrochemical properties using the LCPN-NCAL layer with different weight ratios were systematically investigated. The optimal composition for the EFFC performance with 70 wt% LCPN and 30 wt% NCAL displayed a maximum power density of 1187 mW cm(-2) at 550 degrees C with an open circuit voltage (OCV) of 1.07 V. It has been found that the well-balanced electron and ion conductive phases contributed to the good fuel cell performances. This work further promotes the development of the industrial-grade rare-earth materials applying for the LTSOFC technology. It also provides an approach to utilize the natural source into the energy field., QC 20171017

The single component fuel cell (SCFC) is a novel physical-electrochemical device for energy conversion which is recently discovered. The functional composite materials of Li0.15Ni0.25Cu0.3Zn0.3O2-delta (LNCZO) and Ce0.8Sm0.2O1.9 (SDC)-carbonate are proved as unique materials in SCFC (or one-layer fuel cell). In this work, the microstructure and morphology of two composite materials of LNCZO-SDC-Na2CO3 (LNCZO-NSDC) and LNCZO-SDC-(Li/ Na)(2)CO3 (LNCZO-LNSDC) are investigated by SEM-EDX and HR-TEM. Their catalytic activities for both hydrogen oxidation and oxygen reduction are studied by H-2-TPR and O-2-TPD, respectively. It is discovered for the first time that binary carbonates as ionic conductor mixing with semiconductor homogenously help to form unique semiconducting-ionic microstructure. The particle arrangement and interface conduction in the microstructure significantly influences on the SCFC performances due to different catalytic activity and polarization resistance. Even this, O-2 reduction reaction (ORR) for the single homogeneous layer still predominates in the redox reaction and binary carbonates are in favor of the oxygen conduction and desorption. These fin dings are essential to exactly understand the connections among structure, catalytic activities and performances underlying SCFC., QC 20150109

We report here a single-component reactor consisting of a mixed ionic and semi-conducting material exhibiting hydrogen-air (oxygen) fuel cell reactions. The new single-component device was compared to a conventional three-component (anode/electrolyte/cathode) fuel cell showing at least as good performance. A maximum power density of 300-600 mW cm(-2) was obtained with a LiNiZn-oxide and ceria-carbonate nanocomposite material mixture at 450-550 degrees C. Adding a redox catalyst element (Fe) resulted in an improvement reaching 700 mW cm(-2) at 550 degrees C., QC 20110720

[ES] En este trabajo se presentan los resultados preliminares sobre películas delgadas de YSZ obtenidas mediante la nueva técnica de MOCVD de inyección pulsada para su aplicación como electrolitos sólidos. La originalidad de esta técnica consiste en la preparación e introducción de la fase vapor que se realiza mediante la inyección pulsada de micro-gotas de la solución líquida, que contiene los precursores de los elementos a depositar, dentro de la zona de reacción. Las características de la gota: tamaño, concentración de la solución y frecuencia de inyección determinan el espesor y la micro-estructura de las capas obtenidas. Este método, además de muy reproducible, permite obtener fácilmente estructuras multicapas con bajos ritmos de crecimiento para epitaxias o con altos ritmos de crecimiento para la obtención de heteroestructuras. Se ha puesto a punto esta técnica para la obtención de capas densas de YSZ (circona estabilizada con itria), material comúnmente utilizado como electrolito sólido de alta temperatura en sondas de oxígeno, generadores de oxígeno y SOFC (pilas de combustible de estado sólido). Se pretende obtener dichos dispositivos en forma de multicapas del tipo ánodo/electrolito/cátodo. Para ello, se han depositado capas de YSZ sobre silicio para optimizar los parámetros de depósito pero también sobre sustratos porosos activos que puedan actuar como electrodo en los dispositivos anteriormente descritos., [EN] In this work, we describe the preparation of YSZ layers on porous and non-porous substrates using the Pulsed Injection MOCVD technique for solid electrolyte applications. In this technique, the vapour phase is obtained by injecting micro-droplets of the desired solution delivered from a container kept at room temperature into a heated evaporator connected to a deposition chamber. The droplet characteristics, volume, precursor concentration and injection frequency will control and determine the thickness and the microstructure of the layers. The system offers a high degree of repeatability of the liquid volume injected and thus a high reproducibility of the layers from low to high growth rates. This process has been optimised in order to obtain dense YSZ membranes to be used as solid electrolytes in SOFC, oxygen generators and oxygen sensors. Future work will consist in the preparation of anode-electrolyte-cathode multilayered devices. For this purpose, experimental parameters have been studied and optimised in order to obtain thin YSZ membranes on dense and porous substrates.

Li diffusion in nano- and microcrystalline (1-x)Li2O:xB2O3 composites was investigated with impedance and NMR spectroscopy in the temperature range from 140 K to 500 K. Impedance results for the nanocrystalline system differ drastically from those of the microcrystalline system and show an enhancement of the dc conductivity when adding the insulator B2O3 to the ionic conductor Li2O. 7Li NMR lineshape measurements confirm that this is due to an enhanced fraction of mobile ions in the interfacial regions between the conductor and the insulator. Activation energies obtained from the dc conductivity (0.95 eV) and the 7Li NMR relaxation rate T1-1 (0.29 eV) are independent of the composition of the composites. © 2001 Scitec Publications.

[ES] En este trabajo se discuten los resultados obtenidos en el estudio de fibras eutéticas de ZrO2(Y2O3)-Al2O3 crecidas por fusión zonal mediante láser. Las diferentes condiciones de crecimiento tienen un importante efecto en la microestructura. Se ha medido la conductividad eléctrica de las muestras y relacionado los valores obtenidos con la microestructura y composición de las fibras. Las mayores conductividades conseguidas son de 6.8x10-3 Scm-1 a 900ºC., [EN] The results obtained in the growth of eutectic ZrO2(Y2O3)-Al2O3 fibres by laser floating zone are discussed. The variation of the growth conditions have an important effect on the observed microstructures. Conductivity measurements were carried out at high temperature indicating that a relationship between these values and the microstructure and composition of the samples can be established. The highest conductivity obtained was 6.8x10(-3) Scm-1 at 900ºC.