Mixed Ionic-Electronic Conduction in Pyrochlore Oxides

1990 ◽  
Vol 210 ◽  
Author(s):  
M. Spears ◽  
S. Kramer ◽  
P.K. Moon ◽  
H.L. Tuller
Keyword(s):  
Electronic Transport ◽  
Ionic Conduction ◽  
Structural Disorder ◽  
Electronic Conduction ◽  
Transport Parameters ◽  
Oxygen Ion Conductivity ◽  
Chemical Models ◽  
Oxygen Ion ◽  
Electrochemical Devices ◽  
Low X

AbstractThe transport properties of the pyrochlore solid solution Gd2(ZrxTil-x)2O7 are investigated to clarify the relationships between composition, structural disorder and ionic and electronic transport. The oxygen ion conductivity has been found to increase sharply with increasing Zr content, x, due to enhanced structural disorder, leading to intrinsic ionic conduction at large values ofx. In contrast, the n—type conductivity predominant at low x, decreases sharply above x=0.2. Defect chemical models are presented to account for the simultaneous contributions of both intrinsic and dopant induced disorder. These models are applied to the σ(T, PO2, dopant) data to extract key thermodynamic and transport parameters. The significance of these parameters and the potential application of these materials in electrochemical devices are discussed.

Intrinsic Fast Oxygen Ionic Conductivity in the Gd2(ZrxTil−.)2O7, and Y2 (ZrxTil−x,)2O7, Pyrochlore Systems

1988 ◽  
Vol 135 ◽  
Author(s):  
P.K. Moon ◽  
H.L. Tuller
Keyword(s):  
Solid Solution ◽  
Ionic Conductivity ◽  
Oxygen Vacancy ◽  
Intrinsic Disorder ◽  
Structural Disorder ◽  
The Other ◽  
Oxygen Ion Conductivity ◽  
Oxygen Ion ◽  
O 24 ◽  
The Relationship

AbstractThe pyrochlore solid solution Gd2(Zrx Til−x)2O7, was found to be an attractive system for investigating the relationship between composition, structural disorder and ionic conductivity. Both cation and anion order parameters were found to decrease systematically with increasing substitution of Zr for Ti leading ultimately to intrinsic fast oxygen ion conductivity in the solid solution. The degree of intrinsic disorder was determined quantitatively from doping experiments and was found to be equal to l.0×lO39 exp(-O.24±0.03eV/kT)cm−6sfor x = 0.3 and substantially larger for higher values of x. Oxygen vacancy mobilities, on the other hand, were found to be relatively independent of x with values of μv, = 0.15exp(-0.78 ± 0.02 eV/kT)cm2V−1s−1. These, and more recent results, on Y2 (ZrxTil−x)2O7, are discussed in the context of the similarities between the pyrochlore and fluorite phases.

ELECTRONIC CONDUCTIVITY MEASUREMENTS IN SOLID ELECTROLYTES USING AN ION BLOCKING MICROELECTRODE: NOISE REJECTION BASED ON A MEDIAN FILTER

2013 ◽  
Vol 02 (02) ◽  
pp. 1350009 ◽  
Author(s):  
VEYIS GUNES ◽  
JEAN-YVES BOTQUELEN ◽  
ODILE BOHNKE
Keyword(s):  
Solid Electrolytes ◽  
Ionic Conduction ◽  
Median Filter ◽  
Electronic Conductivity ◽  
Conductivity Measurement ◽  
Heating System ◽  
Electronic Conduction ◽  
Oxygen Ion ◽  
Noise Rejection

In this paper, a method of electronic conductivity measurement is presented. It combines two well known methods of electrochemistry: cyclic voltammetry and chronoamperometry. This DC technique uses the Hebb–Wagner approach to block ionic conduction (when steady state conditions are reached) and allows electronic conduction of solid electrolytes to be determined. In order to get short diffusion times, a micro contact is used as an ion blocking electrode. However, as the electronic conduction in electrolytes is and should be very low, the current is also very low, typically some tens of nanoamps. Thus, the heating system inevitably generates noise problems that are solved using a median filter. As opposed to other related work, our system allows the determination of the conductivities without any preliminary smoothing or fitting of the curves (since the noise is strongly reduced). Some results with oxygen ion conductors are also given.

scholarly journals Stabilization of Superionic-Conducting High-Temperature Phase of Li(Cb9h10) via Solid Solution Formation with Li2(B12H12)

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 330
Author(s):  
Sangryun Kim ◽  
Kazuaki Kisu ◽  
Shin-ichi Orimo
Keyword(s):  
High Temperature ◽  
Solid Solutions ◽  
Ionic Conduction ◽  
Lithium Ion ◽  
High Temperature Phase ◽  
Temperature Phase ◽  
Solid Solution Formation ◽  
Low X ◽  
T Phase ◽  
Complex Anions

We report the stabilization of the high-temperature (high-T) phase of lithium carba-closo-decaborate, Li(CB9H10), via the formation of solid solutions in a Li(CB9H10)-Li2(B12H12) quasi-binary system. Li(CB9H10)-based solid solutions in which [CB9H10]− is replaced by [B12H12]2− were obtained at compositions with low x values in the (1−x)Li(CB9H10)−xLi2(B12H12) system. An increase in the extent of [B12H12]2− substitution promoted stabilization of the high-T phase of Li(CB9H10), resulting in an increase in the lithium-ion conductivity. Superionic conductivities of over 10−3 S cm−1 were achieved for the compounds with 0.2 ≤ x ≤ 0.4. In addition, a comparison of the Li(CB9H10)−Li2(B12H12) system and the Li(CB9H10)−Li(CB11H12) system suggests that the valence of the complex anions plays an important role in the ionic conduction. In battery tests, an all-solid-state Li–TiS2 cell employing 0.6Li(CB9H10)−0.4Li2(B12H12) (x = 0.4) as a solid electrolyte presented reversible battery reactions during repeated discharge–charge cycles. The current study offers an insight into strategies to develop complex hydride solid electrolytes.

Electrical Conductivity and Structural Studies on the Binary System BiI3-Ag2SO4

2012 ◽  
Vol 584 ◽  
pp. 521-525
Author(s):  
S. Austin Suthanthiraraj ◽  
Ayesha Saleem
Keyword(s):  
Electrical Conductivity ◽  
Binary System ◽  
Ionic Conduction ◽  
Structural Characteristics ◽  
Complex Impedance ◽  
Present System ◽  
Rapid Melt Quenching ◽  
Ionic Nature ◽  
Electrochemical Devices ◽  
Silver Sulphate

A new solid-state pseudo binary system BiI3_-Ag2SO4 involving bismuth triiodide (BiI3) and a silver oxysalt namely silver sulphate (Ag2SO4) has been prepared using rapid melt-quenching technique. AC conductivity studies have been carried out on the nine different samples of the (BiI3)x –- (Ag2SO4)(1-x) system with compositions corresponding to x=0.1,0.2,0.3,0.4,0.5,0.6,0.7,0.8 and 0.9 mole fraction at temperatures ranging from room temperature (298 K) to 433K. The bulk resistance values estimated using complex impedance plots indicated that electrical conductivity of the synthesized solid specimens would vary from 2.9 x10-2 to 3.4 x10-6Scm-1 thus suggesting the present system to be ionic in nature. The extent of ionic conduction due to Ag + cation has also been analyzed using Wagner’s dc polarization technique whereas detailed structural characteristics of the various compositions derived from Fourier transform infrared (FTIR) spectroscopy and features of surface morphology of these samples obtained using scanning electron microscopy (SEM) have further supported the ionic nature of the chosen system and suggested possible application as a solid electrolyte in electrochemical devices.

Oxygen-ion Conductivity of Re Tungstates Ln14W4O33 (Ln = Nd, Sm, Gd)

2021 ◽  
Author(s):  
Anna Shlyakhtina ◽  
Nikolay Lyskov ◽  
Sergei Cheryak ◽  
Igor Kolbanev ◽  
Anna Kasyanova ◽  
...  
Keyword(s):  
Ion Conductivity ◽  
Oxygen Ion Conductivity ◽  
Oxygen Ion

Doped Ceria Based Solid Oxide Fuel Cell Electrolytes and their Sintering Aspects: An Overview

2016 ◽  
Vol 835 ◽  
pp. 199-236 ◽  
Author(s):  
Pradyot Datta
Keyword(s):  
Power Generation ◽  
Fuel Cell ◽  
Solid Oxide Fuel Cell ◽  
Operating Temperature ◽  
Solid Oxide ◽  
Ion Conductivity ◽  
Doped Ceria ◽  
Oxide Fuel ◽  
Oxygen Ion Conductivity ◽  
Oxygen Ion

Depletion of fossil fuel at an alarming rate is a major concern of humankind. Consequently, researchers all over the world are putting a concerted effort for finding alternative and renewable energy. Solid oxide fuel cell (SOFC) is one such system. SOFCs are electrochemical devices that have several advantages over conventional power generation systems like high efficiency of power generation, low emission of green house gases and the fuel flexibility. The major research focus of recent times is to reduce the operating temperature of SOFC in the range of 500 to 700 °C so as to render it commercially viable. This reduction in temperature is largely dependent on finding an electrolyte material with adequate oxygen ion conductivity at the intended operating temperature. One much material is Gadolinia doped Ceria (CGO) that shows very good oxygen ion conductivity at the intended operation temperature. The aim of this overview is to highlight the contribution that materials chemistry has made to the development of CGO as an electrolyte.

Processing and Electrochemical Properties of Mixed Conducting Lat-xAxCo1-yFeyO3-δ (A=Sr, Ca)

1994 ◽  
Vol 369 ◽  
Author(s):  
W. J. Weber ◽  
J. W. Stevenson ◽  
T. R. Armstrong ◽  
L. R. Pederson ◽  
J. J. Kingsley
Keyword(s):  
Perovskite Structure ◽  
Applied Field ◽  
Synthesis Method ◽  
Oxygen Ion Conductivity ◽  
Oxygen Ion ◽  
Electrical Conductivities ◽  
Permeation Studies ◽  
Thermogravimetric Studies ◽  
Increasing Temperature ◽  
Significant Flux

AbstractPowder compositions in the series Lat-xAxCo1-yFeyO3-δ (A=Sr, Ca) have been prepared by a combustion synthesis method. Sintering of pressed powders produced high-density test specimens with the perovskite structure. The specimens exhibited high electrical conductivities with appreciable oxygen-ion conductivity that increased with Co content for the compositions studied. Oxygen permeation studies showed a significant flux of oxygen that increased with temperature for specimens in a P(O2) gradient with no applied field. Thermogravimetric studies of the Lat-xCo0.2Fe0.8O3-δ system indicated a reversible mass loss with increasing temperature that increased with Sr content.

scholarly journals Dense lanthanum silicate oxyapatite ceramics obtained by uniaxial pressing and slip casting

2018 ◽  
Vol 50 (4) ◽  
pp. 433-443
Author(s):  
Ramiro Toja ◽  
Nicolás Rendtorffa ◽  
Esteban Agliettia ◽  
Tetsuo Uchikoshi ◽  
Yoshio Sakka ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Vickers Hardness ◽  
Growth Process ◽  
Slip Casting ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Oxygen Ion Conductivity ◽  
Oxygen Ion ◽  
Slip Cast ◽  
Lanthanum Silicate

Lanthanum silicate oxyapatite (LSO) is a promising ion conductive ceramic material, which has higher oxygen ion conductivity at intermediate temperatures (600-800?C) compared to yttria-stabilized zirconia. Its mechanical properties, though important for any of its applications, have been scarcely reported. In this study, we compare apparent densification, open porosity and Vickers hardness of samples conformed by uniaxial pressing and slip casting and fired up to 1600?C. Colloidal processing was optimized for slip casting in order to get high green densities. At sintering temperatures higher than 1400?C, both processing routes yielded comparable densities, although uniaxially pressed samples show slightly better mechanical properties, evidencing that slip cast ones already underwent a grain growth process.

Sign in / Sign up

Export Citation Format

Share Document