Studies on the structural and ionic transport properties at elevated temperatures of La1-xMnO3±δ synthesized by a wet chemical method

被引：19

作者：

Jena, H

Kutty, KVG ^{[1
]}

Kutty, TRN

机构：

[1] Indira Gandhi Ctr Atom Res, Mat Chem Div, Kalpakkam 603102, Tamil Nadu, India

[2] Indian Inst Sci, Ctr Mat Res, Bangalore 560012, Karnataka, India

来源：

JOURNAL OF ALLOYS AND COMPOUNDS | 2003年 / 350卷 / 1-2期

关键词：

electrode materials; rare earth compounds; chemical synthesis; x-ray diffraction; ion conduction;

D O I：

10.1016/S0925-8388(02)00931-3

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Structural transformation and ionic transport properties are investigated on wet-chemically synthesized La1-xMnO3 (X=0.0-0.18) compositions. Powders annealed in oxygen/air at 1000-1080 K exhibit cubic symmetry and transform to rhombohedral on annealing at 1173-1573 K in air/oxygen. Annealing above 1773 K in air or in argon/helium at 1473 K stabilized distorted rhombohedral or orthorhombic symmetry. Structural transformations are confirmed from XRD and TEM studies. The total conductivity of sintered disks, measured by four-probe technique, ranges from 5 S cm(-1) at 298 K to 105 S cm(-1) at 1273 K. The ionic conductivity measured by blocking electrode technique ranges from 1.0X10(-6) S cm(-1) at 700 K to 2.0X10(-3) S cm(-1) at 1273 K. The ionic transference number of these compositions ranges from 3.0X10(-5) to 5.0X10(-5) at 1273 K. The activation energy deduced from experimental data for ionic conduction and ionic migration is 1.03-1.10 and 0.80-1.00 eV, respectively. The activation energy of formation, association and migration of vacancies ranges from 1.07 to 1.44 eV. (C) 2002 Elsevier Science B.V. All rights reserved.

引用

页码：102 / 112

页数：11

共 35 条

[21] Survey of materials selection for ceramic fuel cells .2. Cathodes and anodes [J].