物理化学学报 >> 2011, Vol. 27 >> Issue (04): 863-868.doi: 10.3866/PKU.WHXB20110408

电化学和新能源 上一篇    下一篇

La2(Mo1-xVx)2O9-α的制备及其导电性

许佳, 张明, 徐建红, 马桂林   

  1. 苏州大学材料与化学化工学部, 江苏省有机合成重点实验室, 江苏 苏州 215123
  • 收稿日期:2010-12-17 修回日期:2011-01-17 发布日期:2011-03-29
  • 通讯作者: 马桂林 E-mail:32uumagl@suda.edu.cn
  • 基金资助:

    国家自然科学基金(20771079)资助项目

Synthesis and Electrical Properties of La2(Mo1-xVx)2O9-α

XU Jia, ZHANG Ming, XU Jian-Hong, MA Gui-Lin   

  1. Key Laboratory of Organic Synthesis of Jiangsu Province, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, Jiangsu Province, P. R. China
  • Received:2010-12-17 Revised:2011-01-17 Published:2011-03-29
  • Contact: MA Gui-Lin E-mail:32uumagl@suda.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20771079).

摘要:

采用固相法合成了系列陶瓷样品La2(Mo1-xVx)2O9-α (x=0.02, 0.04, 0.06, 0.08). 粉末X射线衍射(XRD)结果表明样品具有单一立方相La2Mo2O9结构. 采用气体浓差电池、电化学阻抗等电化学方法研究了陶瓷样品在823-1123 K下的导电特性. 系列陶瓷样品已完全抑制La2Mo2O9母体在853 K附近的相变; 各样品在干燥及湿润氧气气氛中几乎为纯氧离子导体, 质子导电性可忽略不计; 氧离子电导率σ随掺杂离子浓度的变化为σ(x=0.02)<σ(x=0.08)<σ(x=0.06)<σ(x=0.04), 这与晶胞自由体积大小的次序完全一致, x=0.04样品具有最高的氧离子电导率0.051 S·cm-1; 氧分压与电导率的关系表明, 在高氧分压气氛中样品是纯的氧离子导体, 在低氧分压气氛中是氧离子与电子的混合导体.

关键词: 氧离子导体, La2Mo2O9, 质子导电性, 气体浓差电池, 电化学阻抗谱

Abstract:

A series of ceramic samples La2(Mo1-xVx)2O9-α (x = 0.02, 0.04, 0.06, 0.08) were synthesized by a solid-state reaction method. X-ray powder diffraction (XRD) patterns show that all the ceramic samples have a single cubic structure. The conductive properties of the ceramic samples were investigated using gas concentration cells and electrochemical impedance spectroscopy at 823-1123 K. All the samples have completely suppressed the phase transition, which occurs in La2Mo2O9 at around 853 K. The ceramic samples are almost pure oxide-ionic conductors and do not possess the protonic conduction in dry and wet oxygen atmospheres. The oxide-ionic conductivity (σ) is affected by the doping level, and increases as follows: σ(x=0.02)<σ(x=0.08)<σ(x = 0.06)<σ(x=0.04). This order is consistent with that of the free volume of the crystal lattice. La2(Mo0.96V0.04)2O9-α has the highest oxide-ionic conductivity of 0.051 S·cm-1. The dependence of conductivity on oxygen partial pressure reveals that the samples are almost pure oxide-ionic conductors in the high oxygen partial pressure range whereas they exhibit mixed ionic and electronic conduction in the low oxygen partial pressure range.

Key words: Oxide-ionic conductor, La2Mo2O9, Protonic conduction, Gas concentration cell, Electrochemical impedance spectroscopy

MSC2000: 

  • O646