Acta Phys. -Chim. Sin. ›› 2011, Vol. 27 ›› Issue (04): 863-868.doi: 10.3866/PKU.WHXB20110408

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

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).

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