Studies on AO-Bi2O3-V2O5 (A = Mg, Ca, Sr, Ba) ceramics as electrolytes

Abstract

An electrolyte is a majorly ion conducting material. Solid electrolytes can be employed with reactive electrodes within a wide temperature range with no leakage problems. Due to its high utility it possesses a lot of applications in the field of batteries and fuel cells particularly in solid oxide fuel cells (SOFCs). The main limitation of SOFC is their high operating (800- 1000 °C) temperature which reduces the lifetime of these devices. So, to improve the lifetime of these devices and make them cost effective, the idea is to reduce their operating temperature. Operating temperature in turn depends upon the type of materials employed in them mainly, the electrolyte. Presently, yttria stabilized zirconia (YSZ) is being used as electrolyte in SOFCs but the main limitation of YSZ is sharp decrease in conductivity below 800 °C. So, it is essential to develop a compatible ion conducting material which can give the better ionic conductivity below 800 °C. Doped bismuth vanadate (Bi4V2O11-δ) ion conductors are known to represent good conductivity ~ 0.2 Scm-1 at 500 °C. Therefore, they can be a promising candidate as electrolytes for intermediate temperature SOFCs (IT-SOFCs). Bi4V2O11-δ based system doped with alkaline earth metals Mg2+, Ca2+, Sr2+ and Ba2+ has been investigated for structural, thermal, optical and electrical properties in context of solid electrolyte.