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Enhanced ionic conductivity of samaria doped ceria thin films through tailoring the dopant concentration and microstructures


EMSL Project ID
19815

Abstract

Development of electrolyte materials that possess high oxygen ion conductance at relatively low temperatures is essential to increase the efficiency and lifetime of electrochemical devices such as solid oxide fuel cells (SOFC). The most advanced SOFCs employ oxide ion conducting zirconia based electrolytes, specifically, yttria stabilized zirconia (YSZ). The conductivity of the electrolyte determines the operating temperature of this device, which is currently around 1000 °C. Lower operating temperatures of ~500 °C would make SOFCs much more cost efficient and, most importantly, facilitate the practical use of SOFCs in electric vehicles. At low operation temperature, it will avoid many undesirable interfacial reactions between electrode and electrolyte materials. At low operation temperatures, superior high ionic conductivity of oxide electrolytes layer (>10-2 S/cm) is required to the success of future fuel cell technology.

Recently, samaria doped ceria (SDC) have received much attention in the literature due to its high ionic conductivity and high oxygen ion transport, and they are considered to be the most promising solid electrolytes for the intermediate temperature solid oxide fuel cells (SOFCs). Although SDC materials show promising results, there are controversies regarding the dopant concentration that provide higher values for ionic conductivity. The discrepancies in ionic conductivity are mostly due to different sample preparation methods and the crystalline quality associated with these methods. Most of the previous experiments in the literature were focused on the polycrystalline ceramics. It was recommended that maintenance of small nanocrystal grain size and utilization of grain boundary interfaces (by adjust density, composition, orientation) can enhance oxygen ionic conductivity in SOFC electrolytes.

Project Details

Project type
Large-Scale EMSL Research
Start Date
2006-07-28
End Date
2009-09-30
Status
Closed

Team

Principal Investigator

Zhongqing Yu
Institution
Nanjing Normal University