TiO2 incorporated YSZ thin films for SOFCs: Thermal evolution to the microstructural, topographical and electrochemical properties

In order to accomplish densification, the conventional YSZ electrolyte layer needs to be sintered at temperatures above 1400 degrees C which often seriously compromises the mechanical integrity of the other functional layers of the SOFC concerned. As TiO2 is a potential sintering aid, hence, 3 wt% TiO2 added YSZ electrolyte material (termed as 3TiYSZ) is used as starting powder to prepare 300 nm thin electrolyte films on NiO/YSZ anode composite and quartz using e-beam evaporation. Post deposition sintering temperature is optimized in 950-1150 degrees C range for better structural, topographical and electrochemical performance. After addition of TiO2, no impurity phases are detected while all the prominent reflections of cubic phased YSZ are present. For 1150 degrees C sintered electrolyte films, maximum crystallite size, reduced microstrain and grain boundary density, and lower roughness are observed. The Nyquist plots confirmed the proper electrolytic response, moreover, the ionic conductivity is found to be thermally activated and enhanced.

Automated summary

To achieve densification of SOFC, the traditional YSZ electrolyte layer needs to be sintered at high temperatures, which compromises the mechanical integrity of other functional layers. In this study, 3 wt% TiO2 added YSZ electrolyte material was used to prepare thin electrolyte films. The sintering temperature was optimized for better structural and electrochemical performance. The addition of TiO2 resulted in improved properties of the electrolyte films, including increased crystallite size and reduced roughness, enhancing the ionic conductivity.