A comparative study of TiO2 doped and undoped yttria stabilized zirconia thin films for solid oxide fuel cell application.

To evaluate the physical and electrochemical variations introduced by the sintering aid TiO2 in the yttria stabilized zirconia (YSZ), a comparison between 3 wt% TiO2 doped YSZ (3TiYSZ) and undoped YSZ films has been carried out. Herein, the NiO/YSZ composite substrates are prepared for the support with enough porosity (32.58%) and surface roughness (16 nm) those are required for better fuel transfer and mechanical integrity. Thin electrolyte films are deposited over NiO/YSZ and fused quartz substrates by performing multiple coating cycles using the slurry spin coating technique. A comparative study has been carried out by observing structural, topographical, and electrochemical properties of the 3TiYSZ and undoped YSZ thin films at 950 °C and 1150 °C sintering temperatures. During X-ray diffraction (XRD) analysis, all the prominent reflections of cubic zirconia are visible in all the samples where no phase distortions are observed with TiO2 addition. For the 3TiYSZ thin films, the grain size is found to be significantly enhanced as compared to the undoped YSZ. The surface topography from atomic force microscopy (AFM) unveils hill like topography and relatively lower roughness for 3TiYSZ thin electrolyte films. The electrical behavior is analyzed through Nyquist data which confirmed the thermal activation of ionic conductivity, while a significant decrement in ionic resistance is observed for 3TiYSZ thin films. Hence, TiO2 played a significant role in enhancing the physical and electrochemical properties at relatively lower sintering temperatures. [ABSTRACT FROM AUTHOR]