Tuning electrochemical properties and thermal stability of YSZ mesoporous thin films for SOFC applications

TL;DR

This study investigates how thermal treatments affect the structure, ionic conductivity, and stability of YSZ mesoporous thin films for SOFCs, revealing enhanced conductivity due to accessible porosity and surface ionic transport.

Contribution

It provides new insights into optimizing YSZ thin films' electrochemical properties through controlled thermal treatments and surface porosity analysis.

Findings

Porosity improves superficial ionic conductivity.

Thermal treatments influence mesostructure stability.

Surface ionic transport reduces activation energy.

Abstract

Dense and mesoporous 4% mol Yttria-stabilized zirconia thin films were deposited on amorphous silica substrates. The effects of the temperature on the mesostructure were analyzed, by applying different thermal treatments to the samples within the range of SOFC operation conditions. Electrochemical impedance spectroscopy measurements rendered evidence of a single mechanism, consistent with grain boundary/surface oxide ion conduction. Our results show that the presence of the highly accessible porosity improves the superficial ionic conductivity, reducing the activation energy of the overall process. Density functional theory calculations on the (110) surface were performed to estimate the associated energy barriers. Our results suggest that ionic transport along the surface of accessible pores connected to the atmosphere could account for the observed reduction in activation energy.