Impedance Spectroscopy Analysis of Ni/YSZ Interfaces Prepared by Liquid Precursor Deposition

Abstract

In the present study, thin film Ni anodes, prepared by liquid precursor deposition on dense YSZ substrates, were analyzed by electrochemical impedance spectroscopy (EIS) in a humidified H2 environment at 500 to 700 °C, with the activation energy of 1.30 eV ascribed to the charge transfer reaction at the Ni – YSZ - gas triple phase boundary (tpb). For comparison, the same Ni precursor was infiltrated into a porous YSZ scaffold and was also then characterized by EIS analysis. A transmission line model was used to analyze the EIS data obtained from the infiltrated Ni-YSZ composite anodes, allowing the separation of the effects of ionic transport in the YSZ network and the impedance due to the electrochemical reaction at the tpb. The activation energy for the latter process was determined to be the same as for the model thin film Ni anode, suggesting that Ni/YSZ interfaces prepared in the form of Ni thin films on YSZ substrate and Ni-YSZ composites by the deposition of the same polymeric Ni precursor exhibit comparable impedance behavior.