Effects of (Li-Na)₂CO₃ on The Electrical Properties of Calcia-Stabilized Zirconia/Carbonate Composite Electrolytes

Department of Chemical Engineering, Faculty of Industrial Technology, Institut Teknologi Bandung, Jl. Ganesha No. 10, Bandung 40132, Indonesia.

^* Corresponding author: hardev@che.itb.ac.id

Abstract

Calcia-Stabilized Zirconia (CSZ) is potential as low-cost electrolytes material for Solid oxide fuel cell (SOFC). It is fluorite structure widely known as oxygen ion conductors. Addition of carbonate salt into fluorite-based electrolyte is common to overcome low conductivity of CSZ as well as to decrease sintering temperature. Increase of ionic conductivity in the SOFC electrolyte is also influenced by presence of protons (H⁺), so it is called mixed-ion electrolytes. In this study, the effect of sintering temperature and carbonate content prepared from mixture of Li₂CO₃ and Na₂CO₃ on the relative density, ionic conductivity and microstructure of electrolyte and fuel cell performance was investigated. The sintered CSZ/carbonate samples were examined physically and electrochemically by using SEM, TEM, XRD, and EIS. The unique detail of nanostructure for CSZ/carbonate was investigated by TEM. The XRD is to observed peak associating with CSZ, Li₂CO₃, and Na₂CO₃, as well as its crystallinity. Moreover, the electrolyte resistance was measured by EIS so that the proton conductivity and oxygen conductivity of CSZ/carbonate can be calculated. The improvement of low-cost electrolyte material such as CSZ can be realized by providing protons pathway.