Preparation and Characterization of Nanocomposite Calcium Doped Ceria Electrolyte With Alkali Carbonates (NK-CDC) for SOFC

Abstract

The entire world’s challenge is to find out the renewable energy sources due to rapid depletion of fossil fuels because of their high consumption. Solid Oxide Fuel Cells (SOFCs) are believed to be the best alternative source which converts chemical energy into electricity without combustion. Nanostructured study is required to develop highly ionic conductive electrolyte for SOFCs. In this work, the calcium doped ceria (Ce0.8Ca0.2O1.9) coated with 20% molar ratio of two alkali carbonates (CDC-M: MCO3, where M = Na and K) electrolyte was prepared by co-precipitation method in this study. Ni based electrode was used to fabricate the cell by dry pressing technique. The crystal structure and surface morphology was characterized by X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM). The particle size was calculated in the range of 10–20nm by Scherrer’s formula and compared with SEM and TEM results. The ionic conductivity was measured by using AC Electrochemical Impedance Spectroscopy (EIS) method. The activation energy was also evaluated. The performance of the cell was measured 0.567W/cm2 at temperature 550°C with hydrogen as a fuel.

Electrochemical study of nanostructured electrode for low-temperature solid oxide fuel cell (LTSOFC)

“…BCFZ electrode displays a maximum electrical conductivity of 6.15 S-cm À1 at temperature of 300°C in hydrogen atmosphere. It has been reported in our previous work [18] that NK-CDC electrolyte possesses an ionic conductivity of 0.1 S-cm À1 at 600°C. Since, BCFZ electrode has more than 60 times higher conductivity than that of NKCDC electrolyte, which concerns the electrical compatibility of BCFZ electrode and NK-CDC electrolyte at interface for ion transportation.…”

“…CDC coated with Sodium-Potassium Carbonates (NK-CDC) electrolyte was prepared by co-precipitation method. The whole procedure has been discussed in our previous work [18].In this work, Cerium Nitrate hexahydrate Ce(NO 3 ) 3 .6H 2 O (Sigma Aldrich, USA) and Calcium Nitrate tetra hydrate Ca(NO 3 ) 2 .4H 2 O (Sigma Aldrich, USA) were used as starting materials. Later on, 20 wt.…”

“…Electrolyte materials play key role for solid oxide fuel cell performance; therefore, the use of those electrolyte materials, which can provide higher ionic conductivity at low temperature is very suitable. It has been proved experimentally that Gadolinium-doped Ceria (GDC), Samarium-doped Ceria (SDC) or Calcium-doped Ceria (CDC) can yield 0.1 S-cm À1 ionic conductivity at 600, 700 or 800°C, whereas YSZ yields this value of ionic conductivity at 1000°C [16][17][18][19][20]. Fang [8] reported that a maximum power density of 388 mW-cm À2 has been found in Ni-SDC cermets at 750°C.…”