Synthesis and properties of gadolinium doped ceria electrolyte for IT-SOFCs by EDTA-citrate complexing method

Abstract

In the present study, gadolinium doped ceria (Ce0.8Gd0.2O2−δ, GDC) electrolytes at different pH have been successfully prepared by EDTA-citrate complexing method for intermediate temperature solid oxide fuel cells (IT-SOFCs). XRD, Raman, FE-SEM, TEM and electrochemical impedance spectroscopy are used for structural and electrical characterizations. XRD patterns of the GDC powder calcined at 873 K for 5 h exhibits the cubic fluorite structure with space group Fm3m. Raman spectra of sintered GDC powder confirms the formation solid solution in corroboration with XRD data. FE-SEM images of sintered GDC pellets at different pH shows well defined grains separated from grain boundaries with good densification. Highest relative density (99%) is obtained for sintered GDC pellet with pH = 10. Electrical conductivity of GDC depends on pH of the solution and the maximum conductivity is 1.6 × 10−2 S cm−1 at 973 K with pH = 10. These preliminary results indicate the possible application of GDC as a potential electrolyte for IT-SOFCs.