Codoped Ceria Electrolyte for Direct Carbon Fuel Cell with Carbon Fly Ash Fuel

Direct carbon fuel cells have higher energy density and efficiency than hydrogen fuel cells. In this study, codoped ceria electrolyte ZrxSm0.2–xCe0.8O2−δ (x = 0.0, 0.05, 0.1, 0.15, 0.2) has been synthesized using the co-precipitation technique. This study aims to explore the effects of Zr4+ doping in samarium-doped ceria. The structural analysis of codoped ceria has been examined by XRD, which illustrates the cubic structure and calculated average crystallite size in the range of 29.14–24.25 nm. The morphology of codoped ceria has been examined by SEM micrograph which revealed that the structure became more uniform and denser. The molecular vibration has been analyzed by Raman spectroscopy which shows vibrational mode at 470 cm–1 of codoped ceria. UV–visible spectroscopy shows a red shift in band gap ranging from 3.68 to 2.67 eV, including the Zr ion in doped ceria. The composition Sm0.0Zr0.2Ce0.8O2−δ has achieved the highest ionic conductivity of 0.047 S cm–1 at 600 °C among all of the samples in the air atmosphere. The obtained power density of Sm0.0 Zr0.2Ce0.8O2−δ is found to be 56 mW cm–2 at 600 °C using carbon fly ash fuel.