Experimental and Theoretical Study of Gallium–Doped Cerium Electrolyte for Fuel Cells

Fuel cells produce clean and green power in an environmentally friendly way. An energy device fuel cell is used because of its higher efficiency and fuel flexibility. A number of efforts have been made to commercialize this technology by reducing its cost and operating temperature, and enhancing the durability. The operating temperature and performance of the cell depend on the electrolyte’s stability and durability. Therefore, Ga–doped ceria electrolyte was synthesized by the coprecipitation technique. X–ray powder diffraction (XRD) spectra confirm the successful doping of gallium into ceria and reveal a cubic structure with crystallite size ranging from 50 to 60 nm. Scanning electron microscope (SEM) analysis confirmed the homogeneous surface morphology of the prepared material. The optical band gap shows a red shift compared to ceria. Thermal analysis shows that sample “d” has the lowest weight loss of 0.33% in the range 20–900 °C. It has been observed that the composition Ga0.04Ce0.96O2−δ exhibited a maximum conductivity of 0.054 S cm–1 at 600 °C. The cell showed a power density of 86 mW cm–2 at 600 °C with an OCV of 1.02 V. Density functional theory depicts that gallium doping reduces the band gap and shifts the O 2p states toward Fermi level, due to which conductivity of the doped system is improved. The results reveal that Ga–doped ceria is an efficient electrolyte for fuel cells.