Unraveling the synergistic effect on ionic transport of ceria via the surface engineering for low-temperature ceramic fuel cells
M.A.K. Yousaf Shah, Yuzheng Lu, Naveed Mushtaq, Muhammad Yousaf, Bin Zhu
Abstract
Recently, the multifunctional semiconductor CeO2 realized high ionic conductivity via surface conduction and delivered higher fuel cell performance. This indicates a promising strategy for the design of an electrolyte for the low-temperature ceramic fuel cell. In this study, we develop a ceria-based electrolyte by surface doping Bi into CeO2 to attain the CeBiO2 (BDC) electrolyte. The designed electrolyte is facilitated with an enriched O-vacancy surface layer, enabling high ionic conduction (0.20 S/cm) and excellent power density (1057 mW/cm2) at 530 °C. The difference in the Fermi level of BDC and CeO2 arises due to the surface doping, which entails the band alignment and establishes the space charge region, thereby constituting a built-in field enhancing the charge transportation and minimizing e-conduction. In order to assist the formation of O-vacancies in the design, the BDC electrolyte density functional theory calculation was also made. These findings suggest surface doping is the best approach to attaining excellent performance and designing electrolytes and electrodes for advanced low-temperature fuel cell technology.