Surface engineered homo-structure enabling the fast ionic conduction for ceramic fuel cells

The primary incentive for designing efficient electrolytes is to enhance the specific energy like power density, ionic conductivity, OCV (open-circuit voltage), and energy efficiency of electrochemical conversion devices. In terms of high-power efficiency, the wide bandgap semiconductor perovskite is considered a suitable candidate for fuel cell application. For example, SrTiO₃ (STO) recently attracted extensive attention regarding good fuel cell performance, which can be further enhanced via surface doping. Here, we designed SCT (SrCo_0.1TiO₃) as an electrolyte to enable high ionic conduction via surface doping (enriched oxygen vacancies). Due to the difference in fermi-level, the space charge region can be built, which later constitutes the BIEF (Built-in electric field), enhancing the ionic conduction at the Surface of SCT. The CFC (Ceramic Fuel Cell) device using the Co-STO electrolyte delivered a maximum fuel cell performance of 782 mW/cm² and higher ionic conductivity of 0.17 S/cm at a low operating temperature of 520 ^oC. DFT (Density function theory) calculation is performed to support the experimental results. The presented surface doping methodology is suitable for designing advanced materials for wide bandgap semiconductors with high ionic conductivity to develop next-generation advances for CFCs (Ceramic Fuel Cells).