Interface engineering to improve electrochemical performance of intermediate-temperature solid oxide fuel cells

The interface between the cathode and the electrolyte is critical in the electrochemical performance of intermediate-temperature solid oxide fuel cells (IT-SOFCs). In this study, the correlation between the structural properties at the interface and the electrochemical performance is investigated with a focus on the ohmic resistance. Electrostatic spray deposition (ESD) is used to optimize the cathode particle size and distribution by controlling the solvent evaporation rate. A mechanical pull-off test is performed to directly assess the structural properties at the interface. Furthermore, electrochemical impedance spectroscopy (EIS) is employed with an equivalent circuit model to establish a quantitative correlation between the contact coverage at the interface and the interfacial resistance. By maximizing contact coverage, a significantly high peak power density of 1.87 W cm⁻² is achieved at 600 °C in a Ni-Gd_0.1Ce_0.9O_1.95 (GDC)-based single cell. The findings indicate that the proposed approach effectively achieves the desired structural properties, thereby enhancing the performance of IT-SOFCs with significant implications for the design and optimization.