Enhanced interface reactivity by a nanowrinkled functional layer for intermediate-temperature solid oxide fuel cells

For high-performance intermediate-temperature solid oxide fuel cells (IT-SOFCs), rational design of the interface between the electrode and electrolyte is essential, because interfacial reactivity often dominates the overall performance. In this study, a unique nanowrinkled structure of a Gd_0.1Ce_0.9O_1.95 functional layer is fabricated by electrostatic spray deposition (ESD) between a porous nanostructured electrode and dense electrolyte, for extended and activated reaction sites at the interfaces. Upon the introduction of the nanowrinkled functional layer, the polarization resistance is reduced 3.3-fold, while the peak power density is increased 2.2-fold (0.034 Ω cm² and 1.19 W cm^-2, respectively) at 650 °C, compared to those of the reference sample. The substantial increases in surface area and grain boundary density in the nanowrinkled functional layer reduce both polarization resistance and activation energy, providing a significant performance enhancement. Our results demonstrate the importance of interface engineering with a cost-effective and simple ESD process to fully utilize the nanostructured electrodes for high-performance IT-SOFCs.