Strain-induced Cracking in Praseodymium-doped Cerium Oxide Thin Films and Its Impact on Oxygen Reduction Reaction Performance

Solid oxide fuel cells (SOFCs) are highly efficient devices for converting chemical energy from fuel into electrical energy. The performance of the air electrode plays a critical role in determining the overall cell performance. To investigate the factors influencing the oxygen reduction activity of electrodes, Pr0.1Ce0.9O2 thin-film electrodes were fabricated using the pulsed laser deposition technique. The morphological characteristics of the films and their impact on electrode performance were systematically examined. It was found that once the thin film reached a critical thickness, tensile stress arising from lattice mismatch induces the formation of regular cracks in the thin-film electrode and may even lead to electrolyte fragmentation. Compared with the crack-free electrode material, the areal specific resistance of the cell decreases from 1.813Ω·cm2 to 0.027 Ω·cm2, and the material demonstrates enhanced stability. Therefore, the morphology and electrochemical activity of the air electrode can be effectively optimized through stress engineering.