Understanding the oxygen reduction reaction in the hierarchically oriented composite cathode with open, straight pores

The cathode-supported solid oxide fuel cells (SOFCs) have recently attracted great attentions due to the unique advantages of excellent fuel gas utilization and superior thermal reduction stability, but the commercialization process is limited by the poor oxygen reduction reaction (ORR) catalytic performance of low porosities and reduced three phase boundaries (TPBs) cathode substrate. In this case, a novel phase inversion tape casting technology (PITC), have been successfully applied and fabricated an advanced full ceramic bilayer composite cathode support (Sr2Fe1.5Mo0.4Ni0.1O6-& delta; (SFMNi) - Gd0.2Ce0.8O1.9 (GDC) support/ functional layer) with open, straight pores. The hierarchically oriented pores can be well-kept after high temperature sintering, which significantly enhance the gas (O2) diffusion process in the porous electrode, thus greatly minimizing even eliminating the concentration resistance. Moreover, the introduction of cathode functional layer remarkably enlarges the TPBs density, which is the active sites for ORR, thereby dramatically reducing the electrochemical activation polarization impedance. The full ceramic cathode support exhibits enhanced ORR kinetics activity with a favorable long-term operational stability, indicating that it is an optimized potential cathode support with great application prospects for SOFCs.