Effects of Sm_0.5Sr_0.5CoO₃-based cathode current-collecting element on the performance of intermediate-temperature solid oxide fuel cells

A new design of cathode current-collecting element (CCCE) based on Sm_0.5Sr_0.5CoO₃, which contains gas channels and an array of truncated-pyramid-shaped contact tips, is synthesized through die pressing followed by a conventional solid-state reaction for intermediate-temperature solid oxide fuel cells (IT-SOFCs). This configuration could not only maintain the high electronic conductivity of the material to ensure the efficiency of current collecting, but also improve the gas diffusion rate at the cathode side. The height h of the channel tips on the CCCEs reaches approximately 60, 120, and 240 μm, respectively, which results in the variation in polarization resistance (R_P) more significantly than the contact area of the tips does. The experiments show that the R_P of the symmetric cells decreased from 0.267 to 0.060 Ω cm² at 800 °C after employing the CCCE with modified parameters. In addition, the measured peak power density of the individual cell is enhanced from 111 to 145 mW cm⁻² at 800 °C. The results show that the cathode current-collecting elements may be potentially useful for applications in IT-SOFCs.