DEVELOPMENT OF LSM/YSZ COMPOSITE ELECTRODES FOR THIN FILM SOLID OXIDE FUEL CELLS

摘要

The effects of cathodic current passage, (La,Sr)MnO_3 (LSM) stoichio-metry and the surface treatment of YSZ electrolyte on the performance of LSM/YSZ composite cathode were investigated. The cathodic current passage had an enhancing/activation effect on the composite cathode made of stoichiometric LSM powder (LSM-A) and YSZ powder, while it had little effect on the composite cathode made of A-site sub-stoichiometric LSM powder (LSM-B) and YSZ powder. An A-site deficiency (～0.1) is effective in inhibiting the formation of the resistive layer such as La_2Zr_2O_7SrZrO_3 between LSM and YSZ. Also, surface treatment of YSZ electrolyte had a major effect on the cathode performance. After polishing the YSZ surface, the measured interfacial resistance of LSM-B/YSZ (50:50 wt%) decreased to 0.27 ohm cm~2 from 0.50 ohm cm~2 on as-sintered YSZ surface at 800℃ in air. The results showed that LSM/YSZ composite cathode performance can be significantly improved by using A-site deficient LSM and thorough surface treatment of YSZ electrolyte.