Characterization of Ce0.8Sm0.2O2−δ-infiltrated La0.8Ca0.2CoO3−δ cathode for solid oxide fuel cells

This work divided into two parts. The first part reports the characteristics of a La0.8Ca0.2CoO3−δ (LCCO) cathode including its chemical bulk diffusion coefficient (Dchem) and chemical surface exchange coefficient (kchem) measured by an electrical conductivity relaxation (ECR) technique. The second part reports two methods to improve the performance of solid oxide fuel cells (SOFCs). One is the use of composite cathode, i.e., mixture of 30 wt% electrolyte and 70 wt% cathode. The other is the use of electrolyte-infiltrated cathode, i.e., the active ionic-conductive electrolyte with nanosize was infiltrated onto a porous cathode surface. In this work, the 0.2 M Ce0.8Sm0.2O1.9 (SDC)-infiltrated La0.8Ca0.2CoO3−δ (LCCO) reveals the maximum peak power density of 305 mW cm−2 at operating temperature of 800 °C with a thin film SDC electrolyte (30 μm), a Ni+SDC anode (1 mm) and a SDC-infiltrated LCCO cathode (20 μm). The enhancement in electrochemical performances by using the electrolyte-infiltrated cathode is ascribed to the creation of electrolyte/cathode phase boundaries, which considerably increase the electrochemical sites for oxygen reduction reaction. Therefore, the infiltrated method is a potential way to improve the performance of SOFCs.