A high performance intermediate temperature fuel cell based on a thick oxide-carbonate electrolyte

A high performance intermediate temperature fuel cell (ITFC) with composite electrolyte composed of codoped ceria Ce0.8Gd0.05Y0.15O1.9 (GYDC) and a binary carbonate-based (52 mol% Li2CO3/48 mol% Na2CO3), 1.2 mm thick electrolyte layer has been developed. Co-doped Ce0.8Gd0.05Y0.15O1.9 was synthesized by a glycine-nitrate process and used as solid support matrix for the composite electrolyte. The conductivity of both composite electrolyte and GYDC supporting substrate were measured by AC impedance spectroscopy. It showed a sharp conductivity jump at about 500 degrees C when the carbonates melted. Single cells with thick electrolyte layer were fabricated by a dry-pressing technique using NiO as anode and Ba0.5Sr0.5Co0.8Fe0.2O3-delta or lithiated NiO as cathode. The cell was tested at 450-550 degrees C using hydrogen as the fuel and air as the oxidant. Excellent performance with high power density of 670 mW cm(-2) at 550 degrees C was achieved fora 1.2 mm thick composite electrolyte containing 40 wt% carbonates which is much higher than that of a cell based on pure GYDC with a 70 mu m thick electrolyte layer.