A proton-conducting In3+-doped SnP2O7 electrolyte for intermediate-temperature fuel cells

We report proton conduction in In3+-doped SnP2O7 in the temperature range from 100 to 300 degrees C, and the performance of a H-2-air fuel cell using this material as the electrolyte. The proton conductivity of In3+-doped SnP2O7 was more than 10(-1) S cm(-1) between 125 and 300 degrees C, and a conductivity value of 1.95 x 10(-1) S cm(-1) was achieved at 250 degrees C. The resulting fuel cell exhibited a reasonable power density of 264 mW cm(-2) at 250 degrees C (electrolyte thickness = 0.35 mm), together with perfect tolerance toward 10% CO and good thermal stability in unhumidified conditions. (c) 2006 The Electrochemical Society.