Effect of cathode sheet resistance on segmented-in-series SOFC power density

Segmented-in-series solid oxide fuel cells with relatively short cell lengths of 1.4 mm were fabricated with varying LSM cathode current collector thicknesses. Increasing the LSM thickness from 11 to 91 μm yielded a factor of 2–3 area-specific resistance decrease and a similar power density increase. The maximum power density measured at 800 °C was 0.53 W cm−2 calculated based on total array area (including interconnect), and 0.9 W cm−2 calculated based on active cell area. A segmented-in-series electrical model was used to quantitatively explain the results based on the decreased cathode sheet resistance. The model also showed that the cell lengths were near optimal for maximizing the power density of these cells.