Development of tubular hybrid direct carbon fuel cell

The hybrid direct carbon fuel cell is a direct carbon fuel cell concept that combines a solid oxide fuel cell with a molten carbonate fuel cell electrode. This offers efficient conversion of coal or biomass derived carbons to electricity. In this study we aim to improve the electrical performance of this cell by using gadolinia doped ceria (GDC) as either a protection layer over a YSZ electrolyte or as the electrolyte itself. In our study, the electrical performance of several tubular cell geometries were investigated using impedance spectroscopy both with and without gas flows of carbon dioxide or nitrogen. Integrity of microstructure including possible layer delamination effects were investigated by SEM. Promising values of power and resistance were observed using a GDC material as electrolyte at intermediate temperature reducing the operation temperature compared to YSZ, doubling the power of each cell.

► Carbon solid fuel has an energy density 10 times higher than hydrogen fuel. ► Carbon solid fuel is easily available compared to hydrogen. ► Tubular cell decreases in size of the final stack and improves continuous fuelling. ► GDC material shows higher stability and ions conductivity than YSZ. ► H-DCFC obtained a level of power twice higher than YSZ electrolyte.