Completely sealed direct carbon solid oxide fuel cell with in situ steam-carbon gasification reaction

Direct carbon solid oxide fuel cells (DC-SOFCs) offer the potential for clean and efficient conversion of chemical energy in carbon fuels into electricity. However, the reverse Boudouard gasification of carbon requires a high operating temperature (≥800 °C), which hinders the development of DC-SOFCs. We present a completely sealed DC-SOFC with in situ steam-carbon gasification. The cells have a symmetrical cell structure (Ag–Ce 0.8 Gd 0.2 O 1.9 /La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3−δ /Ag–Ce 0.8 Gd 0.2 O 1.9 ) and are loaded with K-loaded activated carbon fuel. Ca(OH) 2 and Li 4 SiO 4 are loaded into the anode chamber as the steam feedstock and CO 2 sorbent, respectively. Completely sealed DC-SOFCs with Ca(OH) 2 –C of 0 %, 5 %, 10 %, 15 %, and 20 % have been tested at 700 °C. Compared with a cell with a conventional structure and a completely sealed cell without Ca(OH) 2 loading, the electrochemical performances of all the completely sealed cells with Ca(OH) 2 loading are significantly enhanced. The cell with Ca(OH) 2 to C of 15 % obtained the highest maximum power density of 75 mW cm −2 , which is approximately two-fold that of the conventional DC-SOFC. The mechanism for improving the performance of the cell is the introduction of steam. This study offers a new method to develop high-performance DC-SOFCs and reduce their operating temperatures.