Preparation and Performances of Tubular Cone-shaped Anode-supported Segmented-in-series Direct Carbon Solid Oxide Fuel Cell

To solve the problem of large concentration polarization impedance of anode-supported direct carbon solid oxide fuel cell （DC-SOFC）, tubular cone-shaped anode-supported segmented-in-series solid oxide fuel cell （SOFC） was prepared by an improved gel-casting method. By appropriately increasing content of the solvent, fluidity of the slurry and quality of the obtained product were improved. By increasing content of the pore-forming agent, the porosity of the anode was increased, reducing the diffusion resistance of gas. As-improved SOFC was fueled by hydrogen and operated at 800℃with an open-circuit voltage of 1.05 V. The polarization impedance of the electrochemical impedance spectrum decreased while the maximum power density was 0.67 W·cm–2 and the active area of the cathode was 2.2 cm~2.These SOFC electrochemical performances were significantly higher than that before improvement. Activated carbon loaded on the anode with 5%（in mass） K as catalyst was directedly used as the fuel of SOFCs. Using this anode-supported direct carbon, the DC-SOFC was prepared,showing an open circuit voltage of 1.030 V and a peak power density of 0.74 W·cm–2 at 800℃.This DC-SOFC was discharged at a constant current of 400 m A, and its effective utilization rate of carbon fuel was 31%which was higher than that before improvement（17%）.Four improved tubular cone-shaped single cells were connected in series to form a four-cell stack, showing a peak power of 8.0 W and a corresponding power density of 0.91 W·cm–2 at 800℃,which was higher than that before improvement （4.1 W）,exceeding the maximum of previous reported DC-SOFC, and displayed an effective utilization rate of 15% for carbon fuel.