Investigation of the Abnormal I-V Curve Shape of Hybrid Direct Carbon Fuel Cell Using Lanthanum Strontium Calcium Titanate-Based Anode

Solid oxide direct carbon fuel cells are being developed for use with waste derived materials. We have fabricated solid oxide fuel cells with La 0.2 Sr 0.25 Ca 0.45 M x Ti 1-x O 3-δ (M=Ni, Fe, or Co) anodes, YSZ electrolyte, and LSM cathode. Electrochemical performance of these cells has been evaluated with solid carbon as the fuel and promising results have been recorded. For example, fuel cells with La 0.2 Sr 0.25 Ca 0.45 Ni 0.05 Ti 0.95 O 3-δ anode tested in hybrid direct carbon fuel cell mode reached a maximum power density of 82.3 mW/cm 2 measured in N 2 purging gas at 850 °C. During hybrid direct carbon fuel cell testing with solid carbon fuel and nitrogen purging gas, I-V curves obtained showed an abnormal shape between 0.6V and 0.7 V. To investigate the origin of this line shape, we have used methods such as electrochemical impedance spectroscopy, potentiostatic study, and analysis of off gases from fuel cell using gas chromatography.