Electrochemical characterization and degradation analysis of a flat-chip solid oxide fuel cell fed by ambient temperature inlet gas

Abstract

Temperature distribution plays an essential role in performance of solid oxide fuel cell. This study, for the first time, experimentally investigates the effect of inlet gas temperature on cell. A newly developed flat-chip solid oxide fuel cell (FC-SOFC) is deployed, whose configuration design with two cold ends enables enhanced flexibility and reliability in sealing, connecting and stacking. The complicated elementary processes in the course of FC-SOFC functioning is analyzed by electrochemical impedance spectra (EIS), distribution of relaxation time (DRT) and polarization curve. Experimental results reveal the joint effect of low temperature of inlet gas and fuel flow on FC-SOFC performance when feeding with ambient temperature hydrogen (H2). But at higher current (>0.5A) the effect of fuel gas cooling becomes less significant. Further, the feasibility of FC-SOFC run continuously under a conventional condition close to maximum power at 0.7 V (∼1.5 A) over 700 h is also validated. These findings demonstrate that FC-SOFC system is capable to conduct low temperature H2 discharge without additional complex pre-heating design. Finally, cell behavior and underlying mechanisms at three different stages are thoroughly examined by EIS monitoring and DRT analysis.