Mathematical modelling of proton-conducting solid oxide fuel cells and comparison with oxygen-lon-conducting counterpart

Proton-conducting solid oxide fuel cells (H-SOFC), using a proton-conducting electrolyte, potentially have higher maximum energy efficiency than conventional oxygen-ion-conducting solid oxide fuel cells (O-SOFC). It is important to theoretically study the current-voltage (I-V) characteristics in detail in order to facilitate advanced development of H-SOFC. In this investigation, a parametric modelling analysis was conducted. An electrochemical H-SOFC model was developed and it was validated as the simulation results a-reed well with experimental data published in the literature. Subsequently, the analytical comparison between H-SOFC and O-SOFC was made to evaluate how the use of different electrolytes could affect the SOFC performance. In addition to different ohmic overpotentials at the electrolyte, the concentration overpotentials of an H-SOFC were prominently different from those of an O-SOFC. H-SOFC had very low anode Concentration overpotential but suffered seriously from high cathode concentration overpotential. The differences found indicated that H-SOFC possessed fuel cell characteristics different from conventional O-SOFC. Particular H-SOFC electrochemical modelling and parametric microstructural analysis are essential for the enhancement of H-SOFC performance. Further analysis of this investigation showed that the H-SOFC performance could be enhanced by increasing the gas transport in the cathode with high porosity, large pore size and low tortuosity.