Mathematical modeling of anion exchange membrane-based direct urea/O2 fuel cell incorporating the effects of under-rib mass transport and gaseous bubble formation

Abstract

In this study, a simplified mathematical model was proposed for predicting the performance of an anion exchange membrane-based direct urea/O2 fuel cell (AEM-DUFC-O) with a serpentine flow channel. Because the effects of under-rib mass transfer and gaseous bubble formation were considered, this model exhibited good agreement with both lab-experimental and literature data, with high R2 values of 0.941-0.995 and NRMSE of 0.078-0.019, suggesting that it can reasonably be applied for further analysis and optimization of AEM-DUFC-O. The simulation results indicated that the under-rib mass transfer has a beneficial effect on the fuel cell efficiency, while the formation of gaseous bubbles is detrimental. In addition, the flow-field structure (i.e., rib width and channel dimensions) and operational parameters (i.e., urea and KOH concentrations, temperature, and feeding flow rate) also exhibited crucial impacts and need to be further optimized to maximize the power density output and energy recovery efficiency of AEM-DUFC-O.