Numerical validation of direct ethanol fuel cell operating at high temperature

In the present work, a three-dimensional steady-state model was developed to analyze the performance of high-temperature direct ethanol fuel cell (HT-DEFC) based on polybenzimidazole (PBI) electrolytes. A non-isothermal model of a HT-DEFC setup using a PBI/H3PO4 membrane was employed using computational fluid dynamics (CFD). This work is aiming at a validation of experimental data of HT-DEFC prototypes based on the simulation of polarization curves. The model predicts the mole concentration of H3PO4, heat and current density distributions, as well as mass fraction ethanol during operation at 180 & DEG;C. The heat transfer model was coupled to the electrochemical and mass transport, allowing that a particular heating configuration was investigated considering the temperature distribution on the PBI membrane. We have found that temperature and relative humidity (RH) are mostly related to PBI properties resulting from H3PO4 lixiviation and conductivity decreasing as well as ethanol crossover strongly interferes on the oxygen reduction reaction (ORR) rate, leading to poor HT-DEFC performance.

Automated summary

A three-dimensional steady-state model was developed to analyze the performance of high-temperature direct ethanol fuel cells (HT-DEFC) based on polybenzimidazole (PBI) electrolytes. The model predicted various distributions and concentrations during operation, and investigated the effects of temperature and humidity on the cell's performance. The study found that PBI properties, H3PO4 lixiviation, and ethanol crossover play significant roles in affecting the HT-DEFC performance.