Effect of type and stoichiometry of fuels on performance of polybenzimidazole-based proton exchange membrane fuel cells operating at the temperature range of 120-160 °C

Herein, a proton exchange membrane fuel cell (PEMFC) equipped with phosphoric acid-doped polybenzimidazole (PA-PBI) membrane was exploited to determine the effects of changing type and stoichiometry of feed gas at operating temperature from 120 to 160 degrees C. Results show that maximum power density of proposed system increases as increasing temperature, and varying the type and stoichiometry of feed gas. For example, a typical power density of 0.254, 0.299 and 0.389 W/cm(2) was obtained when operating PEMFC at 120, 140 and 160 degrees C respectively with pure hydrogen (H-2) as feed gas. By contrast, power density of only 0.128, 0.194 and 0.243 W/cm(2) was achieved when operating the PEMFC under identical condition with reformed H-2 as feed gas. On the other hand, when varying oxygen (O-2) stoichiometry from 2 to 6, power density of PEMFC vary from 0.330 to 0.472 W/cm(2) at 160 degrees C. At high temperature and high O2 diffusion rate, reaction kinetics of electrodes and membrane were boosted, resulting lower mass-transfer resistance and higher PEMFC performance. In addition, we conducted long-term operation of PEMFC at 160 degrees C for 500 h to examine durability of PA-PBI. PA-PBI membrane was not lose open circuit voltage (OCV) significantly, indicating its good PEMFC durability. (C) 2021 Elsevier Ltd. All rights reserved.