Development of polybenzimidazole modification with open-edges/porous-reduced graphene oxide composite membranes for excellent stability and improved PEM fuel cell performance

Abstract

In this research work, we have investigated effect of microwave exfoliated open-edges containing porous-reduced graphene oxide nanosheets (rGO NSs) as nanofillers in polybenzimidazole (PBI) membrane electrolyte assembly for high-temperature proton-exchange membrane fuel cell (PEMFC). PBI/rGO composite membranes were formed by incorporating different amounts (1, 2, and 3 wt%) of rGO NSs into the PBI membrane. Among the three rGO-modified PBI membranes, the optimized amount of 2 wt% rGO NSs in PBI/rGO (PBI/rGO-2) composite membrane shows high ionic conductivity and stable cell performance, with superior maximum power density of 372 mW cm−2 at 150 °C. The PBI/rGO-2 composite membrane reveals excellent stable performance for fuel cells and contains 98.3% stable cell voltage after 32 h of measurement. The proposed tentative mechanism shows the attachment of oxygen-containing functionalities with rGO NSs in the PBI membrane to form the PBI/rGO composite membrane. The rGO NSs play a crucial role in the PBI membrane, assisting in improving proton conductivity, mechanical stability, thermal stability, and easy phosphoric acid (PA) intake without PA electrolyte leaching at higher temperatures, resulting in a high-temperature PEMFC with high power density and stability.