Fuel cells are being considered as potential device for converting the chemical energy into the electrical energy through an electrochemical reaction, owing to its high conversion efficiency. Among various type of fuel cells, the polymer electrolyte membrane fuel cells (PEMFCs) are being widely studied as an suitable power sources for automotive, stationary, and portable applications due to its low emissions and high power density. With respect to constituents of PEMFC, a growing scientific interest is observed in the study of polymer electrolyte membrane (PEM) for the past decades. Commercially available membranes exploited in PEMFC are Nafionⓡ owing to its good chemical stability and hig proton conductivity. However, high cost and fuel crossover still hampered its applications in fuel cells. To overcome such shortcomings, many researchers have designed and studied the numerous types of PEMs for fuel cell application.
The aromatic hydrocarbon-based membrane is one of the promising materials for PEMFC because of its excellent thermal and mechanical properties. However, the water filled channels exist in the membranes are narrower compared to Nafion, thus it has limited proton conductivity.
Graphene oxide (GO), a typical pseudo-2D structure bearing various types of oxygen functional groups over its surface. Larger surface area, high thermal and mechanical stability, and electronic insulation provide GO platform to be used as organic filler in the PEMs. Therefore, we were tried to embed the GO into the polymer matrix.
In this study, copolymer/graphene oxide composite membrane has been prepared and tested for its physical and chemical properties towards PEMFC. For casting the membrane, the desired amount of GO was dispersed in DMSO by sonication and then added polymer.
The prepared membranes characterized by 1H-NMR, FT-IR and XRD. FE-SEM was used to observe the cross-section of the membranes and micro porous structure was found at all membrane. Also, the morphology of membranes were investigated by tapping mode AFM, and the images revealed that the membrane has distinct phase separation. From thermogravimetric analysis (TGA), we found that all membranes has good thermal stability with an initial decomposition at 260℃. In addition, the effect of the GO was investigated in terms of water uptake, IEC, proton conductivity. As the addition of GO tends to increase the water uptake value and proton conductivity. Through this result, it has been confirmed that the copolymer/GO composite membrane were effective to achieve suitable PEM for the application of PEMFC.