“Incorporation of Graphene and Graphene-Based Materials into Membranes" by Dr. Maria Perez Paige скачать в хорошем качестве

“Incorporation of Graphene and Graphene-Based Materials into Membranes" by Dr. Maria Perez Paige

The electrolyte, Proton Exchange Membrane, plays an important role in the Membrane Electrode Assembly (MEA) of Polymeric Electrolyte Membranes Fuel Cells, (PEMFCs), acting as ion conductor, electronic insulator and a separator for the reactant gases. Nafion is the most widely used polymeric membrane in this technology. However, because its particular structure it requires a good hydration to lead a high proton conductivity, which limit the operating temperature to lower than 100 oC. Poly[2,2′-m-(phenylene)-5,5′-benzimidazole (PBI) membrane doped with Phosphoric Acid, has been presented as an alternative to Nafion membranes allowing higher operating temperatures, 200oC, which enhances the kinetics of the reactions. However, during the operation of High Temperature Fuel Cells (HT-PEMFCs) these membranes suffer Phosphoric Acid leaching leading to a low proton conductivity and degradation of the fuel cell. Graphene and graphene based materials because their excellent barrier properties, allow only the conductivity of protons, making these materials excellent candidates to incorporate into the electrolyte. The work carried out at The University of Manchester incorporates Single Layer Graphene (SLG) and Graphene Oxide (GO) composite membranes into the MEAs of both PEM Fuel Cells, Low Temperature (LT-PEMFC) and HT-PEMFC. The addition of the SLG produced by CVD into the MEA of LT-PEMFC has demonstrated no change in the proton conductivity, supporting the hypothesis that SLG is a good proton conductor. SLG and GO have been also incorporated successfully into the MEA of HT PEMFC, which use PBI as membrane, to evaluate the proton conductivity and barrier properties, this time to stop the phosphoric acid leaching.