Study On Structure And Performance Of The Membrane Electrode Assembly For PEMFCs

Proton exchange membrane fuel cell(PEMFC) has advantages such as smallvolume, environment friendly, quick start at ambient temperature.It is the most idealpower in the future of hydrogen age.However,because of high cost and complexoperation, commercialization of PEMFC is blocked. The core of PEMFC componentis membrane electrode assembly(MEA), optimizing the structure of the MEA,improve preparation technology can effectively improve the performance of PEMFC,and reduce the cost.The coating method for preparation of gas diffusion electrode (GDE) and hotpressing method for preparation of membrane electrode assembly(MEA) are used inthis article. Through the investigation on different operating temperature and differentoperating pressure MEA performance change,the quality of water and gas balancethese two factors of influence on the performance of the MEA is evaluated. In order toimprove the mass transfer and water balance,micro-porous layer(MPL) isestablished.In other word, anode and cathode of cell has the structure withmembrane│catalyst layers│MPL│diffusion layer.Hydrophobic processing of Carbon paper is studied, the PTFE emulsion macerateconcentration, dipping time and burning temperature, and the best PTFE content areinvestigated.The power density is0.6W/cm~2,the performance is in conformity withthe experiment.MPL is prepared with the hydrophobic carbon paper and without hydrophobiccarbon paper respectively,then MEA performance is evaluated through single cell,theelectrochemical parameter is get with SAS software.The results show that, the withouthydrophobic carbon paper,the best content of PTFE is40%, the highest powerdensity is0.62W/cm~2. The hydrophobic carbon paper shows the best performance atthe30%content of PTFE, the highest power is0.63W/cm~2.Respectively,(NH4)2SO4and NH4HCO3are used as pore-former,the effect ofpore structure,performance of MEA and the best content are studied.The results showthat,when using (NH4)2SO4as pore-former,the best content is1:1, the highest poweris0.68W/cm~2.Pore-former is also used in catalytic layer,and the content is optimized.The results show that pore-former could improve pore structure for mass transfer. And then, thecathode is hydrophobic modified, and best PTFE load is optimized.This paper also studies the different organic solvent to prepare catalytic layer.Malvern Nano ZS nanostructured particle size is used to analyze Nafion sizedistribution in different organic solvent and single cell is assembled.The result showsusing the isopropyl alcohol as solvent cell performance is the best.