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Enhancement of fuel cell performance of sulfonated poly(arylene ether ketone) membrane using different crosslinkers

Munavalli, Balappa B., Kariduraganavar, Mahadevappa Y.
Journal of membrane science 2018 v.566 pp. 383-395
artificial membranes, atomic force microscopy, composite polymers, crosslinking, electric power, fuel cells, ion exchange capacity, microstructure, oxidative stability, phenolphthaleins, polystyrenes, potassium, relative humidity, scanning electron microscopy
Fuel cells are considered as clean and efficient devices for the generation of electric power. The commercial viability of proton exchange membrane fuel cell largely depends on membrane properties. Thus, this paper emphasizes on the preparation of crosslinked sulfonated poly(arylene ether ketone) membranes and their evaluation for fuel cell application. Initially, the copolymer was synthesized using phenolphthalein monomer, potassium 2,5-dihydroxybenzenesulfonate and 4,4′-diflorobenzophenone. To improve the fuel cell performance, the copolymer was crosslinked with different mass% of polystyrene sulfonic acid-co-maleic acid sodium salt (PSSA-MA) and sulphothalic acid (SPTA). The physico-chemical properties of the resulting membranes were studied using various techniques. The microstructure of the membranes was examined by scanning electron microscopy and atomic force microscopy. The oxidative stability was performed in Fenton's solution at 80 °C and indicated that more than 92% of the membrane residue remained with a minimum loss of ion exchange capacity (IEC). The proton conductivity was investigated in fully hydrated state, which revealed that the proton conductivity of both the series of crosslinked membranes was increased with increasing the content of PSSA-MA and SPTA up to 20 mass%. Among the series, 20 mass% of PSSA-MA and SPTA incorporated crosslinked membranes exhibited the highest IEC values of 2.569 and 2.342 meq g⁻¹, respectively. Similarly, the proton conductivity of PSSA-MA and SPTA crosslinked membrane was found to be 0.134 and 0.117 S cm⁻¹ at 80 °C with 100% relative humidity. The performance of fuel cell study revealed that 20 mass% of PSSA-MA and SPTA crosslinked membranes demonstrated an excellent power density of 0.45 W cm⁻² at 0.82 A cm⁻² and 0.42 W cm⁻² at 0.71 A cm⁻², respectively. Thus, these two crosslinked membranes developed here could be used as promising candidates for fuel cell applications.