Cross-Linked Benzoxazine–Benzimidazole Copolymer Electrolyte Membranes for Fuel Cells at Elevated Temperature


Here we report new H<sub>3</sub>PO<sub>4</sub>-doped cross-linked benzoxazine–benzimidazole copolymer membranes showing high proton conductivity and long-term durability for use in proton-exchange membrane fuel cells at elevated temperatures (>100 °C). The cross-linked copolymer membranes were prepared by mixing of poly­[2,2′-(<i>m</i>-phenylene)-5,5′-bibenzimidazole] (PBI) with 3-phenyl-3,4-dihydro-6-<i>tert</i>-butyl-2<i>H</i>-1,3-benzoxazine (<i>p</i>BUa) in <i><i>N,N</i></i>-dimethylacetamide, with subsequent stepwise heating to 220 °C, and even large-sized films (30 cm × 140 m) could be easily prepared. The membranes showed high proton conductivities of up to 0.12 S cm<sup>–1</sup> at 150 °C under anhydrous conditions. Membrane–electrode assemblies (MEAs) employing the membranes showed operating voltages of 0.71 V at 0.2 A cm<sup>–2</sup>. Furthermore, the MEAs displayed long-term durability up to 1999 cycles, with much slower performance decay, −0.03 mV h<sup>–1</sup>, than those prepared using the PBI membrane in <i>in situ</i> accelerated lifetime mode (load cycling testing)

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oai:figshare.com:article/2550790Last time updated on 2/12/2018

This paper was published in FigShare.

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