Sulfonated poly (fluorenyl ether ketone nitrile) membranes used for high temperature PEM fuel cell

A series of sulfonated poly (fluorenyl ether ketone nitrile)s with different equivalent weights (EW) ranging from 681 to 369 g mequiv.^-1 were used to assemble a series of single proton exchange membrane fuel cells (PEMFC) in their turns. The mechanical strength and morphology of the copolymer were studied systematically. This paper mainly evaluated and compared their cell performance. The polarization curves showed that the prepared films have good performance at low temperature and high relative humidity. Due to the increase of temperature, dehydration seriously deteriorated the performance of the cell, especially for the membrane with high electron flow and low proton conductivity. However, at 100 °C, the cell performance of the membrane containing 441 g mequiv.^{- 1} was even better than that of Nafion^@117 membrane. It could even be used at 125 °C. In the short life test, the output power density was stable at about 0.24 W•cm^-2 within 24 h. These results show that our membranes were suitable for the applications of PEM fuel cell at high temperature.