Protic ionic liquid/functionalized graphene oxide hybrid membranes for high temperature proton exchange membrane fuel cell applications

The 1-(3-aminopropyl)-3-methylimidazolium bromide ([APMIm][Br]) functionalized graphene oxide ([APMIm][Br]-GO) and 1-methylimidazolium trifluoromethanesulfonate ([MIm][TfO]) are prepared and used as fillers and proton carrier in the preparation of high temperature hybrid proton exchange membranes (PEMs), respectively. The PEMs are obtained via photo-initiated polymerization of a mixture containing polymerizable oil (styrene/acrylonitrile and divinylbenzene), protic ionic liquid (PIL, [MIm][TfO]), and different content of [APMIm][Br]-GO. The resultant membranes show good thermal stability and excellent mechanical properties. Incorporation of proper amount of [APMIm][Br]-GO significantly increases the proton conductivity of the hybrid membranes, and the membranes with 1.0 wt% [APMIm][Br]-GO shows the highest conductivity (up to 1.48 × 10−2 S cm−1 at 160 °C). Compared with the plain membrane without [APMIm][Br]-GO, the hybrid membranes with [APMIm][Br]-GO show much better PIL retention ability. These properties make this type of PIL-based hybrid membranes suitable for the application of high-temperature proton exchange membrane fuel cells (PEMFCs).