Tetramethyl poly(aryl ether ketone) modified by DABCO cationic polymer for high temperature proton exchange membrane fuel cells

Rationally constructing proton transport channel within high temperature proton exchange membranes (HT-PEMs) plays a critical role in lowering the mass transfer resistance and thus improving the performance of HT-PEM fuel cells (HT-PEMFCs). We herein designed a microphase-separated structure to promote proton transmitting by incorporating 1,4-Diazabicyclo[2.2.2]octane (DABCO) cationic polymer into tetramethyl poly(aryl ether ketone) (TMPAEK). The flexible and cationic segments afforded a polarity difference from TMPAEK, resulting in easier phosphoric acid adsorption. High proton conductivity of 135 mS cm-1 was obtained under anhydrous conditions at 150 oC. Besides, the hydrophilic domains that containing N-heterocycle could stabilize phosphoric acid through hydrogen bonding interactions, resulting in high phosphoric acid retention of ∼80% after 288 hours test. A Peak power density of 496 mW cm-2 was achieved in non-humidified H2/O2 without back pressure at 140 oC, which was higher than that of m-PBI under the same conditions. This work not only paved a way to tailor the ion conductivity of membrane, but also provided a highly competitive membrane for HT-PEMFCs.