Troger?s base polymer blended with poly(ether ketone cardo) for high temperature proton exchange membrane fuel cell applications

Developing membrane electrolyte materials with high performance and low cost is a key factor in promoting the application and commercialization of the high temperature proton exchange membrane fuel cell (HT-PEMFC). In this work, a Tro center dot ger's base (TB) polymer is synthesized from commercially available and low-cost 4,4 '-diamine3,3 '-dimethyl-biphenyl (DMBP) and dimethoxy methane in trifluoroacetic acid via a one-pot TB polymerization reaction under mild conditions. The obtained polymer is composited by TB unit and DMBP moiety (named as DMBP-TB), which occupies a good organic solubility, high thermal stability and excellent chemical resistance. Due to the built-in bicyclic amine rings and intrinsic microporous structure, the pure DMBP-TB membrane exhibits a remarkable phosphoric acid (PA) doping content as high as 1077% in 85 wt% PA solution at room temperature. However, the excessive swelling and poor mechanical integrity hinder the PA doped DMBP-TB membrane as the HT-PEM. Thus, the commercial and low-cost engineering thermoplastic of poly(ether ketone cardo) (PEKC) is employed as the enhanced material to prepare DMBP-TB blend membranes. The DMBP-TB/50% PEKC/149%PA membrane displays an anhydrous conductivity of 0.061 S cm-1 at 180 degrees C and a tensile strength of 8.7 MPa at room temperature, which enables H2-O2 fuel cell with a peak power density of 536 mW cm-2 at 180 degrees C without backpressure, suggesting the utility for HT-PEMFCs.

Automated summary

In this study, a DMBP-TB/PEKC/PA blend membrane with high conductivity and mechanical strength was successfully prepared by synthesizing TB polymer and doping with engineering thermoplastic PEKC. This provides a potential solution for the application of high temperature proton exchange membrane fuel cells.