The Effect of Various Functional Groups on the Morphology and Performances of Crosslinked Addition‐Type Poly(Norbornene)s‐Based Anion Exchange Membranes

ABSTRACT To investigate the effect of different functional groups on the morphology and properties of crosslinked anion exchange membranes (AEMs), a series of novel partially crosslinked addition‐type poly(norbornene)s‐based AEMs were prepared by flexibly grafting N‐methylpyrrolidinium, N‐methylpiperidinium, N‐methylmorpholinium, and 1, 2‐dimethylimidazolium onto an addition‐type poly(norbornene)s backbone. The well‐developed microphase separation morphology was observed for all the prepared crosslinked AEMs using AFM and SAXS. The AEM with N‐methylpyrrolidine groups (CL‐aPNB‐TMHDA‐MPY) constructed more uniform and wider ion transport channel, exhibiting the highest hydroxide conductivity of 122.0 mS cm −1 at 80°C. The AEM‐tethering N‐methylpiperidine cations (CL‐aPNB‐TMHDA‐MPRD) exhibited the best alkaline stability and achieved 90.61% conductivity retention even after being soaked in 1 M NaOH at 80°C for 1008 h. Meanwhile, the order of alkaline stability was CL‐aPNB‐TMHDA‐MPRD>CL‐aPNB‐TMHDA‐MPY>CL‐aPNB‐TMHDA‐DMMI>CL‐aPNB‐TMHDA‐NMM. The peak power density of a H 2 /O 2 fuel cell equipped with CL‐aPNB‐TMHDA‐MPY, CL‐aPNB‐TMHDA‐MPRD, CL‐aPNB‐TMHDA‐NMM, and CL‐aPNB‐TMHDA‐DMMI were 247.3, 218.1, 185.9, and 178.0 mW cm −2 at 80°C, respectively. These results of the comparison of AEMs with different cation groups give some insights for designing high‐performance AEMs in future.