A π-Conjugated Anion-Exchange Membrane with an Ordered Ion-Conducting Channel via the McMurray Coupling Reaction

The McMurry coupling is a facile, gentle and low-cost chemical reaction for synthesizing. Here, for the first time, we employed the McMurry coupling reaction to prepare pi-conjugated anion exchange membranes (AEMs). The inter-chain pi-pi stacking between adjacent benzene rings induces directional self-assembly aggregation and enables highly ordered ion-conductive channels. The resulting structure was characterized through UV/VIS spectrum, X-ray diffraction (XRD) pattern, small-angle X-ray scattering (SAXS), transmission electron microscopy (TEM) and density functional theory (DFT) calculations, leading to high OH conductivity of 135.5 mS cm(-1) at 80 degrees C. Furthermore, the double bonds in the pi-conjugated system also trigger in situ self-crosslinking of the AEMs to enhance dimensional and alkaline stability. Benefiting from this advantage, the as-obtained Cr-QPPV-2.51 AEM exhibits superior alkaline stability (95 % conductivity retention after 3000 hrs in 1 M KOH at 80 degrees C) and high mechanical strength of 34.8 MPa. Moreover, the fuel cell using Cr-QPPV-2.51 shows a maximum peak power density of 1.27 W cm(-2) at 80 degrees C.

Automated summary

The McMurry coupling reaction was used to synthesize pi-conjugated anion exchange membranes (AEMs), which exhibited highly ordered ion-conductive channels and excellent alkaline stability and mechanical strength. These membranes are promising materials for applications in fuel cells.