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

Abstract

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 π‐conjugated anion exchange membranes (AEMs). The inter‐chain π‐π 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 °C. Furthermore, the double bonds in the π‐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 °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 °C.

Polyketone-Based Anion-Exchange Membranes for Alkaline Water Electrolysis

“…To date, no membrane has presented all of these parameters together, and investigations have been focused on efficient AEMs with the required chemical and thermal stability [14]. In this sense, the membrane's chemical and thermal performances depend strongly on the nature of the moiety capable of carrying hydroxyl anions and the polymer backbone [15]. Among the different cationic groups, the quaternary ammonium groups exhibit greater chemical and thermal stability than the quaternary phosphorus or tertiary sulfur groups [13].…”