Dual-Side-Chain-Grafted Poly(phenylene oxide) Anion Exchange Membranes for Fuel-Cell and Electrodialysis Applications

Anion exchange membranes (AEMs) usually suffer from the trade-off between ion conduction and stability. In this work, a series of dual-side-chain-grafted poly(phenylene oxide) AEMs were synthesized to explore how the side-chain architectures influence membrane performance. Our investigations suggest that the AEM containing both a long hydrophobic extender (attached to the cation's central atom) and a hydrophilic additional side chain (beside the cation) show high hydroxide conductivity (21.3 mS/cm at 30 degrees C) and good chemical and dimensional stability (90.5% conductivity retention after 1 M NaOH treatment at 60 degrees C for 528 h). In addition, when a tri-cation side chain and a hydrophobic side chain are incorporated simultaneously, the resulting AEM shows further improved conductivity and stability (50.0 mS/cm at 30 degrees C; 90.6% conductivity retention after 1 M NaOH treatment at 60 degrees C for 528 h); it also shows excellent electrochemical performance when applied in a fuel cell and an electrodialyzer, accomplishing a peak power density of 506 mW/cm(2) and a current efficiency of 96.11%, respectively. Our side-chain manipulation strategy provides a new and effective pathway to balance the ionic conductivity and stability of AEMs.

Automated summary

The synthesized AEMs with specific side-chain structures achieved a good balance between ion conduction and stability, exhibiting excellent electrochemical performance and providing a new effective pathway for the research of AEMs.