Dual-Side-Chain-Grafted Poly(phenylene oxide) Anion Exchange Membranes for Fuel-Cell and Electrodialysis Applications
Lv Li, Jiaao Wang, Lingling Ma, Lei Bai, Anran Zhang, Naeem Akhtar Qaisrani, Xiaoming Yan, Fengxiang Zhang, Gaohong He
Abstract
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 °C) and good chemical and dimensional stability (90.5% conductivity retention after 1 M NaOH treatment at 60 °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 °C; 90.6% conductivity retention after 1 M NaOH treatment at 60 °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/cm2 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.