Quaternized poly(arylene ether benzonitrile) membranes for vanadium redox flow batteries

A series of quaternized poly (arylene ether benzonitrile)s (QAxCN; x = percent quaternization) were synthesized for the vanadium redox flow battery (VRFB) application. The presence of highly polar nitrile groups incorporated in the quaternized polymer chain provides desirable polymer properties (low water uptake, high dimensional stability and low VO(2+ )permeability) without compromising ion conductivity. VRFB single cells using the aforementioned membranes showed excellent performance. The cell using a 15 mu m-thick QA50CN membrane exhibited superior coulombic efficiency (98.2%) and comparable energy efficiency (86.5%) at 40 mA cm(-2) compared to the single cell using Nafion-212 with a coulombic efficiency of 95.5% and an energy efficiency of 86.2%. The cell cycling stability and membrane oxidative stability data confirmed that the QAxCN membranes have the potential to replace Nafion membranes for energy storage in VRFB applications.

Automated summary

A series of quaternized poly(arylene ether benzonitrile)s were synthesized for VRFB applications, showing desirable properties such as low water uptake, high dimensional stability, and low VO(2+) permeability. The membranes exhibited excellent performance in single cells, with high coulombic efficiency and energy efficiency. The cycling stability and oxidative stability data confirmed the potential of QAxCN membranes to replace Nafion membranes in VRFB energy storage applications.