Selective anion exchange membranes for high coulombic efficiency vanadium redox flow batteries

• Published in: Electrochemistry communications 2013-01, Vol.26, p.37-40
• Main Authors: Chen, Dongyang, Hickner, Michael A., Agar, Ertan, Kumbur, E. Caglan
• Format: Article
• Language: English
• Subjects: Anion exchange membrane; Applied sciences; Capacity fade; Coulombic efficiency; Direct energy conversion and energy accumulation; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Self-discharge; Vanadium redox flow battery
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2012.10.007

A quaternary ammonium functionalized poly(fluorenyl ether) anion exchange membrane (AEM) with extremely low VO2+ permeation was characterized for vanadium redox flow battery (VRFB) application. One hundred percent coulombic efficiency (CE) was achieved for the AEM-based VRFB at all the current densities tested. Comparatively, the CE of a N212 membrane-based VRFB was lower than 94% and varied with charge/discharge current density. At current densities lower than 60mAcm−2, the energy effiency of the AEM-based VRFB was higher than that of a device with N212. The cycling performance demonstrated that the AEM-based VRFB was free of capacity fade, which is a consequence of its low VO2+ permeability. These observations are of significant importance for flow batteries that operate intermittently or at moderate current densities. ► Anion exchange membrane blocked the transport of vanadium ions due to the Donnan effect. ► One hundred percent coulombic efficiency of battery was achieved using anion exchange membrane. ► Lower current density gave higher voltage efficiency and energy efficiency. ► No capacity fade for maintenance-free operation