Properties Investigation of Sulfonated Poly(ether ether ketone)/Polyacrylonitrile Acid–Base Blend Membrane for Vanadium Redox Flow Battery Application

Abstract

Acid-base blend membrane prepared from sulfonated poly(ether ether ketone) (SPEEK) and polyacrylonitrile (PAN) was detailedly evaluated for vanadium redox flow battery (VRFB) application. SPEEK/PAN blend membrane exhibited dense and homogeneous cross-section morphology as scanning electron microscopy and energy-dispersive X-ray spectroscopy images show. The acid-base interaction of ionic cross-linking and hydrogen bonding between SPEEK and PAN could effectively reduce water uptake, swelling ratio, and vanadium ion permeability, and improve the performance and stability of blend membrane. Because of the good balance of proton conductivity and vanadium ion permeability, blend membrane with 20 wt % PAN (S/PAN-20%) showed higher Coulombic efficiency (96.2% vs 91.1%) and energy efficiency (83.5% vs 78.4%) than Nafion 117 membrane at current density of 80 mA cm(-2) when they were used in VRFB single cell. Besides, S/PAN-20% membrane kept a stable performance during 150 cycles at current density of 80 mA cm(-2) in the cycle life test. Hence the SPEEK/PAN acid-base blend membrane could be used as promising candidate for VRFB application.

Low vanadium ion permeabilities of sulfonated poly(phthalazinone ether ketone)s provide high efficiency and stability for vanadium redox flow batteries

“…This can be due to the degradation of sulfonic acid groups in VO 2 þ solution. In testing the stability after 30 days of soaking, the weight losses of SPPEK-P-70, SPPEK-P-80 and SPPEK-P-90 membranes are lower than that of SPPEK-TPA membranes (3.87%) at the same conditions [30], and also lower than that of sulfonated poly(ether ether ketone)/polyacrylonitrile acid blend membrane (4.0%) after soaking for two weeks [31]. Even after 60 days of soaking, the weight losses of SPPEK-P-70 and SPPEK-P-80 are still lower than 4.0%.…”

Highly branched sulfonated poly(fluorenyl ether ketone sulfone)s membrane for energy efficient vanadium redox flow battery

“…The VRFB single cell configuration was the same as reported previously [27,49]. The membrane (70 mm  70 mm) was sandwiched between two thermal activated graphite felt electrodes (50 mm  50 mm  5 mm).…”

Thin skinned asymmetric polybenzimidazole membranes with readily tunable morphologies for high-performance vanadium flow batteries

“…These membranes are low-cost and show high vanadium prevention attributed to the rigid main chain which leads to a poor microphase separation and narrow and tortuous ionic channels. 7,[21][22][23][24][25] Nevertheless, the application of these membranes in VFB is hampered by their poor chemical stability, which is considered to be induced by the introduction of ion exchange groups. [26][27][28][29][30] In order to address this issue, Zhang et al started to focus on porous membranes for VFBs, 31 which separates large vanadium ions from small protons by screening mechanism.…”