Composite Anion-Exchange Membrane Fabricated by UV Cross-Linking Vinyl Imidazolium Poly(Phenylene Oxide) with Polyacrylamides and Their Testing for Use in Redox Flow Batteries

Abstract

Composite anion-exchange membranes (AEMs) consisting of a porous substrate and a vinyl imidazolium poly(phenylene oxide) (VIMPPO)/acrylamide copolymer layer were fabricated in a straightforward process, for use in redox flow batteries. The porous substrate was coated with a mixture of VIMPPO and acrylamide monomers, then subsequently exposed to UV irradiation, in order to obtain a radically cured ion-exchange coating. Combining VIMPPO with low-value reagents allowed to significantly reduce the amount of synthesized ionomer used to fabricate the mem- brane down to 15%. Varying the VIMPPO content also allowed tuning the ionic transport properties of the resulting AEM. A series of membranes with different VIMPPO/acrylamides ratios were prepared to assess the optimal composition by studying the changes of membranes properties—water uptake, area resistivity, permeability, and chemical stability. Characterization of the membranes was followed by cycling experiments in a vanadium RFB (VRFB) cell. Among three composite membranes, the one with VIMPPO 15% w/w—reached the highest energy efficiency (75.1%) matching the performance of commercial ion-exchange membranes (IEMs) used in VRFBs (Nafion® N 115: 75.0% and Fumasep® FAP 450: 73.0%). These results showed that the proposed composite AEM, fabricated in an industrially oriented process, could be considered to be a lower-cost alternative to the benchmarked IEMs.

Impact of Formulation of Photocurable Precursor Mixtures on the Performance and Dimensional Stability of Hierarchical Cation Exchange Membranes

“…Moreover, the progressive swell of a coating when a membrane is placed in a fixed position in a cell may cause crack of the membrane due to the internal stress arisen . Composite hIEMs were previously developed and fabricated with the use of a non-UV-reactive solvent in membrane formulation. , It was proposed that the introduction of a nonreactive solvent to the UV-reactive acrylic precursor mixture allows for the preparation of an ionomer matrix initially swollen by the solvent, limiting the expansion of the coating in contact with water. However, a proper solvent selection for membrane formulation is a challenge since ionomer precursors often reveal drastically different solvation properties.…”

Anion Exchange Membranes Based on Bis-Imidazolium and Imidazolium-Functionalized Poly(phenylene oxide) for Vanadium Redox Flow Battery Applications

“…More recently, the usage of AEMs in VRFB applications has attracted great attention because of the low vanadium permeability resulting from the effects of Donnan exclusion on the AEMs cations. , AEMs containing quaternary ammonium, , imidazolium, and pyridinium cations have been investigated for VRFB applications, and those with imidazolium cations have exhibited good performance. − …”

“… 15 , 16 AEMs containing quaternary ammonium, 15 , 16 imidazolium, 17 and pyridinium 18 cations have been investigated for VRFB applications, and those with imidazolium cations have exhibited good performance. 19 − 22 …”

Cross-Linked Anion-Exchange Membranes with Dipole-Containing Cross-Linkers Based on Poly(terphenyl isatin piperidinium) Copolymers

“…As a critical component, effective anion-exchange membranes (AEMs) are widely used in electrochemical technologies, such as anion-exchange membrane fuel cells (AEMFCs), , flow batteries, , and water electrolysis. , Typically, AEMs are composed of polymer backbones, such as poly­(sulfone)­s, poly­(arylene ether ketone)­s, , and poly­(phenylene oxide)­s, ,, and cationic groups . However, recent studies have shown that the polymer backbone with electron withdrawing groups is chemically unstable under alkaline conditions due to the backbone cleavage resulting from hydroxide ion attack .…”

“…As a critical component, effective anion-exchange membranes (AEMs) are widely used in electrochemical technologies, such as anion-exchange membrane fuel cells (AEMFCs), 1,2 flow batteries, 3,4 and water electrolysis. 5,6 Typically, AEMs are composed of polymer backbones, such as poly(sulfone)s, 7 poly(arylene ether ketone)s, 8,9 and poly(phenylene oxide)s, 6,10,11 and cationic groups.…”