Crosslinked anion exchange membrane with improved membrane stability and conductivity for alkaline fuel cells

Abstract

As a core component of anion exchange membrane (AEM) fuel cells, it has practical significance to improve the performance of AEMs. However, it is difficult to obtain AEM with both good stability and high conductivity. In this study, a series of AEMs were prepared by chloromethylation, quaternization, and crosslinking reactions. The quaternization reaction was carried out first to ensure that there are abundant quaternary ammonium groups on AEM and enhance the conductivity of membrane. N,N,N′,N′‐tetramethylethylenediamine was used as a crosslinker to improve membrane stability and mechanical property. A simple, mild, and cost‐effective AEM synthetic route was developed. This strategy achieves a certain balance of electrochemical and physical properties. The effect of the crosslinking reactions on the property of membrane was evaluated. Crosslinked membranes have better dimensional stability (water uptake: 20.2% and swelling ratio: 2.1%), mechanical properties (55.84 MPa), and alkaline stability because crosslinked structures result in large steric hindrance. The mutually independent quaternization and crosslinking reaction do not affect the electrochemical performance of membranes; in the crosslinking reaction stage, crosslinker also reacted as quaternization agent and increased the number of reactive groups in AEM. Thus, the resulting crosslinked AEM exhibits higher ion exchange capacity and ionic conductivities (46.4 mS cm−1). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48169.

Poly(alkyl-biphenyl pyridinium) anion exchange membranes with a hydrophobic side chain for mono-/divalent anion separation

“…The peak at 2.28 ppm corresponds to H3 in the methyl group. After the reaction with 1-bromopentane, a quaternized product gives an additional peak at 4.54 ppm marked as H6 in the 1 H NMR spectra 26 . New peaks from 0.75 to 2.38 ppm are attributed to the alkyl side chain.…”

“…After the reaction with 1-bromopentane, the quaternized product gives an additional peak at 4.54 ppm marked as H6 in the 1 H NMR spectra. 26 New peaks from 0.75 to 2.38 ppm are attributed to the alkyl side chain. H1 in the newly formed pyridinium ion shifted to 9.00 ppm, and H1 in the pyridine ring without the Menshutkin reaction dropped to 8.51 ppm.…”

Diffusion Dialysis for Acid Recovery from Acidic Waste Solutions: Anion Exchange Membranes and Technology Integration

“…One effective strategy for solving this problem and improving membrane stability is crosslinking [ 104 , 105 ]. Wu [ 106 ] studied the properties of PVA-based AEMs crosslinked by different crosslinking agents, such as small alkoxysilanes (tetraethoxysilane (TEOS), γ -glycidoxypropyltrimethoxysilane (GPTMS), monophenyltriethoxysilane (EPh)) and copolymers (glycidylmethacrylate (GMA) and methacryloxypropyl trimethoxy silane (MPS)).…”

“…One effective strategy for solving this problem and improving membrane stability is crosslinking [104,105].…”

Anion exchange membranes based on poly (styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene) grafted poly (2,6‐dimethyl‐1,4‐phenylene oxide)

“…22 Crosslinking is considered as an effective countermeasure to limit swelling behavior to AEMs, since the crosslinked network structure restrains the further expansion of the chain spacing. [23][24][25][26] Hao and Dai et al 27,28 both adopted N,N,N 0 ,N 0 -tetramethyl-1,6-hexanediamine as the crosslinker and synthesized the crosslinked membranes based on SEBS (M:OH-1:1 and QSEBS-C 6 ) with superior dimensional stability. M:OH-1:1 membrane exhibited a low WU (less than 7%) and restrained swelling behavior (swelling ratio [SR] of 8%-5%).…”