Towards the gemini cation anion exchange membranes by nucleophilic substitution reaction

Abstract

As a critical component of alkaline fuel cells, anion exchange membranes determine the energy efficiency, output power density and the long term stability. Recently, the anion exchange membranes with gemini-cation side chains exhibit superior ion conductivity due to their good nanophase separation. However, the costly and complicated synthesis limits their scaling up and commercialization. To address this problem, a convenient synthetic procedure under mild conditions is well developed. A tertiary amine precursor is introduced onto the polymer by the nucleophilic substitution reaction to avoid the conventional chloro/bromo-methylation. Followed by a simple Menshutkin reaction with 6bromo-N,N,N-trimethylhexan-1-aminium bromide, the polymer electrolytes are obtained in a high yield. The resulting anion exchange membranes with high conductivity, good fuel cell performance and restricted swelling suggest the potential for the application in fuel cell devices.

Cation–dipole interaction that creates ordered ion channels in an anion exchange membrane for fastOH−conduction

“…52,53 The To compare our membranes with recently reported AEMs, we summarize the AEMFCs peak power densities as a function of room temperature OH − conductivities for recently reported AEMs that based on similar aryl ether-containing polyaromatics backbone (Figure 4g and Table S2). 9,20,21,47,[54][55][56][57][58][59][60][61][62][63][64][65][66][67][68] And our QA38PPO-P membrane show a competitive OH − conductivity and fuel cell performance among these AEMs. This highlights the advantages of developing AEMs containing well-defined cation-dipole interaction networks, which can form inter-connected ionic channels that facilitate ion transport.…”

Ion Exchange Membrane “ABC” – A Key Material for Upgrading Process Industries

“…The side chains promote the formation of interconnected ion‐conducting channel, which results in high ion conductivity. On this basis, we further optimized the side chain structure by increasing the number (two or three) of the cationic groups (Figures 4c, 4d), [ 32‐33 ] and found that the multi‐functionalized side chains will aggregate together easier to form the well‐connected ion‐conducting channel, the ion transfer efficiency was much higher when introducing three cations in side chain, with hydroxide conductivity of 69 mS/cm at room temperature, which is comparable to that of the proton exchange membrane Nafion. It demonstrated a facile but efficient strategy to design highly OH − conductive IEMs.…”

Fluorinated poly(fluorenyl ether)s with linear multi-cationic side chains for vanadium redox flow batteries

“…Quaternary ammonium-functionalized AEMs are the most widely researched because of their good hydrophilicity and high anion conductivity [27][28][29][30]. Generally, they can be synthesized by two reaction routes: (1) post-halomethylation of polymer precursors followed by quaternization [31][32][33] or (2) direct polymerization of quaternary ammonium-or amine-containing monomers [34][35][36].…”