Quaternized cardo polyetherketone anion exchange membrane for direct methanol alkaline fuel cells

Alkali resistant and conductive guanidinium-based anion-exchange membranes for alkaline polymer electrolyte fuel cells

“…Among the variety of methods used for AAEM synthesis, an important and common method is to modify an existing base polymer, such as poly(phthalazinon ether sulfone ketone) (PPESK) [9], polysulfone (PS) [10] and poly(ether ketone) (PEK) [11]. Typically, the AAEMs are synthesized via chloromethylation of the pristine polymers and subsequent exposure to trimethylamine (TMA) to form the desired benzyltrimethyl-type quaternary ammonium (QA) head-groups [9][10][11].…”

“…Among the variety of methods used for AAEM synthesis, an important and common method is to modify an existing base polymer, such as poly(phthalazinon ether sulfone ketone) (PPESK) [9], polysulfone (PS) [10] and poly(ether ketone) (PEK) [11]. Typically, the AAEMs are synthesized via chloromethylation of the pristine polymers and subsequent exposure to trimethylamine (TMA) to form the desired benzyltrimethyl-type quaternary ammonium (QA) head-groups [9][10][11]. However, there are three potential disadvantages with the use of AAEMs: (1) The commonly used chloromethyl methyl ether, used for the chloromethylation step, is a carcinogen and highly harmful to human health (its use has been restricted since 1970s) [12]; (2) The poor stability of the QA head-groups (the most commonly encountered) in alkaline environments is caused by the attack on the quaternary ammonium groups by the strongly nucleophilic OH -anions via direct nucleophilic displacements, Hofmann elimination reactions, and/or minor side-reactions involving ylide-intermediates [1,[13][14][15]; (3) The lower ionic conductivities observed are due to the weak alkalinity of QA hydroxides (cf.…”

High-performance alkaline fuel cells using crosslinked composite anion exchange membrane

“…at 30 C) [8], QPPESK (0.005 S cm À1 at 30 C) [9], QPEK-C (0.0016 S cm À1 at 20 C) [10], crosslinked SPES-OH (around 0.019 S cm À1 at 20 C) [14], crosslinked xTQAPS (around 0.018 S cm À1 at 20 C) [15], radiation-grafted ETFE (0.034 S cm…”

Membranes for Direct Alcohol Fuel Cells

“…Many kinds of AEMs based on quaternized polymers containing a quaternary ammonium group have been developed and tested in ADAFC, such as polyethersulfone cardo (QPES-C) [205], polyetherketone cardo (QPEK-C) [206], poly (phthalazinone ethersulfone ketone) (QPPESK) [207], poly(arylene ethersulfone) (QPAES) [208][209][210], QPAES cross-linked with tetraphenylolethane glycidyl ether (QPAES/4EP) [210], poly (arylether oxadiazole) (QPAEO) [211], polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (QSEBS) [212], poly(vinyl alcohol) (QPVA) [213], poly(vinyl chloride) (QPVC) [214], and poly (vinylbenzyl chloride) (QPVBC) [215]. The chemical structures of some of these polymers are shown in Fig.…”

“…In fact, the ionic conductivity of ammonium quaternized AEM at room temperature spreads over a wide range of values, from a few mS.cm À1 for QPEK-C [206], QSEBS [212], and QPVA [213], up to 60 and 140 mS.cm À1 for QPAES [209] and QPPEKS [207], respectively. Figure 6.38a shows the conductivity of QPAES membrane as a function of the KOH concentration of the solution where the membrane was equilibrated.…”