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[Display omitted] • Chemically stable dual-methylpipieridinium crosslinker was confirmed. • The QBNTP-MP11 AEM showed excellent conductivity and toughness. • The QBNTP-MP11 AEM displayed outstanding durability. • The BNTP-MP11 AEM exhibited high fuel cell and water electrolysis performance. A series of novel crosslinked poly(binaphthyl-co-terphenyl piperidinium)s (QBNTPs) based on various dual-piperidinium crosslinkers are designed and prepared as anion exchange membranes (AEMs) for alkaline fuel cells and water electrolysis. The excellent alkaline stability of the dual-piperidinium crosslinker with methyl substituent on the C4-position of the piperidinium ring is first confirmed. The as-prepared dual-methylpiperidinium crosslinked poly(binaphthyl-co-terphenyl piperidinium) (QBNTP-MP11) AEM shows an exceptional OH− conductivity (181.2 mS cm−1) and a suppressed swelling ratio (19.7%) at 90 °C. QBNTP-MP11 also exhibits a superior toughness (6.08 MJ m−3) and a marked storage modulus (6.52 × 106 Pa). Additionally, having less than 5% OH− conductivity deterioration after being treated in 2 M NaOH at 80 °C for 1560 h, QBNTP-MP11 demonstrates an outstanding durability. Notably, QBNTP-MP11 can achieve a high peak powder density of 1.41 W cm−2 in a single cell test and an excellent current density of 2.7 A cm−2 at 2.0 V in alkaline water electrolysis. Meanwhile, QBNTP-MP11 demonstrates a desirable durability in a single cell operation and water electrolysis. All those results validate that the durable and robust QBNTP-MP11 has a good application perspective. The work is anticipated to provide a valuable guidance for the design of new stable and high-performance AEMs. [ABSTRACT FROM AUTHOR]

Alkaline stability is the critical issue for the practical application of anion exchange membranes (AEMs) in fuel cells. The benzyltrimethyl ammonium and backbone with C-O linkages of the traditional AEMs are susceptible to attack by hydroxide ions resulting in poor alkaline stability of the AEMs. Herein, we present the preparation of polystyrene-b-poly(ethylene-co-butylene)-b-polystyrene (SEBS) triblock copolymer via grafting, ketone reduction and quaternization for AEM fuel cell applications. The quaternary ammonium (QA) groups are attached to the SEBS backbone free of C-O linkages via long flexible alkyl spacers, which are responsible for the robust alkaline stability of the AEMs. Thus, the hydroxide conductivity of SEBS-CH 2 -QA-1.5 was only decreased by 7.7% and 13.7% after immersing the membranes into a 1 M aqueous KOH solution at 60 and 90 °C for 360 h, respectively. Furthermore, SEBS-CH 2 -QA-1.5 with IEC of 1.23 meq g −1 exhibits a maximum hydroxide conductivity of 56.4 mS cm −1 at 80 °C and a maximum power density of 94.6 mW cm −2 under a current density of 300 mA cm −2 . [ABSTRACT FROM AUTHOR]

A novel type of graphene oxide (GO)/Nafion composite membrane is fabricated and used as a proton exchange membrane for direct methanol fuel cells (DMFCs) in this article. The membranes are prepared by depositing GO nanosheets on the surface of recast Nafion ® 117 via a layer-by-layer (LbL) procedure using 1, 4-phenyldiamine hydrochloride (PDHC) as the cross-linker. This approach prevents the GO nanosheets from dissolving in water and imparts the composite membranes a good stability. The methanol permeability of the composite membranes is lower than that of recast Nafion ® 117 measured under the same conditions. The composite membrane with 80-layered GO nanosheets exhibits a value of 6.7×10 −8 cm 2 s −1 at 30 °C, which is two orders of magnitude lower than that of recast Nafion ® 117. In addition, the relative selectivity of the composite membranes is 5 times higher than that of recast Nafion ® 117. The endurance time of the composite membranes in Fenton׳s reagent is 10 times longer than that of Nafion. Single cell evaluation using the composite membrane with 50-layered GO showed an open circuit voltage (OCV) of 0.67 V. A maximum power density of 64.38 mW cm −2 at a current density of 200 mA cm −2 can be achieved at 60 °C. [ABSTRACT FROM AUTHOR]