Durable dual-methylpiperidinium crosslinked poly(binaphthyl-co-terphenyl piperidinium) anion exchange membranes with high ion transport and electrochemical 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.