Microcrystalline induced physical-crosslinking towards high performance branched anion exchange membrane

Abstract Anion exchange membrane (AEM) is the core component of low-cost anion exchange membrane fuel cell (AEMFC). To realize the commercial application of AEMFC, extremely low swelling of AEM is vital for the membrane electrode assembly preparation and cell integrity, except for high hydroxide conductivity, strength and chemical stability. However, it is hard to achieve extremely low swelling ratio while maintain high conductivity, especially for homogenous membrane. Herein, a series of quaternized poly(trans-1,2-diphenylethylene-co-terphenyl-N,N′-dimethyl piperidinium) with sophisticated structure are synthesized for AEM to address such dilemma. The physical-crosslinking induced by microcrystalline, effectively restricts the swelling of AEM (< 5.8%@80°C). Moreover, branched structure is also introduced to increase the free volume in the polymer membrane, leading to high conductivity up to 275.6 mS cm-1@80°C simultaneously. Accordingly, excellent fuel cell performance with peak power density of 1.13 W cm-2 for H2-O2 at 80°C is attained.