High-performance layered double hydroxide/poly(2,6-dimethyl-1,4-phenyleneoxide) membrane with porous sandwich structure for anion exchange membrane fuel cell applications

Herein, we present a porous-sandwich-structure anion exchange membrane (AEM) to improve the comprehensive performance of the AEM. A series of porous-sandwich-structure AEMs based on triple-cation side chain poly(2,6-dimethyl-1,4-phenylene oxide) (TC-QAPPO) membrane were synthesized by spaying quaternary-ammonium-modified layered double hydroxide (QA-LDH) on the surface of the TC-QAPPO membrane. Compared with the TC-QAPPO membrane, the QA-LDH/TC-QAPPO composite membranes show higher alkaline stability, hydroxide conductivity, and dimensional stability than those of TC-QAPPO membrane. The QA-LDH layer exhibits an impressive ion conductivity and alkali resistant ability, acting as a protective layer to protect the TC-QAPPO membrane from being attacked by hydroxide. The porous structure was designed to accelerate the ion conductivity in QA-LDH layer. The QA-LDH/TC-QAPPO membranes with low swelling ratio exhibits a maximum hydroxide conductivity of 122 mS/cm at 80 degrees C. A long-term stability test demonstrates that the QA-LDH/TC-QAPPO membranes have a maximum retention (85.4%) of hydroxide conductivity in 1M KOH at 80 degrees C for 500 h. Besides, the QA-LDH/TC-QAPPO membrane achieves a maximum power density of 267 mW/cm(2) at current density of 554 mA/cm(2) at 60 degrees C. The porous-sandwich-structure strategy provides a new and reliable method to prepare high-performance AEMs for alkaline fuel cell applications.