Low-tortuosity Ion Transport Channels of Anion-exchange Membranes for Water electrolysis and Fuel cells

The tortuosity of ion transport channels is pivotal for transport of OH ^‒ in anion exchange membranes (AEMs) for water electrolysis and fuel cells. In this study, a strategy to achieve ion transport channels with low tortuosity is reported for the first time in poly (aryl piperidinium) membranes. The tortuosity is reduced by constructing branched micro-clusters and shortening the distance of functional groups within the clusters, enabling effective transport of OH ^‒ . The rigid planar structure with abundant π electrons from triphenylene can reduce the tortuosity of the branched micro-clusters from 2.94 to 2.18. In water electrolysis, QATYP-15 can reach 10.2 A cm ^‒2 at 2V. QATYP-15 can operate stably at 1 A cm ^‒2 for 2110 h with a voltage degradation of 15 µv h ^‒1 . The molecular-level design not only enables efficient OH ^‒ transport, but also provide insightful perspectives for the structural design of high performance AEMs.