Rigid-Flexible Hybrid Proton-Exchange Membranes with Improved Water-Retention Properties and High Stability for Fuel Cells

Abstract

A novel molecular structural design of rigid–flexible hybrid polymer backbone is proposed for proton-exchange membranes (PEMs) with the objective to preserve the material longevity by enhancing the dimensional stability. The effect of the rigid–flexible hybrid backbone is demonstrated based on performance tests for a series of non-fluorinated polyamide–sulfonimide proton conductors, among which the conductivity of the rigid–flexible hybrid structural PEM is nearly 100 % higher than the rigid PEM with almost the same ion-exchange capacity (IEC). The dimensional and mechanical stabilities of these PEMs are better than those of Nafion membranes. The measured conductivity of the rigid–flexible hybrid structural PEM is on the order of 10−2 S cm−1.