Highly Elastic, Healable, and Durable Anhydrous High‐Temperature Proton Exchange Membranes Cross‐Linked with Highly Dense Hydrogen Bonds

Abstract

Proton exchange membranes (PEMs) with excellent durability and working stability are important for PEM fuel cells with extended service life and enhanced reliability. In this study, highly elastic, healable, and durable electrolyte membranes are fabricated by the complexation of poly(urea-urethane), ionic liquids (ILs), and MXene nanosheets (denoted as PU-IL-MX). The resulting PU-IL-MX electrolyte membranes have a tensile strength of ≈3.86 MPa and a strain at break of ≈281.89%. The PU-IL-MX electrolyte membranes can act as high temperature PEMs to conduct protons under an anhydrous condition of the temperatures above 100 °C. Importantly, the ultrahigh density of hydrogen-bond-cross-linked network renders PU-IL-MX membranes excellent IL retention properties. The membranes can maintain more than ≈98% of their original weight and show no decline of proton conductivity after being placed under highly humid conditions of ≈80 °C and relative humidity of ≈85% for 10 days. Moreover, due to the reversibility of hydrogen bonds, the membranes can heal damage under the working conditions of fuel cells to restore their original mechanical properties, proton conductivities, and cell performances.

Recent advances in non-perfluorinated sulfonic acid proton exchange membranes in the energy field

“…These research findings provide theoretical and experimental insights into improving methanol barrier performance through hydrogen bond cross-linking. Wang et al 43 prepared a highly elastic, heatable, and durable membrane material (PU-IL-MX) through the complexation of poly(urea carbamate), ionic liquids (ILs), and MXene nanosheets. The ultra-high density hydrogen bonding cross-linking network inside the membrane endows the PU-IL-MX membrane with excellent IL retention performance and strong self-healing ability.…”