Supramolecular Anchoring of Polyoxometalate Amphiphiles into Nafion Nanophases for Enhanced Proton Conduction

Advanced proton exchange membranes (PEMs) are highly desirable in emerging sustainable energy technology. However, the further improvement of commercial perfluorosulfonic acid PEMs represented by Nafion is hindered by the lack of precise modification strategy due to their chemical inertness and low compatibility. Here, we report the robust assembly of polyethylene glycol grafted polyoxometalate amphiphile (GSiW(11)) into the ionic nanophases of Nafion, which largely enhances the comprehensive performance of Nafion. GSiW(11) can coassemble with Nafion through multiple supramolecular interactions and realize a stable immobilization. The incorporation of GSiW(11) can increase the whole proton content in the system and induce the hydrated ionic nanophase to form a wide channel for proton transport; meanwhile, GSiW(11) can reinforce the Nafion ionic nanophase by noncovalent cross-linking. Based on these synergistic effects, the hybrid PEMs show multiple enhancements in proton conductivity, tensile strength, and fuel cell power density, which are all superior to the pristine Nafion. This work demonstrates the intriguing advantage of molecular nanoclusters as supramolecular enhancers to develop high-performance electrolyte materials.

Automated summary

This study reports the robust assembly of polyethylene glycol grafted polyoxometalate amphiphile (GSiW(11)) into the ionic nanophases of Nafion, which enhances the overall performance of Nafion. GSiW(11) can coassemble with Nafion through multiple supramolecular interactions, increasing the proton content and forming a wide channel for proton transport. Additionally, GSiW(11) reinforces the Nafion ionic nanophase by noncovalent cross-linking. The hybrid PEMs exhibit multiple enhancements in proton conductivity, tensile strength, and fuel cell power density compared to pure Nafion.