Precise Molecular-Level Modification of Nafion with Bismuth Oxide Clusters for High-performance Proton-Exchange Membranes

Fabricating proton exchange membranes (PEMs) with high ionic conductivity and ideal mechanical robustness through regulation of the membrane microstructures achieved by molecular-level hybridization remains essential but challenging for the further development of high-performance PEM fuel cells. In this work, by precisely hybridizing nano-scaled bismuth oxide clusters into Nafion, we have fabricated the high-performance hybrid membrane, Nafion-Bi-12-3 %, which showed a proton conductivity of 386 mS cm(-1) at 80 degrees C in aqueous solution with low methanol permeability, and conserved the ideal mechanical and chemical stabilities as PEMs. Moreover, molecular dynamics (MD) simulation was employed to clarify the structural properties and the assembly mechanisms of the hybrid membrane on the molecular level. The maximum current density and power density of Nafion-Bi-12-3 % for direct methanol fuel cells reached to 432.7 mA cm(-2) and 110.2 mW cm(-2), respectively. This work provides new insights into the design of versatile functional polymer electrolyte membranes through polyoxometalate hybridization.

Automated summary

By precisely hybridizing nano-scaled bismuth oxide clusters into Nafion, a high-performance hybrid membrane, Nafion-Bi-12-3 %, was fabricated, showing excellent proton conductivity and mechanical stability ideal for high-performance PEM fuel cells. Molecular dynamics simulation was employed to clarify the structural properties and assembly mechanisms of the hybrid membrane at the molecular level. The hybrid membrane exhibited a maximum current density of 432.7 mA cm(-2) and power density of 110.2 mW cm(-2) for direct methanol fuel cells, providing new insights into the design of functional polymer electrolyte membranes through polyoxometalate hybridization.