Proton exchange composite membranes comprising SiO2, sulfonated SiO2, and metal-organic frameworks loaded in SPEEK polymer for fuel cell applications

Proton exchange membrane fuel cell (PEMFC) is a promising technology that offers a clean and efficient renewable energy source. The hybrid SiO2, sulfonated SiO2 (S-SiO2), and metal-organic framework-5 (MOF-5) incorporated sulfonated poly (ether ether ketone) (SPEEK) ternary composite membranes are fabricated using dry phase inversion technique for PEMFC. The membrane performance is evaluated in terms of water uptake, ion exchange capacity, methanol permeability, and proton conductivity (PC) measurements. The morphological study of fabricated membranes was carried out using scanning electron microscopy and atomic force microscopy analysis. The mechanical stability is strengthened up to 30-40%, and the PC gets enhanced with the incorporation of MOF-5, achieving simultaneous improvement in proton conduction and membrane stability. The PC of the ternary SPEEK/S-SiO2/MOF-5 membrane is 3.69 x 10(-3) S cm(-1), 32% more than the neat membrane. A significant increase in selectivity of 23% is observed by incorporating S-SiO2 and MOF-5 fillers when compared with the neat membrane. The synergistic effect of MOF-5 and S-SiO2 in the ternary membrane has significantly improved water retention and proton conductivity. The functional -SO3H groups of SiO2 and MOF-5 bonded via acid-base electrostatic interactions with the SPEEK; enhances proton conduction accompanied by suppressing the methanol penetration through membranes.

Automated summary

The study investigates the fabrication and performance of ternary composite membranes for use in proton exchange membrane fuel cells. By incorporating fillers such as MOF-5 and S-SiO2, the mechanical stability and proton conductivity of the membranes are significantly improved.