Title: Sulfonated poly(ether ether ketone)-functionalised silica composite membranes for applications in proton exchange membrane fuel cells

Authors: Vijay Shankar Rangasamy; Savitha Thayumanasundaram; Jean-Pierre Locquet; Niels De Greef; Jin Won Seo

Addresses: Department of Physics and Astronomy, Celestijenlaan 200D Box 2414, Heverlee 3001, Belgium ' Department of Physics and Astronomy, Celestijenlaan 200D Box 2414, Heverlee 3001, Belgium ' Department of Physics and Astronomy, Celestijenlaan 200D Box 2414, Heverlee 3001, Belgium ' Department of Metallurgy and Materials Engineering, Kasteelpark Arenberg 44 – bus 2450, B-3001 Leuven, Belgium ' Department of Metallurgy and Materials Engineering, Kasteelpark Arenberg 44 – bus 2450, B-3001 Leuven, Belgium

Abstract: Sulfonated Poly(ether ether ketone) (SPEEK) and its composites are explored as potential alternatives for Nafion in fuel cell applications. In this work, we investigate the effects of the silica functionalisation route on the thermal, mechanical and structural properties of SPEEK-Silica composite membranes. We compare two different methods - direct sulfonation and co-condensation (sol-gel) - to add sulfonic acid groups to silica nanoparticles, which are used as fillers in SPEEK membranes. The degree of sulfonation (DS) of the cast membranes determined by ¹H NMR ranged from 40% to 86%. TGA-DSC measurement shows higher desulfonation temperatures for the composite membranes, indicating better thermal stability compared to pure SPEEK membranes. DMA results show that the sol-gel membranes are mechanically more stable with a wider operational temperature range than the directly sulfonated and pristine SPEEK membranes. Water uptake of the membranes increases with silica content, indicating the formation of additional water-mediated pathways for proton conduction.

Keywords: SPEEK; silica nanoparticles; PEMFC; sol-gel; sulfonation; dynamic mechanical analysis; DMA; functionalisation; co-condensation; operational temperature range; nanotechnology; composite membranes; proton exchange membrane fuel cells; poly(ether ether ketone); PEEK; composites; thermal stability.

DOI: 10.1504/IJNT.2014.063803

International Journal of Nanotechnology, 2014 Vol.11 No.9/10/11, pp.971 - 992

Published online: 14 Jan 2015 *

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