Blend membranes for direct methanol and proton exchange membrane fuel cells

Abstract

Sulphonated polystyrene ethylene butylene polystyrene (SPSEBS) prepared with 35% sulphonation was found to be highly elastic and enlarged up to 300%−400% of its initial length. It absorbed over 110% of water by weight. A major drawback of this membrane is its poor mechanical properties which are not adequate for use as polymer electrolytes in fuel cells. To overcome this, SPSEBS was blended with poly(vinylidene fluoride) (PVDF), a hydrophobic polymer. The blend membranes showed better mechanical properties than the base polymer. The effect of PVDF content on water uptake, ion exchange capacity and proton conductivity of the blend membranes was investigated. This paper presents the results of recent studies applied to develop an optimized in-house membrane electrode assembly (MEA) preparation technique combining catalyst ink spraying and assembly hot pressing. Easy steps were chosen in this preparation technique in order to simplify the method, aiming at cost reduction. The open circuit voltage for the cell with SPSEBS is 0.980 V which is higher compared to that of the cell with Nafion 117 (0.790 V). From this study, it is concluded that a polymer electrolyte membrane suitable for proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC) application can be obtained by blending SPSEBS and PVDF in appropriate proportions. The methanol permeability and selectivity showed a strong influence on DMFC performance.

In-situ synchrotron SAXS and WAXS investigations on deformation and α–β transformation of uniaxial stretched poly(vinylidene fluoride)

“…Having extraordinary mechanical properties and complicated polymorphism, poly(vinylidene fluoride) (PVDF) has been well known since the 1960s, 1 and has been extensively investigated and applied in many industrial fields due to its excellent and versatile properties, [2][3][4][5][6] such as chemical resistance, 7 abrasion resistance, good biocompatibility, 8,9 radiation resistance, mechanical strength, piezoelectric properties, [10][11][12] and specifically excellent membrane forming capability. [13][14][15][16][17][18] In recent decades PVDF and co-polymers have been increasingly used in devices 19,20 such as sensors, 21 transducers, 22 solar energy device 23 and actuators for different applications. a-PVDF has been used in different structural applications and the properties of amorphous PVDF are also of great interest, as PVDF constitutes the major component in a variety of amorphous fluoroelastomers such as Viton.…”

Sulfonated Polyphosphazene-Montmorillonite Hybrid Composite Membranes for Fuel Cells

“…Advanced Materials Research Vols. 724-725 (2) where W wet and W dry were the weight of the wet and dry membranes, respectively [11]. Swelling ratio (SW) was determined by immersing membrane samples into water at 25 ºC for 24 hours and measuring the change in length before and after the swelling according to the following equation:…”

Membranes for Direct Alcohol Fuel Cells

“…Recently, a composite of PVDF with sulfonated poly(styrene-b-ethylene butylenes-b-styrene) (sPSEBS) was reported to deliver up to 72 mW.cm À2 at 60 C in a DMFC, although the characteristics of the catalysts and the MEA were not described [491].…”