Synthesis and characterization of sulfonated poly (arylene ether sulfone)/silicotungstic acid composite membranes for fuel cells

Abstract

A series of composite membranes based on sulfonated poly (arylene ether sulfone) (SPAES) embedded with powdered silicotungstic acid (STA) was synthesized. SPAES was synthesized by direct aromatic nucleophilic polymerization and then solution blended with STA. Fourier-transform infrared spectroscopy analysis showed that the sulfonic acid groups on the polymer backbone interacted with the tungstic oxide in STA. The composite membranes exhibited a low Heteropolyacid extraction after treatment with water at 60 1C for 24 h. The composite membranes were characterized for water uptake, ionexchange capacity (IEC), hydrolytic stability, proton conductivity and thermal stability in order to evaluate the suitability of these membranes for fuel cells. The proton conductivity of the membranes increased with increasing STA content. With an increase in the STA content, the conductivity of the composite membranes at 30 1C increased from 0.079 to 0.109 S cm À1 , whereas the parent membrane exhibits a proton conductivity of 0.073 S cm À1 . The composite membranes not only had good proton conductivity but also showed excellent thermal stability and mechanical strength. This study shows that the composite membranes based on SPAES and STA can be viable candidates for electrolyte membranes.

A novel fuel cell membrane with high efficiency

“…The detailed procedure for the conductivity measurements was reported in our paper. 32 The measurements were taken in the temperature range of 30-130 C. The tensile strength and Young's modulus of the completely hydrated SPAES membranes were measured using a Universal Testing Machine (UTM), Instron, USA. Samples with a length of 50 mm and a width of 20 mm were tested using a 250 N load cell that was pulled at 50 mm min À1 within a 21 cm gauge length.…”

“…16,17 These drawbacks are the main reasons for the extensive research to develop alternative proton exchange membranes for fuel cells. [18][19][20][21] Sulfonated polyimides, [22][23][24] sulfonated polysulfones, 25,26 sulfonated poly(ether ether ketone)s, [27][28][29] sulfonated poly(arylene ether sulfone)s, [30][31][32] sulfonated polystyrenes, 33,34 and polybenzimidazoles 35,36 have been studied for fuel cell membranes because of their good stability, conductivity and processability. Among these polymers, sulfonated poly(arylene ether sulfone)s have been the centre of attention of recent studies in search of a replacement for Naon®.…”

“…Among these polymers, sulfonated poly(arylene ether sulfone)s have been the centre of attention of recent studies in search of a replacement for Naon®. Although improvements have been achieved with these types of polymers, the proton conductivity at elevated temperatures is still un-satisfactory because of the lack of water retention at temperatures much above 100 C. 32 The post sulfonation process of the high performance materials such as polysulfones, poly ether ether ketones etc., has suggested that these materials are unable to form dened hydrophilic domains. The rigid polymeric backbones prevent the formation of ionic clusters.…”

Preparation of sulfonated polysulfone/sulfonated titanium dioxide hybrid membranes for DMFC applications

“…Aromatic hydrocarbon polymers such as polyimides (PIs), poly(ether ether ketone)s (PEEKs), and poly(arylene ether sulfone)s (PAESs) show high inherent stability, high glass transition, and low cost, as a result they are attractive alternatives which are expected to replace Nafion. Usually, these polymers are sulfonated by chlorosulfonic acid, fuming sulfuric or other strong sulfonating agent.…”

A novel proton conducting polymer electrolyte membrane for fuel cell applications

“…However, (i) the high production cost, (ii) complicated synthesis procedure, (iii) toxic intermediates, and (iv) loss of water uptake at higher temperature that imparts drop in proton conductivity limit their commercial use in fuel cells. 12,13 There is a need to develop alternative membranes of low cost and good retention of proton conduction at elevated temperature. Research has been focused towards the preparation of new low-cost copolymers, which can be employed as proton exchange membrane for fuel cell and other membrane applications.…”