Nanofiber-based polyelectrolytes as novel membranes for fuel cell applications

• Published in: Journal of membrane science 2011-02, Vol.368 (1-2), p.233-240
• Main Authors: Shabani, Iman, Hasani-Sadrabadi, Mohammad Mahdi, Haddadi-Asl, Vahid, Soleimani, Masoud
• Format: Article
• Language: English
• Subjects: Applied sciences; artificial membranes; Bilayer membrane; Chemistry; Colloidal state and disperse state; Electrochemistry; electrolytes; Electrospinning; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cell; Fuel cells; General and physical chemistry; Membranes; methanol; Nanofiber; nanofibers; permeability; Polyelectrolyte; polymers; Porous materials; scanning electron microscopy
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2010.11.048

[Display omitted] ▶ Bead-free electrospun sulfonated poly(ether sulfone) (SPES) nanofibers were prepared. ▶ Bilayer proton exchange membranes prepared using impregnation of electrospun sulfonated poly(ether sulfone) nanofibers by Nafion. ▶ Membranes showed good proton conductivity as well as low methanol permeability. ▶ Incorporation of nanofibers enhanced the proton to methanol selectivity as well as fuel cell performance. Partially sulfonated poly(ether sulfone) (SPES) was prepared and electrospun to bead-free nanofibers. The obtained data from solution conductivity measurements and scanning electron microscopy illustrated that sulfonation leads to a drastic increase in polymer solution conductivity and a considerable decrease in nanofiber diameter and a narrower diameter distribution. The new types of membranes were fabricated using Nafion-filled electrospun mats. The porous SPES nanofibrous membranes were impregnated with appropriate amount of Nafion solution. After a good pore-filling, an excess amount of Nafion solution was used to form a uniform top layer (SPES-N-N). Another bilayer polyelectrolyte membrane was prepared by direct electrospinning of SPES nanofibers on Nafion112 membrane's surface and followed by impregnation of Nafion solution into the pores of electrospun SPES (SPES-N-N112). The membranes were characterized by methanol permeability, proton conductivity, oxidative/hydrolytic stability as well as single cell direct methanol fuel cell (DMFC) performance tests. The proton to methanol selectivity of the SPES nanofiber-based bilayer membranes is about 53,680 and 45,500Sscm−3 for SPES-N-N and SPES-N-N112 in comparison with 28,300 and 40,500Sscm−3 for Nafion112 and Nafion117, respectively. The single cell DMFC performance results revealed that the SPES nanofiber-based bilayer membranes have higher electrochemical performance than Nafion112 and Nafion117 membranes especially in elevated methanol concentration. The results showed that the fabricated bilayer membranes can be used as a promising polyelectrolyte membrane for fuel cell applications.