Investigation of sulfonated poly(ether ether ketone sulfone)/heteropolyacid composite membranes for high temperature fuel cell applications

Abstract

The sulfonated poly(ether ether ketone sulfone) (SPEEKS)/heteropolyacid (HPA) composite membranes with different HPA content in SPEEKS copolymers matrix with different degree of sulfonation (DS) were investigated for high temperature proton exchange membrane fuel cells. Composite membranes were characterized by Fourier transfer infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR band shifts suggested that the sulfonic acid groups on the copolymer backbone strongly interact with HPA particles. SEM pictures showed that the HPA particles were uniformly distributed throughout the SPEEKS membranes matrix and particle sizes decreased with the increment of copolymers' DS. The holes were not found in SPEEKS‐4/HPA30 (consisting of 70% SPEEKS copolymers with DS = 0.8 and 30% HPA) composite membrane after composite membranes were treated with boiling water for 24 h. Thermal stabilities of the composite membranes were better than those of pure sulfonated copolymers membranes. Although the composite membranes possessed lower water uptake, it exhibited higher proton conductivity for SPEEKS‐4/HPA30 especially at high temperature (above 100 °C). Its proton conductivity linearly increased from 0.068 S/cm at 25 °C to 0.095 S/cm at 120 °C, which was higher than 0.06 S/cm of Nafion 117. In contrast, proton conductivity of pure SPEEKS‐4 membrane only increased from 0.062 S/cm at 25 °C to 0.078 S/cm at 80 °C. At 120 °C, proton conductivity decreased to poor 0.073 S/cm. The result indicated that composite membranes exhibited high proton conductivity at high temperature. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1967–1978, 2006

PWA/silica doped sulfonated poly(ether sulfone) composite membranes for direct methanol fuel cells

“…This extraction of HPA would lead to a decrease in proton conductivity and durable lifetime in fuel cell systems. 12 Thus the retention of HPA was considered as one of the key parameters on determining the feasibility of the composite membranes used in the fuel cell systems.…”

“…12,13 Fenton and coworkers 14 recast the Nafion/HPA composite for H 2 /O 2 fuel cell and found that the HPA could increase the conductivity of the membrane. Staiti et al 15 and Shao et al 16 evaluated PWA-doped composite silica/Nafion/PWA membranes for hightemperature DMFCs (145 C).…”

Synthesis and basic properties of sulfonated polysulfone/phosphotungstic acid (H3O40PW12) composite proton exchange membrane

“…It is interesting to note that the proton conductivity of sulfonated poly (ether ether ketone) and polyimide incorporated with PWA showed good dispersion of PWA, and the resulting composite has been quite promising at temperatures higher than the boiling point of water. [7,8] It is suggested that specific interactions between PWA and sulfonated polymers could have a significant influence on fuel cell performance. This phenomenon has been relatively unexplored and deserves attention.…”

Investigation on Structure and Behaviours of Proton Exchange Membrane Materials by TEM

“…To further develop these sulfonated polymers, which can be potentially suitable for applications in proton exchange membrane fuel cell or direct methanol fuel cell systems, some researchers have modified sulfonated polymers. The sulfonated polymers/heteropolyacid and sulfonated polymers/TiO 2 composite membranes exhibited high proton conductivity at high temperature, which are satisfied with the requirement of fuel cell operation at high temperature [36][37][38]. The sulfonated polymers/polyanine and sulfonated polymers/polypyrrole composite membranes decreased methanol permeability with a little lower proton conductivity change, thus showing very good prospective in DMFC application [39,40].…”