Synthesis and proton conductivity of poly(styrene sulfonic acid)/heterocycle‐based membranes

Abstract

BACKGROUND: High proton conduction through anhydrous polymer electrolyte membranes is crucial for the application to chemical energy conversion devices such as fuel cells. In this context, novel proton conductors were produced by doping poly(styrene sulfonic acid) (PSSA) with 1H-1,2,4-triazole (Tri) and 1.12-diimidazol-2yl-2,5,8,11-tetraoxadodecane (imi3), and their physicochemical properties were investigated. RESULTS: Different polymer electrolyte membranes were produced by doping of PSSA with Tri and imi3. PSSATri x and PSSAimi3 x electrolytes were obtained where x is the doping ratio describing moles of Tri or imi3 per mole of -SO 3 H unit. The membranes demonstrated adequate thermal stability at least up to 200 • C and the dopants acted as plasticizers shifting the T g values to lower temperatures. PSSATri 1 has a maximum proton conductivity of 0.016 S cm −1 at 150 • C and the proton conductivity of PSSAimi3 0.5 is approximately 10 −4 S cm −1 at room temperature.CONCLUSIONS: Transparent, homogeneous and freestanding films of PSSATri x and PSSAimi3 x were produced. It was demonstrated that both Tri and imi3 are efficient proton solvents in PSSA host matrix, and they yielded promising defect-type conductivities compared to benzimidazole. Tri-doped membranes clearly showed better conductivity performance at higher temperatures (T > 100 • C). Both PSSATri x and PSSAimi3 x polymer electrolytes can be suggested for fuel cell applications.

Intrinsically proton-conducting poly(1-vinyl-1,2,4-triazole)/triflic acid blends

“…During last few years, the membranes including aromatic heterocyclic protogenic solvents such as imidazole (Im) or benzimidazole (BnIm) have been reported to exhibit high conductivity in the anhydrous state [2][3][4]. The proton-conducting properties of these protogenic solvents are reported to be intrinsic due to autoprotolysis reactions and long-range diffusion of protons occur through a fast-fluctuating dynamical hydrogen bonding network [2,5].…”

Synthesis and characterization of novel hybrid polysulfone/silica membranes doped with phosphomolybdic acid for fuel cell applications

“…These limitations have led to research and develop different polymers as promising alternatives to improve fuel cell perfor mance of the current perfluorosulfonic membranes. One research line involves the sulfonation of aromatic polymers with non perfluorinated backbone such as polyaryl ether ketone [4], poly styrene [5] as well as polybenzimidazoles [6]. Among these polyaromatic materials, polysulfone (PSU) is a commercially avail able polymer and well known for its excellent mechanical, thermal and chemical stability [7].…”

The synthesis and characterization of anhydrous proton conducting membranes based on sulfonated poly(vinyl alcohol) and imidazole

“…Several studies also showed that Im acts as a strong proton donor and acceptor in polymers, which promotes the proton transport process [16][17][18][19][20]. Previously Im is blended with acidic polymers such as PAA (poly(acrylic acid)) [21], PSSA (poly(styrene sulfonic acid)) [22] and PVPA (poly(vinylphosphonic acid)) [23], but these membranes were all soluble in water which might cause stability problem in fuel cell application. In this study, a novel model system was designed in which a stable main polymer, a sulfonic acid group and a heterocyclic group coexist and they interact with the acidic units.…”