Polybenzimidazole/inorganic composite membrane with advanced performance for high temperature polymer electrolyte membrane fuel cells

Abstract

In this work, Al–Si was synthesized via a sol–gel process and introduced in poly 2,2′‐m‐(phenylene)‐5,5′‐bibenzimidazole (PBI). As a result, a series of five Al–Si/PBI composite (ASPBI) membranes (0, 3, 6, 9, and 12 wt%) were developed and characterized for application in high temperature polymer electrolyte membrane fuel cells (HT‐PEMFCs). The chemical and morphological structure of ASPBI membranes were analyzed by Fourier transform infrared spectroscopy, X‐ray diffractometer, and scanning electron microscopy. According to the doping level test and thermogravimetric analysis, as the concentration of Al–Si increased, the doping level increased up to 475% due to the affinity and interaction between Al and phosphoric acid (PA). Moreover, the proton conductivity, current density at 0.6 V, and maximum power density of ASPBI membranes increased up to 0.31 S cm−1, 0.320 A cm−2, and 0.370 W cm−2, respectively, because the increased concentration of Al–Si allows the membranes to hold more PA. Alternatively, as the amount of Al–Si increased, the tensile strength of PA‐doped and ‐undoped membranes decreased. This was caused by both excess PA and aggregation, which can cause serious degradation of the membrane and induce cracks. Furthermore, the PA‐doped and ‐undoped ASPBI12 had the lowest tensile strength of 11.6 and 77.2 MPa. The improved proton conductivity and single cell performance of ASPBI membranes implies that these membranes are possible candidates for HT‐PEMFC applications. However, further studies seeking to enhance the compatibility between PBI and Al–Si and optimize the amount of filler should be performed. POLYM. COMPOS., 38:87–95, 2017. © 2015 Society of Plastics Engineers

Poly(2,5-benzimidazole)/sulfonated sepiolite composite membranes with low phosphoric acid doping levels for PEMFC applications in a wide temperature range

“…7b and c, more and unevenly distributed fibrous-like morphologies can be observed due to the ductile fracture of ABPBI in Fig. 7d and e, indicating that the aggregation of Sep particles may happen when more than 2 wt.% of Sep is added [58]. Fig.…”

“…The results of relative E a fitted from experimental results of proton conductivities by the Arrhenius plots are listed in Table 4. Furthermore, their performance was compared to commercial Nafion 212 at LT and several PBI-clay composite membranes that were used before [33,34,[58][59][60]. Fig.…”

“…The structures and morphologies of the obtained membranes were characterized by XRD and SEM-EDS.Their investigated properties were mechanical properties, thermal, oxidative, and dimensional stabilities, water uptake, PA absorptivity and retention capacity, and proton conductivity. Their performance was compared to ABPBI membrane and commercial Nafion 212 as well as results from references[33,34,[58][59][60].…”

Hydrogen Production by Membrane Water Splitting Technologies

“…It has turned into an attractive research due to its advantages of generating minimum pollution, great power density, and excellent conversion. This is a promising path to be fossil fuel free and to contribute to other sustainable energy sources [25,26].…”

“…Currently, perfluorosulfonic acid polymer membranes like Nafion is accepted as the most widely used applications for both PEM-FC and direct methanol fuel cell (DMFC) because of their superiority and exceptional performance in thermal stability, eminent ionic exchange capacity, and proton conductivity [26,27]. However, the Nafion is costly, and it experiences huge methanol crossover for DMFC with the addition of depletion of proton conductivity when subjected to working temperature beyond 100°C [27].…”