Phosphoric acid doped poly(2,5‐benzimidazole)‐based proton exchange membrane for high temperature fuel cell application |
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| Authors: | Ratikanta Nayak Tapobrata Dey Prakash C Ghosh Arup R Bhattacharyya |
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| Affiliation: | 1. Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai, India;2. Department of Metallurgical Engineering and Materials Science, Indian Institute of Technology Bombay, Powai, Mumbai, India |
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| Abstract: | Undoped and doped poly(2,5‐benzimidazole) (ABPBI) membrane was prepared by solvent casting method using methane sulfonic acid as a solvent and phosphoric acid (H3PO4) as a doping agent. The concentration of H3PO4 was varied from 0 to 60 vol% to enhance the proton conductivity of the ABPBI membrane at higher temperature. Wide angle X‐ray diffraction analysis showed a decrease in crystallinity in ABPBI membrane with increase in H3PO4 doping concentration. The molecular signature and the presence of H3PO4 was observed in 1000–1500 cm?1 in the Fourier transform infrared spectra, which was also supported by a corresponding weight loss at 180°C–200°C in the thermogravimetric analysis. Undoped ABPBI membrane registered the Young's modulus (E) and hardness (H) values of 2.46 and 0.92 GPa, respectively, and the corresponding E and H values for 1.65 doping level of 60 vol% H3PO4 doped ABPBI membrane were 0.14 and 0.067 GPa, respectively. The 60 vol% H3PO4 doped ABPBI membrane with doping level of 1.65 showed highest proton conductivity value of 2.2 × 10?2 S/cm. The impedance spectroscopic analysis and the equivalent circuit model were discussed to understand the nature of proton conduction in H3PO4 doped ABPBI membrane. POLYM. ENG. SCI., 56:1366–1374, 2016. © 2016 Society of Plastics Engineers |
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