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Suobo Zhang - One of the best experts on this subject based on the ideXlab platform.
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a stable anion exchange membrane based on imidazolium salt for Alkaline Fuel Cell
Journal of Membrane Science, 2014Co-Authors: Yanqi Yang, Jing Wang, Jifu Zheng, Suobo ZhangAbstract:Abstract A series of poly(arylene ether sulfone) containing bulky imidazole groups (PSf-Im- x ) have been successfully synthesized based on a novel monomer 2,2′-bis-(2-ethyl-4-methyl-imidazole-1-ylmethyl)-biphenyl-4,4′-diol (EMIPO). After quaternized by n-bromobutane, these polymers are evaluated for Alkaline anion exchange membranes (AEMs). The functional group, 2-ethyl-3-butyl-4-methyl-imidazolium, is employed in these new polymers for reason that attaching bulky groups around the imidazolium ring reduces the access of OH − to imidazolium, which enhances the Alkaline stability of the membranes. The membrane with an IEC value of 2.07 possesses ionic (OH − ) conductivity of 0.014 S cm −1 at 30 °C and 80% of the ionic conductivity is maintained after treatment in 1 M KOH at 60 °C for 144 h.
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synthesis of multi block poly arylene ether sulfone copolymer membrane with pendant quaternary ammonium groups for Alkaline Fuel Cell
Journal of Power Sources, 2011Co-Authors: Zhuo Zhao, Junhua Wang, Shenghai Li, Suobo ZhangAbstract:A series of multi-block poly(arylene ether sulfone)s are synthesized via the copolymerization of bis(4-hydroxyphenol) sulfone, 3,3', 5,5'-tetramethylbiphenol and 4,4'-difluorodiphenyl sulfone. The resulting multi-block copolymers are brominated by using N-bromosuccinmide (NBS) as bromination reagent. The bromomethylated copolymer is solution cast to form clear, creasable films, and subsequent soaking of these films in aqueous trimethylamine to give benzyltrimethylammonium groups. The anion exchange membranes obtained by the solution hydroxide exchange with aqueous sodium hydroxide show varying degrees of ionic conductivity depending on their ion exchange capacity. The highest hydroxide conductivity 0.029 S cm(-1) is achieved with the QBPES-40 membrane having IEC value of 1.62 mequiv g(-1) at room temperature and 100% RH. The obtained anion exchange membranes also have good mechanical properties and dimensional stability, which greatly facilitates the preparation of a MEA and the Cell operation. (C) 2011 Elsevier B.V. All rights reserved.
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novel hydroxide conducting polyelectrolyte composed of an poly arylene ether sulfone containing pendant quaternary guanidinium groups for Alkaline Fuel Cell applications
Macromolecules, 2010Co-Authors: Junhua Wang, Suobo ZhangAbstract:Poly(arylene ether sulfone)s were functionalized with quaternary guanidinium groups in order to investigate their properties as novel polymeric hydroxide exchange membrane materials. The quaternized polymers were synthesized via chloromethylation of poly(arylene ether sulfone)s, followed by reactions with pentamethylguanidine. The resulting quaternized polymers PSGCl-x (where x represents the number of the quaternary guanidinium groups/repeat units) presented an elevated molecular weight and exhibited an outstanding solubility in polar aprotic solvents. Consequently flexible and tough membranes of PSGCl-x with varying ionic content could be prepared by casting from the DMSO solution. Novel anion exchange membranes, PSGOH-x, were obtained by an anion exchange of PSGCl-x with 1 M NaOH at room temperature. The membranes displayed a high ionic conductivity and an exCellent chemical stability. The obtained Alkaline anion exchange membranes (AEMs) showed conductivities almost above 10−2 S cm−1 at room temperatu...
Nanwen Li - One of the best experts on this subject based on the ideXlab platform.
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quaternized poly 2 6 dimethyl 1 4 phenylene oxide anion exchange membranes based on isomeric benzyltrimethylammonium cations for Alkaline Fuel Cells
Journal of Membrane Science, 2020Co-Authors: Chenyang Shao, Rou Chen, Peiwei Zhao, Nanwen LiAbstract:Abstract Benzyltrimethylammonium (BTMA) is most frequently-used organic cations in anion exchange membrane (AEM) materials. However, BTMA-based AEMs always suffer from low ionic conductivity and insufficient Alkaline stability for practical Alkaline Fuel Cells. Here, we present a systematic investigation of a series of side-chain-type poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) AEMs with constitutional isomerism in BTMA cations. Three isomeric BTMA cations, e.g. meta-BTMA, ortho-BTMA, and para-BTMA, were tethered onto PPO backbones via a flexible spacer using CuAAC reaction, producing side-chain-type AEMs, namely m-QPPO, o-QPPO, and p-QPPO membranes, respectively. As expected, side-chain-type PPO AEMs displayed higher hydroxide conductivity as compared to a control PPO-QA membrane where BTMA cations were directly linked on PPO backbones, due to the microphase-separated morphologies as confirmed by small-angle X-ray scattering (SAXS) results. Although these isomeric quaternized PPO copolymers had identical chemical composition and polymer architectures, they did not share similar properties. Specifically, among three side-chain-type AEMs, the highest hydroxide conductivity of 42.8 mS/cm was observed for m-QPPO membrane having meta-BTMA cations with an ion exchange capacity of 1.93 meq./g at 20 °C, as a result of its high water uptake. In addition to high conductivity, m-QPPO membrane showed superior Alkaline stability with respect to o-QPPO and p-QPPO membranes. After 200 h of aging in 1 M NaOH at 60 °C, 85% of the hydroxide conductivity was retained for m-QPPO AEMs, while more than 30% conductivity loss was observed for o-QPPO and p-QPPO membranes. NMR analysis of the aged membrane suggested that SN2 nucleophilic substitution at benzyl groups is the dominant degradation mechanisms. Furthermore, the AEM Fuel Cells using these PPO AEMs with isomeric BTMA cations were investigated, and the Cell with highly conductive and durable m-QPPO membranes exhibited the best performance with a peak power density of 333 mW/cm2 at a current density of 700 mA/cm2 at 60 °C, comparable to other AEMFCs with PPO-based AEMs. Consequently, this work not only provides a facile and effective strategy to precisely synthesize isomeric AEMs, but also contributes to fundamental insights into the structure-property relationship as well as Alkaline Fuel Cell performance for these isomeric BTMA-based AEMs, which are not explored before.
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quaternized poly 2 6 dimethyl 1 4 phenylene oxide anion exchange membranes with pendant sterically protected imidazoliums for Alkaline Fuel Cells
Journal of Membrane Science, 2020Co-Authors: Weibing Sheng, Xixing Zhou, Lexuan Wu, Yinghua Shen, Yingda Huang, Nanwen LiAbstract:Abstract Quaternized poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) copolymers featuring pendant sterically-protected imidazolium groups are presented as new anion exchange membranes (AEMs) for Alkaline Fuel Cell application. Four kinds of imidazoliums, in which the substitutions were located at different positions in imidazolium rings, were grafted on the PPO backbones for systematically assessing structure-property relationship in the resulting imidazolium-based AEMs. Grafting imidazoliums with less substitutions leads to high water uptake as well as sufficient ionic conductivity. The 1,2,4,5-tetramethylimidazolium-functionalized PPO AEM (PPO-TMIm) showed the higher water uptake (53.2 wt%) and hydroxide conductivity (31.7 mS/cm) at room temperature in comparison to the AEM (PPO-TPIm) having sterically-protected 2-(2,4,6-trimethyl)phenyl-4,5-diphenyl-1-methyl- imidazolium. With increasing steric hindrance in the positions of imidazolium rings, PPO-TPIm AEM exhibited superior Alkaline stability. After 192 h of immersion in 1 M NaOH at 80 °C, PPO-TPIm membrane retained 86.7% of the ionic conductivity with no obvious structure change as evidenced by 1H NMR spectroscopy, while dealkylation degradation was observed for AEMs having 1,2,4,5-tetramethylimidazolium and 2-(2,6-dimethyl)phenyl-1-methyl-benzimidazoliums with 16.93% and 19.76% retention of conductivity. Furthermore, these imidazolium-based PPO copolymers were utilized as both polymer electrolyte membranes and ionomers in the membrane electrode assemble for Alkaline Fuel Cell application. A single H2/O2 Fuel Cell testing showed that high peak power density of 128 mA/cm2 at 60 °C was obtained for PPO-TMIm copolymer as an AEM, probably due to its high ion conductivity and comparable Alkaline stability. However, under the same conditions, PPO-TPIm copolymer with the highest Alkaline stability failed to be a separator in Cells, and only 22.1 mW/cm2 of peak power density was achieved as an ionomer in Fuel Cells. These results highlight that both ionic conductivity and Alkaline stability of anion conductive polymers are important for Fuel Cell application as membranes and ionomers.
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anion conductive poly 2 6 dimethyl 1 4 phenylene oxide grafted with tailored polystyrene chains for Alkaline Fuel Cells
Journal of Membrane Science, 2019Co-Authors: Yingda Huang, Cheng Yang, Junping Dong, Nanwen LiAbstract:Abstract A series of polystyrene (PS)-grafted poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) having pendent quaternary ammonium groups were synthesized as anion exchange membranes (AEMs) by the “grafting onto” method via a combination of atom transfer radical polymerization (ATRP) and Cu(I)-catalyzed click chemistry. The length of PS grafting chains was controlled readily during ATRP. As expected, the polystyrene grafting chains showed exCellent miscibility with PPO backbone. Therefore, transparent, flexible and tough membranes were obtained by solution casting. The miscible PS grafting chains induced well-defined hydrophobic-hydrophilic separation of the as-obtained PPO AEMs as confirmed by small-angle X-ray scattering (SAXS) technology. Moreover, the hydrophobic grafting chains can effectively control the water absorption, and thus improve the dimensional stability of AEMs in water. The PS-grafted AEMs showed higher IEC-normalized hydroxide conductivity but lower water uptake than the typical AEM without PS side chains, which may be attributed to the well-defined micro-phase separation in AEMs. The highest hydroxide conductivity of 15.9 mS/cm was achieved at 20 °C in spite of its low IEC value of 1.21 meq./g. Alkaline stability testing in 1 M NaOH at 80 °C demonstrated that PS-grafted PPO AEMs with side-chain-type QA cations showed exCellent Alkaline stability as evidenced by the change of hydroxide conductivity and the 1H NMR analysis after 500 h testing. Further H2/O2 Alkaline Fuel Cell using PS-grafted PPO AEMs showed the maximum power density of 64.4 mW/cm2 at a current density of 140 mA/cm2, which is much higher than that of typical AEMs with C-16 alkyl grafting chains.
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anion conductive poly 2 6 dimethyl phenylene oxide s with clicked bulky quaternary phosphonium groups
Journal of Membrane Science, 2018Co-Authors: Hongying Tang, Nanwen Li, Danfeng Li, Zhenshan Zhang, Zhongbiao ZhangAbstract:Abstract A series of anion exchange membranes (AEMs) having pendent bulky quaternary phosphonium groups (based on the tris(2,4,6-trimethoxyphenyl)phosphane) (TPP-x and LTPP-x) have been designed and prepared by Cu(I)-catalyzed click chemistry for H 2 /O 2 Alkaline Fuel Cell application. In spite of numerous attempts, the high degree of functionalization (DF) copolymer displayed very poor film forming ability. Thus, the tough and transparent membranes were obtained only at IEC level as low as ~ 1.0 meq./g. The as-obtained TPP and LTPP AEMs having bulky phosphonium groups showed lower water uptake than that of the clicked CQA and LCQA membranes based on quaternary ammonium groups in spite of their similar IEC values. Lower ion conductivities were observed for all of the AEMs due to the lower water uptake. However, the bulky phosphonium groups could protect efficiently the core atom in organic cations against hydroxide attack and thus induced exCellent Alkaline stability of AEMs even at high NaOH concentration of 10 M at 80 °C for 200 h, although possibly S N 2 substitution degradation was occurred according to the 1 H NMR results. Interestingly, these AEMs with bulky quaternary phosphonium groups had not initial performance, e.g. no open circuit voltage (OCV) when it was employed as membrane in Fuel Cell probably because no efficient phase boundary forming between the catalyst layer and membrane resulting from the poor compatibility between poly(2,6-dimethyl phenylene oxide)s (PPOs) backbone and bulk phosphonium groups, although they were served as an ionomer successfully for the Fuel Cell in catalyst layer. This new finding that contrasts material Alkaline stability and device operability is extremely important and gives us directions for new polymer designs for high performance anion exchange membrane for Alkaline Fuel Cells.
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1 2 3 triazolium based poly 2 6 dimethyl phenylene oxide copolymers as anion exchange membranes
ACS Applied Materials & Interfaces, 2016Co-Authors: Shuqing He, Shufang Zhang, Min Zhang, Michael D Guiver, Nanwen LiAbstract:Anion exchange membranes (AEMs) based on 1,2,3-triazolium (TAM) were prepared from commercial poly(2,6-dimethyl phenylene oxide) (PPO) via “click chemistry” and subsequent N-alkylation. Flexible and tough membranes with various ion exchange capacities (IECs) were obtained by casting the polymers from NMP solutions. Although the resulting TAM-functionalized PPOs (PPO-TAM) membranes exhibited incomplete ion exchange in 1 M NaOH or NaHCO3 for 24 h even at elevated temperature, the highest hydroxide conductivities of the membranes were above 20 mS/cm at room temperature, which is comparable to many reported AEMs. Alkaline stability tests indicate that the PPO-TAM membranes showed a better Alkaline stability than that of membranes containing imidazolium groups in 1 M NaOH at 80 °C, but still require further improvements in long-term stability for Alkaline Fuel Cell application. An investigation of Alkaline stability of model compounds demonstrated the instability of TAM cations under Alkaline conditions could ...
Tae Hyu Kim - One of the best experts on this subject based on the ideXlab platform.
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cardo poly arylene ether sulfone block copolymers with pendant imidazolium side chains as novel anion exchange membranes for direct methanol Alkaline Fuel Cell
Polymer, 2013Co-Authors: Anil H N Rao, Hyoungjuh Kim, Suk Woo Nam, Tae Hyu KimAbstract:Abstract A series of phenolphthalein-based cardo poly(arylene ether sulfone) (PES) block copolymers containing pendant imidazolium group (PI-PESs) were synthesized as novel anion exchange membranes for direct methanol Alkaline Fuel Cells. These PI-PESs combine the advantages of pendant anion conductors on the polymer side chains with the thermochemical stabilities of the imidazolium group, showing high hydroxide conductivity, together with good physical and chemical stability under basic conditions. The hydroxide conductivity over 0.03 S/cm at 20 °C and 0.1 S/cm at 80 °C was obtained for the PI-PES membranes. In addition, PI-PES membranes show low permeability to methanol (below 6.74 × 10 −8 cm 2 /s) and very high selectivity (over 3.7 × 10 5 S·s/cm 3 ). These properties make the PI-PESs promising candidate materials for anion exchange membranes for direct methanol Alkaline Fuel Cells.
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imidazolium functionalized poly arylene ether sulfone block copolymer as an anion exchange membrane for Alkaline Fuel Cell
Polymer, 2013Co-Authors: Anil H N Rao, Roshni Lilly Thankamony, Hyoungjuh Kim, Suk Woo Nam, Tae Hyu KimAbstract:Abstract An ethyl imidazolium-functionalized poly(arylene ether sulfone) (EI-PES) block copolymer was prepared as a novel anion exchange membrane. The EI-PES polymer was synthesized by polycondensation between the F- and OH-terminated oligomers, followed by benzylic bromination and imidazolium functionalization (homogeneous functionalization). The quaternary ammonium-functionalized PES (QA-PES) was also prepared by heterogeneous functionalization, and the properties were compared with EI-PES. The membrane obtained from EI-PES showed a well-defined phase separated morphology between hydrophobic and hydrophilic ionic units of the block copolymer. An IEC of 1.45 meq/g with hydroxide conductivity of 0.03 S/cm at r.t. was observed for EI-PES. The EI-PES membrane also displayed exCellent dimensional, thermal, mechanical and chemical stabilities.
Suddhasatwa Asu - One of the best experts on this subject based on the ideXlab platform.
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synthesis characterization and application of platinum based bi metallic catalysts for direct glucose Alkaline Fuel Cell
Electrochimica Acta, 2011Co-Authors: Debika Asu, Suddhasatwa AsuAbstract:Abstract In the context of development of direct glucose Fuel Cell (DGFC), low metal loading (ca. 15 wt.%) bi-metallic platinum–bismuth (PtBi/C) and platinum–gold (PtAu/C) catalysts are synthesized by immobilizing metal sols on carbon substrate (Vulcan XC 72R). Physical characterization of electro-catalysts, studied using TEM, SEM, EDX and XRD, reveals the formation of nano-sized metal particles on carbon substrate. The cyclic voltammetry and chronoamperometry of the prepared catalysts point out that PtAu/C is more active and stable than PtBi/C and commercial PtRu/C towards glucose electro-oxidation in Alkaline medium. The catalysts are tested as anode in batch DGFC using activated charcoal as cathode in different glucose and electrolyte (KOH solution) concentrations at ambient temperature (30 °C). Open-circuit voltage of ∼0.9 V is obtained for PtAu/C and commercial PtRu/C and 0.8 V for PtBi/C anode in 0.2 M glucose and in 1 M KOH. However, the peak power density per unit metal loading or specific peak power density obtained is 1.6 mW cm−2 mg−1 for PtAu/C followed by PtBi/C (1.25 mW cm−2 mg−1) and commercial PtRu/C (1.13 mW cm−2 mg−1). For PtBi/C and PtRu/C, the Cell performance increases up to 0.2 M glucose concentration and then decreases. However, for PtAu/C catalyst the Cell performance increases up to 0.3 M glucose concentration and then decreases. A prominent transition zone is observed in which current density sharply decreases with the decrease in voltage (increase in overpotential) for PtBi/C and PtRu/C at 0.3 M glucose concentration, which is not observed in the case of PtAu/C. The transition zone for PtAu/C is insignificant and at higher glucose concentration (0.4 M) pointing out that PtAu/C is much stable catalyst than PtBi/C and commercial PtRu/C.
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a study on direct glucose and fructose Alkaline Fuel Cell
Electrochimica Acta, 2010Co-Authors: Debika Asu, Suddhasatwa AsuAbstract:Abstract Direct glucose Fuel Cell (DGFC) has huge potential as a power source in low power long term portable devices. Electro-oxidation of glucose and fructose on PtRu/C catalyst are studied using cyclic voltammetry in Alkaline medium to study the reason for deactivation of glucose Fuel Cell. A simple direct glucose Fuel Cell with PtRu/C as anode and activated charcoal as cathode was constructed and operated to study the effect of different temperature and concentration of glucose and KOH. An open-circuit voltage (OCV) of 0.91 V is obtained using 0.3 M glucose in 1 M KOH solution. OCV increased with the increase in glucose concentration. The maximum peak power density of 1.38 mW cm −2 is obtained using 0.2 M glucose in 1 M KOH at 30 °C and it decreases with further increase in glucose concentration and temperature. In order to determine the reason for decrease in performance of glucose Fuel Cell due to conversion of glucose to fructose, the Fuel Cell was operated using 0.2 M fructose in 1 M KOH. The peak power density delivered is 0.57 mW cm −2 . The DGFC is continuously operated for 260 h at constant load of 500 Ω produces final constant voltage of 0.21 V.
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direct Alkaline Fuel Cell for multiple liquid Fuels anode electrode studies
Journal of Power Sources, 2007Co-Authors: Anil Verma, Suddhasatwa AsuAbstract:Abstract A direct Alkaline Fuel Cell with a liquid potassium hydroxide solution as an electrolyte is developed for the direct use of methanol, ethanol or sodium borohydride as Fuel. Three different catalysts, e.g., Pt-black or Pt/Ru (40 wt.%:20 wt.%)/C or Pt/C (40 wt.%), with varying loads at the anode against a MnO 2 cathode are studied. The electrodes are prepared by spreading the catalyst slurry on a carbon paper substrate. Nickel mesh is used as a current-collector. The Pt–Ru/C produces the best Cell performance for methanol, ethanol and sodium borohydride Fuels. The performance improves with increase in anode catalyst loading, but beyond 1 mg cm −2 does not change appreciably except in case of ethanol for which there is a slight improvement when using Pt–Ru/C at 1.5 mA cm −2 . The power density achieved with the Pt–Ru catalyst at 1 mg cm −2 is 15.8 mW cm −2 at 26.5 mA cm −2 for methanol and 16 mW cm −2 at 26 mA cm −2 for ethanol. The power density achieved for NaBH 4 is 20 mW cm −2 at 30 mA cm −2 using Pt-black.
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experimental evaluation and mathematical modeling of a direct Alkaline Fuel Cell
Journal of Power Sources, 2007Co-Authors: Anil Verma, Suddhasatwa AsuAbstract:The performance of a direct Alkaline Fuel Cell (AFC) is studied separately using methanol, ethanol and sodium borohydride as Fuel. Potassium hydroxide solution was used as an electrolyte. Pt-black and manganese dioxide catalyst were used to prepare the anode and cathode electrodes. Ni mesh was used as current collector. The direct Alkaline Fuel Cell was constructed with the prepared anode and cathode electrodes and Ni mesh. The current density–Cell voltage characteristics of the Fuel Cell were determined by varying load and at different experimental conditions, e.g., electrolyte concentration, Fuel concentration and temperature. The Fuel Cell performance increases initially with the increase in electrolyte (KOH) concentration and then decreases with further increase of the same. The Cell performance increases initially and then no appreciable improvement noticed with the increase in Fuel concentration. The performance of the Fuel Cell increases with increase in temperature in general with the exception to NaBH4 Alkaline Fuel Cell. A mathematical model for the direct Alkaline Fuel Cell is developed based on reaction mechanism available in the literature to predict the Cell voltage at a given current density. The model takes into account activation, ohmic, concentration overpotentials and other losses. The model prediction is in fair agreement with the experimental data on current–voltage characteristics and captures the influence of different experimental conditions on current–voltage characteristics.
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direct use of alcohols and sodium borohydride as Fuel in an Alkaline Fuel Cell
Journal of Power Sources, 2005Co-Authors: Anil Verma, Suddhasatwa AsuAbstract:Abstract The performance of an Alkaline Fuel Cell (AFC) was studied at different electrolyte concentrations and temperatures for the direct feeding of methanol, ethanol and sodium borohydride as Fuels. Potassium hydroxide is used as the electrolyte in the Alkaline Fuel Cell. The anode was prepared by using Pt black, carbon paper and Nafion dispersion. Nickel mesh was used as the current collector. A standard cathode made of manganese dioxide/carbon paper/Ni-mesh/Teflon dispersion (Electro-Chem-Technic, UK) was used for testing the Fuel Cell performance. The experimental results showed that the current density increases with increase in KOH concentration. Maximum current densities of 300, 270 and 360 A m −2 were obtained for methanol, ethanol and sodium borohydride as Fuel respectively with 3 M KOH electrolyte at 25 °C. The Cell performance decreases with further increase in the KOH concentration. The current density of the Alkaline Fuel Cell increases with increase in temperature for all the three Fuels. The increase in current density with temperature is not as high as expected for sodium borohydride. These results are explained based on an electrochemical phenomenon and different associated losses.
Anil H N Rao - One of the best experts on this subject based on the ideXlab platform.
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cardo poly arylene ether sulfone block copolymers with pendant imidazolium side chains as novel anion exchange membranes for direct methanol Alkaline Fuel Cell
Polymer, 2013Co-Authors: Anil H N Rao, Hyoungjuh Kim, Suk Woo Nam, Tae Hyu KimAbstract:Abstract A series of phenolphthalein-based cardo poly(arylene ether sulfone) (PES) block copolymers containing pendant imidazolium group (PI-PESs) were synthesized as novel anion exchange membranes for direct methanol Alkaline Fuel Cells. These PI-PESs combine the advantages of pendant anion conductors on the polymer side chains with the thermochemical stabilities of the imidazolium group, showing high hydroxide conductivity, together with good physical and chemical stability under basic conditions. The hydroxide conductivity over 0.03 S/cm at 20 °C and 0.1 S/cm at 80 °C was obtained for the PI-PES membranes. In addition, PI-PES membranes show low permeability to methanol (below 6.74 × 10 −8 cm 2 /s) and very high selectivity (over 3.7 × 10 5 S·s/cm 3 ). These properties make the PI-PESs promising candidate materials for anion exchange membranes for direct methanol Alkaline Fuel Cells.
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imidazolium functionalized poly arylene ether sulfone block copolymer as an anion exchange membrane for Alkaline Fuel Cell
Polymer, 2013Co-Authors: Anil H N Rao, Roshni Lilly Thankamony, Hyoungjuh Kim, Suk Woo Nam, Tae Hyu KimAbstract:Abstract An ethyl imidazolium-functionalized poly(arylene ether sulfone) (EI-PES) block copolymer was prepared as a novel anion exchange membrane. The EI-PES polymer was synthesized by polycondensation between the F- and OH-terminated oligomers, followed by benzylic bromination and imidazolium functionalization (homogeneous functionalization). The quaternary ammonium-functionalized PES (QA-PES) was also prepared by heterogeneous functionalization, and the properties were compared with EI-PES. The membrane obtained from EI-PES showed a well-defined phase separated morphology between hydrophobic and hydrophilic ionic units of the block copolymer. An IEC of 1.45 meq/g with hydroxide conductivity of 0.03 S/cm at r.t. was observed for EI-PES. The EI-PES membrane also displayed exCellent dimensional, thermal, mechanical and chemical stabilities.
