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Ronghuan He - One of the best experts on this subject based on the ideXlab platform.
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preparation and investigation of various Imidazolium functionalized poly 2 6 dimethyl 1 4 phenylene oxide anion exchange membranes
Electrochimica Acta, 2016Co-Authors: Jingshuai Yang, Xiangnan He, Ronghuan HeAbstract:Abstract Imidazolium-type anion exchange membranes (AEMs) were prepared by functionalization of bromomethylated poly(2,6-dimethyl-1,4-phenyleneoxide) with six kinds of imidazole compounds, respectively, to investigate the correlation of the grafted Imidazolium structure and the physicochemical properties of the membrane. The chemical structure of substituted groups in Imidazolium cations would highly influence the ion exchange capacity, ionic conduction, mechanical strength, as well as stability in strong alkaline solutions of the AEMs. The membrane having C2-methyl and N3-butyl substituted groups in the Imidazolium pendants exhibited superior properties among the prepared AEMs, i.e., an IEC of around 1.03 mmol g −1 , hydroxide ion conductivity of 42.5 mS cm −1 at 80 °C, and tensile strength at break of 15.0 MPa, respectively. In addition, this membrane showed high alkaline stability and no obvious decline in conductivity was observed after being exposed to 1 M KOH at 60 °C for 180 h.
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phosphoric acid doped Imidazolium polysulfone membranes for high temperature proton exchange membrane fuel cells
Journal of Power Sources, 2012Co-Authors: Jingshuai Yang, Qingfeng Li, Jens Oluf Jensen, Lars Nilausen Cleemann, Niels J Bjerrum, Ronghuan HeAbstract:Abstract A novel acid–base polymer membrane is prepared by doping of Imidazolium polysulfone with phosphoric acid for high temperature proton exchange membrane fuel cells. Polysulfone is first chloromethylated, followed by functionalization of the chloromethylated polysulfone with alkyl imidazoles i.e. methyl (MePSU), ethyl (EtPSU) and butyl (BuPSU) Imidazoliums, as revealed by 1H NMR spectra. The Imidazolium polysulfone membranes are then doped with phosphoric acid and used as a proton exchange membrane electrolyte in fuel cells. An acid doping level of about 10–11 mol H3PO4 per mole of the Imidazolium group is achieved in 85 wt% H3PO4 at room temperature. The membranes exhibit a proton conductivity of 0.015–0.022 S cm−1 at 130–150 °C under 15 mol% water vapor in air, and a tensile strength of 5–6 MPa at 130 °C under ambient humidity. Fuel cell tests show an open circuit voltage as high as 0.96 V and a peak power density of 175–204 mW cm−2 at 150 °C with unhumidified hydrogen and air under ambient pressure.
Weibing Sheng - 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 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.
Jingshuai Yang - One of the best experts on this subject based on the ideXlab platform.
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ionic crosslinking of Imidazolium functionalized poly aryl ether ketone by sulfonated poly ether ether ketone for anion exchange membranes
Joint International Conference on Information Sciences, 2017Co-Authors: Dengji Zhang, Jingshuai YangAbstract:Two N3-substituted imidazoles 1,2-dimethylimidazole and 1-butyl-2-methylimidazole were chosen to functionalize poly(aryl ether ketone), respectively. The generated Imidazolium cations could electrostatically react with sulfonate ions of the sulfonated poly(ether ether ketone) forming the ionic crosslinking structure of the membranes. The changes in crosslinking degree and the alkyl chain-length on N3 site of the Imidazoliums could highly affect the properties of the anion exchange membranes (AEMs). The AEMs functionalized by 1-butyl-2-methylimidazole exhibited superior properties compared to those functionalized by 1,2-dimethylimidazole according to the tolerance tests of the AEMs towards hot alkaline solutions. After exposed to 1M KOH at 80°C for 200h, the 1-butyl-2-methylimidazole modified AEMs maintained the ion exchange capacity of above 85%, the conductivity of about 70%, and the tensile stress at break of around 80%, respectively. The hydrophile-lipophile balance of the polymer membranes was calculated and proposed to better understand the correlation between structures and properties of the AEMs. The degradation of the Imidazolium functional groups of the AEMs under the attack of hydroxide ions was evidenced by FT-IR analysis.
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preparation and investigation of various Imidazolium functionalized poly 2 6 dimethyl 1 4 phenylene oxide anion exchange membranes
Electrochimica Acta, 2016Co-Authors: Jingshuai Yang, Xiangnan He, Ronghuan HeAbstract:Abstract Imidazolium-type anion exchange membranes (AEMs) were prepared by functionalization of bromomethylated poly(2,6-dimethyl-1,4-phenyleneoxide) with six kinds of imidazole compounds, respectively, to investigate the correlation of the grafted Imidazolium structure and the physicochemical properties of the membrane. The chemical structure of substituted groups in Imidazolium cations would highly influence the ion exchange capacity, ionic conduction, mechanical strength, as well as stability in strong alkaline solutions of the AEMs. The membrane having C2-methyl and N3-butyl substituted groups in the Imidazolium pendants exhibited superior properties among the prepared AEMs, i.e., an IEC of around 1.03 mmol g −1 , hydroxide ion conductivity of 42.5 mS cm −1 at 80 °C, and tensile strength at break of 15.0 MPa, respectively. In addition, this membrane showed high alkaline stability and no obvious decline in conductivity was observed after being exposed to 1 M KOH at 60 °C for 180 h.
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phosphoric acid doped Imidazolium polysulfone membranes for high temperature proton exchange membrane fuel cells
Journal of Power Sources, 2012Co-Authors: Jingshuai Yang, Qingfeng Li, Jens Oluf Jensen, Lars Nilausen Cleemann, Niels J Bjerrum, Ronghuan HeAbstract:Abstract A novel acid–base polymer membrane is prepared by doping of Imidazolium polysulfone with phosphoric acid for high temperature proton exchange membrane fuel cells. Polysulfone is first chloromethylated, followed by functionalization of the chloromethylated polysulfone with alkyl imidazoles i.e. methyl (MePSU), ethyl (EtPSU) and butyl (BuPSU) Imidazoliums, as revealed by 1H NMR spectra. The Imidazolium polysulfone membranes are then doped with phosphoric acid and used as a proton exchange membrane electrolyte in fuel cells. An acid doping level of about 10–11 mol H3PO4 per mole of the Imidazolium group is achieved in 85 wt% H3PO4 at room temperature. The membranes exhibit a proton conductivity of 0.015–0.022 S cm−1 at 130–150 °C under 15 mol% water vapor in air, and a tensile strength of 5–6 MPa at 130 °C under ambient humidity. Fuel cell tests show an open circuit voltage as high as 0.96 V and a peak power density of 175–204 mW cm−2 at 150 °C with unhumidified hydrogen and air under ambient pressure.
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 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.
Xixing Zhou - 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 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.
