The novel sulfonated polybenzimidazole(sPBI)/amine functionalized titanium dioxide(AFT) composite membrane is devised and studied for its capability of the application of high temperature proton exchange membrane fuel...The novel sulfonated polybenzimidazole(sPBI)/amine functionalized titanium dioxide(AFT) composite membrane is devised and studied for its capability of the application of high temperature proton exchange membrane fuel cells(HT-PEMFCs),unlike the prior low temperature AFT endeavors.The high temperature compatibility was actualized because of the filling of free volumes in the rigid aromatic matrix of the composite with AFT nanoparticles which inhibited segmental motions of the chains and improved its thermal stability.Besides,amine functionalization of TiO2 enhanced their dispersion character in the sPBI matrix and shortened the interparticle separation gap which finally improved the proton transfer after establishing interconnected pathways and breeding more phosphoric acid(PA) doping.In addition,the appeared assembled clusters of AFT flourished a superior mechanical stability.Thus,the optimized sPBI/AFT(10 wt%) showed 65.3 MPa tensile strength;0.084 S·cm^-1 proton conductivity(at 160℃;in anhydrous conditions),28.6% water uptake and PA doping level of 23 mol per sPBI repeat unit.The maximum power density peak for sPBI/AFT-10 met the figure of0.42 W·cm^-2 at 160℃(in dry conditions) under atmospheric pressure with 1.5 and 2.5 stoichiometric flow rates of H2/air.These results affirmed the probable fitting of sPBI/AFT composite for HT-PEMFC applications.展开更多
Development of high-performance ion-selective membranes is crucial for achieving efficient ion separation in water treatment and energy storage applications.In this study,we demonstrate the strategic incorporation of ...Development of high-performance ion-selective membranes is crucial for achieving efficient ion separation in water treatment and energy storage applications.In this study,we demonstrate the strategic incorporation of acid-base pairs within a polybenzimidazole matrix through controlled sulfonation.By leveraging these intermolecular interactions,we enhance the Li^(+)/Mg^(2+)selectivity of the membrane.At an optimal sulfonation degree,the SP45 membrane forms a cross-linked structure,featuring contracted ionic clusters and discrete hydrophilic domains with limited interconnectivity.This unique microstructure imposes significantly higher energy barriers for the transmembrane transport of Mg^(2+),thereby endowing the SP45 membrane with exceptional perm-selectivity of 48.1 at a current density of 2 mA cm^(-2).Cycling stability tests reveal that the Li^(+)/Mg^(2+)selectivity degradation remains below 10%across multiple cycles in diverse mixed-salt systems.In practical brine ion distillation tests,we achieved a separation factor of exceeding 60,000 between Li^(+)and Mg^(2+)utilizing a 4-stage ion-distillation device equipped with the prepared SP45 membranes.This work provides fundamental insights into ion transport regulation through molecular-level acid-base pairs engineering,opening new avenues for advanced ion-selective separation membranes.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21776034,21476044 and 21406031)Joint Funds of the National Natural Science Foundation of China(U1663223)+1 种基金National Key Research and Development Program of China(2016YFB0101203)Changjiang Scholars Program(T2012049)。
文摘The novel sulfonated polybenzimidazole(sPBI)/amine functionalized titanium dioxide(AFT) composite membrane is devised and studied for its capability of the application of high temperature proton exchange membrane fuel cells(HT-PEMFCs),unlike the prior low temperature AFT endeavors.The high temperature compatibility was actualized because of the filling of free volumes in the rigid aromatic matrix of the composite with AFT nanoparticles which inhibited segmental motions of the chains and improved its thermal stability.Besides,amine functionalization of TiO2 enhanced their dispersion character in the sPBI matrix and shortened the interparticle separation gap which finally improved the proton transfer after establishing interconnected pathways and breeding more phosphoric acid(PA) doping.In addition,the appeared assembled clusters of AFT flourished a superior mechanical stability.Thus,the optimized sPBI/AFT(10 wt%) showed 65.3 MPa tensile strength;0.084 S·cm^-1 proton conductivity(at 160℃;in anhydrous conditions),28.6% water uptake and PA doping level of 23 mol per sPBI repeat unit.The maximum power density peak for sPBI/AFT-10 met the figure of0.42 W·cm^-2 at 160℃(in dry conditions) under atmospheric pressure with 1.5 and 2.5 stoichiometric flow rates of H2/air.These results affirmed the probable fitting of sPBI/AFT composite for HT-PEMFC applications.
基金supported by the National Key Research and Development Program of China(2022YFB3805100)National Natural Science Foundation of China(22222812 and 22178330).
文摘Development of high-performance ion-selective membranes is crucial for achieving efficient ion separation in water treatment and energy storage applications.In this study,we demonstrate the strategic incorporation of acid-base pairs within a polybenzimidazole matrix through controlled sulfonation.By leveraging these intermolecular interactions,we enhance the Li^(+)/Mg^(2+)selectivity of the membrane.At an optimal sulfonation degree,the SP45 membrane forms a cross-linked structure,featuring contracted ionic clusters and discrete hydrophilic domains with limited interconnectivity.This unique microstructure imposes significantly higher energy barriers for the transmembrane transport of Mg^(2+),thereby endowing the SP45 membrane with exceptional perm-selectivity of 48.1 at a current density of 2 mA cm^(-2).Cycling stability tests reveal that the Li^(+)/Mg^(2+)selectivity degradation remains below 10%across multiple cycles in diverse mixed-salt systems.In practical brine ion distillation tests,we achieved a separation factor of exceeding 60,000 between Li^(+)and Mg^(2+)utilizing a 4-stage ion-distillation device equipped with the prepared SP45 membranes.This work provides fundamental insights into ion transport regulation through molecular-level acid-base pairs engineering,opening new avenues for advanced ion-selective separation membranes.
