In order to improve the proton conductivity of hollow silica spheres （HSS）/perfluorosulfonic acid ion-exchange （PFSA） composite membranes as proton exchange membrane,sulfonic acid groups were grafted onto the surf...In order to improve the proton conductivity of hollow silica spheres （HSS）/perfluorosulfonic acid ion-exchange （PFSA） composite membranes as proton exchange membrane,sulfonic acid groups were grafted onto the surfaces of HSS via post grafting methods.TEM images and FT-IR spectra of the obtained sulfonic acid groups modified hollow silica spheres （SAMHSS） illustrated that the sulfonic acid groups were successfully grafted onto the surfaces of HSS.Water uptake and swelling degree of SAMHSS/PFSA composite membranes were found much higher than those of HSS/PFSA membranes due to the introduction of hydrophilic sulfonic acid groups.In a range from 50 ℃ to 130 ℃,the highest conductivity of composite membranes was obtained when 5 wt% SAMHSS was loaded.The maximum conductivity reached 7.5×10-2 S·cm-1 at 100 ℃ and 100% relative humidity,even the temperature increased to 130 ℃,the conductivity of composite membranes with 5 wt% SAMHSS could reach 3.7×10-2 S·cm-1 at 100 % relative humidity,while the conductivity of the recast PFSA was only 2.2×10-3 S·cm-1.展开更多
Due to the designability of their proton transport channels,high-performance long-lasting composite proton exchange membranes(PEMs)are currently the subject of extensive research.However,the compatibility and channel ...Due to the designability of their proton transport channels,high-performance long-lasting composite proton exchange membranes(PEMs)are currently the subject of extensive research.However,the compatibility and channel order of the internal components of the composite membranes are still challenging.In this work,hollow polypyrrole(PPy)nanotube structures were obtained to provide a nitrogen source and to act as a skeleton to confine and separate cobalt nanoparticles on the surface of PPy nanotubes.Finally,zeolitic imidazolate framework material-67(ZIF-67)was attached to the surface.By using this method,PPy@ZIF-67 filler can minimize the particle size and inhibit Co^(2+)ions from aggregating,thus constructing a reasonably distributed transport channel and improving the proton transport capacity.As a result,the synthesized polymer nanotubes loaded metal-organic framework(MOF)nanofiber network can enhance the physicochemical properties and stability of the membrane by providing a more extensive interfacial interaction.In addition,the composite membrane has excellent ionic conductivity and power density,reaching 233.7 mS cm^(–1) and 837 mW cm^(–2) at 80℃ and 100%humidity.It indicates that the nanofibrous MOF structure not only improves the compatibility with the substrate but also provides sufficient leap points for proton transport via the interfacial conduction pathway between the PPy@ZIF-67 filler and the substrate,thus allowing the resulting composite membrane to facilitate proton transfer via the Vehicle and Grotthuss mechanisms synergistically.展开更多
Using the hydrogen-bonding interaction between graphene oxide（GO） and sulfonated polyethersulfone （SPES）, we constructed the multilayer structure of GO and SPES on the polyester tiber mats via layer-by-layer self-...Using the hydrogen-bonding interaction between graphene oxide（GO） and sulfonated polyethersulfone （SPES）, we constructed the multilayer structure of GO and SPES on the polyester tiber mats via layer-by-layer self-assembly. In each self-assembled layer, sulfonic acid groups are arranged along the a^s of fiber, which provides the long-range proton transmission channels, promoting the rapidly proton conduction. The performances of the composite membranes based on SPES and multilayer assembled polyester fiber mats were studied. The results show that the proton conductivity of composite membranes increases with the increasing assembly layers. At the same time, the mechanical properties and methanol-resistance of the composite membranes were obviously improved.展开更多
The design of the catalyst layer(CL)offers a feasible way to realize the commercialization of proton exchange membrane fuel cells(PEMFCs).An in-depth understanding of catalyst inks is critical to achieving the optimal...The design of the catalyst layer(CL)offers a feasible way to realize the commercialization of proton exchange membrane fuel cells(PEMFCs).An in-depth understanding of catalyst inks is critical to achieving the optimal CL structure and cell performance.In this work,the effects of the solvent evaporation process during ink drying on the formation of the CL microstructure are particularly considered to reveal the structure-property correlations among the catalyst ink,drying process,CL microstructure and fuel cell performance.An increase in the alcohol content of the catalyst ink increases the amount of free ionomers while allowing the ionomer backbone to be more stretched in the dispersion medium.The higher alcohol content contributes to rapid solvent evaporation and thus inhibits the formation of coffee rings;as a result,a more developed ionomer network with a denser pore structure is obtained.Therefore,the alcohol-rich electrode exhibits better proton conduction capability,but higher oxygen transport resistance.For complex fuel cell operating conditions,a catalyst ink formulation with 50 wt%alcohol content is preferred due to its proper ionomer and pore size distribution,providing satisfactory fuel cell performance.展开更多
基金Funded by National Natural Science Foundation of China(No.50803046)
文摘In order to improve the proton conductivity of hollow silica spheres （HSS）/perfluorosulfonic acid ion-exchange （PFSA） composite membranes as proton exchange membrane,sulfonic acid groups were grafted onto the surfaces of HSS via post grafting methods.TEM images and FT-IR spectra of the obtained sulfonic acid groups modified hollow silica spheres （SAMHSS） illustrated that the sulfonic acid groups were successfully grafted onto the surfaces of HSS.Water uptake and swelling degree of SAMHSS/PFSA composite membranes were found much higher than those of HSS/PFSA membranes due to the introduction of hydrophilic sulfonic acid groups.In a range from 50 ℃ to 130 ℃,the highest conductivity of composite membranes was obtained when 5 wt% SAMHSS was loaded.The maximum conductivity reached 7.5×10-2 S·cm-1 at 100 ℃ and 100% relative humidity,even the temperature increased to 130 ℃,the conductivity of composite membranes with 5 wt% SAMHSS could reach 3.7×10-2 S·cm-1 at 100 % relative humidity,while the conductivity of the recast PFSA was only 2.2×10-3 S·cm-1.
基金The author would like to thank the National Key R&D Program of China(Project No.2021YFE0104700).
文摘Due to the designability of their proton transport channels,high-performance long-lasting composite proton exchange membranes(PEMs)are currently the subject of extensive research.However,the compatibility and channel order of the internal components of the composite membranes are still challenging.In this work,hollow polypyrrole(PPy)nanotube structures were obtained to provide a nitrogen source and to act as a skeleton to confine and separate cobalt nanoparticles on the surface of PPy nanotubes.Finally,zeolitic imidazolate framework material-67(ZIF-67)was attached to the surface.By using this method,PPy@ZIF-67 filler can minimize the particle size and inhibit Co^(2+)ions from aggregating,thus constructing a reasonably distributed transport channel and improving the proton transport capacity.As a result,the synthesized polymer nanotubes loaded metal-organic framework(MOF)nanofiber network can enhance the physicochemical properties and stability of the membrane by providing a more extensive interfacial interaction.In addition,the composite membrane has excellent ionic conductivity and power density,reaching 233.7 mS cm^(–1) and 837 mW cm^(–2) at 80℃ and 100%humidity.It indicates that the nanofibrous MOF structure not only improves the compatibility with the substrate but also provides sufficient leap points for proton transport via the interfacial conduction pathway between the PPy@ZIF-67 filler and the substrate,thus allowing the resulting composite membrane to facilitate proton transfer via the Vehicle and Grotthuss mechanisms synergistically.
基金Supported by the National Natural Science Foundation of China（No.21574017）.
文摘Using the hydrogen-bonding interaction between graphene oxide（GO） and sulfonated polyethersulfone （SPES）, we constructed the multilayer structure of GO and SPES on the polyester tiber mats via layer-by-layer self-assembly. In each self-assembled layer, sulfonic acid groups are arranged along the a^s of fiber, which provides the long-range proton transmission channels, promoting the rapidly proton conduction. The performances of the composite membranes based on SPES and multilayer assembled polyester fiber mats were studied. The results show that the proton conductivity of composite membranes increases with the increasing assembly layers. At the same time, the mechanical properties and methanol-resistance of the composite membranes were obviously improved.
基金financially supported by the National Key Research and Development Program of China(2018YFB1502503)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA21090101)。
文摘The design of the catalyst layer(CL)offers a feasible way to realize the commercialization of proton exchange membrane fuel cells(PEMFCs).An in-depth understanding of catalyst inks is critical to achieving the optimal CL structure and cell performance.In this work,the effects of the solvent evaporation process during ink drying on the formation of the CL microstructure are particularly considered to reveal the structure-property correlations among the catalyst ink,drying process,CL microstructure and fuel cell performance.An increase in the alcohol content of the catalyst ink increases the amount of free ionomers while allowing the ionomer backbone to be more stretched in the dispersion medium.The higher alcohol content contributes to rapid solvent evaporation and thus inhibits the formation of coffee rings;as a result,a more developed ionomer network with a denser pore structure is obtained.Therefore,the alcohol-rich electrode exhibits better proton conduction capability,but higher oxygen transport resistance.For complex fuel cell operating conditions,a catalyst ink formulation with 50 wt%alcohol content is preferred due to its proper ionomer and pore size distribution,providing satisfactory fuel cell performance.
