Sulfonated polyether ether ketone (SPEEK) with variou s degree of sulfonation (DS) were synthesized by reaction of PEEK with sulfo nic acid as sulfonating agent and solvent.Their proton conductivity and methanol pe rm...Sulfonated polyether ether ketone (SPEEK) with variou s degree of sulfonation (DS) were synthesized by reaction of PEEK with sulfo nic acid as sulfonating agent and solvent.Their proton conductivity and methanol pe rmeability as a function of the degree of sulfonation were investigated.For 46 .71% DS,proton conductivity was 1.68×10 -2S/cm at 80℃ and 4.25×10 -2S/cm at 100℃,which is closed to or superior to that of Nafion 115 me mbrane at the same conditions.Methanol permeability of SPEEK was considerable s maller than that of Nafion 115 membrane.Because of their high conductivity and low methanol permeability,SPEEK membranes appear to be excellent candidate for use in DMFC applications.展开更多
该文分析了膨胀石墨双极板(EGBPs)各向异性结构对燃料电池水热管理与输出性能的影响。建立了三维两相非等温数值模型,对比了4种典型复合材料结构下温度、电流密度、水含量等参数的分布特征,揭示了双极板传热特性与输出性能的耦合效应。...该文分析了膨胀石墨双极板(EGBPs)各向异性结构对燃料电池水热管理与输出性能的影响。建立了三维两相非等温数值模型,对比了4种典型复合材料结构下温度、电流密度、水含量等参数的分布特征,揭示了双极板传热特性与输出性能的耦合效应。结果表明:沿质子传递方向热导率(k_z)对燃料电池性能具有显著影响,在2.2 A cm^(-2)电流密度下,将k_z从常规结构的5 W·m^(-1)·K^(-1)提升至280 W·m^(-1)·K^(-1),可以使输出性能提高22 m V;沿流道气体流动方向的热导率(k_y)是影响散热能力的关键因素,将k_y与k_z提高至280 W·m^(-1)·K^(-1),或者实现各向同性结构(k_x=k_y=k_z=20 W·m^(-1)·K^(-1)),均能够使膜电极组件(MEA)核心区域的温度降低2℃左右。因此,提高k_y与k_z并实现各向同性结构是膨胀石墨双极板技术的未来发展目标之一。展开更多
Sulfonated phenolphthalein poly(ether sulfone) (SPES C) with various sulfonation degree were synthesized by reaction of PES C with sulfonic acid as sulfonating agent and solvent.Their proton conductivity and methanol ...Sulfonated phenolphthalein poly(ether sulfone) (SPES C) with various sulfonation degree were synthesized by reaction of PES C with sulfonic acid as sulfonating agent and solvent.Their proton conductivity and methanol permeability as a function of the degree of sulfonation were investigated.For 70 21% degree of sulfonation,proton conductivity was 3 45×10 -2 S/cm at 100℃,which is closed to or superior to that of Nafion 115 membrane at the same conditions (4 19×10 -2 S/cm).Methanol permeability of SPES C was considerable smaller than that of Nafion 115 membrane.Because of their high conductivity and low methanol permeability,SPES C membranes appear to be excellent candidate for use in DMFC applications.展开更多
In order to solve the methanol crossover problem caused by the poor alcohol rejecting ability of the Nafion TM membranes currently used in direct methanol fuel cell (DMFC),polyvinylidene fluoride(PVDF)was blended with...In order to solve the methanol crossover problem caused by the poor alcohol rejecting ability of the Nafion TM membranes currently used in direct methanol fuel cell (DMFC),polyvinylidene fluoride(PVDF)was blended with Nafion material to prepare a new type of membrane for DMFC and its ionic conductivity and the methanol permeability was investigated.PVDF was used here to regulate the ratio between hydrophilic group and the hydrophobic group exist in the blend membranes according to the hydrophilic hydrophobic balance theory proposed in pervaporation.The adding of PVDF lead to a great improvement of the membrane’s MeOH rejection.When PVDF content was increased from 25% to 75%,the MeOH permeability was reduced from～10 -7 to ～10 -9 cm 2/s,1 to 3 orders of magnitude lower than that of Nafion117.The membrane conductivity decreased,although remaining at high value(～10 -4 S/cm),with the increase of PVDF content.Compared with the Nafion117 membrane,the PVDF Nafion blend membrane with only 25% of Nafion showed an improvement in performance by about 40 times,if the ratio( σ/P ) was adopted to characterize the performance of a membrane for DMFC.Percolation theory,cocontinuous morphology features and phase transition model were applied to explain the behavior of membrane conduction.展开更多
文摘Sulfonated polyether ether ketone (SPEEK) with variou s degree of sulfonation (DS) were synthesized by reaction of PEEK with sulfo nic acid as sulfonating agent and solvent.Their proton conductivity and methanol pe rmeability as a function of the degree of sulfonation were investigated.For 46 .71% DS,proton conductivity was 1.68×10 -2S/cm at 80℃ and 4.25×10 -2S/cm at 100℃,which is closed to or superior to that of Nafion 115 me mbrane at the same conditions.Methanol permeability of SPEEK was considerable s maller than that of Nafion 115 membrane.Because of their high conductivity and low methanol permeability,SPEEK membranes appear to be excellent candidate for use in DMFC applications.
文摘该文分析了膨胀石墨双极板(EGBPs)各向异性结构对燃料电池水热管理与输出性能的影响。建立了三维两相非等温数值模型,对比了4种典型复合材料结构下温度、电流密度、水含量等参数的分布特征,揭示了双极板传热特性与输出性能的耦合效应。结果表明:沿质子传递方向热导率(k_z)对燃料电池性能具有显著影响,在2.2 A cm^(-2)电流密度下,将k_z从常规结构的5 W·m^(-1)·K^(-1)提升至280 W·m^(-1)·K^(-1),可以使输出性能提高22 m V;沿流道气体流动方向的热导率(k_y)是影响散热能力的关键因素,将k_y与k_z提高至280 W·m^(-1)·K^(-1),或者实现各向同性结构(k_x=k_y=k_z=20 W·m^(-1)·K^(-1)),均能够使膜电极组件(MEA)核心区域的温度降低2℃左右。因此,提高k_y与k_z并实现各向同性结构是膨胀石墨双极板技术的未来发展目标之一。
文摘Sulfonated phenolphthalein poly(ether sulfone) (SPES C) with various sulfonation degree were synthesized by reaction of PES C with sulfonic acid as sulfonating agent and solvent.Their proton conductivity and methanol permeability as a function of the degree of sulfonation were investigated.For 70 21% degree of sulfonation,proton conductivity was 3 45×10 -2 S/cm at 100℃,which is closed to or superior to that of Nafion 115 membrane at the same conditions (4 19×10 -2 S/cm).Methanol permeability of SPES C was considerable smaller than that of Nafion 115 membrane.Because of their high conductivity and low methanol permeability,SPES C membranes appear to be excellent candidate for use in DMFC applications.
文摘In order to solve the methanol crossover problem caused by the poor alcohol rejecting ability of the Nafion TM membranes currently used in direct methanol fuel cell (DMFC),polyvinylidene fluoride(PVDF)was blended with Nafion material to prepare a new type of membrane for DMFC and its ionic conductivity and the methanol permeability was investigated.PVDF was used here to regulate the ratio between hydrophilic group and the hydrophobic group exist in the blend membranes according to the hydrophilic hydrophobic balance theory proposed in pervaporation.The adding of PVDF lead to a great improvement of the membrane’s MeOH rejection.When PVDF content was increased from 25% to 75%,the MeOH permeability was reduced from～10 -7 to ～10 -9 cm 2/s,1 to 3 orders of magnitude lower than that of Nafion117.The membrane conductivity decreased,although remaining at high value(～10 -4 S/cm),with the increase of PVDF content.Compared with the Nafion117 membrane,the PVDF Nafion blend membrane with only 25% of Nafion showed an improvement in performance by about 40 times,if the ratio( σ/P ) was adopted to characterize the performance of a membrane for DMFC.Percolation theory,cocontinuous morphology features and phase transition model were applied to explain the behavior of membrane conduction.
