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
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
Ba0.95Ce0.9Y0.1O3－α solid electrolyte was prepared by high temperature solid state reaction. The electrochemical oxygen permeation (oxygen pumping) rates and oxide ion transport number in this electrolyte were detec...Ba0.95Ce0.9Y0.1O3－α solid electrolyte was prepared by high temperature solid state reaction. The electrochemical oxygen permeation (oxygen pumping) rates and oxide ion transport number in this electrolyte were detected in the temperature of 600～ 1000℃ . It was found that this electrolyte exhibited the oxide ion conduction with the oxide ion transport number of 0.3～ 0.5.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.
文摘Ba0.95Ce0.9Y0.1O3－α solid electrolyte was prepared by high temperature solid state reaction. The electrochemical oxygen permeation (oxygen pumping) rates and oxide ion transport number in this electrolyte were detected in the temperature of 600～ 1000℃ . It was found that this electrolyte exhibited the oxide ion conduction with the oxide ion transport number of 0.3～ 0.5.
