Radiation-induced grafting of styrene onto polytetrafluoroethylene (PTFE) membranes was studied by a simultaneous irradiation technique.Grafting was carded out usingγ-radiation from a ^(60)Co source at room temperatu...Radiation-induced grafting of styrene onto polytetrafluoroethylene (PTFE) membranes was studied by a simultaneous irradiation technique.Grafting was carded out usingγ-radiation from a ^(60)Co source at room temperature. Effects of absorbed dose,atmosphere,dose rate,and the concentration of initial monomer on the degree of grafting (DOG) were investigated and the most appropriate grafting condition was obtained.Subsequently,sulphonation of the grafted PTFE membrane (PTFE-g-PS) was carried out and a series of ion exchange membranes (PTFE-g-PSSA) was prepared.Further characterizations of FTIR,TGA,and SEM testified that grafting and sulphonation of the membranes were successfully processed;moreover,grafting of styrene not only occurred in the surface of PTFE membrane,but also in the micropores of the membrane.Ion exchange capacity (IEC) and conductivity were found increase with the grafting yield.The results suggest that at a low dose,such as 17 kGy,the ion exchange membrane (IEM) which will be suitable for vanadium redox battery (VRB) use can be obtained.展开更多
The electrochemical behavior of the V( Ⅳ )/V( Ⅴ ) redox couple at a glassy carbon electrode was investigated. Cyclic voltammetry(CV) results indicated that electrode process of the V( Ⅳ )/V( Ⅴ ) couple was electro...The electrochemical behavior of the V( Ⅳ )/V( Ⅴ ) redox couple at a glassy carbon electrode was investigated. Cyclic voltammetry(CV) results indicated that electrode process of the V( Ⅳ )/V( Ⅴ ) couple was electrochemically quasi-reversible with a rate constant of 8 × 10^-4 cm/S . Increasing concentration of sulfuric acid was electrochemically favourable for the V( Ⅳ )/V( Ⅴ )couple while elevated temperature was unfavourable for this system. Constant-current electrolysis results showed that current efficiency of more than 95 % could be achieved, which indicated that the V( Ⅳ )/V( Ⅴ ) couple had excellent electrolytic performance and was suitable for the application as the anolyte of redox flow batteries.展开更多
以含有异丙基溴侧基的聚醚醚酮为原子转移自由基聚合(ATRP)大分子引发剂,通过ATRP法在聚醚醚酮主链上接枝引入聚苯乙烯磺酸钠侧链,得到侧链型磺化聚醚醚酮质子交换膜(SSPEEK).采用溶液共混法在SSPEEK膜中引入钠基蒙脱土(Na-MMT),制备SSP...以含有异丙基溴侧基的聚醚醚酮为原子转移自由基聚合(ATRP)大分子引发剂,通过ATRP法在聚醚醚酮主链上接枝引入聚苯乙烯磺酸钠侧链,得到侧链型磺化聚醚醚酮质子交换膜(SSPEEK).采用溶液共混法在SSPEEK膜中引入钠基蒙脱土(Na-MMT),制备SSPEEK/Na-MMT钒电池质子交换复合膜.热重分析表明,复合膜具有较好的耐热性;扫描电镜显示,Na-MMT均匀分散在SSPEEK中.复合膜的钒离子渗透率由SSPEEK膜的1.24×10-5cm2·min-1降为4.88×10-6cm2·min-1,低于Nafion117膜的钒离子渗透率,阻钒能力优于Nafion117膜.电流密度为30 m A·cm-2时,以复合膜组装的电池的放电时间为215 min,长于Nafion117膜的198 min.在高放电电流密度下SSPEEK/Na-MMT膜的库伦效率与Nafion117膜相当.展开更多
基金Supported by The Scientific Research Foundation of State's Education Ministry for the Returned Overseas Chinese Scholars.
文摘Radiation-induced grafting of styrene onto polytetrafluoroethylene (PTFE) membranes was studied by a simultaneous irradiation technique.Grafting was carded out usingγ-radiation from a ^(60)Co source at room temperature. Effects of absorbed dose,atmosphere,dose rate,and the concentration of initial monomer on the degree of grafting (DOG) were investigated and the most appropriate grafting condition was obtained.Subsequently,sulphonation of the grafted PTFE membrane (PTFE-g-PS) was carried out and a series of ion exchange membranes (PTFE-g-PSSA) was prepared.Further characterizations of FTIR,TGA,and SEM testified that grafting and sulphonation of the membranes were successfully processed;moreover,grafting of styrene not only occurred in the surface of PTFE membrane,but also in the micropores of the membrane.Ion exchange capacity (IEC) and conductivity were found increase with the grafting yield.The results suggest that at a low dose,such as 17 kGy,the ion exchange membrane (IEM) which will be suitable for vanadium redox battery (VRB) use can be obtained.
文摘The electrochemical behavior of the V( Ⅳ )/V( Ⅴ ) redox couple at a glassy carbon electrode was investigated. Cyclic voltammetry(CV) results indicated that electrode process of the V( Ⅳ )/V( Ⅴ ) couple was electrochemically quasi-reversible with a rate constant of 8 × 10^-4 cm/S . Increasing concentration of sulfuric acid was electrochemically favourable for the V( Ⅳ )/V( Ⅴ )couple while elevated temperature was unfavourable for this system. Constant-current electrolysis results showed that current efficiency of more than 95 % could be achieved, which indicated that the V( Ⅳ )/V( Ⅴ ) couple had excellent electrolytic performance and was suitable for the application as the anolyte of redox flow batteries.
文摘以含有异丙基溴侧基的聚醚醚酮为原子转移自由基聚合(ATRP)大分子引发剂,通过ATRP法在聚醚醚酮主链上接枝引入聚苯乙烯磺酸钠侧链,得到侧链型磺化聚醚醚酮质子交换膜(SSPEEK).采用溶液共混法在SSPEEK膜中引入钠基蒙脱土(Na-MMT),制备SSPEEK/Na-MMT钒电池质子交换复合膜.热重分析表明,复合膜具有较好的耐热性;扫描电镜显示,Na-MMT均匀分散在SSPEEK中.复合膜的钒离子渗透率由SSPEEK膜的1.24×10-5cm2·min-1降为4.88×10-6cm2·min-1,低于Nafion117膜的钒离子渗透率,阻钒能力优于Nafion117膜.电流密度为30 m A·cm-2时,以复合膜组装的电池的放电时间为215 min,长于Nafion117膜的198 min.在高放电电流密度下SSPEEK/Na-MMT膜的库伦效率与Nafion117膜相当.
