The safety and performance of lithium-ion batteries(LIBs)largely depend on the structural design and performance characteristics of the separator.Commercial polyolefin separators suffer from problems such as poor ther...The safety and performance of lithium-ion batteries(LIBs)largely depend on the structural design and performance characteristics of the separator.Commercial polyolefin separators suffer from problems such as poor thermal stability,insufficient porosity,and inferior electrolyte wettability,which not only easily lead to battery safety issues but also significantly affect the ionic conductivity and energy density of the batteries.Herein,we have designed a facile,efficient and controllable methodology to develop a high-porosity poly(m-phenylene isophthalamide)(PMIA)separator with both excellent wettability and superior thermal resistance by a vapor-induced phase separation technique.Specifically,the PMIA separator undergoes a thermal shrinkage of less than 1%even after being treated at 200℃ for one hour,which greatly enhances the thermal safety of the battery.In addition,a continuous and interconnected high-porosity structure(porosity of 69%)is formed by utilizing a stable and controllable solvent exchange rate,thereby constructing abundant channels for the transportation of ions within the battery.Moreover,the amide groups in the PMIA molecular structure further confer the separator with excellent wettability,enabling it to possess outstanding electrolyte absorption capacity(electrolyte absorption rate of 270%).As a result,the Li||LFP full cell with PMIA separator exhibits excellent capacity and cycling stability,maintaining a reversible specific capacity of 105.6 mAh g^(-1)after 600 cycles at 5 C.And Li||NCM811 full cell with PMIA separator show no significant degradation(168.1 mAh g^(-1)at 0.5 C)after long-cycle at high temperature.These results indicate the potential of the PMIA separator for high thermal stability and high energy battery,and the scalability of this technology also provides new ideas and directions for the preparation of separators with superior comprehensive performance.展开更多
In order to solve the problem of oily wastewater,the poly(m-phenyleneisophthalamide)(PMIA)braided tube reinforced(PBR)poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether)(PFA)hollow fiber membrane with thermal and...In order to solve the problem of oily wastewater,the poly(m-phenyleneisophthalamide)(PMIA)braided tube reinforced(PBR)poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether)(PFA)hollow fiber membrane with thermal and solvent resistant property was prepared via no-solvent green method.The membrane surface and pore structure was optimized by changing the sintering temperature and graphene(GE)content.The morphologies showed that the spherical surface with good lipophilicity was formed,and the excellent mechanical strength with a favorable interface bonding state could be obtained due to the PFA melts permeating into the supporting layer.The doping of GE produced synergistic effects with the sintering temperature owing to its good thermal conductivity and pore formation.The PBR-PFA/GE hollow fiber membrane exhibited good hydrophobicity and lipophilicity with more than 97%separation efficiency for different oil products at-0.02 MPa.With the addition of GE,the average pore size first increases and then decreases,and the porosity gradually decreases.In addition,the hollow fiber membrane showed high separation ability to the water-in-oil emulsion,and maintained a stable flux recovery rate after recycling,making it possible to apply in the field of oily wastewater treatment.展开更多
Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength ...Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength and poor electrolyte affinity limit its application in LIBs.In this work,a new PMIA@polyacrylonitrile-polyvinylidene fluoride hexafluoropropylene-titanium dioxide(PMIA@PAN/PVDFHFP/TiO_(2))composite fibrous separator with a coaxial core-shell structure was developed by combining coaxial electrospinning,hot pressing,and heat treatment techniques.This separator not only inherits the exceptional thermostability of PMIA,showing no evident thermal shrinkage at 220 ℃,but also reveals improved mechanical strength(29.7 MPa)due to the formation of firm connections between fibers with the melted PVDF-HFP.Meanwhile,the massive polar groups in PVDF-HFP play a vital role in improving the electrolyte affinity,which renders the separator a high ionic conductivity of 1.36×10^(-3)s/cm.Therefore,the LIBs with PMIA@PAN/PVDF-HFP/TiO_(2)separators exhibited excellent cycling and rate performance at 25℃,and a high capacity retention rate(76.2%)at 80℃for 200 cycles at 1 C.Besides,the lithium metal symmetric battery assembled by the separator showed a small overpotential,indicating that the separator had a role in inhibiting lithium dendrites.In short,the PMIA@PAN/PVDF-HFP/TiO_(2) separator possesses a wide application prospect in the domain of LIBs.展开更多
A self-made PMIA asymmetric nanofiltration membrane was used for arsenic removal from drinking water by NF process. Effects of feed concentration, operating pressure, pH and existing ions on As(V) removal were investi...A self-made PMIA asymmetric nanofiltration membrane was used for arsenic removal from drinking water by NF process. Effects of feed concentration, operating pressure, pH and existing ions on As(V) removal were investigated. Experimental results showed that As(V) rejection was higher than 90% in the range of investigated As feed concentrations. The As(V) rejection increased slightly with pressure increase, As(V) rejection was higher than 90% in the pressure range of 0.4 MPa to 0.8 MPa. As(V) rejection increased significantly from 83% at pH 3 to 99% at pH 9. The presence of NaCl enhanced As(V) rejection in the range of feed concentration, and As(V) rejection can reach up to 99% at a feed As concentration of 100 μg/L, whereas there was a rejection decrease of 8% in the presence of Na2SO4 at every feed concentration. The results showed the As(V) detected in the permeate was lower than the EPA recommended MCL up to a feed As concentration of approximately 10 μg/L in the experimental research range.展开更多
The colored poly(m-phenylene isophthalamide)(PMIA)spinning solution was prepared by wet spinning and the die-swell of the colored PMIA spinning solution was done when it was extruded from a die in this experiment.The ...The colored poly(m-phenylene isophthalamide)(PMIA)spinning solution was prepared by wet spinning and the die-swell of the colored PMIA spinning solution was done when it was extruded from a die in this experiment.The properties and structures of colored PMIA fibers were characterized by scanning electron microscopy(SEM).The colored PMIA spinning dopes were first commixed in a pressurizer and then spun into a coagulation bath.The effect of die swell on the colored PMIA solution was resulted from the viscoelastic properties of the colored PMIA solution in the spinning process.The results showed that the die-swell ratio of the colored PMIA solution increased linearly with increasing the pressure and die length/diameter ratio(L/D).At the same pressure and L/D,the die-swell ratio decreased with the increase of filter layers and temperature.Also,optimized spinning parameters of the dopedyed PMIA fiber were obtained.展开更多
基金supported by the National Natural Science Foundation of China(52273059,52403046)the Science and Technology Plans of Tianjin(22JCYBJC01030)+1 种基金the Tianjin Research Innovation Project for Postgraduate Students(2022BKY145)partially supported by financial contributions from Yantai Tayho Advanced Materials Co.,Ltd。
文摘The safety and performance of lithium-ion batteries(LIBs)largely depend on the structural design and performance characteristics of the separator.Commercial polyolefin separators suffer from problems such as poor thermal stability,insufficient porosity,and inferior electrolyte wettability,which not only easily lead to battery safety issues but also significantly affect the ionic conductivity and energy density of the batteries.Herein,we have designed a facile,efficient and controllable methodology to develop a high-porosity poly(m-phenylene isophthalamide)(PMIA)separator with both excellent wettability and superior thermal resistance by a vapor-induced phase separation technique.Specifically,the PMIA separator undergoes a thermal shrinkage of less than 1%even after being treated at 200℃ for one hour,which greatly enhances the thermal safety of the battery.In addition,a continuous and interconnected high-porosity structure(porosity of 69%)is formed by utilizing a stable and controllable solvent exchange rate,thereby constructing abundant channels for the transportation of ions within the battery.Moreover,the amide groups in the PMIA molecular structure further confer the separator with excellent wettability,enabling it to possess outstanding electrolyte absorption capacity(electrolyte absorption rate of 270%).As a result,the Li||LFP full cell with PMIA separator exhibits excellent capacity and cycling stability,maintaining a reversible specific capacity of 105.6 mAh g^(-1)after 600 cycles at 5 C.And Li||NCM811 full cell with PMIA separator show no significant degradation(168.1 mAh g^(-1)at 0.5 C)after long-cycle at high temperature.These results indicate the potential of the PMIA separator for high thermal stability and high energy battery,and the scalability of this technology also provides new ideas and directions for the preparation of separators with superior comprehensive performance.
文摘采用并列电纺技术制备了具有并列结构的Sb_(2)O_(3)@PMIA/TPP@PVDF-CTFE锂离子电池复合隔膜,对复合隔膜的力学性能、热稳定性能、阻燃性能、电解液润湿性等性能进行分析测试。结果表明,复合隔膜具有较高的力学性能(拉伸强度为11.7 MPa),优异的热稳定性(220℃下热处理0.5 h后只有略微形变),良好的阻燃性能和优异的电解液润湿性,且其孔隙率和吸液率也较高(分别为277%、78%),离子电导率也高达2.67 m S/cm,表明制备的并列结构复合隔膜有效的提高了电池的安全性与离子传输能力。
基金funding provided by the National Natural Science Foundation of China(52103035,52173038).
文摘In order to solve the problem of oily wastewater,the poly(m-phenyleneisophthalamide)(PMIA)braided tube reinforced(PBR)poly(tetrafluoroethylene-co-perfluoropropyl vinyl ether)(PFA)hollow fiber membrane with thermal and solvent resistant property was prepared via no-solvent green method.The membrane surface and pore structure was optimized by changing the sintering temperature and graphene(GE)content.The morphologies showed that the spherical surface with good lipophilicity was formed,and the excellent mechanical strength with a favorable interface bonding state could be obtained due to the PFA melts permeating into the supporting layer.The doping of GE produced synergistic effects with the sintering temperature owing to its good thermal conductivity and pore formation.The PBR-PFA/GE hollow fiber membrane exhibited good hydrophobicity and lipophilicity with more than 97%separation efficiency for different oil products at-0.02 MPa.With the addition of GE,the average pore size first increases and then decreases,and the porosity gradually decreases.In addition,the hollow fiber membrane showed high separation ability to the water-in-oil emulsion,and maintained a stable flux recovery rate after recycling,making it possible to apply in the field of oily wastewater treatment.
基金supported by the Natural Science Foundation of Sichuan Province(Nos.2023YFG0096,2022NSFSC2008 and 2023NSFSC0442).
文摘Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength and poor electrolyte affinity limit its application in LIBs.In this work,a new PMIA@polyacrylonitrile-polyvinylidene fluoride hexafluoropropylene-titanium dioxide(PMIA@PAN/PVDFHFP/TiO_(2))composite fibrous separator with a coaxial core-shell structure was developed by combining coaxial electrospinning,hot pressing,and heat treatment techniques.This separator not only inherits the exceptional thermostability of PMIA,showing no evident thermal shrinkage at 220 ℃,but also reveals improved mechanical strength(29.7 MPa)due to the formation of firm connections between fibers with the melted PVDF-HFP.Meanwhile,the massive polar groups in PVDF-HFP play a vital role in improving the electrolyte affinity,which renders the separator a high ionic conductivity of 1.36×10^(-3)s/cm.Therefore,the LIBs with PMIA@PAN/PVDF-HFP/TiO_(2)separators exhibited excellent cycling and rate performance at 25℃,and a high capacity retention rate(76.2%)at 80℃for 200 cycles at 1 C.Besides,the lithium metal symmetric battery assembled by the separator showed a small overpotential,indicating that the separator had a role in inhibiting lithium dendrites.In short,the PMIA@PAN/PVDF-HFP/TiO_(2) separator possesses a wide application prospect in the domain of LIBs.
文摘A self-made PMIA asymmetric nanofiltration membrane was used for arsenic removal from drinking water by NF process. Effects of feed concentration, operating pressure, pH and existing ions on As(V) removal were investigated. Experimental results showed that As(V) rejection was higher than 90% in the range of investigated As feed concentrations. The As(V) rejection increased slightly with pressure increase, As(V) rejection was higher than 90% in the pressure range of 0.4 MPa to 0.8 MPa. As(V) rejection increased significantly from 83% at pH 3 to 99% at pH 9. The presence of NaCl enhanced As(V) rejection in the range of feed concentration, and As(V) rejection can reach up to 99% at a feed As concentration of 100 μg/L, whereas there was a rejection decrease of 8% in the presence of Na2SO4 at every feed concentration. The results showed the As(V) detected in the permeate was lower than the EPA recommended MCL up to a feed As concentration of approximately 10 μg/L in the experimental research range.
文摘The colored poly(m-phenylene isophthalamide)(PMIA)spinning solution was prepared by wet spinning and the die-swell of the colored PMIA spinning solution was done when it was extruded from a die in this experiment.The properties and structures of colored PMIA fibers were characterized by scanning electron microscopy(SEM).The colored PMIA spinning dopes were first commixed in a pressurizer and then spun into a coagulation bath.The effect of die swell on the colored PMIA solution was resulted from the viscoelastic properties of the colored PMIA solution in the spinning process.The results showed that the die-swell ratio of the colored PMIA solution increased linearly with increasing the pressure and die length/diameter ratio(L/D).At the same pressure and L/D,the die-swell ratio decreased with the increase of filter layers and temperature.Also,optimized spinning parameters of the dopedyed PMIA fiber were obtained.
