固态电池因其优异的性能备受关注,但是与传统的液态电池相比,离子传输能力偏弱,原因是固-固界面离子传输困难。本文制备了以聚偏氟乙烯-六氟丙烯(PVDF-HFP)为基的固态电解质膜,并探究PVDF-HFP和增塑剂乙氧基化三羟甲基丙烷三丙烯酸酯(ET...固态电池因其优异的性能备受关注,但是与传统的液态电池相比,离子传输能力偏弱,原因是固-固界面离子传输困难。本文制备了以聚偏氟乙烯-六氟丙烯(PVDF-HFP)为基的固态电解质膜,并探究PVDF-HFP和增塑剂乙氧基化三羟甲基丙烷三丙烯酸酯(ETPTA)质量比为1.0∶0.3、1.0∶0.4、1.0∶0.5时对电解质膜离子传输的影响,并组装成以磷酸铁锂为正极、锂片为负极的固态电池,研究其电化学性能。研究发现:当PVDF-HFP和ETPT质量比为1.0∶0.4时,锂离子迁移数达0.89,电化学窗口可达4 V,离子电导率达到8×10^(-5)S/cm,表现出良好的稳定性。将质量比为1.0∶0.4的电解质膜装配成固态电池,经过激活之后,首先在0.1C的倍率下进行测试,首圈充电比容量为133 m A·h/g,首圈放电比容量为129 m A·h/g,在20圈循环测试后,放电比容量也能保持在120 mA·h/g以上,容量保持率为92%。展开更多
Polyvinylidene fluoride-hexafluoropropylene （PVdF-HFP） / clay nanocomposite membranes were prepared by phase inversion method through controlling retention time to apply for a lithium ion secondary batteries. Increa...Polyvinylidene fluoride-hexafluoropropylene （PVdF-HFP） / clay nanocomposite membranes were prepared by phase inversion method through controlling retention time to apply for a lithium ion secondary batteries. Increased membrane porosity with macrovoids was observed at increasing retention time. Partially intercalated structures of PVdF-HFP/clay nanocomposite membranes were confirmed by X-ray diffraction （XRD） analysis. PVdF-HFP membranes containing various kind of clay showed the increase of membrane modulus compared to the pristine PVdF-HFP membrane.展开更多
Solid polymer electrolytes(SPEs)are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries.Nevertheless,the poor ionic conductivity at room temperature(RT)and low ...Solid polymer electrolytes(SPEs)are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries.Nevertheless,the poor ionic conductivity at room temperature(RT)and low resistance to Li dendrites seriously hinder the commercialization of SPEs.Herein,we design a bifunctional flame retardant SPE by combining hydroxyapatite(HAP)nanomaterials with Nmethyl pyrrolidone(NMP)in the PVDF-HFP matrix.The addition of HAP generates a hydrogen bond network with the PVDF-HFP matrix and cooperates with NMP to facilitate the dissociation of Li TFSI in the PVDF-HFP matrix.Consequently,the prepared SPE demonstrates superior ionic conductivity at RT,excellent fireproof properties,and strong resistance to Li dendrites.The assembled Li symmetric cell with prepared SPE exhibits a stable cycling performance of over 1200 h at 0.2 m A cm^(-2),and the solid-state LiFePO_4||Li cell shows excellent capacity retention of 85.3%over 600 cycles at 0.5 C.展开更多
High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method acc...High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field poling.The decisive effect of the poling electric field on the power generating capability was confirmed by the experiments.For pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity dramatically.In the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 V.Meanwhile,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,respectively.The effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC.展开更多
文摘采用热致相分离技术成功制备出聚偏氟乙烯-六氟丙烯(PVDF-HFP)多孔膜,相图分析表明,PVDF-HFP/环丁砜体系发生固-液分相.SEM显示膜由球晶和丝状结晶组成.随聚合物浓度增加,多孔膜的结晶度、孔隙率以及平均孔径均降低,由多孔膜制得的凝胶聚合物电解质膜,其吸液率和电导率也降低,但多孔膜的力学性能提高.所有样品在20℃时的电导率超过2×10-3S/cm,电化学窗口大于4.5 V.
文摘固态电池因其优异的性能备受关注,但是与传统的液态电池相比,离子传输能力偏弱,原因是固-固界面离子传输困难。本文制备了以聚偏氟乙烯-六氟丙烯(PVDF-HFP)为基的固态电解质膜,并探究PVDF-HFP和增塑剂乙氧基化三羟甲基丙烷三丙烯酸酯(ETPTA)质量比为1.0∶0.3、1.0∶0.4、1.0∶0.5时对电解质膜离子传输的影响,并组装成以磷酸铁锂为正极、锂片为负极的固态电池,研究其电化学性能。研究发现:当PVDF-HFP和ETPT质量比为1.0∶0.4时,锂离子迁移数达0.89,电化学窗口可达4 V,离子电导率达到8×10^(-5)S/cm,表现出良好的稳定性。将质量比为1.0∶0.4的电解质膜装配成固态电池,经过激活之后,首先在0.1C的倍率下进行测试,首圈充电比容量为133 m A·h/g,首圈放电比容量为129 m A·h/g,在20圈循环测试后,放电比容量也能保持在120 mA·h/g以上,容量保持率为92%。
基金funded by Fundamental R&D Program for core Technol-ogy of Materials of Korean Ministry of Knowledge Economy
文摘Polyvinylidene fluoride-hexafluoropropylene （PVdF-HFP） / clay nanocomposite membranes were prepared by phase inversion method through controlling retention time to apply for a lithium ion secondary batteries. Increased membrane porosity with macrovoids was observed at increasing retention time. Partially intercalated structures of PVdF-HFP/clay nanocomposite membranes were confirmed by X-ray diffraction （XRD） analysis. PVdF-HFP membranes containing various kind of clay showed the increase of membrane modulus compared to the pristine PVdF-HFP membrane.
基金supported by the National Natural Science Foundation of China (Grant Nos.51604089,51874110,22173066,21903058)the Natural Science Foundation of Heilongjiang Province (Grant No.YQ2021B004)Open Project of State Key Laboratory of Urban Water Resource and Environment (Grant No.QA202138)。
文摘Solid polymer electrolytes(SPEs)are one of the most promising alternatives to flammable liquid electrolytes for building safe Li metal batteries.Nevertheless,the poor ionic conductivity at room temperature(RT)and low resistance to Li dendrites seriously hinder the commercialization of SPEs.Herein,we design a bifunctional flame retardant SPE by combining hydroxyapatite(HAP)nanomaterials with Nmethyl pyrrolidone(NMP)in the PVDF-HFP matrix.The addition of HAP generates a hydrogen bond network with the PVDF-HFP matrix and cooperates with NMP to facilitate the dissociation of Li TFSI in the PVDF-HFP matrix.Consequently,the prepared SPE demonstrates superior ionic conductivity at RT,excellent fireproof properties,and strong resistance to Li dendrites.The assembled Li symmetric cell with prepared SPE exhibits a stable cycling performance of over 1200 h at 0.2 m A cm^(-2),and the solid-state LiFePO_4||Li cell shows excellent capacity retention of 85.3%over 600 cycles at 0.5 C.
基金supported by National Natural Science Foundation of China(No.51703015)Fundamental Research Funds for the Central Universities(No.2020CDJQY-A008).
文摘High piezoelectric composite films composed of poly(vinylidene fluoride-co-hexafluoropropylene)(PVDF-HFP)and ferromagnetic cobalt ferrite(CoFe_(2)O_(4))(0.00 wt%to 0.2 wt%)are prepared by a solution casting method accompanied by uniaxial stretching and high electric field poling.The decisive effect of the poling electric field on the power generating capability was confirmed by the experiments.For pure PVDF-HFP films,when the maximum electric field Emax is 120 MV/m,the calibrated open circuit voltage reaches 2.93 V,which is much higher than those poled at lower electric fields(70 MV/m:1.41 V;90 MV/m:2.11 V).Furthermore,the addition of CoFe_(2)O_(4)also influences the piezoelectricity dramatically.In the samples containing 0.15 wt%CoFe_(2)O_(4),the calibrated open circuit voltage increases to the maximum value of 3.57 V.Meanwhile,the relative fraction of theβ-phase and the crystallinity degree are 99%and 48%,respectively.The effects of CoFe_(2)O_(4)nanoparticles on initial crystallization,uniaxial stretching and high electric field poling are investigated by XRD,FTIR and DSC.
