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
液态电解质锂离子电池因其潜在的安全性问题,发展新的固态电解质锂离子电池是目前所研究的热点。磷酸铝钛锂(Li_(1.5)Al_(0.5)Ti_(1.5)(PO_(4))_(3),LATP)是一种NASICON型陶瓷材料,由于其空气稳定性和较好的Li^(+)导电性而备受关注。然...液态电解质锂离子电池因其潜在的安全性问题,发展新的固态电解质锂离子电池是目前所研究的热点。磷酸铝钛锂(Li_(1.5)Al_(0.5)Ti_(1.5)(PO_(4))_(3),LATP)是一种NASICON型陶瓷材料,由于其空气稳定性和较好的Li^(+)导电性而备受关注。然而,为了达到良好的离子导电性并降低晶界阻抗,LATP需要950℃以上的高温来实现致密化,这对于大规模应用来说耗时且昂贵。本文使用简单的溶液浇铸法,通过将LATP嵌入共聚物PVDF-HFP(聚偏氟乙烯-六氟丙烯)基体,合成新的复合固态电解质膜。在此基础上,以磷酸铁锂(LiFePO_(4))为正极,使用PVDF-HFP/LATP复合固态电解质膜进行电池组装。在室温下,利用X射线衍射仪(X-ray diffractometer,XRD)、扫描电子显微镜(scanning electron microscope,SEM)对不同质量比的固态电解质膜进行物理特性研究,并进行相关电化学测试。结果表明,PVDF-HFP/LATP质量比为5∶1的复合固态电解质膜,其LATP的NASICON型晶体结构得到了很好的保持;制备的聚合物固态电解质膜具有阻燃性;组装的半电池在常温条件下锂离子迁移数达到0.70。全电池在20次充放电循环下,放电比容量保持率为85%。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
采用非溶剂挥发法制备了锂离子电池聚偏氟乙烯-六氟丙烯(PVDF-HFP)基多孔聚合物电解质膜,研究了非溶剂乙二醇不同温度下挥发对多孔聚合物电解质膜孔结构及性能的影响。扫描电子显微镜(SEM)、差示扫描量热法(DSC)、拉伸测试和交流阻抗法...采用非溶剂挥发法制备了锂离子电池聚偏氟乙烯-六氟丙烯(PVDF-HFP)基多孔聚合物电解质膜,研究了非溶剂乙二醇不同温度下挥发对多孔聚合物电解质膜孔结构及性能的影响。扫描电子显微镜(SEM)、差示扫描量热法(DSC)、拉伸测试和交流阻抗法等测试手段分别对制备的聚合物电解质膜的微观形貌、结晶度、机械强度和室温离子电导率进行表征。结果表明,非溶剂乙二醇挥发温度对多孔聚合物电解质膜的物理和电化学性能影响显著;温度较低时,无法成膜;温度较高时,膜截面呈蜂窝状的大孔结构;当温度从60℃升至100℃时,拉伸强度从6.49 MPa增至21.39 MPa,室温离子电导率从1.07 m S/cm降至0.14 m S/cm。综合分析,利用非溶剂挥发法制备PVDF-HFP基多孔聚合物电解质膜,非溶剂乙二醇挥发温度选在70~90℃之间较为合适。展开更多
Electrochemical behavior of layered LiNi0.5Mn0.5O2 in LiNO3 aqueous solution and its cyclic fading mechanism in electrolytes with different pH values were investigated. CV results show that LiNi0.5Mn0.5O2 has good ele...Electrochemical behavior of layered LiNi0.5Mn0.5O2 in LiNO3 aqueous solution and its cyclic fading mechanism in electrolytes with different pH values were investigated. CV results show that LiNi0.5Mn0.5O2 has good electrochemical reversible behaviors in 5 mol/L LiNO3 solution. Meanwhile, the electrode in 5 mol/L LiNO3 with pH value of 12 demonstrates the best electrochemical stability. Based on the electrochemical impedance spectroscopy （EIS）, X-ray diffraction （XRD） and scanning electron microscopy （SEM） results, it is proposed that suppressed charge-transfer resistance is the major reason, which is probably ascribed to the more stable electrode surface and less structure change.展开更多
采用溶剂挥发法,以丙酮和DMF做混合溶剂制备PVDF-HFP/PMMA聚合物电解质,通过X射线衍射、热失重分析、交流阻抗、恒流充放电循环及倍率充放电等测试手段,考察了PMMA的添加量对聚合物电解质性能的影响.研究发现当PMMA的添加量为50%时,聚...采用溶剂挥发法,以丙酮和DMF做混合溶剂制备PVDF-HFP/PMMA聚合物电解质,通过X射线衍射、热失重分析、交流阻抗、恒流充放电循环及倍率充放电等测试手段,考察了PMMA的添加量对聚合物电解质性能的影响.研究发现当PMMA的添加量为50%时,聚合物电解质表现出最佳性能,室温离子电导率从0.26 m S/cm提升到1.35 m S/cm,以Li Co O2作正极材料,锂片作负极材料组装的聚合物锂离子电池初始容量从80.1 m Ah/g提升到143.6 m Ah/g,在0.2 C倍率条件下,50个循环后容量保持率还能达到80%,表现出优异的锂离子电池性能.展开更多
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%。
文摘液态电解质锂离子电池因其潜在的安全性问题,发展新的固态电解质锂离子电池是目前所研究的热点。磷酸铝钛锂(Li_(1.5)Al_(0.5)Ti_(1.5)(PO_(4))_(3),LATP)是一种NASICON型陶瓷材料,由于其空气稳定性和较好的Li^(+)导电性而备受关注。然而,为了达到良好的离子导电性并降低晶界阻抗,LATP需要950℃以上的高温来实现致密化,这对于大规模应用来说耗时且昂贵。本文使用简单的溶液浇铸法,通过将LATP嵌入共聚物PVDF-HFP(聚偏氟乙烯-六氟丙烯)基体,合成新的复合固态电解质膜。在此基础上,以磷酸铁锂(LiFePO_(4))为正极,使用PVDF-HFP/LATP复合固态电解质膜进行电池组装。在室温下,利用X射线衍射仪(X-ray diffractometer,XRD)、扫描电子显微镜(scanning electron microscope,SEM)对不同质量比的固态电解质膜进行物理特性研究,并进行相关电化学测试。结果表明,PVDF-HFP/LATP质量比为5∶1的复合固态电解质膜,其LATP的NASICON型晶体结构得到了很好的保持;制备的聚合物固态电解质膜具有阻燃性;组装的半电池在常温条件下锂离子迁移数达到0.70。全电池在20次充放电循环下,放电比容量保持率为85%。
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.
文摘采用非溶剂挥发法制备了锂离子电池聚偏氟乙烯-六氟丙烯(PVDF-HFP)基多孔聚合物电解质膜,研究了非溶剂乙二醇不同温度下挥发对多孔聚合物电解质膜孔结构及性能的影响。扫描电子显微镜(SEM)、差示扫描量热法(DSC)、拉伸测试和交流阻抗法等测试手段分别对制备的聚合物电解质膜的微观形貌、结晶度、机械强度和室温离子电导率进行表征。结果表明,非溶剂乙二醇挥发温度对多孔聚合物电解质膜的物理和电化学性能影响显著;温度较低时,无法成膜;温度较高时,膜截面呈蜂窝状的大孔结构;当温度从60℃升至100℃时,拉伸强度从6.49 MPa增至21.39 MPa,室温离子电导率从1.07 m S/cm降至0.14 m S/cm。综合分析,利用非溶剂挥发法制备PVDF-HFP基多孔聚合物电解质膜,非溶剂乙二醇挥发温度选在70~90℃之间较为合适。
基金Project(21301193)supported by the National Nature Science Foundation of ChinaProject(2013M530356)supported by the China Postdoctoral Science Foundation Funded+1 种基金Project(CUSZC201303)supported by the Scientific Research Foundation of Central South Universitythe Open-End Found for Valuable and Precision Instruments of Central South University
文摘Electrochemical behavior of layered LiNi0.5Mn0.5O2 in LiNO3 aqueous solution and its cyclic fading mechanism in electrolytes with different pH values were investigated. CV results show that LiNi0.5Mn0.5O2 has good electrochemical reversible behaviors in 5 mol/L LiNO3 solution. Meanwhile, the electrode in 5 mol/L LiNO3 with pH value of 12 demonstrates the best electrochemical stability. Based on the electrochemical impedance spectroscopy （EIS）, X-ray diffraction （XRD） and scanning electron microscopy （SEM） results, it is proposed that suppressed charge-transfer resistance is the major reason, which is probably ascribed to the more stable electrode surface and less structure change.
文摘采用溶剂挥发法,以丙酮和DMF做混合溶剂制备PVDF-HFP/PMMA聚合物电解质,通过X射线衍射、热失重分析、交流阻抗、恒流充放电循环及倍率充放电等测试手段,考察了PMMA的添加量对聚合物电解质性能的影响.研究发现当PMMA的添加量为50%时,聚合物电解质表现出最佳性能,室温离子电导率从0.26 m S/cm提升到1.35 m S/cm,以Li Co O2作正极材料,锂片作负极材料组装的聚合物锂离子电池初始容量从80.1 m Ah/g提升到143.6 m Ah/g,在0.2 C倍率条件下,50个循环后容量保持率还能达到80%,表现出优异的锂离子电池性能.
