PVDF-HFP微孔膜电解质的制备及性能

以N,N-二甲基甲酰胺为溶剂,水为非溶剂经相转移制备聚偏氟乙烯-六氟丙烯聚合物电解质,用扫描电子显微镜、交流阻抗和线性扫描对所制聚合物膜进行表征.实验结果表明:相转移法制得的微孔膜孔隙丰富,吸液率可达480%,电化学稳定窗口为5.5 V,浸取电解液后室温离子电导率为4.7 mS?cm-1;以LiCoO2为正极制得的聚合物电池0.2 C充放电, 首次放电平台为3.85 V以上, 放电容量为133.5 mA?h?g-1,循环过程中充放电效率高于98%,50次循环后容量保持为130 mA?h?g-1,以0.5 C和1 C放电时分别能保持0.1 C放电容量的94%和92%.     

聚合物锂离子电池负极电化学性能研究

制备了聚合物锂离子电池用负极 ,对其首次充放电效率、比容量、不同放电倍率下放电性能进行了测试 .首次充放电容量分别为 340 m A· h·g- 1和 310 m A·h· g- l,库仑效率可达 91% .以锂锰氧为正极组装了聚合物锂离子电池 ,通过测试表明制备的聚合物锂离子电池具有较好的循环性和大电流放电能力 .所制负极可应用于聚合物锂离子电池中 .     

PVP/PVDF-HFP微孔聚合物电解质的制备及性能

以聚偏氟乙烯-六氟丙烯(PVDF-HFP)和聚乙烯基吡咯烷酮(PVP)为基质材料,采用倒相法,在不同的PVP:PVDF-HFP配比下合成PVP/PVDF-HFP微孔聚合物电解质膜,将制备的微孔膜浸入电解液中活化得到了一系列锂离子电解质膜,并通过扫描电镜、力学、红外光谱进行能分析。研究结果表明:所制备的微孔聚合物电解质膜在PVP:PVDF-HFP配比(质量比)为0.2:1时综合性能最好,其吸液率为210%,抗拉强度为2.86 N/mm2,电导率为1.82×10-3 S/cm,电化学稳定窗口为5.7 V。     

一种新型聚合物锂离子电池的制备和性能研究

采用一种新颖简单的方式处理负极片,并在其表面形成一层厚度均匀、孔隙丰富的聚合物膜。以此聚合物膜作为锂离子电池的隔膜组装聚合物锂离子电池并测试电池的电化学性能。性能测试显示聚合物锂离子电池性能优越,表明该方法可用于聚合物锂离子电池的工业化生产。     

细菌纤维素凝胶聚合物电解质的制备与性能

利用溶剂转换法制备新型锂离子电池凝胶聚合物电解质(GPE).通过扫描电子显微镜(SEM)、傅里叶变换红外光谱(FTIR)、热重(TG)分析、广角X射线衍射(WXRD)、力学拉伸及交流阻抗等测试,分析了细菌纤维素凝胶聚合物电解质的微观形态、结构以及电化学性能.研究结果表明:室温下细菌纤维素凝胶聚合物电解质的离子电导率高达1.6×10-2S/cm,拉伸强度达到39.8MPa,其在锂离子电池开发中具有良好的应用前景.     

一种新型聚合物锂离子电池的制备和性能研究

采用一种新颖简单的方式处理负极片,并在其表面形成一层厚度均匀、孔隙丰富的聚合物膜。以此聚合物膜作为锂离子电池的隔膜组装聚合物锂离子电池并测试电池的电化学性能。性能测试显示聚合物锂离子电池性能优越,表明该方法可用于聚合物锂离子电池的工业化生产。     

正极自支撑的聚合物电解质的制备

以N,N-二甲基甲酰胺为溶剂,聚偏氟乙烯-六氟丙烯为聚合物基质,采用直接挥发溶剂法制备正极自支撑的聚合物电解质,并以锂为负极制备LiCoO2聚合物电池.用扫描电子显微镜和循环伏安实验对聚合物电解质进行表征,用红外光谱分析了电解质微孔的形成机理,并对聚合物电池的充放电性能和界面阻抗进行测试。结果表明:直接挥发溶剂制得的聚合物电解质孔穴丰富,电化学稳定窗口达5.5 V.采用正极自支撑电解质可改善材料的力学性能,降低电池的界面阻抗;制备的聚合物电池界面性质稳定,循环40次后容量保持率为97.5%,0.5C和1C倍率放电分别能保持0.1C放电容量的97.8%和95.7%.     

纳米CoOOH颗粒的合成及其作为锂离子电池负极材料的研究

以CoSO4·6H2O和NaOH为原料,采用共沉淀法,在一定温度下反应一段时间得到深棕色产物.利用X射线衍射(XRD),透射电镜(TEM),热分析(TG-DTA),恒流充放电测试等方法对所产物结构,形貌,大小等进行分析表征及电化学性能测试.实验结果表明,产物为分散均匀的200nm CoOOH颗粒,且该材料作为锂离子电池负极材料,首圈放电容量达到2 100mAh·g-1,循环20圈后,放电容量保持800mAh·g-1.此方法合成的纳米尺寸的CoOOH作为锂离子电池负极材料具有较好的电化学性能.     

PMMA添加量对PVDF-HFP聚合物电解质结构及性能的影响

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.     

锂电池复合型聚合物电解质材料研究进展

综述了近年来国内外在锂离子电池复合型固态聚合物电解质和复合型凝胶聚合物电解质材料的研究进展。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

正~~