Vinyl ethylene sulfite as a film-forming additive in propylene carbonate-based electrolyte for lithium ion batteries

在当今能源危机的时代，锂离子电池由于具有更高的比功率、比能量等突出优势，已成为目前综合性能最好的电池体系之一。电解液是锂离子电池的重要组成部分，它在很大程度上影响着电池的电化学性能和安全性能。其中，碳酸丙烯酯（PC）是锂离子电池电解液中非常重要的溶剂，然而，当以PC为溶剂的电解液应用于含有石墨类电极材料的锂离子电池时，PC和溶剂化的锂离子会共同嵌入到石墨层间，导致石墨结构破坏，影响电池的电化学性能。 研究发现在PC基电极液中加入适当的添加剂能有效地解决上述问题。本论文选择了一种新的含有不饱和双键和亚硫酸酯双官能团的有机分子——乙烯基亚硫酸乙烯酯（VES），作为锂离子电池PC基电解液的添加剂。...In today's era of energy crisis, lithium ion battery has become the best battery system on integrated performance because it has the merits of high power density in volume and high specific energy. Electrolyte is a very important component for the lithium ion battery, it could greatly influence the electrochemical performance and the safety of the battery. Propylene carbonate (PC) is an attractive...学位：工学硕士院系专业：化学化工学院化学系_应用化学学号：2052006115202

Effect of Fluoroethylene Carbonate Additive on the Performance of Lithium Ion Battery

在1MOl·l-1lIPf6/碳酸乙烯酯(EC)+碳酸二甲酯(dMC)+碳酸甲乙酯(EMC)(EC、dMC、EMC体积比为1∶1∶1)电解液中加入体积比为2%的添加剂氟代碳酸乙烯酯(fEC),用循环伏安法(CV)、扫描电镜(SEM)、能量散射光谱(EdS)、电化学阻抗谱(EIS)等方法,研究了fEC对锂离子电池性能及石墨化中间相碳微球(MCMb)电极/电解液界面性质的影响.结果表明,体积比2%fEC的添加可以抑制部分电解液溶剂的分解,在MCMb电极表面形成一层性能优良的固体电解液相界面(SEI)膜,降低了电池的阻抗,明显提高了电池的比容量和循环稳定性.Fluoroethylene carbonate (FEC) with a volume ratio of 2% was added to the electrolyte containing 1 mol· L-1 LiPF6 in ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC) (1∶1∶1 by volume).The effects of FEC on lithium ion battery performance and on the mesocarbon microbead (MCMB) electrode/electrolyte interphase were studied by cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electrochemical impedance spectroscopy (EIS).The results indicated that the application of a 2% (volume ratio) of FEC suppressed electrolyte decomposition and caused the formation of an excellent solid electrolyte interphase (SEI) film on the MCMB electrode.The battery resistance decreased while the specific capacity and cyclic stability of the battery increased.国家基础研究重大项目计划(2007CB209702)资

Electrochemical Behavior of Vinyl Ethylene Sulfite as an Electrolyte Film-forming Additive in Lithium Ion Batteries

研究了具有不饱和双键和亚硫酸酯双官能团的乙烯基亚硫酸乙烯酯(VES)作为锂离子电池电解液成膜添加剂对中间相碳微球(CMS)和lIfEPO4电极电化学性能的影响.结果表明:在1MOl/llIClO4/PC电解液体系中,少量的VES(5%)能够在电化学过程中先于PC在CMS表面还原,形成稳定的SEI膜,明显抑制PC和溶剂化锂离子共嵌入石墨层间,改善了电池的循环性能.此外,电解液1MOl/llIClO4/PC+5%VES(V∶V)在lIfEPO4电极中展现出良好的电化学稳定性.A film-forming additive, vinyl ethylene sulfite (VES) with both vinylene group and sulfite group, affects the electrochemical performance of carbonaceous mesophase spherules (CMS) and LiFePO4 electrode.The results indicated that a small amount of VES (5%) could be reduced prior to the propylene carbonate (PC) solvent on the surface of CMS electrode in PC-based electrolyte to form a stable solid electrolyte interphase (SEI) layer, so co-intercalation of PC and solvated lithium ions to graphite could be suppressed.Furthermore, the electrolyte of 1 mol/L LiClO4/PC+5%VES (V∶V) exhibited excellent electrochemical stability in the LiFePO4 electrode.国家自然科学基金(Nos.20473068;29985310);国家“973”计划(No.2007CB209702)资助项

Effect of Fluoroethylene Carbonate Additive on the Performance of Lithium Ion Battery

Fluoroethylene carbonate (FEC) with a volume ratio of 2% was added to the electrolyte containing 1 mol L-1 LiPF6, in ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC) (1: 1: 1 by volume). The effects of FEC on lithium ion battery performance and on the mesocarbon microbead (MCMB) electrode/electrolyte interphase were studied by cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electrochemical impedance spectroscopy (ETS). The results indicated that the application of a 2% (volume ratio) of FEC suppressed electrolyte decomposition and caused the formation of an excellent solid electrolyte interphase (SEI) film on the MCMB electrode, The battery resistance decreased while the specific capacity and cyclic stability of the battery increased

Electrochemical Behavior of Vinyl Ethylene Sulfite as an Electrolyte Film-forming Additive in Lithium Ion Batteries

A film-forming additive, vinyl ethylene sulfite (VES) with both vinylene group and sulfite group, affects the electrochemical performance of carbonaceous mesophase spherules (CMS) and LiFePO4 electrode. The results indicated that a small amount of VES (5%) could be reduced prior to the propylene carbonate (PC) solvent on the surface of CMS electrode in PC-based electrolyte to form a stable solid electrolyte interphase (SEI) layer, so co-intercalation of PC and solvated lithium ions to graphite could be suppressed. Furthermore, the electrolyte of 1 mol/L LiClO4/PC+5%VES (V:V) exhibited excellent electrochemical stability in the LiFePO4 electrode

Effect of Ethylene Sulfate as Electrolyte Additive on Performance of Li-ion Batteries

在1MOl/llIPf6/碳酸乙烯酯+碳酸二甲酯+碳酸甲乙酯(体积比1∶1∶1)电解液中,采用恒流充放电测试、循环伏安法(CV)、扫描电子显微镜(SEM)、能量散射光谱(EdS)、电化学阻抗谱(EIS)等测试技术,研究了添加剂硫酸亚乙酯(dTd)对锂离子电池性能及石墨化中间相碳微球(MCMb)电极/电解液界面性质的影响。结果表明,在电解液中引入体积分数0.01%dTd后,MCMb/lI电池可逆放电容量从300MA.H/g提高至350MA.H/g,电池总阻抗降低,循环稳定性提高。CV测试发现,在首次还原过程中,dTd在电极电位1.4V左右(VSlI/lI+)发生电化学还原,参与了MCMb电极表面固体电解质相界面膜(SEI膜)的形成过程。同时,dTd对lIMn2O4电极性能无不良影响。Ethylene sulfate( DTD) was studied as an additive to 1 mol/L LiPF6 /ethylene carbonate( EC) + dimethyl carbonate( DMC) + methyl ethyl carbonate( EMC) ( 1∶ 1∶ 1 by volume) electrolyte for lithium ion batteries.The effects of DTD on lithium ion battery performance and on the mesocarbon microbead( MCMB) electrode/electrolyte interphase were investigated by galvanostatic charge-discharge measurements,cyclic voltammetry( CV) ,scanning electron microscopy( SEM) ,energy dispersive spectroscopy( EDS) and electro-chemical impedance spectroscopy ( EIS).The results show that DTD with a volume ratio of 0.01% can increase the reversible discharge capacity( from 300 mA.h/g to 350 mA.h/g) and cycleability of MCMB/Li cell.SEM observation and EIS analysis suggest that DTD facilitates the morphology of solid electrolyte interface( SEI) formed on the surface of the MCMB electrode and reduces the total resistance of the cell.CV measurements reveal that DTD can be electrochemically reduced at potentials around 1.4 V( vs Li/Li + ) during the first reduction engaged in the formation of SEI.At the same time,DTD has no adverse effect on the LiMn2O4 electrode.国家“九七三”资助项目(2007CB209702

Study of Starch-base Degradable Plastics Ⅱ ──Accelerated Aging Test of PE Plastics Filled With Starch In Ultraviolet Light

[中文文摘]研究了光敏剂诱发ＰＥ光降解机理以及改性淀粉、顺丁烯二酸酐等对填充ＰＥ塑料相态结构的影响；紫外光加速老化过程中试样拉伸强度、断裂伸长率随组成、光照时间的变化关系；认为合理地协调各填充组分的用量和关系，可实现填充ＰＥ塑料紫外光降解性能的可控制性。[英文文摘]The mechanism of photodegradation induced by photosensitizer and the effect of the modified starch and maleic anhydride on the phase structure of PE plastics filled with starch were studied. The relationships of the tensile strength and elongation at rupture and with composition and lighting duration of PE plastics filled with starch were also discussed. The results suggested that the controllability of photodegradation of PE plastics filled with starch in ultraviolet light could be achieved through harmonizing the content and relation of filled components reasonably

Study of Starch- base Degradable PlasticsⅢ——Degraded Test In The Environment

[中文文摘]对所设计的可环境降解塑料进行了大量的现场环境降解实验 ,包括大气直接曝露老化试验和埋土降解试验 ,获得了许多有意义的结果 .结果表明 ,各填充组分与 PE组成的复合材料 ,经大气直接曝露老化后再埋土将使降解性能得到显著的体现 ,经对各填充组分的合理设计 ,可望获得时控光 /生物降解塑料.[英文文摘]A mass of degraded tests of the degradable plastics designed in these papers in the real environment including aging test in atmosphere and degraded test in soil were carried through, which provided a large number of first hand data, and some good degradation efficiency were observed from them. The tests indicated that the composite materials composed with various additives and PE plastics designed in this paper possessed better degradable performance when they were embedded into soil after being exposed in atmosphere than embedded into soil directly. It was achieved to control photo and biodegradable plastics through devising each filled component reasonably

Study of Starch-base Degradable Plastics I—— Physical Modification of Starch and Phase Structure of PE Filled with Starch

[中文文摘]研究了偶联剂对淀粉的物理改性 ,改性淀粉加入量对填充 PE塑料体系相态结构、力学性能的影响 ,认为偶联剂的加入量大于淀粉含量的 1.0 %时 ,可获得具有较好的对 L L DPE掺混性的疏水化改性淀粉 ;提出了物理改性淀粉、增容剂等填充 PE塑料多组份共混体系的“夹心面包”模型和Al3 + 与淀粉间的配位络合物模型.[英文文摘]Physical modification with coupling agent of starch and the effect of the content of the modified starch on the phase structures and the mechanical properties of PE Plastics filled with starch was studied.It is suggested that the hydrophobic modified starch in the nature of good compatibility with L LDPE can be obtained when the amountof coupling agent is more the1 .0% .The layer bread model of the multicomponent blended system of PE plastics filled with physical modified starch,compatilizer and so on, and the coordination complex model between Al3+ and Starch were proposed