一种新型锂离子二次电池用有机电解液的性能研究_英文_

一种新型锂离子二次电池用有机电解液的性能研究_英文_

第44卷　增刊2　

2005年　11月中山大学学报(自然科学版)

ACTA　SCIE

NTIARUM　NATURALIUM　UNIVERSITATIS　SUNYATSENIVol144　Sup12

　

Nov1　2005

PropertiesofaNewElectrolyteSolutionforΞ

Li-ionBatteries

LIWei-hong,DAIYong-nian,YANGBin,YAOYao-chun,GAO(InstituteofVacuumMetallurgyandMaterials,KunmingEngineering650093,China)

Abstract:Recently,thechoiceanduseofnewelectrolytesportanttoimprovethereversiblecapacityandcycleabilityoflithiumionbatteries.InourtheofECandDMCwithdifferentconcentrationsandusedtheminthebuttoncells(LiCoO2cathodeMespheres(CMS)anode)toinvestigatetheelectrochemicalpropertiesoftheelectrolytes.Fromthe,thebestcompositionratioof1molΠLLiPF6inECΠDMC(3∶7volumeratio)wasshowntoimprovethecarbonandlong-termcycleabilitywhencomparedwiththeotherconcentrations.Keywords:EC(ethylenecarbonate);DMC(dimethylcarbonate);SEI(solidelectrolyteinterface)

+

CLCnumber:TQ151142　　Documentcode:A　　ArticleID:052926579(2005)S220019203

1　Introduction

Since1991,thelithiumionbatteryofSonyCompanyhasappearedonmarket.Moreandmoreresearcherspaidattentiontoit.Moreover,moststudieshavebeenonde2velopingnewelectrodematerialsandnewelectrolyteforLi-ionbatteries.Thechoiceanduseofelectrolytesarebe2comingmoreandmoreimportanttoimprovethecapacityandcyclingpropertiesoflithiumionbatteries.

Thetheoreticalformulaofconductivityofsolvents[1]is

k=

Tab11　Physiochemicalpropertiesofcarbonatesolventscom2

)[2-4]monlyusedinLi-ionbatteries(25℃

items

ViscosityΠ(10

-3

ECPC65518

2)

DMC311517

2)

EMC219

DEC218515

2)

-11)

Pa?s)1193

1)

εDielectricconstantΠ89178

215015889016478017534

Oxidizationpotentials+

ΠV(vs1LiΠLi)ANDN

BolingpointΠ℃MeltingpointΠ℃

518

2)

——

—108-55

—161423837

18191511242-49

316817903

216810127-43

i[(Zi)2FCi]

1)At40℃;2)Onsurfaceofglasscarbonunder20℃

ηγ6πi

(1)

2　Experimental

Somesolventshavehighdielectricconstant,suchas

ethylenecarbonate(EC)andpropylenecarbonate(PC),somesolventshavelowviscosity,suchasdimethylcar2bonate(DMC),diethylcarbonate(DEC)andethylmethylcarbonate(EMC),wechosethebinarysolventsofethyl2enecarbonate(ECΠdielectricconstant:89178,viscosity:

-3-1

1193×10Pa1s)anddimethylcarbonate(DMCΠdi2

-3-1

electricconstant:311,viscosity:015889×10Pa1s)toinvestigatetheelectrochemicalbehaviorsinLi-ionbat2teries.WemakebuttoncellsofLiCoO2cathodematerialsandCarbonaceousMesophaseSpheres(CMS)anodemate2rialstoinvestigatetheelectrochemicalpropertiesoftheelectrolyteswithdifferentconcentration.(Tab12)

ZiisthechargenumberofIion;Ciisthemolarconcen2

trationofIion;FistheFaradayconstant;ηisthevis2cosityofthesolvent;γolventradiusofIion.iisthes

From(1)wecanseeCiandηareimportantfactorsoftheconductivity.Weintendtofindasolventwithhighdielectricconstantandlowviscosity,butfromTab11wecanseethesolventwithhighdielectricconstantalwayshashighviscosity,andtheonewithlowviscosityalwayshaslowdielectricconstant.Infact,weoftenchooseasolventwithhighdielectricconstantandtheothershavelowvis2cosity,andthenmixthemtogethertogetnewbinarysol2ventswithhigherdielectricconstantandlowerviscosity.Thephysiochemicalpropertiesofcarbonatesolventscom2monlyusedinLi-ionbatterieswerelistedinTab11

Ξ收稿日期:2005-07-10

基金项目:云南省重点实验室基金资助项目(14051038);院士学科建设经费资助项目(13028019)作者简介:李伟宏(1979年生),女,助教;E-mail:lisa-ll@1261com? 1994-2010 China Academic Journal Electronic Publishing House. All rights reserved. http://ki.net

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