6556

6121

كارشناسي ارشد

مهندسي مواد

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي مواد

1390

دوازده، 84ص.: مصور، جدول، عكس، نمودار

ص.ع. به فارسي و انگليسي

احمد ساعتچي، كيوان رئيسي

حسين توانايي

15/1/90

محمد حسين عنايتي، محمد ژياني

1396/10/10

كتابنامه

مواد

مهندسي مواد

ID6121

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Preparation and Characterization of Composite Carbon Nanofibers andTin Alloy Electrode to be Used as Anodes for Lithium Ion Batteries Alireza Saatchi a saatchi@me iut ac ir Date of Submission 2011 08 09 Department of Materials Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisors Prof Ahmad Saatchi Supervisor Email asaatchi@cc iut ac irAssoc Prof Keyvan Raeissi Supervisor Email k raeissi@cc iut ac irAbstract Batteries as the portable power source have genrally been the limiting factor in reducing the weightand size of portable electronics Significant amount of research in material design carried out by solid statechemists material physicists material scientists and electrochemists have resulted in the invention oflighter and smallert batteries One of the most important steps towards this trend is the introduction ofLithium Ion Batteries LIBs as lithium is the lightest and smallest alkalai metal Nevertheless thedevelopment of this technology confronts major challenges in finding a suitable anode material with all theessential carachteristics such as high capacitiy and good cycling charge discharge performances Carbon based materials have been most commonly used as anode materials of LIBs due to their excellent cyclingbehavior However Scientists are looking for an alternative for carbon since it s capacitiy for lithiuminsertion is intrinsically limited Alloys such as Si based and Sn based with much higher theoreticalcapacities have also been studied but none have succeeded in producing an anode material to substitutecarbon All of these alloys unlike carbon fail to withstand the volume changes of insertion and de insertionof lithium ions during charging and discharging of the battery Thereby the anode material craks after a fewcycles and inner particles loose contact with current collector and eventually the high capacity fades away Different approaches have been taken to solve this probem Multicomponent materials such as Sn Sb alloyshave much better cycling performances than single component ones due to their complex reactionmechanisms with lithium ions The use of nanomaterials and or porous materials will also improve thedimentional integrity of the anode material during cycling However some technical problems such as re agregation of nanometer sized particles render these soloutions impractical and unreliable One moreeffective remedy is to disperse superfine alloy particles in an amorphous carbon membrane which not onlyprevents the nanometer sized alloy particles from aggregation but can also act as a buffer against volumeexpansions In the present study a Sn Sb alloy is electrodeposited on a Carbon Nanofiber CNF membrane CNF is produced by the electrospinning of PAN precursor followed by a heat treatment that consists ofstabilization carbonization and activation CNF with a complex porous structure with perfectly inter related pores and extreamly high surface area provides noble electrochemical performances as electrodematerials of any battery system CNF is also among the best known carbon structures for LIB anodematerials and by using it as a template for a high capacity alloy we attempt to retain the unique structuralcharacteristics in the coated layer In the resulting composite the thin web morphology of CNF which isdetermined by various stages of heat treatment provides space for the otherwise irreversible reaction of thealloys with lithium ions Keywords Lithium Ion Battery Anode Material Si Sn Sb Carbon Nanofiber Electrodeposition Electrospinning

احمد ساعتچي، كيوان رئيسي

حسين توانايي

محمد حسين عنايتي، محمد ژياني