Interactions of lithium-carbon nanosystems: Molecular dynamics simulations and density functional theory calculations

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Tezin Türü: Doktora

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, Türkiye

Tezin Onay Tarihi: 2008

Öğrenci: RENGİN PEKÖZ

Danışman: ŞAKİR ERKOÇ

Özet:

Single walled carbon nanotubes have been attracting interest for their electronic, magnetic, chemical and mechanical properties. Moreover, since they are ideal nano-containers, the adsorption and absorption properties provide them to be used as Li/Li+ ion batteries. The capacity, rate capability and cycle life of the batteries are the important points which must be improved to have better results. In this thesis Li/Li+ ion doped carbon nano structures are investigated theoretically in order to contribute to the lithium battery technology. The present studied carbon nano structures are the fullerenes, single-walled carbon nanotubes, pristine and defected (Stone-Wales and mono-vacancy defected) carbon nanocapsules. The Li/Li+ interactions with these nano structures have been investigated using semi-empirical molecular orbital method at PM3 level, density functional theory method with B3LYP exchange-correlation functional using 3-21G or 6-31G basis sets. Furthermore, the systems have been investigated by molecular dynamics simulations in which Tersoff potential and an empirical many-body potential have been used to define the various interactions. In this thesis the optimized geometries, thermodynamical quantities, interfrontier molecular orbital eigenvalues and dipole moments of the studied systems have been reported.