Investigation of the structural properties of ionic liquids as battery electrolyte material and optoelectronic device

The increasing interest in electrical-electronic based devices and the development of technological communication resources have accelerated research and development activities on energy storage systems. In this study, information is given about rechargeable batteries, which have an important potential in terms of scientific studies and industrial production design in the class of chemical energy storage technologies, and ionic liquids as electrolyte material. Experimental analysis for ionic liquids has been increasing in recent years in the field of chemical syntheses, electrochemical and photovoltaic properties. In addition to experimental studies, the use of quantum mechanical modeling techniques in scientific studies provides savings in research and development costs of materials. Also, nonlinear optical measurement techniques for ionic liquids are remarkable in experimental studies and theoretical calculations. In this thesis, cation-anion interactions, [Anion–]–n[Li+] structural properties, transition state analyzes, nonlinear optical properties of ionic liquids were investigated using quantum mechanical and electronic structure calculation methods. Stronger hydrogen bonding and cation-anion bonding abilities for selected and designed ionic liquid structures were compared with the crystallographic results in the literature. The structures and transition states formed according to the proton positions on the hydrogen bond axes were modeled by potential energy surface scanning. Cation-anion and [Anion–]–n[Li+] interaction energies were calculated with the help of Grimme dispersion models D2, D3 versions and CP approximation calculations. Electric dipole moment, polarizability, first-second hyperpolarizability values were calculated statically and dynamically. More efficient and stable structures were evaluated in terms of nonlinear optical properties.