Computational Electrochemistry Study Of Derivatives Of Anthraquinone And Phenanthraquinone Analogues:the Substitution Effect

In this thesis,lithium ion battery systems are studied based on the principle of computational chemistry with the appropriate calculation methods and intermediate level basis sets.This investigation is divided into two sections.In the first section,we present the effects of the number and position of the electron withdrawing groups on the redox potential and the mass energy density of the derivatives of anthraquinone and phenanthraquinone analogues.In the system of non-aqueous organic electrolyte,the interactions between the functional groups of the solvents and the lithium ion are analyzed in the second section.The first chapter introduces recent improvements in the study of lithium ion battery and electrolyte solution,the classification and properties of organic electric cathode materials,theoretical calculation method during the simulation of calculating,including solvent model,NICS criteria constitute the most frequently used aromaticity indices,and AIM theory.The substituent effect on fused heteroaromatic anthraquinone and phenanthraquinone are investigated by density functional calculations to determine some guidelines for designing potential cathode materials for rechargeable Li-ion batteries.The calculated redox potentials of the quinone derivatives change monotonically with increasing number of substitutions.Full substitution with electron-withdrawing groups brings the highest redox potential;however,mono-substitution results in the largest mass energy density.Carbonyl groups are the most favorable active Li-binding sites;moreover,intramolecular lithium bonds can be formed between Li atoms and electronegative atoms from the substituent groups.The lithium bonds increase the redox potential by improving the thermodynamic stabilization of the lithiation derivatives.Furthermore,the calculation of nucleus-independent chemical shift indicates that the derivatives with Li-bound carbonyl groups are more stable than the bare derivatives.The third chapter is centered on the study of another key part of lithium-ion batteries.Non ?aqueous organic electrolyte includes lithium salts and organic solvents.The analysis of energy level of HOMO of solvent molecules to determine substitution effects on the antioxidant activity of solvent molecules.Next,exploring fluorine atom's influence on the strength of the interactions between the functional groups of the solvents and the lithium ion based on the AIM theory.Finally,the effect of substituent groups on the desolvation energies of lithium ion in various solvents was analyzed.