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To date, lithium-ion batteries have been extensively gained attention due to their promising potential in the industry. Despite their promising properties, improving their poor power density is still needed for practical applications. In addition, sustaining the high redox potential in the lithium-ion batteries is prerequisite for exhibiting the high energy and power densities Conclusions First-Principles Density Functional Theory Modeling Study on the Redox Chemistry of Graphene Oxides Affected By Placement Geometry of Oxygen Functional Groups Sunghee Kim 1 , Jonghoo Park 1 , Young Yoo 2 , Seonguk Yun 2 , David Wu 3 , Dr. Ki Chul Kim 2,3 , Dr. Seung Woo Lee 1 , Dr. Seung Soon Jang 3 1 The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology 2 School of Chemical & Bimolecular Engineering, Georgia Institute of Technology 3 School of Materials Science and Engineering, Georgia Institute of Technology References 1. Lee, Seung Woo et al. 'Nanostructured Carbon-Based Electrodes: Bridging The Gap Between Thin-Film Lithium-Ion Batteries And Electrochemical Capacitors'. Energy Environ. Sci. 4.6 (2011): 1972. 2. Winget, P., C. J. Cramer, and D. G. Truhlar. 'Computation Of Equilibrium Oxidation And Reduction Potentials For Reversible And Dissociative Electron-Transfer Reactions In Solution'. Theoretical Chemistry Accounts 112.4 (2004). 3. Winget, Paul, Eric J. Weber, Christopher J. Cramer, and Donald G. Truhlar. "Computational Electrochemistry: Aqueous One-electron Oxidation Potentials for Substituted Anilines." Physical Chemistry Chemical Physics 2.6 (2000): 1231-239. Web. Redox Chemistry. Carbonyl Group > Hydroxyl Group Redox Chemistries wer e not influenced by increasing the number neighboring hydroxyl functional groups. Hydroxyl groups are not highly reactive for the redox reactions. Redox Chemistry wer e influenced by increasing the number of neighboring carbonyl functional groups. Background of School of Material Science and Engineering 771 Ferst Drive NW, Atlanta, GA 30332-0245, USA Objective In this study, we investigated the redox chemistry of graphene oxides cluster models with well-controlled hydroxyl functional groups at the edge. First-principles density functional theory approach was employed to understand the geometric e ect of the incorporated hydroxyl functional groups on the redox chemistry. Our study will provide an insight on the strategy for improving the redox potentials of graphene-based electrode candidates. The George W. Woodruff School of Mechanical Engineering 801 Ferst Drive NW, Atlanta, GA 30332-0245, USA 2-neighboring hydroxyl groups 3-neighboring hydroxyl groups 3-isolated hydroxyl groups 4-isolated hydroxyl groups Functional Group Redox Chemistry (V) HOMO (eV) LUMO (eV) Electron Affinity (eV) Pristine graphene 1.4 -5.38 -2.31 -1.45 1-hydroxyl group 1.4 -5.24 -2.31 -1.46 2-neighboring hydroxyl groups 1.5 -5.20 -2.36 -1.51 3-neighboring hydroxyl groups 1.4 -5.10 -2.33 -1.49 3-isolated hydroxyl groups 1.3 -5.17 -2.24 -1.41 4-isolated hydroxyl groups 1.4 -5.10 -2.32 -1.49 1-carbonyl group 2.9 -5.02 -2.44 -2.96 2-neighboring carbonyl groups 3.1 -5.38 -4.05 -3.18 3-neighboring carbonyl groups 3.7 -5.51 -4.25 -3.11 1-epoxide group 2.0 -5.10 -2.86 -2.04 2-isolated epoxide groups 2.3 -4.90 -3.21 -2.36 • Calculation: a. Jaguar b. PBE0 functional with 6-31+G** basis set • Analysis Methods: 1. Geometry Optimization 2. Thermodynamics Free Energy 3. Solvation Energy Density Functional Theory (DFT): • Task: o Perform Geometry Optimization o Comparison Geometry Optimization energy data with increasing multiplicity tips o Perform Thermodynamics Free Energy At Room Temperature o Perform Solvation Energy o Compute to Reduction potential equation o Obtain Redox Chemistry Introduction Methods Results Modeling Scheme Graphene’s large surface ar ea and high specific capacity Improved discharge capacity up to 160% when added to Cathode material Future Works Motivation • Graphene has 54 Carbons in the group • Functional Groups: Hydroxyl and Carbonyl 2-neighboring carbonyl groups 3-neighboring carbonyl groups Conclusions Carbonyl functional group. E ect of the number of carbonyl functional groups and position. Investigating the redox chemistry with PWB6K DFT-functional. Investigating the e ect of the functional group type on the redox chemistry. • Modeling Software: Cerius2 Evaluating G red (R, sol) (according to Truhlar’s method) using Thermodynamic Cycle of Electrochemical Reduction for species R Gas-phase reduction free energy + Solvation free energy Poisson-Boltzmann solvation model G red R , sol ( ) = G red R , gas ( ) + G solv R ( ) G solv R ( ) ( ) H red E nF sol R G E + = , 0 ( ) Li H red E E nF sol R G E + = , Li w.r.t. 0 Computation ) V 44 . 4 ( = H E V 05 . 3 = Li E 1.0 1.5 2.0 2.5 3.0 3.5 4.0 -3.5 -3.0 -2.5 -2.0 -1.5 -1.0 Electron Affinity (eV) Redox Chemistry (V) Electron Affinity
