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Intercalation of Lithium into Graphite: Effects of Surface Chemical Composition from First-Principles Simulations
preprintsubmitted on 21.12.2018, 20:19 and posted on 26.12.2018, 14:57 by Tuan Anh Pham, Kyoung E. Kweon, Amit Samanta, Mitchell Ong, Vincenzo Lordi, John Pask
Understanding Li+ transfer at graphite-electrolyte interfaces is key to the development of next-generation lithium ion batteries. In this work, we investigate the Li+ kinetics at these interfaces and we elucidate key factors that determine the ion transport from first-principles, by coupling ab-initio molecular dynamics simulations with solvation model calculations. We show that surface chemical composition significantly influences the kinetics of ion intercalation from the liquid into the graphite anode. We find that this is partly related to the ion desolvation process, which varies notably for different graphite surfaces. In addition, interfacial polarization is found to play an important role in determining energy barriers for ion transfer. We also discuss the impact of electrode potentials, which is often neglected in conventional first-principles calculations despite being a key factor in device configurations. Our study provides insights into the coupling of electronic and ionic effects of interfacial chemistry on ion transport, which has broad implications in optimizing electrode-electrolyte interfaces for further improvement of ion batteries.