2018/01/26 by Ajay Muralidharan, Muralidharan, Ajay, Mangesh I. Chaudhari +5
Engineering · #Advanced Battery Materials and Technologies #Advanced Battery Technologies Research #Advancements in Battery Materials #Chemical Physics (physics.chem-ph) #FOS: Physical sciences
paper · pdf · doi:10.48550/arxiv.1801.08907
openalex publication_date 2018/01/26 · openalex created_date 2022/10/04 · openalex updated_date 2026/07/28
Li+ transport within a solid electrolyte interphase (SEI) in lithium ion\nbatteries has challenged molecular dynamics (MD) studies due to limited\ncompositional control of that layer. In recent years, experiments and ab initio\nsimulations have identified dilithium ethylene dicarbonate (Li2EDC) as the\ndominant component of SEI layers. Here, we adopt a parameterized,\nnon-polarizable MD force field for Li2EDC to study transport characteristics of\nLi+ in this model SEI layer at moderate temperatures. The observed correlations\nare consistent with recent MD results using a polarizable force field,\nsuggesting that this non-polarizable model is effective for our purposes of\ninvestigating Li+ dynamics over long time scales. Mean-squared displacements\ndistinguish three distinct Li+ transport regimes in EDC ballistic, trapping,\nand diffusive. Compared to liquid ethylene carbonate (EC), the nanosecond\ntrapping times in EDC are significantly longer and naturally decrease at higher\ntemperatures. New materials developed for fast-charging Li-ion batteries should\nhave smaller trapping regions. The analyses implemented in this paper can be\nused for testing transport of Li+ ion in novel battery materials. Non-Gaussian\nfeatures of van Hove self -correlation functions for Li+ in EDC, along with the\nmean-squared displacements, are consistent in describing EDC as a glassy\nmaterial compared with liquid EC. Vibrational modes of Li+ ion, identified by\nMD, characterize the trapping and are further validated by electronic structure\ncalculations.\n