Molecular dynamics investigation of electric field altered behavior of lithium ion battery electrolytes

Electric field alters the behavior of electrolytes. In spite of its importance, the dynamic behavior of lithium ion battery (LIB) electrolytes in the presence of electric field is not well studied. In this study, we probe 1 M ethylene carbonate (EC) and propylene carbonate (PC) based electrolytes of LiPF6 salt in the presence of unidirectional electric field to understand its effect on their transport and structural properties. Drift and diffusivity of the ions increase exponentially with the electric field strength. More importantly, the diffusivity becomes direction dependent. The changes in the molecular level organization of the electrolyte is responsible for the observed variations in the transport properties. Comparison of EC and PC based electrolytes suggest that various entities of PC electrolyte are dynamically lethargic. In the presence of electric field, PC molecules solvate lithium ion strongly compared to EC, throwing insights into the issue of PC co-intercalation that results in the rapid degradation of the LIB. The distinct solvation behavior shown by the electrolytes in response to the electric field emphasizes the need for study of electrolytes of advanced batteries in the presence of electric field. (C) 2019 Elsevier B.V. All rights reserved.