Dynamic behavior in lithium ion/graphene/propylene carbonate electrolyte systems through molecular dynamics simulation

Abstract

The dynamic behavior of lithium ions in Li+/graphene/propylene carbonate (PC) electrolyte system was investigated by molecular dynamics (MD) simulation. The simulated system is composed of Li+, PC and graphene sheets (Gr). The radial distribution function and distribution of carboxyl oxygen atoms around Li+ indicate Li+ and PC can form coordination complexes, and the coordination number can be up to 5, which accords well with the experimental and density functional theory calculation results from literatures. The interaction energies and conductivity were obtained from the trajectories of MD simulation. The graphites were exfoliated into few-layer graphene and the dispersed graphene flakes system can keep stable because of the strong interaction between PC and Gr. The conductivity of the Li+/PC system increases with addition of Gr, which agrees well with the experimental observations. The results obtained in the current work are useful for the future design of PC-based electrolyte systems.