Molecular dynamics studies of combined carbon/electrolyte/lithium-metal oxide interfaces

Molecular dynamics simulations are performed on three-dimensional unit cells with periodic boundary conditions for a combined system representing anode-electrolyte-cathode materials. Evaluations of structural changes in bulk phases and at liquid-solid interfaces, as well as lithiumion diffusion coefficients in each phase are performed. Calculated solid-phase diffusion coefficients of lithium ions in carbons are in the range 10(-14) to 10(-13) m(2) s(-1). The presence of curved regions in the modeled amorphous carbon slows the diffusion of lithium ions and allows a higher lithium storage capacity than in graphite. In the lithium-metal oxide system, the lithium ionic diffusion coefficients are in the order of 10(-12) to 10(-11) m(2) s(-1). A spatial variation is found in the diffusion of lithium ions within the modeled cathode phase. (c) 2007 Elsevier B.V. All rights reserved.