Molecular dynamics simulation of lithium diffusion in Li 2O–Al 2O 3–SiO 2 glasses

Abstract

The molecular dynamics (MD) computer simulation technique has been used to study the structure of lithium aluminosilicate (LAS) glasses and the diffusion of lithium ions. Five kinds of lithium aluminosilicate glasses with different R (ratio of the concentration of Al to Li) values are simulated. The structural features of the simulated glasses are analyzed using Radial Distribution Functions (RDFs) and Pair Distribution Functions (PDFs). With the increase of R, the environments of the Li ions alter from bonding to non-bridging oxygen to bonding to the bridging oxygen associated with tetrahedral Al. The diffusion coefficients and activation energy of lithium ion diffusion in simulated lithium aluminosilicate glasses were calculated and the values are consistent with those in experimental glasses. When R equals 1.00, lithium ions have the lowest activation energy for diffusion. The relationship between the activation energy for lithium diffusion and the composition of these glasses is similar to that previously observed for sodium in sodium aluminosilicate glasses.