Li Ion Diffusion Mechanisms in Bulk Monoclinic Li₂CO₃ Crystals from Density Functional Studies

Density functional studies of Li + ion diffusion mechanisms in bulk monoclinic lithium carbonate Li 2 CO 3 crystals are performed to identify the stable Li + interstitial positions and migration barriers. The migration barrier for Li + diffusion between the planes defined by Li 2 CO 3 units along the open channels [010] is found to be very small at 0.28 eV, while a higher migration barrier of 0.60 eV was found for the diffusion across the planes. These results show that diffusion of Li + in Li 2 CO 3 is favorable along the [010] channels. The implications for Li + ion transport in solid electrolyte interphases (SEI) in Li ion batteries are discussed.