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 Li2CO3 crystals are performed to identify the stable Li+ interstitial positions and migration barriers. The migration barrier for Li+ diffusion between the planes defined by Li2CO3 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 Li2CO3 is favorable along the [010] channels. The implications for Li+ ion transport in solid electrolyte interphases (SET) in Li ion batteries are discussed.