Atomic structure and defect energetics of LiCoO2 grain boundary

•We model the sample grain boundary of LiCoO2, one of important Li cathode materials.•Rigid body translation was found the asymmetric GB is more stable than symmetric GB.•The vacancy formation energy of Li and O was estimated with first principles calculations.•This model boundary can help to find a new dopant to improve Li diffusions.

An atomic structure of LiCoO2 model grain boundary, Σ2 [1120](1102), is introduced and grain boundary energies with rigid body translations are investigated systematically to find the most stable interface structures. It is found that the coordinated structures of Co and O in the vicinity of grain boundary are strongly related to grain boundary energy. Examining nonstoichiometry at grain boundary, the defect energetics of Li and O site at grain boundary are estimated. In addition, the effect of grain boundary on Li diffusion is investigated to calculate Li diffusion across grain boundary.

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