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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