Although the treatment of F-based GICs in the same category as other GICs is controversial, we included F as a target element in our study. The structural relaxations through the first-principles calculation based on DFT were performed on the initial structures using the plane-wave basis projector augmented wave method as implemented in the Vienna ab-initio simulation package . To consider vdW interaction, we tested various correction methods in the GICs. Consequently, we selected the rev-vdW-DF2 method proposed by Hamada , which was implemented using the algorithm of Román-Pérez and Soler because it reproduced excellent reported structures of GICs.