A series of structural characterizations demonstrated that the introduction of Li-ions with over-stoichiometric ratios led to the localized formation of a unique nanophase (S-phase), which stabilized the coplanar Li-ion conformation and enabled lithium superionic conduction. The construction of this face-sharing lithium structure has great application prospects for improving the ionic conductivity of FCC-type oxides. The research in this work deepens the understanding of the mechanism of rapid lithium ion migration in oxide materials and will accelerate the development of new oxide electrolytes for all-solid-state batteries. Although the present materials exhibit almost equal lithium ion conduction with the current hot oxide-based solid electrolyte (such as lithium garnet, lithium peroxide and Na superionic conductor (NASI CON) lithium oxide), there are still many challenges to overcome for their potential applications. For example, the preparation conditions of the material are harsh, requiring high temperature quenching at 1050 C. Secondly, the o-LISO compounds are sensitive to air and need to be stored in the glove box. Nonetheless, the face-sharing strategy proposed by Chen et al. is inspiring for the exploration of new solid functional materials in structures that were previously overlooked.