Crossover from Metal to Insulator in Dense Lithium-Rich Compound $textrm{CLi}_{4}$

Crystal structures of $textrm{CLi}_4$ compounds are explored through emph{ab} emph{initio} evolutionary methodology. Phase transition from metal to semimetal and semiconductor, and eventually to insulator with increasing pressure are revealed under pressure. Pressure-induced evolution of anti-metallization has been described quantitatively by Fermi Surface Filling Ratio and electron energy band gap using emph{ab} emph{initio} emph{GW} calculations. Anti-metallization is attributed to the hybrid valence electrons and their repulsion by core electrons into the lattice interstices. Very weak electron-phonon coupling interactions are found in the metallic phases, resulting in very low superconducting temperature.